AP Bio Sig Ass 2
How do you get recombination frequency?
(# of recombinants/# of total offspring) x 100 = %
What is negative feedback?
A loop in which the response reduces the initial stimulus. i.e. insulin being made so no more is needed.
If energy is not created or destroyed, why isn't all energy used?
A lot of energy is lost in chemical reactions as heat. Heat can only be used as work if there is temperature difference that results in thermal energy flowing as heat from a warmer location to a cooler one.
What is an enzyme?
A macromolecule that acts as a catalyst, a chemical agent that speeds up a reaction without being consumed by the reaction. Most enzymes are proteins but some are not.
What is albinism?
Albinism is a recessive case that causes lack of pigmentation in skin, hair, eyes, etc.
What are the two types of fermentation?
Alcohol fermentation and lactic acid fermentation
What is a genetic map?
Alfred H. Sturtevant worked out a method for constructing this, which is an ordered list of the genetic loci along a particular chromosome.
What is the quaternary structure?
The overall protein structure that results from the aggregation of these polypeptide subunits.
What is the partial charge of water?
The oxygen is partially negative and the hydrogen is partially positive, making a polar covalent bond.
What is genetic recombination?
The production of offspring with combinations of traits that differ from those found in either P generation parent.
What is a solution?
A liquid that is a completely homogenous mixture of two or more substances.
What is a virus?
A little more than DNA or sometimes RNA enclosed by a protective coat, which is often simply protein.
What is a polymer?
A long molecule consisting of many similar or identical building blocks linked by covalent bonds.
What is the ∆G of the reaction?
-686 kcal per mol. This means it happens spontaneously and releases 686.
What were Mendel's theories following this experiment?
-Alternative versions of genes account for variation. -For each character, an organism inherits two copies of a gene, one from each parent. -If wo alleles at a locus differ then the dominant determines the appearance. -The law of segregation
Explain the methyl group.
-CH3 Affects the expression of genes when on DNA or on proteins bound to DNA. Affects the shape and function of male and female sex hormones. Compound name: methylated compound Example: 5 methyl cytosine, a component of DNA that has been modified by addition of a methyl group.
Explain the carboxyl group.
-COOH Acts as an acid (can donate H+) because the covalent bond between oxygen and hydrogen is so polar. Compound name: carboxylic acid, or organic acid. Example: Acetic acid, which gives vinegar its sour taste.
Explain the amino group.
-NH2 Acts as a base; can pick up an H+ from the surrounding solution (water, in living organisms). Compound name: amine Example: Glycine, an amino acid.
Explain the hydroxyl group.
-OH Is polar due to electronegative oxygen. Forms hydrogen bonds with water, helping dissolve compounds such as sugars. Compound name: alcohol Example: Ethanol, the alcohol present in beverages.
Explain the phosphate group.
-OPO3 (2-) Contributes negative charge (1- when positioned inside a chain of phosphates; 2- when at the end). When attached, confers on a molecule the ability to react with water, releasing energy. Compound name: organic phosphate. Example: glycerol phosphate, which takes part in many important chemical reactions in cells.
Explain the sulfhydryl group.
-SH Two -SH groups can react, forming a "cross link" that helps stabilize protein structure. Hair protein cross links maintain the straightness or curliness of hair; in hair salons, perms break the cross links, then re form them while the hair is in the desired shape. Compound name: Thiol Example: Cysteine, a sulfur containing amino acid.
How is chemiosmosis different in mitochondria and chloroplasts?
1. Chloroplasts' energy come from water while in mitochondria, they are from organic molecules. 2. In mitochondria, the H+ is pushed into a gradient in the inter membrane space and diffuses through the ATP synthase into the matrix. In chloroplasts, the H+ is pushed into a gradient in the thylakoid space and diffuses through an ATP synthase into the stroma. ATP is made there to go to the calvin cycle.
What are the two main points of On the Origin of Species?
1. Contemporary species arose from a succession of ancestors that differed from this (descent with modification.) 2. Natural selection is an evolutionary mechanism for descent with modification.
What were Darwin's three observations of nature?
1. Individuals in a population vary in their traits, many of which seem to be heritable. 2. A population can produce far more offspring than can survive to produce offspring of their own. 3. Species generally suit their environments, they are adapted to them.
Why can't we tell the exact number of ATP made?
1. NADH = ATP is not an equal number 2. ATP yield depends on if NAD+ or FAD2+ is used 3. The proton motive force isn't just used to make ATP
What were Chargaff's two rules?
1. The base composition of DNA varies between species. 2. For each species, the percentages of A and T bases are roughly equal and the percentages of G and C bases are roughly equal.
What are four aspects of regulation of response?
1. The degree of amplification depends on the function of the specific molecules in the pathway. 2. The steps in the pathway provide control points where the cell's response can be further regulated. 3. The overall efficiency of the response is enhanced by the presence of scaffolding proteins. 4. Termination of the signal
What is the estimate of total number of species?
10 million to 100 million.
How many essential elements do plants have?
17
How many electrons can the first shell hold?
2
How many amino acids exist?
20
How many essential elements do humans have?
25
How many parts are there to meiosis?
2: meiosis I and meiosis II
What is the number of possible combinations when chromosomes assort independently?
2^n
What happens during the energy payoff phase?
4 ADP + P go in and form 4 ATP. Meanwhile 2 NAD+ + 4e- + 4H+ go in and yield 2 NADH + 2H+ and 2 pyruvate + 2H2O come out of the equation.
How many chromosomes does a typical juan somatic cell have?
46.
How many chromosomes do human somatic cells have?
46. 2 pairs of 23, one from each parent.
What is the photosynthetic chemical equation?
6CO2 + 6H2O + light energy -> C6H12O6 + 6O2
What is photosynthesis' redox reaction?
6CO2 becomes reduced to C6H12O6 and 6H2O becomes oxidized to 6O2
How many electrons can the rest of the shells hold?
8
What are the sub phases of interphase?
90% of the cycle. G1 phase S phase: DNA synthesis G2 phase
How many elements are recognized?
92
Explain the carbonyl group.
=C=O Sugars with ketone groups are called ketoses, those with aldehydes are called aldoses. Compound name: Ketone (carbonyl group is within the carbon skeleton) or aldehyde (carbonyl group is at the end of a carbon skeleton) Example: Acetone, the simplest ketone Propanal, an aldehyde
What is a protein?
A biologically functional molecule made up of one or more polypeptides, each folded and coiled into a specific three dimensional structure.
What is electroporation?
A brief electrical pulse is applied to a solution containing cells creates temporary holes in their plasma membranes, through which DNA can enter.
What is a scientific theory?
A broader scope than a hypothesis which proposes something general enough to spin off many new, specific hypotheses that can be tested.
What is an asymmetric carbon?
A carbon that is attached to four different atoms or groups of atoms.
What is a positively charged ion called?
A cation.
What is pinocytosis?
A cell continually "gulps" droplets of fluid into tiny vesicles. This way the cell obtains molecules dissolved in the droplets. It is non specific for substances it transports.
What is phagocytosis?
A cell engulfs a particle by extending pseudopodia around it and packaging it within a membranous sac called a food vacuole. It will be digested after fusing with a lysosome.
What is cell fractionation?
A centrifuge, which spins test tubes holding mixtures of disrupted cells at a series of increasing speeds. At each speed, the resulting force causes a subset of the cell's components to settle to the bottom of the tube, forming a pellet. At lower speeds, the pellet consists of larger components, and higher speeds result in a pellet with smaller components.
What is transformation?
A change in genotype and phenotype due to the assimilation of external DNA by a cell.
What is a primary cilia?
A cilia that is generally non motile and acts as a signal receiving "antenna" for the cell.
How does cleavage happen in an animal cell?
A cleavage furrow, a shallow groove in the cell surface near the old metaphase plate, appears. On the cytoplasmic side, a contractile ring of actin microfilaments associated with molecules of the protein myosin. The actin and myosin interact and the ring contracts. This is like pulling a drawstring. This depends until the parent cell is pinched in two, making two separate cells.
What is an expression vector?
A cloning vector that contains a highly active bacterial promoter just upstream of a restriction site where the eukaryotic gene can be inserted in the correct reading frame. The bacterial host cell will recognize the promoter and proceed to express the foreign gene now linked to that promoter. Such expression vectors allow the synthesis of many eukaryotic proteins in bacterial cells.
What is Adenosine Triphosphate (ATP)?
A complicated organic phosphate that consists of an organic molecule called adenosine attached to three phosphate groups.
What is a cell cycle checkpoint?
A control point in the cell cycle where stop and go ahead signals can regulate the cycle. Three important checkpoints are in the G1, G2 and M phases.
What is the TATA Box?
A crucial promoter DNA sequence that forms the initiation complex at a eukaryotic promoter.
What is a cell cycle control system?
A cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle.
What is Huntington's Disease?
A degenerative disease of the nervous system that is caused by a lethal dominant allele that has no obvious phenotypic effect until 45.
What is a deletion?
A deletion occurs when a chromosomal fragment is lost. The affected chromosome is then missing certain genes.
In secondary structure, what is the a helix?
A delicate coil held together by hydrogen bonding between every fourth amino acid.
What is a punnett square?
A diagrammatic device for predicting the allele composition of offspring from a cross between individuals of known genetic makeup. A capital letter symbolizes dominant allele and a lowercase letter symbolizes recessive allele.
What is cystic fibrosis?
A lethal genetic disease. Gets one out of every 2,500 people of European descent. Normal allele codes for a membrane protein that functions in the transport of chloride ions between certain cells and the extracellular fluid. If the channels are defective, there are abnormally high concentrations of extracellular chloride, which causes the mucus to be stickier and thicker. This builds up leading to many effects including poor absorption of nutrients from the intestines, chronic bronchitis, and recurrent bacterial infections.
What is a photosystem?
A light harvesting complex composed of a reaction center complex surrounded by several light harvesting complexes.
What is the dependent variable?
A factor that is measured in the experiment.
What are plastids?
A family of closely related plant organelles including the amyloplast (stores amylose) and chromoplast (stores pigments).
What is a zygote?
A fertilized egg that is diploid because it contains two haploid sets of chromosomes bearing genes representing the maternal and paternal family lines.
What is a nucleotide composed of?
A five carbon sugar (pentose), a nitrogenous base, and one or more phosphate groups.
What is achondroplasia?
A form of dwarfism that occurs in one out of every 25,000 people. Heterozygous individuals have the phenotype.
What is a translocation?
A fragment joins a nonhomologous chromosome.
What is the nuclear matrix?
A framework of protein fibers extending throughout the nuclear interior.
What is a sex linked gene?
A gene coated on either sex chromosome. Those located on the Y are y linked genes. Those located on the X are x linked genes.
What is a regulatory gene?
A gene that is located some distance from the operon and has its own promoter which usually creates the repressors for a system.
What is a maternal effect gene?
A gene that, when mutant in the mother, results in a mutant phenotype in the offspring, regardless of the offspring's own genotype.
What is a life cycle?
A generation to generation sequence of stage in the reproductive history of an organism, from conception to production of its own offspring.
What is a linkage map?
A genetic map based on recombination frequency.
What is the linkage in a disaccharide called?
A glycosidic linkage, a covalent bond formed between two monosaccharides by a dehydration reaction.
What is an absorption spectrum?
A graph plotting a pigment's light absorption versus wavelength.
What is a vaccine?
A harmless variant or derivative of a pathogen that stimulates the immune system to mount defenses against the harmful pathogen.
What is the sphere of water molecules around each dissolved ion called?
A hdration shell.
What type of capsid does tobacco mosaic virus have?
A helical capsid with the overall shape of a rigid rod.
What is a character?
A heritable feature that varies among individuals.
What is a phosphorylation cascade?
A hypothetical pathway in which phosphorylation is relayed down a transduction pathway.
What is a bicoid?
A larva that is two tailed.
What is surface tension in water?
A measure of how difficult it is to stretch or break the surface of a liquid. This is related to cohesion because the hydrogen bonds make the water very compact, therefore water has a high surface tension.
What is a lysosome?
A membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest (hydrolyze) macromolecules.
How can allosteric enzymes be regulated by feedback inhibition?
A metabolic pathway is halted by the inhibitory binding of its end product to an enzyme that acts early in the pathway. The molecule works to inhibit the enzyme which changes the shape of the active site thereby not allowing the substrate in and halting production of products.
What is the primary electron acceptor?
A molecule capable of accepting electrons and becoming reduced.
What steep gradient does an animal cell maintain?
A much higher concentration of K+ and a low concentration of Na+ inside the cell. The plasma membrane helps to keep these by pumping Na+ out and K+ in.
What is a silent mutation?
A mutation that has no observable effect on the phenotype.
What is fetoscopy?
A needle thin tube containing a viewing scope and fiber optics is inserted into the uterus.
What is a cytoskeleton?
A network of fibers extending throughout the cytoplasm. It is composed of microtubules, microfilaments, and intermediate filaments.
What are the collagen fibers embedded in?
A network woven out of proteoglycans. These consist of a small core protein with many carbohydrate chains covalently attached.
What is the portion of a nucleotide without any phosphate groups called?
A nucleoside.
What is the nucleosome 10nm fiber level of packing?
A nucleosome is a "bead on a string" which is linker DNA with DNA wound twice around a protein core of eight histones. The amino end of each histone extends outward.
What is within the centrosome?
A pair of centrioles, each composed of nine sets of triplet microtubules arranged in a ring.
What is fermentation?
A partial degradation of sugars or other organic fuel that occurs without the use of oxygen.
What is a metabolic pathway?
A pathway that begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product. Each step is catalyzed by a specific enzyme.
What is the bond between amino acids called?
A peptide bond.
What is a virulent phage?
A phage that replicates only by a lytic cycle.
What is density dependent inhibition?
A phenomenon in which crowded cells stop dividing.
What are parental types?
A phenotype that matches either of the phenotypes of the P generation originally.
What happens during linear electron flow?
A photon strikes one of the pigment molecules in PS II (680) boosting the energy level. As the electron falls to ground state, the next pigment is raised. This goes on until it reaches the P680 pair of chlorophyll a molecules in reaction center complex. They are excited to a high estate. This electron is transferred from the excited P680 to the primary electron acceptor. An enzyme catalyzes the splitting of H2O into 2 protons, two electrons, and oxygen. The electrons go to the pair replacing the transferred ones. The H+ are released into the thylakoid space. Oxygens meet up and leave as O2. Excited electrons leave the primary electron acceptor of PS II and go to PS I via electron transport chain (plastoquinone Pq and plascotyanin Pc). This exergonic process creates energy for the synthesis of ATP. As electrons pass through, H+ are pumped into the thylakoid space, creating a gradient inside. The same thing happens in PS I reaction center, exciting an electron of the P700 pair of chlorophyll a. The photo excited electrons passed to Ferredoxin Fd in a second electron transport chain. No gradient is made here. NADP+ gets the electrons to make NADPH.
What is chorionic villus sampling?
A physician inserts a narrow tube through the cervix into the uterus and suctions out a tiny sample of tissue from the placenta. More rapid than amniocentesis and can be performed between the 8th and 10th week of pregnancy.
What is amniocentesis?
A physician inserts a needle into the uterus and extract about 10 mL of amniotic fluid. Some genetic disorders can be detected from the presence of certain molecule sin the amniotic fluid itself.
What happens if plants and their surroundings are hypertonic?
A plant cell will lose water to surroundings. As the plant cell shrivels, the plasma membrane pulls away from the cell wall in a phenomenon called plasmolysis.
What is ethylene?
A plant hormone that helps promote fruit ripening and regulates growth (C2H4)
What is vertical transmission of a plant virus?
A plant inherits a viral infection from a parent.
What is horizontal transmission of viral plant diseases?
A plant is infected from an external source of the virus Because the invading virus must get past the plant's outer protective layer of cells, a plant becomes more susceptible to viral infections if it has been damaged.
What is the middle lamella?
A thin layer rich in sticky polysaccharides called pectins that glues adjacent cells together.
What is cellulose?
A polysaccharide that is a major component of the tough walls that enclose plant cells. It is the most abundant organic compound on Earth. It is made of glucose but it is slightly different from starch.
What is a spontaneous process?
A process, by itself, that leads to an increase in entropy, which can proceed without requiring an input of energy.
What is Duchenne muscular dystrophy?
A progressive weakening of the muscles and loss of coordination. This is the absence of a muscle protein called dystrophin in a specific locus on the X chromosome. More common in men because of X linked.
What is the nucleolus?
A prominent structure in the non dividing nucleus, It is a mad where rRNA is synthesized from DNA. Proteins are also imported from the cytoplasm and assembled with rRNA into small and large subunits of ribosomes.
What is a growth factor?
A protein released by certain cells that stimulates other cells to divide.
What is a cyclin?
A protein that gets its name from its cyclically fluctuating concentration in the cell. It must bind to a certain type of kinase in order for the kinase to be active.
What it the H+ gradient referred to as?
A proton motive force, emphasizing the capacity of the gradient to perform work. The force drives H+ back across the membrane through the H+ channels provided by ATP syntheses.
What is an aster?
A radial array of short microtubules that extend from each centrosome.
What is PKU?
A recessively inherited disorder that occurs in about one out of every 10,000 births in the US. Can't properly metabolize th amino acid phenylalanine.
What is the difference between a reciprocal and nonreciprocal translocation?
A reciprocal, nonhomologous chromosomes exchange fragments. In a nonreciprocal, a chromosome transfer a fragment but receives none in return.
What is a centromere?
A region of the chromosomal DNA where the chromatid is attached most closely to its sister chromatid. The attachment is mediated by potions bound to the centromeric DNA; other proteins condense the DNA, giving the duplicated chromosome a narrow "waist."
How does a phosphorylation cascade work?
A relay molecule activates protein kinase 1, which transfer a phosphate from ATP to an inactive molecule of protein kinase 2. This now catalyzes the phosphorylation of protein kinase 3. This phosphorylates a protein that brings about the cell's response to the signal. Enzymes called protein pho sphatases catalyze the removal of the phosphate groups from the proteins, making them inactive again.
How are restriction enzymes used during cloning to make a recombinant DNA plasmid?
A restriction enzyme cuts the sugar phosphate backbone in a very specific location. DNA fragment from another source is added. Base pairing of sticky ends produces various combinations. Fragments from different DNA molecules are cut by the same restriction enzyme. DNA ligase seals the strands and voila, recombinant plasmid.
What important role do actin filaments play (Microfilaments)?
A role in actin and myosin interactions to cause contraction of muscle cells. This also happens in amoeba where the cell crawls along a surface by extending cellular extensions called pseudopodia. Th interactions also work in cytoplasmic streaming, a circular flow of cytoplasm within cells.
How has PDGF been tested in labs?
A sample of human connective tissue is cut into small pieces. Enzymes are used to digest the extracellular matrix, resulting in the suspension of free fibroblasts. Cells are transferred to culture vessels containing a bias growth medium of glucose, amino acids, salts, and antibiotics. PDGF is added to half he vessels. There was more growth with PDGF>
What is inquiry?
A search for information and explanations of natural phenomena.
What is a gene?
A section of the DNA of the chromosome.
What does a tRNA molecule consist of?
A single RNA strand that is only 80 nucleotides long. Because of the complementary stretches of nucleotide bases that can hydrogen bond to each other this strand folds back on itself and forms a three dimensional structure.
What is a single nucleotide polymorphism?
A single base pair site where variation is found in at least 1% of the population.
What is asexual reproduction?
A single individual is the sole parent and passes copies of all its genes to its offspring without the fusion of gametes. Usually single celled eukaryotic organisms can reproduce asexually by mitotic cell division, in which DNA is copied and allocated equally to two daughter cells.
What is a corepressor?
A small molecule that cooperates with a repressor protein to switch an operon off. As tryptophan accumulates, more tryptophan molecules associate with trp repressor molecules, which can then bind to the trp operator and shut down production of the tryophan pathway enzymes.
What is the process of initiation in translation?
A small ribosomal subunit binds to a molecule of mRNA. In bacteria, the site recognizes a specific nucleotide sequence on the mRNA just upstream of the start codon. An initiator tRNA, with the anticodon, base pairs with the stat codon. This tRNA carries a certain amino acid. In eukaryotes, the small subunit has tRNA bound and binds to the 5' cap and then moves downstream along the mRNA until it reaches the start codon. The arrival of a large ribosomal subunit completes the initiation complex. Initiation factors are required to bring all the translation components together. Hydrolysis of GTP provides the energy for the assembly. The initiator tRNA is in the P site; the A site is available to the tRNA bearing the next amino acid.
What is a peroxisome?
A specialized metabolic compartment bounded by a single membrane. They contain enzymes that remove hydrogen atoms from various substrates and transfer them to oxygen to make hydrogen peroxide.
What is a model organism?
A species that is easy to grow in the lab and lends itself particularly well to the questions being investigated.
What is synaptic signaling?
A specific type of local signaling that occurs in the animal nervous system. An electrical signal along a nerve cell triggers the secretion of neurotransmitter molecules. They act as chemical signals, diffusing across the synapse - the space between the nerve cell and target cell - triggering a response in the target cell.
What happens in prophase II?
A spindle forms again from the centrosomes. The chromosomes of two sister chromatids move towards metaphase plate.
What happens to introns?
A spliceosome binds to several short nuclide sequences along an intron, including key sequences at each end. The intron is then released and rapidly degraded, thud the spliceosome enjoins together the two exons that flanked the intron.
What is RNA splicing?
A stage in RNA processing in the eukaryotic nucleus which includes the removal of large portions of the RNA molecule that is initially synthesized.
What is a compound?
A substance consisting of two or more different elements combined in a fixed ratio. (NaCl, H2O)
What is an element?
A substance that cannot be broken down into other substances by chemical reactions.
What is an acid?
A substance that increase the hydrogen ion concentration of a solution.
What is a buffer?
A substance that minimizes changes in the concentrations of H+ and OH- in a solution. The presence of buffers allows biological fluids to maintain a relatively constant pH despite the addition of acids or bases. It does this by accepting hydrogen ions from the solution when they are in excess and donating hydrogen ions to the solution when they have been depleted.
What is a base?
A substance that reduces the hydrogen ion concentration of a solution.
What is a concentration gradient?
A substance will diffuse down its concentration gradient, the region along which the density of a chemical substance increases or decreases.
What is cooperativity?
A substrate molecule binding to one active site in a multisubunit enzyme triggers a shape change in all the subunits, thereby increasing catalytic activity at the other active sites
What is cellular respiration?
A system of aerobic respiration used to rear to the process of creating ATP out of a catabolic pathway.
What is an isolated system?
A system that is unable to exchange either energy or matter with its surroundings outside. Like a liquid in a thermos bottle.
What is a hypothesis?
A tentative answer to a well framed question - an explanation on trial.
What is anchorage dependence?
A trait that most cells exhibit that in order to divide, they must be attached to a substratum, such s the indie of a culture flask or the extracellular matrix of a tissue.
What is an electrogenic pump?
A transport protein that generates voltage across a membrane.
What are ligand gated ion channels?
A type of embrace receptor containing a region that can at as a gate when the receptor changes shape. When a signaling molecule binds as a ligand to the receptor protein, the gate opens or closes allowing or blocking the flow of specific ions, such as Na+ or Ca2+, through a channel in the receptor.
What is cholesterol?
A type of steroid that is crucial in animals. It is a common component of animal cell membranes and is a precursor for vertebrate sex hormones. It is made in the liver.
What is a water molecule shaped like?
A wide V, with two hydrogen atoms joined to the oxygen atom by single covalent bonds.
How does a cell wall come to be?
A young plant cell first secretes a relatively thin and flexible wall called the primary cell wall. When the cell matures and stops growing, it strengthens thew all either by secreting hardening substances or adding a secondary cell wall between th plasma membrane and the primary wall.
What type of allele exists in more than just two forms?
ABO gblood groups is determined by I^A, I^B, and i. Causing blood to be either A, B, AB< or O.
What is a cloning vector?
ADNA molecule that can carry foreign DNA in a host cell and replicate there.
What is the start codon?
AUG, also codes for methionine.
How many species have so far been identified and named?
About 1.8 million. (290,000 plant, 57,000 vertebrate, 1 million insects)
What is the pH for basic solutions?
Above 7
What is the chromosome theory of inheritance?
Accroding to this, Mendelian genes have specific loci along chromosomes, and it is the chromosomes that undergo segregation and independent assortment.
What are the different compounds of the citric acid cycle?
Acetyl CoA - citrate - isocitrate (isomer) - ketogluterate - succinyl CoA - succinate - fumarate - malate - oxaloacetate
Out of the citric acid cycle (also known as the tricarboxylic acid cycle or the Krebs cycle), what are the inputs and outputs?
Acetyl CoA is the only thing that goes in. Excluding what comes out of pyruvate oxidation, each turn creates 2 CO2, 3NADH, ATP, and FADH2. However, because there are two molecules of pyruvate, the cycle always completes two turns and therefore there is 4CO2, 6NADH, 2ATP, 2FADH2.
What is the currently accepted model for the action of enhancers and transcription activators?
Activator proteins bind to the distal control elements on the enhancer. A DNA bending protein brine the bound activators closer to the promoter. General transcription factors, mediator proteins, and RNA polymerase II are nearby. The activators bind to certain mediator proteins and general transcription factors, helping form an active transcription initiation complex on the promoter.
How is gene expression coordinated in eukaryotes?
Activator proteins in the nucleus recognize the control elements and bind to them, promoting simultaneous transcription of the genes, no matter where they are in the genome. This often happens in response to chemical signals from outside the cell. A steroid enters a cell and binds to a specific intracellular receptor protein, forming a hormone receptor complex that serves as a transcription activator.
What is DNA methylation?
Adding methyl groups can lead to the condensation of chromatin and reduced transcription.
What are insertions or deletions?
Additions or losses of nucleotide pairs in genes. These are usually more disastrous than substitutions.
What bases always pair together?
Adenine and Thymine or Uracil. Guanine and Cytosine
Explain purines and pyrimidines with respect to the double helix.
Adenine and guanine are purines which have two rings and cytosine and thymine are pyrimidines which have one ring. Therefore purines and pyrimidines have to go together in order to account for the 2 nm diameter of the double helix.
What role does adhesion play with water?
Adhesion of water by hydrogen bonds to the molecules of cell walls helps counter the downward pull of gravity.
What happens during crossing over?
After interphase, the chromosomes are duplicated and sister chromatids are held together by proteins. Each homolog associates along the length. The DNA molecules of two nonvoter chromatids are broken at corresponding points. The synaptonemal complex begins to form, attaching one homolog to the other. When the complex is formed, the two are said to be in synapsis. The DNA breaks are closed up when each broken end is joined to the corresponding segment of the non sister chromatid, producing crossovers. When the synaptonemal complex disassembles, the homologs move a little apart but remain attached. The points of attachment where crossovers occur show up as chiasmata and the chromosomes continue to condense.
What disease did Archibald Garrod study?
Alkaptonuria. This disorder causes urine to be black because it contains the chemical alkapton which darkens with exposure to air. He said that most people have an enzyme that metabolizes alkapton whereas people with the disease have an inability to make that metabolic enzyme.
What are somatic cells?
All body cells except the reproductive cells.
How is specificity of cell signaling and coordination of response explained?
All cells have different embedded proteins, therefore the same molecule binding to different cells is going to have different effects. Epinephrine on the liver is going to speed up breakdown of glycogen whereas on heart cells, it'll just speed up the heartbeat.
What is the operon?
All together the operator, the promoter, and the genes that they control.
What does this law only apply to?
Allele pairs located on different chromosomes, or genes that are really far apart on the chromosome.
What are microfilaments called, what are they, what are they made of, and what do they do?
Also called Actin filaments. Two intertwined strands of actin Made of actin Maintains cell shape; changes in cell shape; helps with muscle contraction; cytoplasmic strewing in plant cells; cell motility; division of animal cells.
What are microtubules called, what are they, what are they made of, and what do they do?
Also called Tubulin polymers Hollow tubes It's made of tubulin, a dmer consisting of a tubulin and B tubulin. It maintains cell shape; helps cell motility (cilia and flagella); moves chromosomes in cell division; helps move organelles.
What are carriers?
Although phenotypically normal with regard to the disorder, heterozygotes may transmit the recessive allele to their offspring and thus are called carriers.
What is an example of an emergent property in chloroplasts?
Although photosynthesis occurs in an intact chloroplast, it will not take place in a disorganized test tube mixture of chlorophyll and other chloroplast molecules.
What is hemophilia?
An X linked recessive disorder defined by the absence of one or more of the proteins required for blood clotting.
What is polygenic inheritance?
An additive effect of two or more genes on a single phenotypic character. In a way, the converse of pleiotropy. If there are three dark skin genes, ABC, contributing one unit of darkness, an AABBCC person is very black while an aabbcc person is really white. Mating of AaBbCc could get seven different skin colors. There are so many intermediate phenotypes in this situation.
What is glycerol?
An alcohol; each of its three carbons bears a hydroxyl group.
What is down syndrome?
An aneuploid condition that affects one out of 830 children in the US. The result of an extra chromosome 21, so it's called trisomy 21. Includes characteristic facial features, short stature, correctable heart defects, and developmental delays. Increased chance of developing leukemia and Alzheimer's but lower blood pressure, atherosclerosis, stroke, and solid tumors. Almost all males and half females are sexually underdeveloped and sterile. Frequency increases with age of the mother.
What is a negatively charged ion called?
An anion.
What is NAD+?
An electron carrier that functions in cellular respiration. It can cycle easily between oxidized NAD+ and reduced NADH states.
What is adenylyl cyclase?
An enzyme embedded in the plasma membrane that converts ATP to cAMP in response to an extracellular signal.
What is telomerase?
An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells, thus restoring their original length and compensating for the shortening that occurs during DNA replication.
What is a nuclease?
An enzyme that cuts out DNA.
What is RNA polymerase?
An enzyme that pries the two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand, thus elongating the RNA polynucleotide. Unlike DNA polymerases, it can start a chain from scratch without a primer.
What is a protein kinase?
An enzyme that transfers phosphate groups from ATP to a protein.
What is the endoplasmic reticulum?
An extensive network of membranes that accounts for more than half the total membrane in many eukaryotic cells. It consists of a network of membranous tubules and sacs called cistern. The inside is called the ER lumen or cisternal space. It is continuous with the nuclear envelope.
Instead of cell walls, what do animal cells have?
An extracellular matrix (ECM). This consists of glycoproteins and other carbohydrate containing molecules secreted by the cells.
What is the cell wall?
An extracellular structure of plant cells that distinguishes them from animal cells. The wall protects the plant cell, matins its shape, and prevents excessive uptake of water.
What type of capsid does an adenovirus have?
An icosahedral capsid with a glycoprotein spike at each vertex.
Definition of a virus?
An infectious particle consisting of little more than genes packaged in a protein coat.
What is sickle cell disease?
An inherited blood disorder that is caused by the substitution of one amino acid valine for the normal one glutamic acid at a particular position in the primary structure of hemoglobin, the protein that carries oxygen in red blood cells. Sickle cells aggregate into chains deforming some of the cells into a sickle shape.
What is the three dimensional space where an electron is found 90% of the time called?
An orbital.
What is a karyotope?
An ordered display of chromosomes that are arranged in pairs, starting with the longest chromosomes.
What is an amino acid?
An organic molecule with both an amino group and a carboxyl group. It has an asymmetric carbon, a side chain, and a hydrogen as well.
What is homozygous?
An organism that has a pair of identical alleles for a character is said to be homozygous for the gene controlling that character. (PP) (pp) These plants breed true because all their gametes have the same allele.
What is heterozygous?
An organism that has two different alleles for a gene is said to be heterozygous for that gene. Heterozygotes produce gametes with different alleles, so they are not true breeding.
What is phenotype?
An organism's appearance or observable traits.
What is genotype?
An organism's genetic makeup.
What is a reaction center complex?
An organized association of proteins holding a special pair of chlorophyll a molecules.
What are the two ways to generate ATP without the use of oxygen?
Anaerobic respiration and fermentation
What is endocrine signaling?
Another name for long distance hormone signaling. This is where specialized cells release hormone molecules, which travel via the circulatory system to other parts of the body, where they reach target cells that can recognize and respond to the hormones.
What is chitin?
Another structural polysaccharide, the carbohydrate used by arthropods to build their exoskeletons. It is also found in fungi and used in surgical thread.
Why are diphtheria, botulism, and scarlet fever so harmful to humans?
Because certain prophage genes cause the host bacteria to make toxins.
How do the sugar phosphate backbones run in DNA?
Antiparallel, which means tat their subunits run in opposite directions.
What is a diploid cell?
Any cell with two chromosome sets that has a diploid number of chromosomes, 2n.
What does it mean to be hydrophilic?
Any substance that has an affinity for water.
What is matter?
Anything that takes up space and has mass.
What is visible light?
Anywhere on the spectrum from 380 nm to 750 nm in wavelength because it can be detected as colors by the human eye. 380 is purple and 750 is red.
What is an example of a channel protein?
Aquaporins. They allow entry of 3 billion water molecules per second.
What is an epidemic vs a pandemic?
Epidemic is a widespread outbreak, a pandemic is a global epidemic.
What is a hydrophobic interaction in tertiary structure?
As a polypeptide folds into its functional shape, amino acids with hydrophobic side chains usually end up in clusters at the core of the protein, out of contact with water.
How do many ion channels function?
As gated channels, which open or close in response to stimulus. This can either be electrical or a specific substance binding.
How does elongation of the RNA strand work?
As the RNA polymerase moves along the DNA, it untwists the double helix and pairs it with RNA molecules. After synthesis, the new RNA molecule peels away from the DNA template and the double helix reforms.
Why is liquid water denser than ice?
At 0 degrees C, the molecules become locked into a crystalline lattice, each water molecule hydrogen bonded to four partners. The hydrogen bonds keep the molecules at arm's length, far enough apart to make ice about 10% less dense than water.
How does independent assortment of chromosomes lead to genetic variation?
At metaphase I, the homologous pairs are situated at the metaphase plate but either may orient closer to a given pole and this is random. There is a 50% chance that a particular daughter cell of meiosis I will get the maternal chromosome or the paternal chromosome.
How do saturated fats exist?
At room temperature, the molecules of a saturated fat, such as the fat in butter, are packed closely tighter because no kinks which means its a solid. Most of these are animal fats.
How do unsaturated fats exist?
At room temperature, the molecules of an unsaturated fat such as olive oil cannot pack together closely enough to solidify because of the kinks. They are usually referred to as oils. Most of these are vegetable fats.
What is the plasma membrane?
At the boundary of every cell, this functions as a selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell.
What is a replication fork?
At the end of the bubble is a replication fork which is a Y shaped region where the parental strands of DNA are being unwound.
What are the other chromosomes called?
Autosomes.
How does the lac operon work?
B galactosidase isn't naturally made in large quantities in e. coli so it has to be synthesized when lactose is present. The regulatory gene, lack, codes for an allosteric repressor protein that can switch off the lac operon by binding to the proofer. The lac repressor is active by itself and is always bound to the operator. When an inducer inactivates the repressor, (allolactase), it binds to the lac repressor and alters its shape, taking it away from the operator and allowing the lac operon to synthesize the enzyme to break down lactose.
What is an inversion?
If a chromosomal fragment reattaches to the original chromosome but in reverse orientation.
What are the three domains of life?
Bacteria, Archaea, and Eukarya.
What are some organisms that exist in polyploidy?
Bananas are triploid, Wheat are hexaploid, Strawberries are octoploid.
Why are fats hydrophobic?
Because The long hydrocarbon chains are non polar.
Why are dominant alleles that cause a lethal disease much less common than recessive lethal diseases?
Because a lethal recessive allele can be passed on through carriers but a lethal dominant causes the death of afflicted individuals before they an mature and reproduce. But, a late onset disease can be passed on.
Why did everyone think protein was genetic material?
Because biochemists had identified proteins as a class of macromolecules with great heterogeneity and specificity of function, essential requirements for the hereditary material. Little was known about nucleic acids who seemed far too uniform to account for specific inherited traits.
Why does water have such a high heat of vaporization?
Because in order to vaporize water, the hydrogen bonds must be broken before the molecules can exit from the liquid in the form of water vapor.
Why is the last step called oxidative phosphorylation?
Because it is powered by the redox reactions of the electron transport chain.
Why is photorespiration bad for a plant?
Because it just uses up ATP and produces no sugar. It just takes materials from the calvin cycle and releases CO2. It's very energetically costly.
Why is carbon dioxide often considered inorganic?
Because it's a very simple molecule that lacks hydrogen even though it contains carbon.
How does color blindness affect boys and girls differently?
Because it's an X linked trait, a girl would have to be born to a color blind father, with a carrier mate or a color blind mate. A boy will get it if his mother is a carrier, his father is colorblind, or both.
Why is the trp operon a repressible operon?
Because its transcription is usually on but can be inhibited or repressed when a specific small molecule binds allosterically to a regulatory protein.
Why is water a very versatile solvent?
Because of the extreme electronegativity of its atoms, it is a very polar molecule. This allows it to dissolve ionic compounds like salt. The oxygen regions of the water are negatively charged and attracted to sodium cations. Hydrogen are attracted to chloride anions.
Why is a high specific heat of water beneficial to the surrounding area?
Because of the high specific heat of water relative to other materials, water will change its temperature less than other liquids when it absorbs or loses a given amount of heat. A large body of water can absorb and store a huge amount of heat from the sun in the daytime and during summer while warming up only a few degrees. At night and during winter, the gradually cooling water can warm the air. This moderates air temperatures in coastal areas. This also stabilizes ocean temperatures, helping out marine life.
Why is a ribosome one giant ribozyme?
Because ribosomal RNA is the main constituent of the A and P sites and of the interface between the two subunits; it also acts as the atavist of peptide bond formation.
Why isn't it a big explosion when H+ falls down the chain and meets O2?
Because the H+ is derived from organic molecules rather than H2 and also, it is done in such a small series of steps that creates energy rather than combusts right away.
Why are the lac and trp operons negatively controlled?
Because the operons are switched off by the active form of the repressor proteins.
Why is the concept of enantiomers important int he pharmaceutical industry?
Because the two enantiomers of a drug may not be equally effective, like methamphetamine. One is the addictive stimulant drug, and the other is an active ingredient in an over the counter vapor inhaler for treatment of nasal congestion.
Why can't human gametes be made by mitosis?
Because they would be diploid like the somatic cells. At the next round of fertilization, when two gametes fused, the normal chromosome 46 would become 92 and each generation would double.
What is the pH for acidic solutions?
Below 7
What are dyneins?
Bending of flagella and cilia requires large motor proteins called dyneins that are attached along each outer microtubule doublet. A typical dyne in protein has two feet that walk along the microtubule of the adjacent doublet, using ATP for energy. The outer doublets and two central microtubules are held together by proteins. The walking movement happens on one side of the circle at a time. This creates the whole thing to bend.
What happens in anaphase II?
Breakdown of proteins allow sister chromatids to move towards opposite poles as individual chromosomes.
What are catabolic pathways?
Breakdown pathways that release energy by breakage down complex molecules into simpler compounds. Major example, cellular respiration.
What is a test cross and when is it necessary?
Breeding an organism of unknown genotype with a recessive homozygote. If you don't know whether a plant is homozygous PP or heterozygous Pp, you can cross with a pp homozygous and if any of the offspring exhibit the recessive trait, you know it's heterozygous.
How does water moderate air temperature?
By absorbing heat from air that is warmer and releasing the stored heat to air that is cooler.
How does the pH scale run?
By factors of 10.
What are the redox processes in the equation for cell respiration?
C6H12O6 becomes oxidized to CO2and 6O2 becomes reduced to 6H2O.
What does ∆G represent?
If -, the amount of work it's available to perform. If +, the amount of energy required to perform.
What is the equation for cellular respiration?
C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy (ATP+Heat)
How do cell surface proteins relate to AIDS?
CD4 a protein, is on the surface of immune cells that helps HIV infect these cells, leading to AIDS> A small number of people have a gene that doesn't code for CCR5. Turns out that HIV has to bind to both CD4 and CCR5 and the people with the unusual gene don't have the latter so they can't get AIDs. Interfering with CD4 could cause dangerous side effects so interfering with CCR5 as a coreceptor is beneficial for drugs like maraviroc.
What is the simplest possible form of the equation and why isn't it used more often?
CO2 + H2O -> CH2O + O2. Not used because CH2O is not an actually sugar but is just the general formula for a carbohydrate.
What is more widely used than cAMP as a second messenger?
Ca2+ because there is a relatively small amount of it in the cytosol but a lot is housed in the smooth ER. When triggered, the smooth ER will shoot it out, causing a contraction or some other signal.
What four other elements account for the rest?
Calcium, Phosphorus, Potassium, and Sulfur.
What are oncogenes?
Cancer causing genes.
What is unique about carbon's valence?
Carbon atoms can form diverse molecules by bonding to four other atoms. This is because carbon has 6 electrons, therefore there are 4 in the valence shell.
What are the three phases of the calvin cycle?
Carbon fixation Reduction Regeneration
What are the four major atomic components of organic molecules?
Carbon, hydrogen, oxygen, and nitrogen.
What is a common buffer in the human system?
Carbonic acid which forms when CO2 reacts with water in blood plasma.
What are cis-trans isomers (formerly known as geometric isomers)?
Carbons have covalent bonds to the same atoms, but these atoms differ in their spatial arrangements due to the inflexibility of double bonds.
What are integrins?
Cell surface receptor proteins that are built into the plasma membrane. They span the membrane and bind on their cytoplasmic side to the associated proteins attached to microfilaments of the cytoskeleton.
What are G protein coupled receptors?
Cell surface transmembrane receptors that work with the help of a G protein, a protein that binds the energy rich molecule GTP. They are very specific in shape and have one single polypeptide in seven transmembrane a helices. They have specific loops that are binding sites for signaling molecules.
What happens in prophase I?
Centrosome movement, spindle formation, nuclear envelope breakdown, and chromosome condensation. Crossing over occurs. Each homologous pair have chiasmata where crossovers are. Microtubules attach to kinetochores at the centromere of each homolog.
What are the two types of transport proteins?
Channel proteins Carrier proteins
What are multifactorial characters?
Characters that are influenced collectively by many factors, both genetic and environmental.
What are the three kinds of work a cell does?
Chemical - pushing the endergonic reactions that would not occur spontaneously. Transport - pumping substances across membranes against the direction of spontaneous movement Mechanical - beating of cilia, contraction of muscle cells, and the movement of chromosomes during cellular reproduction
What are catalysts?
Chemical agents that selectively speed up chemical reactions without being consumed by the reaction.
What are functional groups?
Chemical groups that are directly involved in chemical reactions. Each has certain properties, such as shape and charge, that cause it to participate in chemical reactions in a characteristic way.
What is the process in which energy stored in the form of a hydrogen ion gradient across a membrane is used to drive cellular work such as the synthesis of ATP called?
Chemiosmosis.
What are the three types of pigments in chloroplasts?
Chlorophyll a, the key light capturing pigment that participates directly in the light reactions. Chlorophyll b, the accessory pigment Carotenoids, more accessory pigments
What are homologous chromosomes or homologs?
Chromosomes of a pair that have the same length, centromere position, and staining pattern.
What is an experiment?
Involves manipulation of one factor in a system in order to see the effects of changing it.
What are viroids?
Circular RNA molecules that infect plants. They don't encode pro tines but replicate in host plant cells, using their enzymes. Cause errors in the regulatory systems that control plant growth.
What are properties unique to water?
Cohesion Adhesion Moderation of Temperature High Specific Heat Evaporative Cooling Floating Ice Universal Solvent Hydrophobic and Hydrophilic substances
What is the most abundant glycoprotein in the ECM of most animal cells?
Collagen, which forms strong fibers outside the cell.
What is a family pedigree?
Collected information about a family's history for a particular trait and assembled it into a family tree describing the traits of parents and children across the generations.
What is cohesion in water molecules?
Collectively the linkages of hydrogen bonds make water more structured than most other liquids. The hydrogen bonds hold the substance together.
What are ribosomes?
Complex made of ribosomal RNA and protein, cellular components that carry out protein synthesis. They are not considered organelles because they are not membrane bounded.
What are isomers?
Compounds that have the same numbers of atoms of the same elements but different structures and hence different properties.
What are growth factors?
Compounds that stimulate nearby target cells to grow and divide.
What is a type of hydrophilic molecule that does not dissolve because of its size?
Cotton - consists of giant molecules of cellulose, which can form hydrogen bonds of water because of polarity. That's why cotton towels dry very well but don't dissolve in the washing machine.
How does crossing over lead to genetic variation?
Crossing over produces recombinant chromosomes which are individual chromosomes that carry genes derived from two different parents. This makes new combinations and new possibilities.
What are these kinases called?
Cyclin dependent kinases or Cdks.
What can misfolding of proteins cause?
Cystic fibrosis, Alzheimers, Parkinsons, and mad cow disease.
What are most of the electron carriers in the transport chain called?
Cytochromes, their prosthetic group is a heme group.
How does the sodium potassium pump work?
Cytoplasmic Na+ binds to the sodium potassium pump. Na+ binding stimulates phosphorylation by ATP. This leads to a change in protein shape, reducing the affinity for Na+ which is released out. The new shape has a high affinity for K+ which binds to the extracellular side and triggers the release of phosphate. Loss of phosphate restores the protein's original shape which has no affinity for K+. K+ is released into the cell and affinity for Na+ is high again.
What is pattern formation?
Cytoplasmic determinants and inductive signals both contribute to the development of a spatial organization in which the tissues and organs of an organism are all in their characteristic places.
What are channel proteins that transport ions called?
Ion channels.
What are the two functions of a lysosome?
Digesting food - a food vacuole forms and then fuses with a lysosome whose enzymes digest the food. Autophagy - lysosome breaks down damaged organelles.
What are the two types of nucleic acids?
DNA and RNA
How can the p53 cause cancer?
DNA damage is an intracellular signal that is passed via protein kinases leading to the activation of p53. This promotes transcription of the gene for a protein that inhibits the cell cycle. In a mutant version, The DNA damage signals the p53, but if it is missing, there is no activation of transcription and the cell cycle in not inhibited. This could cause the ras gene to overact and increase cell division and the mutation would be passed, creating cancer.
What is gene expression?
DNA directs RNA synthesis, and through RNA, controls protein synthesis.
What is the summary of meiosis in relation to mitosis?
DNA replication occurs during interphase before meiosis I begins. There are two divisions, including prophase, metaphase, anaphase, and telophase. There is one synapsis occurring during prophase I along with crossing over between non sister chromatids resulting in chiasmata. There are four daughter cells, each genetically different from the parent cell and from each other. This produces gametes in animal or spores in plants, duress the number of chromosome sets by half and introduces genetic variability among the gametes or spores.
What is the summary of mitosis in relation to meiosis?
DNA replication occurs during interphase before mitosis begins. There is one division including prophase, pro metaphase, metaphase, anaphase, and telophase. There is no synapsis or crossing over. There are two daughter cells, each identical to the parent cells with the same number of chromosomes. This enables muticellular animals or plants to arise from a single cell; produces cells for growth repair, and, in some species, asexual reproduction; produces gametes in the gametophyte plant.
What are transposons?
DNA segments that can move from one location to another within a cell's genome.
How does genetic information generally flow?
DNA-RNA-protein
What is quantitative data?
Data often expressed as numerical measurements and organized into tables and graphs.
What is qualitative data?
Data often in the form of recorded descriptions rather than numerical measurements.
What are the four types of chromosomal structure changes?
Deletion, duplication, inversion, translocation.
What sugar is present in DNA and RNA?
Deoxyribose in DNA and Ribose in RNA.
What is the difference between the sugars?
Deoxyribose lacks an oxygen atom on the second carbon to the ring.
How do monosaccharides differ?
Depending on where the carbonyl group is placed, it is either an aldose or a ketoses. There are 3, 5, and 6 carbon sugars. Spatial arrangements may vary in isomers.
Why is chromatin structure a reason for gene expression?
Depending on whether the chromatin is ready to bind things that can read it determines whether or not that particular stretch of DNA is expressed or not.
What is inductive reasoning?
Deriving generalizations from a large number of specific observations.
What are isotopes of an element?
Different atomic forms of the same element due to a difference in neutrons. Although the isotopes of an element have slightly different masses, they behave identically in chemical reactions.
What are alleles?
Different versions of genes.
What are compounds formed by ionic bonds called?
Ionic compounds or salts.
What are enhancers?
Distal control elements that are far away from a gene or intron. The rate of gene expression can be changed by the binding of specific transcription factors (activators or repressors) to the control elements of enhancers.
What is binary fission?
Division in half. Refers to the process and to the asexual reproduction of single celled eukaryotes, such as amoeba.
What is the basic classification of animals?
Domain Kingdom Phylum Class Order Family Genus Species
What are some model organisms?
Drosophila Melanogaster (Fly) Arabidopsis Thaliana (Mustard) Caenorhabditis Elegans (Worm) Danio Rerio (Zebrafish) Mus Musculus (Mouse) Escherichia Coli (Bacteria)
What is RNA processing?
During this, both ends of the primary transcript are altered. Also, in most cases, certain interior sections of the RNa molecule are cut out and the remaining parts spliced together.
What are some cells attached to the ECM by?
ECM glycoproteins such as fibronectin.
What is luminal B breast cancer?
ERa++ PR++ Her2- Not a great prognosis, but not bad. Usually lacks expression of HER2 and is treated with drugs that target Era and inactivate it. Tamoxifen is the best known drug for this. Can also be treated with drugs that inhibit estrogen synthesis.
What is luminal A breast cancer?`
ERa+++ PR++ Her2- Good prognosis. Usually lacks expression of HER2 and is treated with drugs that target Era and inactivate it. Tamoxifen is the best known drug for this. Can also be treated with drugs that inhibit estrogen synthesis.
What is basal like breast cancer?
ERa- PR- HER2- Worst prognosis; very aggressive The basal like subtype is triple negative and does to express anything. Often has a mutation in the tumor suppressor BRCA1. Treatments can't target specifically and there are no target treatments, just cytotoxic chemotherapy which selectively kills fast growing cells.
What is HER2 breast cancer?
ERa- PR- Her2++ Bad prognosis. Unresponsive to rherpaies aimaed at Era and PR. Patients with the Her2 subtype are treated with perception, an antibody protein that inactivates they tyrosine kinase activity of Her2.
How does cell signaling work in mating yeast cells?
Each cell type secretes a mating factor that binds to receptors on the other type of cell. Binding of the factors to receptors induces changes in the cells that lead to their fusion. The nucleus of the fused cell includes all the genes from the original cells.
What happens during telophase I and cytokinesis?
Each half of the cell has a complete haploid set of duplicated chromosomes. Each is composed of two sister chromatids. One or both chromatids include regions of non sister chromatid DNA. In animal cells, a cleavage furrow forms. In plant cells, a cell plate forms. No chromosome duplication occurs
How are cilia and flagella organized?
Each has a group of microtubules sheathed in an extension of the plasm membrane. Nine doublets of microtubules are arranged in a ring with two single microtubules in its center. (9+2 arrangement). Non motile cilia typically have a 9+0 pattern.
What is the structure of mitochondria?
Each is enclosed with two phospholipid bilayers. the outer is smooth but the inner is convoluted with infoldings called cristae. There is the inter membrane space between the membranes and the mitochondrial matrix. The mitochondria has some small circular DNAs.
What is the host range of a virus?
Each particular virus can only infect cells of a limited number of host species called the host range.
What are DNA polymerases?
Enzymes that catalyze the synthesis of new DNA by adding nucleotides to a preexisting chain. There are two that play major roles in replication, DNA polymerase III and I.
For each character, an organism inherits two copies of a gene, one from each parent. What does this mean?
Each somatic cell is a diploid organism with two sets of chromosomes, one from each parent. A genetic locus is represented twice in a diploid. The genes are the same or different. (P v F1)
What is the dispersive model of replication?
Each strand of both daughter molecules contains a mixture of old and newly synthesized DNA.
What is a trait?
Each variant for a character, such as purple or white color for flowers.
What is another name for the maternal effect genes?
Egg polarity genes.
What type of capsid does an influenza virus have?
Eight different RNA molecules, each wrapped in a helical capsid, and an outer envelope studded with glycoprotein spikes.
What is signal amplification?
Elaborate enzyme cascades amplify the cell's response to a signal. Each tier provides more and more of the certain substance. You would only need a couple of epinephrine molecules to bind to the plasma membrane to release hundreds of millions of glucose molecules from glycogen.
What are van der waals interactions?
Electrons are not always evenly distributed; at any instant, they may accumulate by chance in one part of a molecule or another. The results are ever changing regions of positive and negative charge that enable all atoms and molecules to stick to one another.
How do electrons flow through the transport chain?
Electrons from NADH are dropped off at the complex 1, flavoprotein. Electrons are passed to FeS and then to ubiquinone, an electron carrier (hydrophobic). FADH2 electrons come in at complex II at a lower energy. NADH is higher energy.
What are essential elements?
Elements that an organism neds to live a healthy life and reproduce.
What is an open system?
Energy and matter can be transferred between the system and its surroundings. Organisms are open systems.
What is the first law of thermodynamics?
Energy can be transferred and transformed, but t cannot be created or destroyed. Also known as the principle of conservation of energy.
What is the major function of fats?
Energy storage. Because plants aren't mobile, they can deal with having all that polysaccharide, but animals have to move so fat is a good compact reservoir of fuel which they store in adipose cells.
What are protein phosphatases?
Enzymes that can rapidly remove phosphate groups from proteins, dephospho rylation. By doing so, it inactivate the protein kinases and makes them usable again. This turns off the signal transduction pathway when the initial signal is no longer present.
What are restriction enzymes?
Enzymes that cut DNA molecules at a limited number of specific locations.
How can protein processing regulate gene expression?
Eukaryotic polypeptides are often processed and undergo chemical modifications hat make them functional. Regulatory proteins are activated or inactivated by reversible addition of phosphate groups and proteins destined for the surface of animal cells accrue sugars. Cell surface proteins and many others must be transported to target destinations. Regulation can occur at any of the steps involved in edifying or transporting a protein. Most proteins are degraded at some point and a cell commonly attaches ubiquitin to mark a protein for destruction. Proteasomes recognize this and degrade them.
What would happen if ice didn't float?
Eventually all ponds, lakes, and oceans would freeze. This also allows animals to continue living underneath the ice when the top freezes during the winter or in cold places.
What is the second law of thermodynamics?
Every energy transfer or transformation increases the entropy to eh universe. There is an unstoppable trend toward randomization of the universe as a whole.
What wavelengths do chloroplasts absorb?
Everything but yellow/green. Which is why they appear yellow/green.
What are the two types of reactions in metabolism?
Exergonic and endergonic reactions.
What are variables?
Factor that vary in an experiment.
What are the most biologically important lipids?
Fats, phospholipids, and steroids.
How does platelet derived growth factor help division in fibroblasts, a type of connective tissue cell?
Fibroblasts have PDGF receptors on their llama membranes. The binding of PDGF molecules to these receptors triggers a signal transduction pathway that allows the cells to pass the G1 checkpoint and divide. PDGF stimulates fibroblast division not only in the artificial conditions of cell culture, but also in an animal's body. When an injury occurs, platelets release PDGF in the vicinity. The proliferation of fibroblasts heals the wound.
What components make up a prokaryotic cell?
Fimbrae, nucleoid, ribosomes, plasma membrane, cell wall, capsule, flagella.
What is the pathway to colorectal cancer?
First the loss of tumor suppressor gene APC must happen. A small benign growth or polyp appears and the ras oncogene is activated. There is a loss of tumor suppressor gene SMAD4 and then a loss of tumor suppressor gene p53. Additional mutations lead to a malignant tumor or carcinoma.
What are the two types of structural domains commonly found in a large number of activator proteins?
First, DNA binding domain (a part of the protein's three dimensional structure that binds to dNA). Second, an activation domains that bind other regulatory proteins or components of the transcription machinery, facilitating a series of protein protein interactions that result in enhanced transcription of a gene.
What properties of RNA enable them to function as enzymes?
First, RNA is single stranded which means that a region of RNA may base pair which gives the molecule a specific three dimensional structure. Second, some of the bases in RNA contain functional groups that can participate in catalysis. Third, the ability of RNA to hydrogen bond with other nucleic acid molecules adds specificity to its catalytic activity.
What are the two levels of metabolic control?
First, cells can adjust the activity of enzymes already present. Second, cells can adjust the production level of certain enzymes. (regulate expression of genes coding these enzymes)
Why haven't all bacteria been wiped out by lytic phages?
First, natural selection favors bacterial mutants without surface proteins that can be recognized by viruses. Second, when phage DNA does enter a bacterium, the DA is identified as firegn and cut up by restriction enzymes
What three processes contribute to the emergence of viral diseases?
First, the mutation of existing viruses. This is because viral RNA polymerases do not proofread. Second, dissemination of a viral disease from a small isolated human population. International travel, blood transfusions, sex, and abuse of drugs helps this. Third, zoonoses.
What organelles does an animal cell have?
Flagellum Centrosome Cytoskeleton (microfilaments, intermediate filaments, microtubules) Microvilli Peroxisome Mitochondrion Lysosome Golgi Apparatus Ribosomes Plasma membrane Nucleus (Chromatin, Nucleolus, Nuclear Envelope)
What is the shape of two carbon atoms joined by a double bond and all atoms attached to those on the same plane?
Flat molecule. (Ethene)
What are the functions of rough ER?
Folding proteins and adding carbohydrates Shielding proteins from the cytosol Also a membrane factory for the cell.
What are the different types of vacuoles?
Food vacuoles - formed by phagocytosis and are in association with lysosomes. Contractile vacuoles - pump excess water out of a cell, maintaining a suitable concentration of ions and molecules in the cell. Small vacuoles - in plants these can hold organic compounds, toxic compounds, pigments, etc. Central vacuole - found in mature plant cells and develops by small vacuoles. The solution inside is called cell sap and is the cell's main repository of inorganic ions, including potassium and chloride. The cell grows larger as it retains water.
What are chloroplasts?
Found in plants and algae, the sites of photosynthesis. This process in chloroplasts converts solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds such as sugars from carbon dioxide and water.
How many levels of order are there for protein structure?
Four levels of order. Primary Secondary Tertiary Quaternary
What are the two different types of ribosomes?
Free ribosomes which are suspended in the cytosol and bound ribosomes which are attached to the outside of the endoplasmic reticulum or nuclear envelope. They are identical and can switch roles but make different proteins. Bound ribosomes make secretive proteins and free ribosomes make proteins that work in the cell.
What is a proteome?
The entire set of proteins expressed by a given cell or group of cells.
What is the life cycle of a human?
Gametes are the only haploid cells. Meiosis occurs in germ cells during the production of gametes, which undergo no further cell division prior to fertilization. After this, the diploid zygote divides by mitosis, producing a multicellular organism that is diploid.
What are linked genes?
Genes located near each other on the same chromosome tend to be inherited together in genetic crosses; such genes are said to be genetically linked and are called linkd genes.
What are tumor suppressor genes?
Genes whose normal products inhibit cell division. Their encoded proteins help prevent uncontrolled cell growth. They either function in preventing the cell from accumulating mutations or control the adhesion of cells to each other or to the extracellular matrix.
What is DNA?
Genetic material made of nucleic acid.
How does next generation sequencing work?
Genomic DNA is fragmented and fragments of 400-1,000 base pairs are selected. Each fragment is isolated with a bead in a droplet of aqueous solution. The fragment is copies over and over by PC. All the 5' ends of the strand are captured by the bead. Eventually 10^6 identical copies of the same strand are attached to the bead. This is placed into a mall well along with DNA polymerases and primers that can hybridize the 3' end of the single template strand. Each well in the plate has a different DNA fragment to be sequenced. A solution of one of the four nucleotides is added to all the wells and then washed off. This is done for dATP, dTTp, dGTP, and dCTP. in each well, if the next base on the template strand is complementary to the aded nucleotide, the nucleotide is joined to the growing strand, releasing PP, which causes a flash of light. The nucleotide is washed off and a different nucleotide is added. If the nucleotide is not complementary to the next template base, it is not joined to the strand and there is not a flash. The processes of adding and washing off the four nucleotides is repeated until every fragment has complete complementary strand. The pattern of flashes reveals the sequence of the original fragment in each well.
What is the net reactants and products of the system?
Glucose -> 2 pyruvate + 2H2O 4 ATP formed - 2 ATP used -> 2 ATP 2 NAD+ + 4e- + 4H+ -> 2NADH + 2H+
What is the route of electrons in cellular respiration?
Glucose -> NADH-> electron transport chain -> oxygen
.What happens during the energy investment phase?
Glucose begins outside of the mitochondria and 2 tap are used and 2ADP + 2P come out.
How does fermentation work?
Glycolysis happens and then reactions that regenerate NAD+ by transferring electrons from NADH to pyruvate or derivatives of pyruvate.
What happens in alcohol fermentation?
Glycolysis yields 2 ATP and then 2 pyruvate are converted to acetaldehyde which releases carbon dioxide and then reduced by 2 NADH to ethanol. This regenerates the NAD+ to be used again when more glucose comes in. CO2 created gives alcohol the bubbly.
What happens in lactic acid fermentation?
Glycolysis yields 2 ATP and then is converted to 2 pyruvate which are reduced by 2 NADH to make lactate (an ionized form of lactic acid). This happens in human muscle cells when no oxygen is present.
What are the three metabolic stages of cellular respiration?
Glycolysis, Pyruvate Oxidation and the Citric Acid Cycle, Oxidative Phosphorylation: Electron Transport and Chemiosmosis
What is the replicative cycle of an enveloped RNA virus?
Glycoproteins on the viral envelope bind to specific receptor molecules on the host ell, promoting viral uptake by the cell. The capsid and viral genome enter the cell. Digestion of the capsid by cellular enzymes releases the viral genome. The viral genome functions as a template for synthesis of complementary RNA strands by a viral RNA polymerase. New copies of viral genome RNA are made using the complementary RA strands as templates. Complementary RNA strands also function as mRNA, which mistranslated into both capsid proteins in the cytosol and glycoproteins for the viral envelope in the ER and golgi. Vesicles transport envelope glycoproteins to the plasma membrane. A capsid assembles around each viral genome molecule. Each new virus buds from the cell, its envelope studded with viral glycoproteins embedded in membrane derived from the host cell.
Is it more important for a cell to have a greater or smaller surface area to plume ratio?
Greater.
What is the big picture of all of photosynthesis?
H2O goes into the light reactions and O2 comes out. ATP and NADPH are made in the light reactions and cycle through the calvin cycle returning as NADP+ and ADP + P. CO2 enters the calvin cycle and comes out as sugar.
What is an unsaturated fatty acid?
Has one or more double bonds, with one fewer hydrogen atom on each cis double bonded carbon, resulting in a kink of the fat.
What was a typical Mendelian breeding experiment?
He cross pollinated two contrasting, true breeding pea varieties, like purple and white flowered plants.
What was Morgan's first experiment after getting a mutated fly?
He crossed the white eyed male with a red eyed female. The F2 generation had a 3:1 red to white ratio but the only weird thing was that only the males had white eyes. This meant that the trait was located on the X chromosome with no corresponding allele on the Y. There was no wild type allele present to mask the recessive in the males which is how they expressed. A female could only have white eyes if both her X chromosomes had the recessive.
What experiment did Beijerinck conduct to rule out that bacteria caused tobacco mosaic disease?
He extracted sap from tobacco plant with tobacco mosaic disease and then passed the sap through a porcelain filter to trap bacteria. He rubbed the filtered sap on healthy tobacco plants and the healthy plants became infected. This proved that it was not, in fact, bacteria causing the problems but something that they didn't yet know about.
What did Morgan get from crossing flies with gray bodies and normal wings with flies with black body and vestigial wings?
He found tat he was much more likely to get the two parental types rather than the mixing of genes. He concluded that body color and wing size must be close together on the chromosome and are therefore inherited together in specific combinations.
What was the conclusion of the experiment?
He identified a variety of organic molecules that are common in organisms including simple compounds like formaldehyde CH2O and hydrogen cyanide HCN. This gave proof that organic molecules may have been synthesized abiotically on early Earth.
What is phosphorylation?
He light reactions generate ATP, using chemiosmosis to power the addition of a phosphate group to ADP.
How did Mendel's dihybrid cross lead to his law of independent assortment?
He mixed F1 plants of genotype YyRr which exhibited both dominant phenotypes. If the law of dependent assortment was correct, then the F1 hybrids would sort their two gametes' traits together and get YR and yr only. The other independent assortment hypothesis was that the two pairs of alleles segregated independently of each other. Therefore, YR, Yr, yR, and yr would be the equal classes of gametes. There would be 16 types of crosses with a 9:3:3:1 ratio. Mendel tested this cross and he found the second hypothesis to be correct.
How did Mendel cross breed flowers?
He removed the stamens from the purple flower. Transferred sperm bearing pollen from the stamens of the white flower to egg bearing carpel of the purple flower. He waited for pollinated carpel to mature into a pod and then planted the seeds.
What experiments did Griffith do?
He studied two strains of the bacterium that causes pneumonia. He took living S cells which killed the mice. He took living R cells (nonpathogenic) which didn't kill the mice. He took heat killed S cells which didn't kill the mice. He took heat killed S cells and living R cells and mixed them which killed the mice. This meant that the living R bacteria had been transformed into pathogenic S bacteria by an unknown, heritable substance from the dead S cells that enabled the R ells to make capsules
What is isotonic?
If a cell without a cell wall, such as an animal cell, is immersed in an environment that is isotonic to the cell, there will be no net movement of water across the plasma membrane.
Why does high specific heat come from hydrogen bonding?
Heat must be absorbed in order to break hydrogen bonds; by the same token, heat is released when hydrogen bonds form. A calorie of heat causes a relatively small change in the temperature of water because much of the heat is used to disrupt hydrogen bonds before the water molecules can begin moving faster.
How can localized tumors be treated?
High energy radiation. Chemotherapy.
What is the histone level of packing??
Histones are responsible for the first level of DNA packing. Each is small and are mostly positively charged so that they bind tightly to the negatively charged DNA. Most common types are H2A, H2B, H3, H4. H1 is also available.
What is the mating, or crossing, of two true breeding varieties called?
Hybridization.
What are carotenoids?
Hydrocarbons that are various shades of yellow and orange because they absorb violet and blue green light. They are mainly for photo protection because they absorb and dissipate excessive light energy that would otherwise damage chlorophyll or interact with oxygen, forming reactive oxidative molecules that are dangerous to the cell.
What is the simplest atom?
Hydrogen, which has no neutrons. It is a single proton with a single electron.
What are most hydrocarbons considered to be?
Hydrophobic, they don't mix with water.
What are the seven chemical groups most important in biological processes?
Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl.
What is the happiest state for plant and animal cells?
Hypotonic for plant, isotonic for animal.
What is a duplication?
If a deleted fragment becomes attached as an extra segment to a sister chromatid. Or a detached fragment could attach to a non sister chromatid of a homologous chromosome.
What is metastasis?
If a few tumor cells separate from the original tumor, enter the blood vessels and lymph vessels, travel to other parts of the body, and proliferate there and form a new tumor.
What is monosomic?
If a gamete has no copy of a particular chromosome and has 2n-1 diploid cell.
How do X linked genes affect people differently?
If an X linked trait is due to a recessive allele, a female will express the phenotype only if she is homozygous for that allele. Because males have only one locus, they are homozygous for such cases. Any male receiving the recessive allele from his mother will express the trait. That's why more males than females have X linked recessive disorders.
What is trisomic?
If an extra chromosome is present in a cell so that it is diploid 2n+1.
What is polyploidy?
If an organism has more than two complete chromosome sets in all somatic cells.
What is aneuploidy?
If either of the aberrant gametes unites with a normal one at fertilization, the zygote will also have an abnormal number of a particular chromosome.
What is a benign tumor?
If the abnormal cells remain at the original site and have too few genetic and cellular changes to survive at another site.
What is denaturation of a protein?
If the pH, salt concentration, temperature, or other aspects of its environment are alter,d the weak chemical bonds and interactions within a protein may be destroyed, causing the protein to unravel and lose its native shape. It is then biologically inactive.
How can ATP be used in energy coupling?
If the ∆G of an endergonic reaction is less than the amount of energy released by ATP hydrolysis, then the two reactions can be coupled so that the coupled reactions are exergonic. This usually involves phosphorylation, the transfer of a phosphate group from ATP to some other molecule, such as the reactant. The recipient molecule with the phosphate group covalently bonded to it is then called a phosphorylated intermediate.
What is a saturated fatty acid?
If there are no double bonds between argon atoms composing a chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton.
What is the difference between miRNAs and siRNAs?
It is based on subtle differences in the structure of their precursors, which in both cases are RNA molecules that are mostly double stranded.
What is a non polar covalent bond?
In a covalent bond between two atoms of the same element, the electrons are shared equally because the two atoms have the same electronegativity.
What is the biggest difference with transcription and translation between prokaryotes and eukaryotes?
In a prokaryote, they sort of happen simultaneously because there is no nucleus. In eukaryotes, transcription and RNA processing happen in the nucleus and then translation begins outside.
How does DNA cloning work?
In addition to their bacterial chromosome, e. coli and many other bacteria also have plasmids, small, circular DNA molecules that are replicated separately. Researchers first obtain a plasmid and insert DNA from another source into it. The resulting plasmid is now a recombinant DNA molecule, a molecule containing DNA from two different sources, very often different species. The plasmid is then returned to a bacterial cell, producing a recombinant bacterium. This cell reproduces through repeated cel divisions to form a clone of cells, a population of genetically identical cell.s
What are centrosomes?
In animal cells, microtubules grow out of centrosomes, a region that is often located near the nucleus.
How does termination of transcription work?
In bacteria transcription proceeds through a terminator sequence in the DNA. This functions as a termination signal, causing the polymerase to detach from the DNA and release the transcript which requires no further modification. In eukaryotes, RNA polymerase II transcribes a sequence on the DNA called the polyadenylation signal sequence AAUAAA in the pre mrRNA. When this appears, it is immediately bound by certain proteins in the nucleus. Then downstream from the sequence, these proteins cut it free from the polymerase releasing there mRNA.
What is a terminator?
In bacteria, the sequence that signals the end of transcription.
How can the ras protein cause cancer?
In the normal pathway, a growth factor binds to a receptor tyrosine kinase and stimulates a G protein (Ras) to create an intracellular phosphorylation cascade. This then activates the transcription factor which stimulates a protein that causes cells to divide. In the mutant pathway, the Ras G protein is stimulated without phosphorylation via the tyrosine kinase and therefore continues to add to the phosphorylation cascade without needing the growth factor, leading to increased cell division and over expression.
Where else does DNA exist?
In the nucleus, small circular DNA molecules may exist in the mitochondria or chloroplasts called extranuclear genes or cytoplasmic genes.
What are transcription factors?
In eukaryotes, these mediate the binding of RNA polymerase and the initiation of transcription.
Because this technique allows us to see the mRNA in place in the intact organism, what is this technique called?
In situ hybridization.
Where does most photosynthesis happen in plants?
In the leaves
What is deductive reasoning?
Involves logic that flows in the opposite direction, from the general to the specific.
What is mismatch repair?
In this, other enzymes remove and replace incorrectly paired nucleotides that have resulted from replication errors. The segment is cut by nuclease and the resulting gap is then filled in with nucleotides, using the undamaged strand as a template.
How is cotransport medically relevant?
In treating dysentery. Normally sodium in waste is reabsorbed maintaining constant levels in the body but diarrhea gets rid of it so rapidly that that's not possible. To treat this, patents are given something to drink containing high levels of salt and glucose. The solutes are tank up by the sodium glucose cotransporters on the surface of intestine cells and passé through the cells into the blood.
What are dihybrids?
Individuals heterozygous for two characters being followed in a cross YyRr
What are prions?
Infectious proteins that appear to cause a number of degenerative brain diseases in various animal species. Mostly they are a misfiled form of a protein normally present in brain cells. When the prion gets into the cell, it converts the normal protein molecules to the misfiled prion versions. These aggregate into a complex that can convert other normal proteins to prions. This interferes with normal cellular function and causes diseases symptoms.
What is epigenetic inheritance?
Inheritance of traits transmitted by mechanisms not involving the nucleotide sequence itself.
What is the basic overview of transcription?
Initiation: After RNA polymerase binds to the promoter, the DNA strands unwind, and the polymerase initiates RNA synthesis at the start point on the template strand. Elongation: The polymerase moves downstream, unwinding the DNA and elongating the RNA transcript 5'-3'. They then reform a double helix. Termination: Eventually, the RNA transcript is released, and the polymerase detaches from the DNA.
What are the other second messengers involved in the Ca+ pathway and how do they work?
Inositol triphosphate (IP3) and Diacylglycerol (DAG). A signal molecule binds to a receptor leading to activation of phospholipase C. This cleaves a plasma membrane phosphoolipid called PIP2 into DAG and IP3. DAG functions as a second messenger. IP3 diffuses through the cytosol and binds to gated calcium channel in the ER, causing it to open. Ions flow out of the ER, raising the Ca2+ level in the cytosol. The ions activate the next protein in another signaling pathway.
What is a provirus?
Integrated DNA in a chromosome that never leaves the host cell's genome, remaining a permanent resident of the cell.
What is the 30nm fiber level of packing?
Interactions between histone tails of one nucleosome and the linker DNA cause association. H1 is finally involved and the interactions cause the fiber to coil or fold, becoming a chromatin fiber of 30nm.
What are intermediate called, what are they, what are they made of, and what do they do
Intermediate filmants Fibrous proteins coiled into cables Made of one of several different proteins (such as keratins) Maintains cell shape; anchorage of nucleus and certain other organelles; formed the nuclear lamina.
What are enantiomers?
Isomers that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon.
What exactly does a linkage map portray and not portray?
It DOES portray the order of genes along a chromosome, but DOES NOT accurately portray the precise locations of those genes.
What is the basic concept of the electron transport chain?
It accepts electrons from NADH from the breakdown products of the first stages and passes them from one molecule to another. A the end of the chain, they are combined with O an H+ to form water.
What does cohesion due to hydrogen bonding allow water to do?
It aides in the transport of water and dissolved nutrients against gravity in plants. Water from the roots reaches the leaves through a network of water conducting cells. As water evaporates from a leaf, hydrogen bonds cause water molecules leaving the veins to tug on molecules farther down, and the upward pull is transmitted through the water conducting cells all the way to the roots.
What is histone acetylation?
It appears to promote transcription by opening up the chromatin structure.
How does the process of cell division work in e. coli?
It begins when the DNA of the bacterial chromosome begins to replicate at the origin of replication, producing two origins. One moves toward the end of the cell, which elongates. The plasma membrane pinches inward, creating two cells.
What is topoisomerase?
It breaks swivels, and rejoins the parental DNA ahead of the replication fork, relieving the strain caused by unwinding.
What is an electron transport chain?
It consists of a number of molecules, mostly proteins, built into the inner membrane of the mitochondria of eukaryotic cells. Electrons removed from glucose are shuttled by NADH to the higher energy end of the chain, at the lower energy end, O2 captures these electrons along with hydrogen nuclei H+ forming water.
What is a eukaryotic cell?
It contains membrane enclosed organelles. (Nuclei, Golgi, ER, etc.)
What is ATP?
It contains the sugar ribose, with the nitrogenous base adenine, and a chain of three phosphate groups bonded to it.
If sexual reproduction is more energy expensive than asexual, why do we do it?
It generates genetic diversity which keeps species alive.
How is the 3' end of the pre mRNA molecule modified?
It gets a poly A tail which is a bunch more adenines added on.
How can a cow digest cellulose?
It harbors protists and prokaryotes in its gut to digest the cellulose.
What is a fatty acid?
It has a long carbon skeleton, usually 16 to 18 canon atoms in length. The carbon at one end of the skeleton is a part of a carboxyl group, the functional group that gives these molecules the name fatty acid.
What is an electron?
It has one unit of negative charge.
What is a proton?
It has one unit of positive charge.
What are the effects of high heat of vaporization?
It helps moderate Earth's climate. AA lot of solar heat absorbed by seas is consumed during the evaporation of surface water. As moist air goes pole ward, it release heat as it condenses and forms rain.
How is evaporative cooling beneficial?
It helps the temperature in lakes and ponds and provides something that keeps terrestrial animals from overheating. This is what causes sweating.
How is RNA different than DNA?
It is chemically similar except that it contains ribose instead of deoxyribose and has the nitrogenous base uracil rather than thymine. An RNA molecule is usually a single strand.
What is a neutron?
It is electrically neutral.
How does aldosterone move through the system?
It is made in the adrenal gland above the kidneys. It then moves through the circulatory system to all the cells, but only the kidney cells respond. It passes through the membrane and binds to a receptor protein in the cytoplasm. The hormone receptor complex enters the nucleus an binds to specific genes. The bound protein acts as a transcription factor, starting transcription of the gene into mRNA. This is translated into a protein that controls water and sodium flow in kidney cells, affecting blood volume.
What is the structure of a ribosome?
It is made up of potions and ribosomal RNAs. It has a large and small subunit that are made in the nucleolus. The subunits come together when attached to an mRNA molecule. The A site holds the tRNA carrying the next amino ace that will be added to the chain. The P site holds the tRNA carrying the growing polypeptide chain. The E site is where discharged tRNAs leave the ribosome. It holds the tRNA and mRNA in close proximity and positions the new amino acid so that it can be added to the carboxyl end of the growing polypeptide.
What is a fat?
It is not a polymer but it is a large molecule assembled from smaller molecules by dehydration reactions. It is constructed from two kinds of smaller molecules: glycerol and fatty acids.
Why is glycolysis seen everywhere?
It is seen throughout evolution as the old way to make ATP without oxygen. Because cyanobacteria didn't start making oxygen until like 2.7 billion years ago, organisms had to make ATP without it.
What is a phospholipid?
It is similar to a fat molecule but has only two fatty acids attached to glycerol rather than three. The third hydroxyl group of glycerol is joined to a phosphate group, which has a negative electrical charge in the cell. Typically, an additional small charged or polar molecule is also linked to the phosphate group. Choline for example.
What is an inducible operon?
It is usually off but can be stimulated or induced she a specific small molecule interacts with a regulatory protein. The best example is the lac operon.
What role does cholesterol play in membrane fluidity?
It is wedged between phospholipids. At high temperatures, it makes the membrane less fur by restraining phospholipid movement. But because it also hinders the close packing of phospholipids, lowers the temperature required for the membrane to solidify. "Fluidity buffer" for the membrane.
What is a prokaryotic cell?
It lacks a nucleus or other membrane enclosed organelles and is generally smaller than a eukaryotic cell.
How does Paramecium Caudatum live?
It lives in pond water, which is hypotonic to the cell. It has a plasma membrane that is less permeable to water than the membranes of most other cells. It also has a contractile vacuole which ups out water.
How does the active site provide a healthy environment for the reaction?
It may provide a microenvironment that is more conducive to a particular type of reaction than the solution itself would be without the enzyme. If the active site has amino acids with acidic R groups, the site may be a place of low pH in a neutral cell. This would help H+ transfer to the substrate.
How does the active site help lower the activation energy?
It may stretch the molecules toward their transition state form, stressing and bending critical chemical bonds that must be broken during the reaction. Activation energy is proportional to the difficulty of breaking the bonds, so doing this helps approach the transition state and reduces mount of free energy needed to be absorbed.
What does the word spontaneous mean and not mean?
It means that a process will occur without requiring an input of energy, not that it will happen fast.
How is the 5' end of the pre mRNA molecule modified?
It receives a 5' cap, a modified form of guanine.
When does the membrane change fluidity?
It remains fluid as temperature decreases until the phospholipids settle closely packed and the membrane solidifies. It only remains fluid at a lower temperature if rich in phospholipids with unsaturated hydrocarbon tails. As temperature rises, they move farther apart and it becomes more fluid.
How does a cell divide?
It replicates its DNA, allocates the two copies to opposite ends of the cell, and only then splits into daughter cells.
What is the law of segregation?
It states that the two alleles for a heritable character segregate during gamete formation and end up in different games. So an egg or sperm gets one of the two alleles that are present in the somatic cells of the parent making the gamete.
What exactly does epinephrine do in the body?
It stimulates the breakdown of glycogen within liver cells. Glycogen breakdown releases glucose 1 phosphate which is converted to glucose 6 phosphate. The liver and muscle cells can use this in glycolysis or the compound can be stripped of phosphate and released into the cell as glucose to fuel the body. Therefore, this shows that epinephrine stimulates the mobilization of fuel reserves which can be used by the animal to defend itself or run away. (fight or flight)
What do two opposite headed arrows indicate in a reaction?
That it is reversible.
What experiment was done to prove the evolution of enzymes?
It was tested whether the function of ß-galactosidase would change over time in populations of e. coli. This breaks down lactose into glucose and galactose. The researchers introduced random mutations in e. coli and then tested the bacteria for their ability to break down a different disaccharide with fucose in the place of galactose. At the end, the "evolved" enzyme bound the new substrate much faster and stronger than the original enzyme.
Which would gain more from increasing CO2, a C3 plant or a C4 plant?
It would benefit C3 plant shy lowering the amount of photorespiration that occurs. However, rising CO2 means higher temperatures which would only affect C3 plants.
Why is P680 the strongest biological oxidizing agent?
Its electron hole must be filled. This helps the transfer of electrons from the split water molecule.
What are sister chromatids?
Joined copies of the original chromosome.
Thermal energy?
Kinetic energy associated with the random movement of atoms or molecules; this can transfer from one object to another through heat.
What are scaffolding proteins and how do they regulate signal transduction pathways?
Large relay proteins to which several other relay proteins are simultaneously attached.
What are vacuoles?
Large vesicles derived from the endoplasmic reticulum and golgi apparatus.
What are purines?
Larger, with a six membered ring fused to a five membered ring. Adenine and Guanine.
What are the different variations in carbon skeleton?
Length - carbon skeletons vary in length Branching - skeletons may be branched or unbranched Double bond position - The skeleton may have double bonds, which can vary in location Presence of rings - some carbon skeletons are arrange din rings. In the abbreviated structural formula for each compound, each corner represents a carbon and its attached hydrogens.
What is euchromatin?
Less compacted, more dispersed.
What is NADP+?
Light absorbed by chlorophyll drives a transfer of the electors and hydrogen ions from water to this acceptor.
What type of capsid does a bacteriophage T4 have?
Like the other T even phages, has a complex capsid consisting of an icosahedral head an a tail apparatus.
What are steroids?
Lipids characterized by a carbon skeleton consisting of four fused rings.
Which is denser, liquid water or solid water?
Liquid water, so basically ice floats.
What are polysaccharides?
Macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages.
What are quantitative characters?
Many characters, such as human skin color and height, vary in the population in gradations along a continuum.
What is alternative RNA splicing?
Many genes are known to give rise to two or more different polypeptides, depending on which segments are treated as eons during RNA processing
What is an electron transport chain made of?
Many proteins and prosthetic groups, non protein components essential for the catalytic functions of certain enzymes.
What are cytoplasmic determinants?
Maternal substances in the egg that influence the course of early development. After fertilization, early mitotic divisions distribute the zygote's cytoplasm into separate cells. The nuclei of these cels may thus be exposed to different cytoplasmic determinants, depending on which portions of the zygotic cytoplasm a cell received.
What is the fungi and protist life cycle?
Meiosis of the zygote creates diploids which go through mitosis to make a haploid unicellular or multicellular organism. This goes through mitosis to make gametes which are fertilized to form a unicellular zygote. This again goes through meiosis.
What are macromolecules?
Members of the three class of large molecules: carbohydrates, proteins, and nucleic acids.
How do proteins aid with intercellular joining?
Membrane proteins can hook together in various kinds of junctions like tight and gap.
What are viral envelopes?
Membranous envelope that surrounds the capsids of influenza viruses which are derived from the membranes of the host cell and contain host cell phospholipids and membrane proteins.
If the two alleles at a locus differ, then one, the dominant allele, determines the organism's appearance; the other, the recessive allele, has no noticeable effect on the organism's appearance. What does this mean?
Mendel's F1 plants had purple flower because the allele for that trait is dominant and the allele for white flowers is recessive.
How do proteins aid in attachment to the cytoskeleton?
Microfilaments or other elements may be noncovalently bound to membrane proteins, a function that helps maintain cell shape and stabilizes the location of certain membrane pro tines.
What are flagella and cilia and how are they different?
Microtubule containing extensions that project from some cells. Motile cilia occur in large numbers on the cell surface. Flagella are limited to one or a few per cell. They differ in beating pattern. Flagella have an undulating motion like a fish. Cilia work like oars.
How are X chromosomes inactivated?
Modification of the DNA and proteins bound to it, called histones. This includes attachment of methyl groups to DNA nucleotides. A particular region of each X chromosome has genes involved in the activation. Two regions, one on each associate with each other then one of the genes, XIST, becomes active on the chromosome that is the barr body. Copies of RNA product of this gene attach to the X chromosome on which they are made, covering it.
What are domains in proteins?
Modular architecture consisting of discrete structural and functional regions.
What is an emergent property of the carbon skeleton?
Molecule diversity arising from variation of carbon skeletons.
What are many substances measured as?
Moles.
What is dehydration synthesis?
Monomers are connected by a reaction in which two molecules are covalently bonded to each other with the loss of a ager molecule.
What are the repeating units that serve as the building blocks of a polymer called?
Monomers.
What are the simplest carbohydrates?
Monosaccharides, or simple sugars.
What happens when a female is X?
Monosomy X, known as Turner syndrome is the only viable monosomy in humans. They are phenotypically female, but are sterile because their sex organs do not mature. They are provided with estrogen replacement therapy and may develop secondary sex characteristics. Normal intelligence.
How does basic allosteric regulation work?
Most enzymes oscillate between tow different shapes, one active and one inactive. The binding of an activator to a regulatory site, often located where the subunits join, stabilizes the shape of the functional molecule. The binding of an inhibitor stabilizes the inactive form of the enzyme.
What is induction?
Most influential are the signals impinging on an embryonic cell from other embryonic cells in the vicinity, including contact with cell surface molecules on neighboring cells and the binding of growth factors secreted by them. Such signals cause changes in the target cells, called induction.
What is genomics?
The process of studying while sets of genes (or other DNA) in one or more species.
What are C3 plants?
Most plants that use initial fixation of carbon via rubisco and adds CO2 to ribulose biphosphate. They are called C3 plants because the first organic product of carbon fixation is a three carbon compound.
What does cell motility generally require?
Motor proteins.
What are the mechanisms in play when the microtubules shorten?
Motorprotein mechanisms. There is the pacman method, where the motor proteins walk along the microtubules towards the centrosomes, depolymerizing the microtubules as they go along. At the same time, the chromosome are reeled in by motor proteins at the spindle poles.
What are embryonic lethals?
Mutations with phenotypes causing death at the embryonic or larval stage.
In the equation Na + Cl -> Na+ + Cl-, what is oxidized, reduced and what are the agents of each?
Na becomes oxidized (loses electron) Cl becomes reduced (gains electron) Na is reducing agent (donates the electron) Cl is the oxidizing agent (takes the electron)
What are pyrimidines?
Nitrogenous bases with one six membered ring of carbon. Cytosine, Thymine, and Uracil.
Can any substance move through any protein?
No, a transport protein is specific for the substance it translocates. Example, a specific carrier for glucose can pass through glucose much faster than it could go through on its own but the transport is so selective that it rejects fructose, a structural isomer of glucose.
Is a polypeptide the same thing as a protein?
No, because it is not yet folded functionally. A functional protein is not just a polypeptide chain, but one or more polypeptides precisely twisted, folded and coiled into a molecule of unique shape.
Do all redox reactions involve the complete transfer of electrons from one substance to another
No, some change degree of electron sharing. If the covalent bonds are shared equally between bonded atoms, they are equally electronegative. When something reacts, and another substance that is more electronegative gets involved, like oxygen, the sharing becomes less centralized and causes partial charges.
Do prokaryotes have membrane bound organelles?
No.
Do all salts have equal numbers of cations and anions?
No. MgCl2 has a 1:2 ratio.
What are photons?
Non tangible objects that each have a fixed quantity of energy that is inversely related to the wavelength of light: the shorter the wavelength, the greater energy of each photon of light.
What are ncRNAs?
Noncoding RNAs
What are exons?
The other regions that are eventually expressed, usually by being translated into amino acids sequences.
What are the easiest molecules to cross the lipid bilayer?
Nonpolar molecules like CO2 and O2 are hydrophobic and can dissolve in the lipid bilayer of the membrane and cross without the aid of membrane proteins.
What are the three types of side chains in amino acids?
Nonpolar; hydrophobic Polar; hydrophilic Electrically charged; hydrophilic
What are cofactors?
Nonprotein helpers that enzymes require for catalytic activity. These may rebound tightly to the enzyme as permanent residents, or bound loosely and reversibly.
What are emergence properties?
Novel properties that emerge at each level of biological organization that are absent from the preceding level.
What happens in telophase II and cytokinesis?
Nuclei form, the chromosomes condense, cytokinesis occurs. There are four daughter cells, each with a haploid set of chromosomes that are all different from each other because of independent assortment and crossing over.
What organelles does a plant cell have?
Nucleus (Nuclear Envelope, Nucleolus, Chromatin) Golgi Apparatus Mitochondrion Peroxisome Plasma Membrane Cell Wall Plasmodesmata Chloroplast Cytoskeleton (Microfilaments, Microtubules) Central Vacuole Ribosomes Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum
What is paracrine signaling?
Numerous cells can simultaneously receive and respond to the molecules of growth factor produced by a single cell in their vicinity.
What was the bicoid experiment?
Nusslein Volhard hypothesized that bicoid normally codes for a morphogen that specifics the head end of the embryo. To begin o test, they used molecular techniques to determine whether the mRNA and protein encoded by this gene were found int he anterior end of the fertilized egg and early embryo of wild type flies. Bicoid mRNA was confined to the anterior end of the unfertilized egg. Later in development, Bicoid protein was seen to be concentrated in cells at the anterior end of the embryo. The location of bicoid mRNA and the diffuse gradient of bicoid protein seen later are consistent with the hypothesis tat bicoid protein is a morphogen specifying formation of head specific structures.
After glycolysis occurs, what needs to be present to move on to pyruvate oxidation?
O2
What are recombinant types or recombinants?
Offspring that have new combinations of traits. Nonparental types.
What is a type of hydrophobic molecule?
Oils and fats.
What is photorespiration?
On hot days, to prevent water from leaving the plant, a C3 plant will close its stomata. There is a declining level of CO2 and the leaf starts using O2 in place of it. The product splits and the two carbon compound leaves the chloroplast. Peroxisomes and mitochondria within the plant cell rearrange and split this compound, releasing CO2. This is called photorespiration because it occurs in light (photo) and consumes O2 while producing CO2 (respiration).
How does Tay Sachs disease prove that dominance/recessiveness depends on the level of phenotype?
On the organismal level, Tay Sachs is recessive because two copies means the child has it. On the biochemical level, the lipid metabolizing enzyme in heterozygotes is medium which is incomplete dominance. At the molecular level, heterozygous individuals produce equal numbers o formal and dysfunctional enzyme molecules so it is codominant.
What is termination of the signal?
Once the signal molecules stop binding with such frequency to the proteins, the number falls below a certain threshold and the transduction pathway stops.
What is a radioactive isotope?
One in which the nucleus decays spontaneously, giving off particles and energy.
What is an aqueous solution
One in which the solute is dissolved in water; water is the solvent.
What happen when chlorophyll and other pigments absorb light?
One of the molecule's electrons is elevated to an orbital where it has more potential energy. This makes the pigment in an excited state. The electron can't stay there so it drops down to the ground state orbital again and releases the excess energy as heat.
What is HIV?
One of the most famous retroviruses that causes AIDS. HIV contains two identical molecules of single stranded RNA and two molecules of reverse transcriptase.
What is an endergonic reaction?
One that absorbs free energy from its surroundings. ∆G is positive. They are non spontaneous.
What is a controlled experiment?
One that is designed to compare an experimental group with a control group.
How does energy flow through an ecosystem?
One way, usually entering as light and exiting as heat.
Of the three subatomic particles discussed, what are directly involved in chemical reactions?
Only electrons.
How does a new DNA strand elongate?
Only in the 5'-3' direction.
What is the difference between Estradiol and Testosterone?
Only their functional groups are different.
Why are transcription factors important?
Only when a transcription initiation complex is formed can transcription begin.
When does a hormone signal work?
Only when it is being given to intact cells. When added to a test tube, no glycogen phosphorylase was created to break down glycogen. This means that epinephrine does not interact directly with the enzyme; intermediate steps must happen. Also, the plasma membrane is necessary for transmission of the signal.
How do the two sugar phosphate backbones run?
Opposite each other, so in an antiparallel direction. One goes 5'-3' other goes 3'-5'
What are the main properties of life?
Order Evolutionary Adaptation Regulation Energy Processing Growth and Development Response to the Environment Reproduction
What are hydrocarbons?
Organic molecules consisting of only carbon and hydrogen. Atoms of hydrogen are attached to the carbon skeleton wherever electrons are available for covalent bonding.
What is feedback regulation?
The output, or product, of a process regulates that very process.
What are consumers?
Organisms such as animals that feed on producers and other consumers.
What are facultative anaerobes?
Organisms, including yeasts and many bacteria, that can ale enough ATP to survive using either fermentation or respiration.
What are the five unifying themes of biology?
Organization Information Energy and Matter Interactions Evolution
What is the reading frame?
Our ability to extra that intended message from a written language depends on reading the symbols in the correct groupings - that is, in the correct reading frame. If the letters are grouped incorrectly by starting at the wrong point, it is gibberish.
What is aerobic respiration?
Oxygen is consumed as a reactant along with the organic fuel.
What four elements make up 96% of living matter?
Oxygen, Carbon, Hydrogen, and Nitrogen.
What is the C4 pathway?
PEP carboxylase in mesophyll cells adds CO2 to PEP, forming the four carbon product oxaloacetate. PEP has a much higher affinity for CO2 than rubisco and no O2 affinity which means that it can fix carbon more efficiently than rubisco when the stomata are partially closed. Then the mesophyll cells export the four carbon products to bundle sheath cells through plasmodesmata. Within these cells, these 4 carbon compounds release CO2, which is made into organic material by rubisco and the calvin cycle. This also regenerates pyruvate which is brought to mesophyll cells and uses ATP to be converted to PEP. These cells carry out cyclic electron flow just to create ATP.
What happens in metaphase I?
Pairs of homologs are now arranged at metaphase plate. Both chromatids of one homolog attached to kinetochore microtubules from one pole. The oner homolog is attached to opposite pole microtubules.
What are the two major populations of proteins in membranes?
Peripheral proteins Integral proteins
What are temperate phages?
Phages capable of using both modes of replicating within a bacterium.
What are the three types of endocytosis?
Phagocytosis (eating) Pinocytosis (drinking) Receptor mediated endocytosis (a form of pino)
What types of linkages form nucleic acids?
Phosphodiester linkages to create a sugar phosphate backbone.
What are the two types of photosystems that make up the light reactions?
Photosystem II (also known as P680 because that's the wavelength that the pigment absorbs) and photo system I (also known as P700 because that's the wavelength that the pigment absorbs)
What are mutagens?
Physical and chemical agents that interact with DNA in ways that cause mutations. X rays, high energy radiation, UV light.
What are plant growth regulators?
Plant hormones that sometimes travel in vessels but more often reach their targets by ovine through cells or by diffusing through the air as a gas.
What are the three (sort of four) kingdoms included in eukarya?
Plantae, Fungi, and Animalia which are distinguished by mode of nutrition. Protists don't really count but are linked in sometimes.
What are true breeding plants?
Plants that had produced only the same variety as the parent plant for many generations.
What are CAM plants (crassulacean acid metabolism)?
Plants that open their stomata during the night and close them during the day. This helps desert plant conserve water but prevents CO2 from entering the leaves. When the stomata are open at night, that's when the CO2 entersand is incorporated.
What are candidates for the original sources of viral genomes?
Plasmids and transposons.
What is hydrolysis?
Polymers are disassembled to monomers by hydrolysis, a process that is essentially the reverse of the dehydration reaction.
What are nucleic acids?
Polymers made of monomers called nucleotides.
What determines whether a ribosome is free in the cytosol or bound to rough ER?
Polypeptide synthesis begins in the cytosol as a free ribosomes translates an mRNA molecule. This goes to completion unless the polypeptides that are destined for the endomembrane system or for secretion are marked by signal peptide. This is recognized as it emerges from the ribosome by a signal recognition particle. This secrets the ribosome to a receptor protein built into the ER membrane.
How does the lagging strand get synthesized?
Primase joins RNA nucleotides into a primer. DNA pol III adds DNA nucleotides to the primer forming okazaki fragment 1. After reaching the next RNA primer to the right, DNA pol III detaches and fragment 2 is primed. Then DNA pol III adds DNA nucleotides detaching when it reaches the fragment 1 primer. DNA pol I replaces the RNA with DNA, adding nucleotides to the 3' end of fragment 2 and earlier fragment 1. DNA ligase forms a bond between the newest DNA and the DNA of fragment 1.
What are the two main forms of cells?
Prokaryotic and Eukaryotic.
What type of cell are bacteria and archaea?
Prokaryotic cells.
What are the phases of meiosis?
Prophase I Metaphase I Anaphase I Telophase I and cytokinesis Prophase II Metaphase II Anaphase II Telophase II and cytokinesis
What are the five stages of mitosis?
Prophase, prometaphase, metaphase, anaphase, and telophase.
What do defensive proteins do?
Protection against disease. Antibodies inactivate and help destroy viruses and bacteria.
What controls rhythmic fluctuations in the abundance and activity of cell cycle?
Protein kinases and cyclins.
What are chaperonins?
Protein molecules that assist in the proper folding of other proteins. An unfolded polypeptide enters the cylinder from one end. Cap attachment causes the cylinder to change shape, creating a hydrophilic environment for polypeptide folding. The cap comes off, and the properly folded protein is released.
What are single strand binding proteins?
Proteins that bind to and stabilize the unwound parental strands, keeping them from repairing.
What are carrier proteins?
Proteins that hold onto their passengers and change shape in a way that shuttles them across the membrane.
How does DNA replication begin?
Proteins that initiate DNA replication recognizes this sequence and attach to the DNA, separating the two strands and opening up a replication "bubble." Then replication proceeds in both directions until the entire molecule is copied.
What are glycoproteins?
Proteins with carbohydrates covalently bonded to them.
What are the two types of nitrogenous bases?
Purines and pyrimidines.
What is the basic concept of pyruvate oxidation?
Pyruvate enters the mitochondrion and is oxidized to a compound called acetyl CoA.
What are ribozymes?
RNA molecules that function s enzymes. In tetrahymena, self splicing occurs int eh production of ribosomal RNA.
How do ncRNAs act to remodel chromatin structure?
RNA transcripts are produced from centromeric DNA. Each RNA transcript is used as a template by a yeast enzyme that synthesizes the complementary strand forming double stranded RNA. The double stranded RNA is processed into short single stranded siRNAs that associate with proteins, forming the complexes. The complexes bind the RNA transcripts being produced from the centromeric DNA and are tethered to the centormere region. Proteins in the complexes recruit enzymes that chemically modify the histones within the chromatin and initiate condensation. This leads to the formation of heterochromatin at the centromere.
How are protein kinases different than RTKs?
RTKs are specific protein kinases that phosphorylate tyrosine's. Most cytoplasmic protein kinases act on proteins different than themselves. They act usually on serene or threonine.
What are redox reactions?
Reactions where there is a transfer of one or more electrons from one reactant to another.
What are the three steps of cell signaling?
Reception, Transduction, Response
What are intracellular receptor proteins?
Receptor proteins that are found in the cytoplasm or inside the nucleus. Signaling molecules have to be small and hydrophobic in order to penetrate the membrane to get to the protein. Examples: steroid hormones, thyroid hormones, nitric oxide, etc.
What is data?
Recorded observations.
Chemical energy?
Refers to the potential energy available for release in a chemical reaction.
What is proteomics?
Refers to the study of sets of proteins and their properties.
What is an ultrasound?
Reflected sound waves are used to produce animate of the fetus by a simple noninvasive procedure.
What is the secondary structure of a protein?
Regions stabilized by hydrogen bonds between atoms of the polypeptide backbone.
How does alternative RNA splicing provide an opportunity for regulation of gene expression?
Regulatory proteins specific to a cell type control intron exon choices by binding to regulatory sequences within the primary transcript and this changes whether or not segments of DNA are considered introns or exons and are spliced out.
When do repressible and inducible enzymes get used?
Repressible enzymes generally function in anabolic pathways. Inducible enzymes usually function in catholic pathways.
What are gametes?
Reproductive cells that have 23 chromosomes.
What are trace elements?
Required elements by an organism in only minute quantities.
How was the cell cycle control system discovered?
Researchers at the University of Colorado wondered whether a cell's progression through the cell cycle is controlled by cytoplasmic molecules. They selected cultured mammalian cells that were at different phases of the cell cycle and induced them to fuse. The two that were in S and G1 both fused to S phase and DNA was synthesized in both. When an M and G1 were fused, they both went to M.
What do receptor proteins do?
Respond to chemical stimuli. Receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells.
What is cir du chat?
Results from a specific deletion in chromosome 5. They will be severely intellectually disabled, has a small head with unusual facial features, and has a cry that sounds like a cat. individuals usually die in infancy or early childhood.
What is reverse transcriptase polymerase chain reaction to create cDNA?
Reverse transcriptase is added to a test tube containing mRNA isolated from a sample of cells. Reverse transcripts makes the first DNA strand using the mRNA as a template and a short poly-dT as a DNA primer. mRNA is degraded by another enzyme. DNA polymerase synthesizes the second DNA strand, using a primer in the reaction mixture. The result is cDNA, which carries the complete coding sequence of the gene, but no introns.
What are competitive inhibitors?
Reversible inhibitors that resemble the normal substrate molecule and compete for admission into the active site. They reduce the productivity of enzymes by blocking substrates from entering active sites. This inhibition is overcome by increasing the concentration of substrate molecules to get into the sites before inhibitors?
What are vesicles?
Sacs made of membrane.
What is radiometric dating?
Scientists measure the ratio of different isotopes and calculate how many half lives (in years) have passed since an organism as fossilized or a rock was formed. Different elements are used based on the range of half life for the organism.
What is incomplete dominance?
Seen when red snapdragons are crossed with white snapdragons. The F1 hybrids have a phenotype somewhere between those of the two parental varieties. This comes from the flowers of the heterozygotes having less red pigment than the red homozygotes.
What are control elements?
Segmes of noncoding DNA that serve as binding sites for the proteins called transcription factors, which in turn regulate transcription.
What do enzymatic proteins do?
Selective acceleration of chemical reactions. Digestive enzymes catalyze the hydrolysis of bonds in food molecules.
What are autotrophs?
Self feeders that sustain themselves without eating anything derived from other living wings. They produce their organic molecules from CO2 another inorganic raw materials obtained from the environment.
What was the hypothesis for genetic variation in the 1800s?
The blending hypothesis, the idea that genetic material contributed by two parents mixes just like blue and yellow paints to make green.
What is quorum sensing?
Sensing the concentration of signaling molecules allows bacteria to monitor the local density of cells. Quorum sensing allows bacterial populations to coordinate their behaviors in activities that require a given number of cells acting synchronously.
What are the origins of replication?
Short stretches of DNA having a specific sequence of nucleotides where the replication of a chromosome begins.
What is local signaling?
Signaling that happens between two cells that are close together, either through plasmodesmata and gap junctions, or cell cell recognition.
What happens in anaphase I?
Sister chromatid cohesion proteins breakdown. Homologs move toward opposite poles. Sister chromatids are still together.
What are plasmids?
Small circular DNA molecules found in bacteria and in the unicellular eukaryotes called yeasts.
What are second messengers?
Small nonprotein water soluble molecules or ions that are involved in signaling pathways. They can speed through the cell by diffusion.
What are point mutations?
Small scale mutations of one or a few nucleotide pairs.
What are the two different types of ER?
Smooth and Rough ER. Smooth has no ribosomes, rough has ribosomes on the outer surface.
How do proteins aid with cell-cell recognition?
Some glycoproteins serve as identification tags that are specifically recognized by membrane proteins of other cells.
What are enzymes?
Specialized macromolecules that speed up chemical reactions.
What are glyoxysomes?
Specialized peroxisomes that are found in the fat storing tissues of plant seeds. They contain enzymes that initiate the conversion of fatty acids to sugar, which thate emerging seedling uses as a source of energy and carbon until it can produce its own sugar by photosynthesis.
What is in vitro mutagenesis?
Specific mutations are introduced into a cloned gene, and the muted gene is returned to a cell in such a way that it disables the normal cellular copies of the same gene. If the introduced mutates alter or destroy the function of the gene product, the phenotype of the mutant cell may help reveal the function of the missing normal protein.
How can initiation of translation regulate gene expression?
Specific sequences or structures within the UTRs of the 5' or 3' end can prevent the attachment of ribosomes.
What is the difference in glucose in starch v. cellulose?
Starch is made of a glucose and cellulose is made of B glucose. This is based on where the hydroxyl group attaches. a is attached below the 1 carbon and in B, the hydroxyl is attached above 1 carbon. As a result, the enzymes that hydrolyze starch can't hydrolyze cellulose, so it just passes right through humans, simulating the digestive tract to secrete mucus to pass through.
What is RNA interference?
The blocking of gene expression by siRNA and is used in laboratories as a means of disabling specific genes to investigate how they function.
How do plants store sugars for later use in the form of storage polysaccharides?
Starch, a polymer of glucose monomers, as granules within cellular structures known as plastids, which include chloroplasts. These have 1-4 linkages like the glucose units in maltose. The simplest form of starch, amylose, is unbranched. Amylopectin, a more complex starch, is a branched polymer with 1-6 linkages at branch points.
What is the multiplication rule?
States that to determine the probability of two independent events occurring together, you must multiply the probability of one event by the other. The probability of tossing a coin heads up twice in a row is 1/2 x 1/2 = 1/4
What are polyribosomes or polysomes?
Strings of ribosomes that trail along the mRNA.
What are the three types of isomers?
Structural isomers Cis-trans isomers Enantiomers
What are chromosomes?
Structures that carry the genetic information. Each chromosome contains one long DNA molecule associated with many proteins. The complex of DNA and proteins making up chromosomes is called chromatin.
What are pigments?
Substances that absorb visible light. The wavelengths that a pigment absorbs disappears.
What does it mean to be hydrophobic?
Substances that are nonionic and non polar and cannot form hydrogen bonds repel water.
What are morphogens?
Substances that establish an embryo's axes and other features of its form.
What are missense mutations?
Substitutions that change one amino acid. This may have little effect on the protein.
What is the catalytic cycle?
Substrate enters active site. Enzyme changes shape so that the active site induces fit around the substrate. They are held in active site by weak interactions like hydrogen and ionic bonds. Substrates are converted to products. They are released and active site is available for new substrate molecules.
How does molecular control of the cell cycle at the G2 checkpoint work?
Synthesis of cyclin begins in the late S phase and continues through G2. Because cyclin is protected from degradation during this stage, it accumulates. It combines with Cdk, producing MPF. When enough MPF molecules accumulate, the cell passes the G2 checkpoint and begins mitosis. MPF promotes mitosis by phosphorylating various proteins. MPFs activity peaks during metaphase. During anaphase, the cyclin component of MPF is degraded, terminating the M phase. The cell enters G1. During G1, the degradation of cyclin continues and the Cdk component of mPF is recycled.
What are the functions of the smooth ER?
Synthesis of lipids Metabolism of carbohydrates Detoxification of drugs and poisons Storage of calcium ions
What does primase do?
Synthesizes RNA primers, using the parental DNA as a template.
What is nucleotide excision repair?
Teams of enzymes detect and repair damaged DNA, such as thymine dimer caused by ultraviolet radiation, which distorts the DNA molecule. A nuclease enzyme cuts the damaged DNA strand at two points and the damaged section is removed. Repair synthesis by a DNA polymerase fills in the missing nucleotides. DNA ligase seals the free end of the new DNA to the old DNA, making the strand complete.
What are telomeres?
Telomeres are parts of the end of chromosomal DNA molecules that do not contain genes but instead typically consist of multiple repetitions of one short nucleotide sequence. For example, TTAGGG is the human telomeres. They prevent the daughter molecules' ends from activating the cell's systems for monitoring DNA damage. They also act as a buffer zone that provides protection against the organism's genes shortening. When the primer is removed and cannot be replaced by DNA pol I, the telomere is shortened, rather than the actual DNA sequences.
What are the environmental factors important to enzymes?
Temperature and pH
What must a scientific hypothesis be?
Testable.
What is the shape of a carbon atom with four single bonds to the same atoms?
Tetrahedral. (Methane)
What is an atom?
Th esmallest unit of matter that still retains the properties of an element.
A phospholipid is an amphipathic molecule, what does this mean?
That it has both a hydrophilic region and a hydrophobic region.
What is the common misconception about Oxygen in photosynthesis?
That the O2 given off by plants is derived from CO2. Rather, it is actually derived from H2O. The prevailing hypothesis for a long time was that photosynthesis split carbon and then added water to the carbon to make a carbohydrate.
What is the problem presented with activation energy?
That usually the activation energy is high and therefore the reaction, even spontaneous, will not occur without a heat push. The problem is, high temperature denatures proteins and kills cells. Also, heat would speed up all reactions, not just the ones that need it.
What is the looped domains 300 nm fiber level of packing?
The 30 nm fiber forms loops called looped domains attached to a chromosome scaffold composed of proteins, making up the big fiber. This is rich in topoisomerase.
What is the directionality of nucleic acids?
The 5' end has a phosphate group and the 3' end has a hydroxyl group.
How is DNA sequenced?
The DNA is first cut into fragments and then each fragment s sequenced. This is carried out by machines.
What is the promoter?
The DNA sequence where RNA polymerase attaches and initiates transcription.
What are their hybrid offspring referred to as?
The F1 generation.
What is the generation after?
The F2 generation.
What did Mendel observe when he crossed two true breeding plants?
The P generation had two different colors, but if the blending hypothesis was true then the F1 generation would have pale purple flowers but it didn't. They were rather all purple but Mendel knew that the white didn't just go away. The F2 generation had a 3:1 purple to white flower ratio.
What are the true breeding parents referred to as?
The P generation.
What is the lytic cycle?
The T4 phage uses its tail fibers to bind to specific surface proteins on an e. coli cell that act as receptors. The sheath of the tail contracts, injecting the phage DNA into the cell and leaving the empty capsid outside. DNA is hydrolyzed and the phage DNA directs production of phage proteins and copies of the phage genome, using components within the cell. Three separate sets of proteins self assemble to form phage head,s tails, and tail fibers. The phage genome is packaged inside and the capsid as the head forms. The phage directs production of an enzyme that damages the bacterial cell wall, allowing fluid to enter. The cell swells and bursts, releasing 100-200 phage particles.
What are sex chromosomes?
The X and Y chromosomes.
What is the system for grasshopper, cockroach, and insect sex?
The X0 system. There is only one type of sex chromosome, the X. Females are XX; mass have only one sex chromosome X0. Sex of the offspring is determined by whether the sperm cell contains an X chromosome or no sex chromosome.
What is the system for human sex?
The XY system. In mammals, the sex of an offspring depends on whether the sperm cell contains an X chromosome or a Y. XX is female XY is male.
What is the system for birds, fishes and other insects' sex?
The ZW system. The sex chromosomes present in the egg determine the sex of the offspring. The sex chromosomes are designated Z and W. Females are ZW and males are ZZ.
What is tonicity?
The ability of a surrounding solution to cause a cell to gain or lose water. This depends on the concentration of solutes that cannot cross the membrane relative to that inside the cell.
How does the active site help two or more reactants?
The active site provides a template on which these can come together in a proper orientation for a reaction to occur.
What is reduction?
The addition of electrons to another substance.
What is chromatin?
The entire complex of DNA ad proteins that is the building material of chromosomes.
What is the specific heat of a substance?
The amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1 degree C.
What is the process of elongation of the polypeptide chain?
The anticodon of an incoming aminoacyl tRNA base pairs with the complementary mRNA codon in the A site. Hydrolysis of GTP increases the accuracy and efficiency of this step. An rRNA molecule of the large ribosomal subunit catalyzes the formation of a peptide bond between the amino group of the new amino acid in the A site and the carboxyl end of the growing polypeptide in the P site. This remove the polypeptide from the tRNA in the P site and attaches it to the amino acid on the tRNA in the A site. The ribosome translocates the tRNA in the A site to the P site. A the same time, the empty tRNA int he P site is moved to the E site, where it is released. The mRNA moves among with its bound tRNAs, bringing the next codon to be translated into the A site.
What is electronegativity?
The attract of a particular atom for the electrons of a covalent bond.
What happens when someone is infected with cholera?
The bacteria form a biofilm on the lining of the small intestine and produce a toxin that chemically modifies a G protein involved in regulating salt and water secretion. This modified G protein can't hydrolyze GTP to GDP so it stays stuck active and stimulates adenylyl cyclase to make cAMP. This high concentration cause the intestinal cells to make large amounts of salts and water follows by osmosis. An infected person will develop profuse diarrhea and die soon from dehydration.
What does the basal body become in animals?
The basal body of the fertilizing sperm's flagellum enters the egg and becomes a centriole.
What is nucleic acid hybridization?
The base pairing of one strand of a nucleic acid to the complementary sequence on a strand from another nucleic acid molecule.
What is cyclic AMP?
The binding of epinephrine to the plasma membrane of a liver cell elevates the cytosolic concentration o this compound. It is converted from ATP by adenylyl cyclase and then is a second messenger to protein kinase A, a serene or threonine protein kinase.
What are the levels of biological organization?
The biosphere Ecosystems Communities Populations Organisms Organs and Organ systems Tissues Cells Organelles Molecules
What is taxonomy?
The branch of biology that names and classifies species.
What is the basic concept of the citric acid cycle?
The breakdown of glucose to carbon dioxide is completed.
What does "energy stored in bonds" actually mean?
The breaking of bonds does not release energy. It actually requires energy. The phrase just means the potential energy that can be released when new bonds are formed after the original bonds break, as long as the products are of lower free energy than the reactants.
What is carbon fixation?
The calvin cycle incorporates each CO2 molecule by attaching it to a five carbon sugar named RuBP. Rubisco catalyzes this (most abundant chloroplast protein). This splits in two, making 3 phosphoglycerate (2 molecules).
Where do the processes take place?
The calvin cycle occurs in the stroma. The light reactions take place in the membrane of the thylakoids.
What is energy defined as?
The capacity to cause change.
What is energy?
The capacity to cause change.
Why doesn't glucose immediately come out of the calvin cycle?
The carbohydrate produced directly from the calvin cycle is actually a three carbon sugar called glyceraldehyde 3 phosphate. For the net synthesis of one molecule of G3P, the cycle must take place three times with three molecules of CO2. Therefore, six turns must be completed of the calvin cycle in order to make a full molecule of glucose.
What is hypotonic?
The cell is immersed in a solution with less non penetrating solutes than inside the cell. Water will enter the cell faster than it leaves, which will cause it to swell and lyse.
What is hypertonic?
The cell is immersed in a solution with more non penetrating solutes than inside the cell. The cell will lose water, shrivel, and probably die.
What happens when a plant cell is immersed in a hypotonic solution?
The cell wall helps maintain the cell's water balance.
What is the smallest unit of organization that can perform all activities required for life?
The cell.
How do animals get around these problems?
The cells of most terrestrial animals are bathed in an extracellular fluid that is isotonic to the cells.
What is the atomic nucleus?
The center of an atom.
What happens during metaphase?
The centrosomes are now at opposite poles of the cell and the chromosomes have all arrived at the metaphase plate. For each chromosome, the kinetochores of the sister chromatics are attached to the kinetochore microtubules coming from opposite poles.
What are hormones?
The chemicals used in long distance signaling.
What is photosynthesis?
The chloroplasts in plants and other photosynthetic organisms capture light energy that has traveled 150 million kilometers from the sun and convert it to chemical energy that is stored in sugar and other organic molecules.
What happens during prophase?
The chromatin fibers become tightly coiled, condensing into chromosomes. The nucleoli disappear and the duplicated chromosome appears as two identical sister chromatids joined at the centromeres and by cohesions. The mitotic spindle begins to form. It is made of centrosomes and microtubules that extend from them called asters. They move away from each other, propelled by the lengthening microtubules between them.
How do chromosomes duplicate and get split up?
The chromosome is a long thin chromatin fiber containing one DNA molecule and associated proteins. When getting ready to divide, it condenses into a chromosome with a centromere in the middle. Once duplicated, this consists of two sister chromatids connected along their lengths by sister chromatid cohesions. Each chromatid contains a copy of the DNA molecule. Molecular and mechanical processes separate the sister chromatids into two chromosomes and distribute them to two daughter cells.
What is a genome?
The entire library of genetic instructions that an organism inherits.
What happens in metaphase II?
The chromosomes are at the metaphase plate. The two sister chromatids are not identical because of crossing over in meiosis I. The kinetochores are attached to microtubules from opposite poles.
How do dinoflagellates reproduce?
The chromosomes attach to the nuclear envelope, which remains intact. Microtubules apes through the nucleus inside cytoplasmic tunnels, reinforcing the spatial orientation of the nucleus, which then divide in a process like bacterial binary fission.
What are the two sides of the golgi referred to as?
The cis and trans face. The cis is the receiving side and located near the ER. The trans face gives rise to vesicles that pinch off and travel to other sites.
What is adhesion?
The clinging of one substance to another.
In a phylogenic tree, what does each branch point represent?
The common ancestor of the evolutionary lineages originating there and their descendants.
How does the fact that a living cell is not in equilibrium keep us alive?
The constant flow of materials in and out of the cell keep stye metabolic pathways from ever reaching equilibrium, and the cell continues to do work throughout its life. As long as the cell is working, it won't die. That is why it's important for organisms to be open systems.
What is osmoregulation?
The control of solute concentrations and water balance.
What are aminoacyl tRNA syntheses?
The correct matching up of tRNA and amino acid is carried out by these enzymes. The active site of each fits only a specific combination of amino acid and tRNA.
What happens in the calvin cycle?
The cycle incorporates CO2 from the air into organic molecules already present in the chloroplast.
What happens in cytokinesis?
The cytoplasm cleaves, differently in plants and animals.
What is the voltage across the membrane?
The cytoplasmic side of the cell is slightly negative in charge relative to the extracellular side because of unequal distribution of anions and cations on the sides.
What is morphogenesis?
The development of the form of an organism and its structures.
What are electron shells?
The different places that electrons are found, each with a characteristic average distance and energy level.
What is passive transport?
The diffusion of a substance across a biological membrane because the cell does not have to expend energy to make it happen.
What is osmosis?
The diffusion of free water across a selectively permeable membrane, whether artificial or cellular.
What is a wavelength?
The distance between crests of electromagnetic waves.
What are map units?
The distances between genes. One map unit is 1% recombination frequency.
What is cytokinesis?
The division of the cytoplasm.
What is mitosis?
The division of the genetic material in the nucleus.
How does a drosophila develop from an egg to a larva?
The egg is surrounded by support cells within one of the mothers ovaries. The developing egg enlarges as nutrients and mRNAs are supplied to it by other support cell which shrink. Eventually the mare egg fills the shell that is secreted by the follicle cells. The egg is fertilized within the mother and then laid. It develops into a segmented embryo and then a larva, which has three stages.
What is the oxidizing agent?
The electron acceptor that creates oxidation in the other substance.
How does the H+ gradient stay replenished?
The electron transport chain uses the exergonic flow of electrons from NADH and FADH2 to pump H+ across the membrane from the matrix into the inter membrane space.
What i the nuclear envelope?
The enclosing of the nucleus that separates it from the cytoplasm. It is a double membrane of lipid bilayers. The envelope is perforated by pore structures. At the lip of each pore, the inner and outer membranes are continuous.
.What are the products?
The end materials in a reaction.
What is positive feedback?
The end product speeds up its own production. i.e. clotting of blood.
What are the two phases of glycolysis?
The energy investment phase and the energy payoff phase
What is kinetic energy?
The energy of motion.
What is potential energy?
The energy that matter possess because of its location or structure.
Potential energy?
The energy that matter possesses because elf its location or structure.
What is the electromagnetic spectrum?
The entire range of radiation.
What is the replicative cycle of HIV?
The envelope glycoproteins have the virus bind to specific receptors on the white blood cells. The virus fuses with the cell's plasma membrane. The capsid proteins are removed, releasing the viral proteins and RNA. Reverse transcriptase catalyzes the synthesis of a DNA strand complementary to the viral RNA. Then a second DNA strand is made and the double stranded DNA is incorporated as a provirus into the cell's DNA. Proviral genes are transcribed into RNA molecules, which serve as genomes for other viruses. Vesicles transport glycoproteins to the cell's plasma membrane. Capsids are assembled around viral genomes and reveres transcriptase molecules. New viruses with viral envelope glycoproteins, bud from the host cell.
What is an ATP synthase?
The enzyme that makes TP from ADP and inorganic phosphate.
What is DNA ligase?
The enzyme that seals it all up. It catalyzes the formation of covalent bonds that close up the sugar phosphate backbones of DNA strands.
What is the enzyme separase?
The enzyme that separates the cohesions of the sister chromatids.
What is systems biology?
The exploration of a biological system by analyzing the interactions among its parts.
What is differential gene expression?
The expression of different genes by cells with the same genome.
What was Sturtevant's hypothesis for recombination frequency?
The farther apart two genes are, the higher the probability that a crossover will occur between them and therefore the higher the recombination frequency.
What is linear electron flow?
The flow of electrons through the photosystems and other molecular components built into the thylakoid membrane that occurs during the light reactions of photosynthesis.
What is the triplet code?
The flow of information from gene to protein is based on the triplet code. The genetic instructions for a polypeptide chain are written in the DNA as a series of non overlapping, three nucleotide words. The series of words in a gene is transcribed into a complementary series of non overlapping, three nucleotide words in mRNA, which is then translated into a chain of amino acids.
What is the currently accepted model of the animal cell plasma membrane?
The fluid mosaic model where the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.
What is dideoxy chain termination method for sequencing DNA?
The fragment of DNA to be sequenced is denatured into a single strand and incubated in a test tube with the necessary ingredients for DNA synthesis: a primer designed to base pair with the known 3' end of the template strand, DNA polymerase, the four dNTPs, and the four ddNTPs, each tagged with a specific fluorescent molecule. Synthesis of each new strand starts at the 3' end of the primer and continues until a ddNTP happens to be inserted instead of the equivalent dNTP. the incorporated ddNTP prevents further elongation of the strand. Eventually a set of labeled strands of every possible length is generated, with the color of the tag representing the last nucleotide in the sequence. The labeled strands in the mixture are separated by passage thorough a gel that allows shorter strands to more through more quickly than long ones. For DNA sequencing, the gel is in a capillary tue, and its small diameter allows a fluorescence detector to sense the color of each fluorescent tag as the strands come through. Strands differing in length by as little as one nucleotide can be distinguished from each other.
How does random fertilization lead to genetic variation?
The fusion of a male gamete with a female gamete is random because we don't know who's going to mate with who. Because of independent assortment, the possibility of getting a specific combination is 1 out of (2^23 x 2^23) which is like 7 trillion.
How do ligand gated ion channels work?
The gate remains closed until a ligand binds to the receptor. The gate opens and specific ions can flow through the channel and rapidly change the concentration of that particular ion inside the cel. This change directly affects the activity of the cell.
What are viral genomes?
The genomes can be double stranded DNA, single stranded DNA, double stranded RNA, or single stranded RNA.
What is the system for bees and ants' sex?
The haplo diplo system. There are no sex chromosomes in most species of bees and ants. Females develop from fertilized eggs and are thus haploid. Males develop from unfertilized eggs and are haploid; they have no fathers.
What are the three major body parts of arthropods?
The head, the thorax, and the abdomen.
What is the overall structure of a double helix.
The hydrogen bonds in the middle keep the hydrophobic interior away from the surrounding aqueous solution and the sugar phosphate backbone keeps the negatively charged parts away from each other on the outside. The helix makes one full turn every 3.4 nm long its length. There are 10 layers of base pairs in each full turn. A pairs with T and G pairs with C. There are two hydrogen bonds between AT and there are three hydrogen bonds between GC.
What can't pass through the lipid bilayer?
The hydrophobic interior of the membrane impedes direct passage of ions and polar molecules which are hydrophilic. Glucose and water can pass but only very very slowly.
What is the one gene one enzyme hypothesis?
The hypothesis that a gene dictates the production of a specific enzyme.
What is the primary transcript?
The initial RNA transcript from any gene, including those specifying RNA that is not translated into protein.
What is the activation energy?
The initial investment of energy for starting a reaction - the energy required to contort the reactant molecules so that bonds can break. This is usually found in heat or thermal energy.
What is a primer?
The initial nucleotide chain that is produced during DNA synthesis that is a short stretch of RNA.
How does the ATP synthase work and where is it?
The inner mitochondrial membrane. H+ ions flow down their gradient through a stator. They enter binding sites with a rotor, changing the shape so that it spins. Each H+ makes one turn before leaving and passing through another channel into the matrix. The spinning rotor cause the rod to turn which is positioned in the knob below. Turning of the rod activates the catalytic sites that produce ATP from ADP and P.
What is a spectrophotometer?
The instrument that measures the ability of a pigment to absorb various wavelengths of light.
What is the cytoplasm?
The interior of the cell which refers to the region between the nucleus and the plasma membrane in eukaryotes.
What is thermal energy?
The kinetic energy associated with the random movement of atoms or molecules.
What is the primary structure of a protein?
The linear chain of amino acids.
What are the differences between prokaryotic and eukaryotic cells?
The location of the DNA. In a eukaryotic cell, the DNA is in the nucleus. In a prokaryote, the DNA is in a region called the nucleoid.
What is the anticodon?
The loop extending from one end of theL includes the anticodon, the particular nucleotide triplet that base pairs to a specific mRNA codon.
What is oxidation?
The loss of electrons from one substance.
What are the two alternative mechanisms for replication of double stranded DNA viruses?
The lytic cycle and the lysogenic cycle.
What are codons?
The mRNA nucleotide triplets.
What is the proton pump?
The main electrogenic pump of plants, fungi, and bacteria, which actively transports protons out of the cell. This transfers positive charge from the cytoplasm to the extracellular solute.
What are chemical reactions?
The making and breaking of chemical bonds, leading to changes in the composition of matter.
What is the independent variable?
The manipulated factor.
What is entropy?
The measure of disorder, or randomness.
What is temperature?
The measure of energy that represents the average kinetic energy of the molecules in a body of matter, regardless of volume, whereas the total thermal energy depends in part on the matter's volume.
What is substrate level phosphorylation?
The mechanism used to make a smaller amount of ATP directly by a few reactions of glycolysis and the citric acid cycle. This occurs when an enzyme transfers a phosphate group from a substrate molecule to ADP, rather than adding an inorganic phosphate to ADP like in oxidative phosphorylation.
How do proteins aid with signal transaction?
The membrane protein may have a binding site with a specific shape that fits the chemical messenger like a hormone. tThis could cause the protein to change shape, relaying the message to the inside of the cell.
What are stomata?
The microscopic pores on the leaf.
What is the mitotic spindle?
The microtubules that begin to form in the cytoplasm during prophase. It's just microtubules and associated proteins.
what was the experimental group?
The models with the non native coloration.
What is positional information?
The molecular cues that control pattern information that are provided by ectoplasmic determinants and inductive signals.
What is sickle cell disease?
The most common inherited disorder among African people which affects one out of every 400. Caused by the substitution of an amino acid. When the oxygen content of an affected individual's blood is low, the sickle cell hemoglobin proteins aggregate into long fibers that deform the red cells into a sickle shape. They clump and clog small blood vessels. This kills people which makes it unsure why the gene is still around, but it is probably because being a heterozygote causes reduction of malaria attacks in that specific person.
What was the control?
The mouse models resembling the native mice in the habitat.
What is diffusion?
The movement of particles of any substance so that they spread out into the available space. In the absence of other forces, a substance will diffuse fro where it is more concentrated to where it is less concentrated. It does not require energy.
What is active transport?
The moving of a solute across the membrane against its concentration gradient.
What is a coenzyme?
The name for a cofactor that is an organic molecule.
How are standard viruses named?
The name identifies which forms of two girl surface proteins are present: hemagglutinin and neuraminidase.
What is the cortex?
The network of microfilaments that help give the outer cytoplasmic layer of the cell, the cortex, these semisolid consistency of a gel, in contrast with the more fluid state of the interior cytoplasm.
What role do ion channels play in nerve cells?
The neurotransmitter molecules released at a synapse bind as ligands to ion channels, causing them to open. This triggers an electrical signal that propagates down the length of the receiving cell.
What are introns?
The noncoding segments of nucleic acid that lie between coding regions are called intervening sequences or introns.
What are proto-oncogenes?
The normal versions of these cellular genes that code for proteins that stimulate normal cell growth and division.
How do diatoms and some yeasts reproduce?
The nuclear envelope also remains intact during cell division. The microtubules form a spindle within the nucleus. Microtubules separate the chromosomes, and the nucleus splits into two daughter nuclei.
What happens during G2 of interphase?
The nuclear envelope encloses the nucleus which contains duplicated chromosomes that are not yet condensed. Two centrosomes with centriole pairs have formed by the duplication of a single centrosome. They organize the microtubules of the spindle.
What happens during prometaphase?
The nuclear envelope fragments and the microtubules extending from the centrosomes now invade the nuclear area. The chromosomes are more condensed. Each of the chromatids of each chromosome has a kinetochore, a protein structure at the centromere. Some of the microtubules attach to the kinetochores and start to jerk them back and forth. Nonkinetochore microtubules interact with those from the opposite pole of the spindle.
What does the endomembrane system include and what does it do?
The nuclear envelope, the endoplasmic reticulum, the golgi apparatus, lysosomes, various kinds of vesicles and vacuoles, and the plasma membrane. It synthesizes proteins and transports the proteins into membranes and organelles or out of the cell. It metabolizes and moves lipid sand detoxifies poisons.
What is the nuclear lamina?
The nuclear side of the envelope is lined with this, a netlike array of portion filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope.
What does the chemical behavior of an atom depend mostly on?
The number of electrons in its outermost shell. These are called valence electrons in the valence shell.
What is molarity?
The number of moles of solute per liter of solution. M = m/L
What is the atomic number?
The number of protons in an atom and is written as a subscript to the left of the symbol for the elemtn.
What are lipids?
The one class of large biological molecules that does not include true polymers, and they are generally not big enough to be considered macromolecules. They are only grouped together because they mix poorly, if at all, with water.
What are the three varieties of life cycle?
The one in humans, alternation of generations (plants and some algae), and fungi and some protists.
What is the template strand?
The one of the two DNA strands that is transcribed because it provides the pattern or template for the sequence of nuclides in an RNA transcript.
How does pH affect an enzyme?
The optimal pH for an enzyme is 6-8 but in certain cases like pepsin, the pH is 2 or something different.
What is a clone?
The organism that comes out of asexual reproduction, or a group of genetically identical individuals?
What is regeneration of RuBP?
The other G3P goes through modifications to once again become ribulose biphosphate. Meanwhile, 3 ATPs are used up and the ADP goes back to the light reactions to become ATP again.
What was the basic idea of DNA replication proposed by Watson and Crick?
The parental molecule has two complementary strands. Firs the two DNA strands are separated, each parental strand now serves as a template or complementary strand. Nucleotides complementary to the parental strand are connected to form the sugar phosphate backbones of the new daughter strands.
How has winter wheat adapted?
The percentage of unsaturated phospholipids increases in autumn, which helps keep the membranes from solidifying during winter.
What are the plasmodesmata?
The perforations in the cell wall that connect cells.
What is the lysogenic cycle with a temperate phage?
The phage attaches to a host cell and injects its DNA. Phage DNA circularizes. Factors determine whether at this point, the lytic cycle is induced or the lysogenic cycle is entered. If the latter, page DNA integrates into the bacterial chromosome, becoming a prophage. The bacterium reprocess normally, copying the prophase and transmitting it to daughter cells.
What is the mitotic M phase?
The phase of the cell cycle that includes both mitosis and cytokinesis. The shortest part of the cell cycle.
What is the G0 phase?
The phase that cells spend their time in when they are not needing to divide. (brain cells, nerve cells, etc.)
What is the wild type?
The phenotype for a character most commonly observed in natural populations. Notation is +.
What is complete dominance?
The phenotype of the heterozygote and the dominant homozygote are indistinguishable because one allele in a pair showed complete dominance over the other.
How does a photon travel through the photosystem?
The photon hits a pigment molecules and excites it. The excitement is passed down the light harvesting complex until it reaches the chlorophyll a molecules. They boost one of their electrons to a higher energy level and transfer them to the primary electron acceptor.
What does the side chain of an amino acid determine?
The physical and chemical properties of a particular amino acid. It affects the functional role in a polypeptide.
What is the nucleus?
The place in the cell that contains most of the genes in the eukaryotic cell.
What is selective permeability?
The plasma membrane's ability to allow some substances to cross it more easily than others.
What are tight junctions?
The plasma membranes of cells are tightly pressed, bound by specific proteins. They establish a barrier that prevents leakage of extracellular fluid across a layer of epithelial cells. These are used in skin.
What is chemical equilibrium?
The point at which the reactions offset one another exactly. It does NOT mean that the reactants and products are equal in concentration.
What is a nonsense mutation?
The point mutation can also change a codon for an amino acid into a stop codon.
What are chiasmata?
The points of crossing over in chromosomes.
What are polynucleotides?
The polymers of nucleic acids.
What lines each pore and regulates the entry and exit of proteins and RNAs?
The pore complex.
What is free energy?
The portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell.
What is reductionism?
The practice of reducing complex systems to simpler components that are more manageable to study.
What is turgor pressure?
The pressure that a cell wall exerts back onto the cell which opposes further water up take. At this point the cell is turgid.
What is the addition rule?
The probability that any one of two or more mutually exclusive events will occur is calculated by adding their individual probabilities. So the possibility of two heterozygous parents having a heterozygous child is 1/4 + 1/4 = 1/2
What is cell differentiation?
The process by which cells become specialized in structure and function.
What is evolution?
The process of change that has transformed life on Earth from its earliest beginnings to the diversity of organisms living today.
What is crossing over?
The process of occasionally breaking the physical connection between specific alleles of genes on the same chromosome which accounts for the recombination of linked genes. A set of proteins orchestrates an exchange of corresponding segments of one maternal and one paternal chromatid. Portions of two non sister chromatids trade places.
What is exocytosis?
The process of secreting certain molecules by the fusion of vesicles with the plasma membrane. Many secretory cells use this to export products.
What is transformation?
The process that causes cells to behave like cancer cells.
What is a capsid?
The protein shell enclosing the viral genome. They are built up of capsomeres.
What happens during oxidation of pyruvate to acetyl CoA?
The pyruvate molecules enter the mitochondrion via active transport and pyruvate is converted to acetyl CoA. This happens when pyruvate's carboxyl group is given off as CO2, the two carbon fragment is oxidized and NAD+ becomes NADH, creating acetate. Then coenzyme A is attached via sulfur atom to the acetate making acetyl CoA.
What is the heat of vaporization?
The quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state.
What are substrates?
The reactant an enzyme acts on.
How does a receptor tyrosine kinase work?
The receptors exist as individual units (monomers). Each has an extracellular ligand binding its, an a helix spanning the membrane, and an intracellular tail containing multiple tyrosine's. The binding of a signaling molecule causes the two monomers to associate, forming a dimer in dimerization. This activates the tyrosine kinase region of each monomer, each adds a phosphate from an ATP molecule to a tyrosine on the tail of the other monomer. Now that the receptor is activate, it is recognized by specific relay proteins inside the cell. Each protein binds to a specific phosphorylated tyrosine, undergoing a structural change that activates the bound protein. Each triggers a cell transaction pathway.
Kinetic energy?
The relative motion of objects. Moving objects perform work by imparting motion on other matter.
What is a polypeptide backbone?
The repeating sequence of atoms that create a polypeptide. They range in length from a few amino acids to a thousand or more. it has an amino end (N terminus) and a carboxyl end (C terminus)
What is a nucleotide pair substitution?
The replacement of one nucleotide and its partner with another pair of nucleotides. Depending on where in the codon this mutation is, it may or may not have an affect on the encoded protein.
What is a repressor?
The repressor binds to the operator and blocks attachment of RNA polymerase to the promoter.
What is cell division?
The reproduction of cells.
What is the active site of an enzyme?
The restricted region of the enzyme that binds to the substrate. It is typically a pocket or groove on the surface o the enzyme where catalysis occurs.
What is the G1 checkpoint?
The restriction point and is the most important. if the cell receives a go ahead signal at the G1, it will usually complete the G1, S, G2 and M phases and divide. If it does not receive the go ahead, it will exit the cycle, switching into a nondividng G0 phase.
What is genetics?
The scientific study of heredity and hereditary variation.
What is biology?
The scientific study of life.
What is the SRY gene?
The sex determining region of the Y. In the absence of SRY, the gonads develop into ovaries. SRY codes for a protein that regulates other genes.
What is a covalent bond?
The sharing of a pair of valence elections by two atoms.
What is a nucleic acid probe?
The short, single stranded nucleic acid that can be either RNA or DNA and is the complementary molecule of the nucleic acid hybridization.
What is a ligand?
The signaling molecule that specifically binds to another molecule, often a larger one.
What are mitochondria?
The sites of cellular respiration, the metabolic process that uses oxygen to derive the generation of ATP by extracting energy from sugars, fats, and other fuels.
What is the substance that is dissolved called?
The solute.
What is the dissolving agent called?
The solvent.
What is a locus?
The specific location of a gene along the length of a chromosome.
What are reactants?
The starting materials in a reaction.
What is the leading strand?
The strand made in the normal way. DNA polymerase II can synthesize a complementary strand continuously by elongating the new DNA in the 5'-3' direction. DA pol III remains in the replication fork on that template strand and continuously adds nucleotides to the new complementary strand as the fork progresses. Only one primer is required for the synthesis of the leading strand.
What is the transcription unit?
The stretch of DNA downstream from the promoter that is transcribed into an RNA molecule.
What is a double helix?
The structure that DNA molecules have with two polynucleotides or "strands" that wind around an imaginary axis.
What is organic chemistry?
The study of compounds containing carbon .
What is thermodynamics?
The study of the energy transformations that occur in a collection f matter.
What is the reducing agent?
The substance that gives the electron and reduces the other substance.
What is the mass number?
The sum of protons plus neutrons in the nucleus of an atom.
What is the molecular mass?
The sum of the masses of all the atoms in a molecule.
What is the primary input of energy?
The sun.
What is transcription?
The synthesis of RNA using information in the DNA. It is just rewritten from DNA to RNA. For a protein coding gene, the resulting RNA molecule s a faithful transcript of the gene's protein building instructions. This is called messenger RNA because it carries a genetic message from the DNA to the protein synthesizing machinery of the cell.
What is translation?
The synthesis of a polypeptide using the information in the mRNA. There is a change in language in this star. The cell must translate the nucleotide sequence of an mRNA molecule into the amino acid sequence of a polypeptide. The site of translation is a ribosome.
What is reception?
The target cell detects a signaling molecule from outside the cell. The signaling molecule binds to a receptor protein on the cell surface.
What is allosteric regulation?
The term used to describe any case in which a protein's function at one site is affected by the binding of a regulatory molecule to a separate site.
What is determination?
The term used to refer to the point at which an embryonic cell is irreversibly committed to becoming a particular cell type. Basically the process by which a cell attains its determined fate.
What is the half life of an isotope?
The time it takes for 50% of the parent isotope to decay.
What are subatomic particles?
The tiny bits of matter that compose an atom.
How do tortoiseshell cats become that pattern?
The tortoiseshell gene is on the X chromosome, and the phenotype requires the presence of two different alleles, one for orange fur and one for black fur. Only females can have both alleles, because only they have two X chromosomes. If a female cat is heterozygous for the tortoiseshell gene, she is that. Orange patches are formed by populations of the cells in which the X chromosome with the orange allele is active.
What is metabolism?
The totality of an organism's chemical reactions. It is an emergent property of life that arises from orderly interactions between molecules.
What is the whole complex of transcription factors and RNA polymerase II bound to the promoter called?
The transcription initiation complex.
What is response?
The transducer signal triggers a specific cellular response. This can be basically anything like catalysis by enzyme, rearrangement of the cytoskeleton, or actuation of specific genes.
What is transfer RNA?
The translator of the message of a series of codons along an mRNA molecule. It transfers amino acids from a cytoplasmic pool of them to a growing polypeptie in a ribosome.
What is heredity?
The transmission of traits from one generation to the next.
How does the tryptophan operator work?
The trp operon is always turned on. The operon can be switched off by a protein that is called the trp repressor. This binds to th operator and blocks attachment of RNA polymerase. This is reversible and only happens when the repressor is allosterically activated. This happens when enough tryptophan has accumulated to shift it into its active shape and it binds to the operator. Tryptophan functions as a corepressor.
What is codominance?
The two alleles each affect the phenotype in separate, distinguishable ways. The human MN blood group is determined by codominant alleles for two specific molecules located on the surface of red blood cells, the M and N molecules. Heterozygotes have MN.
What is the trans isomer?
The two atoms are on opposite sides.
What is the cis isomer?
The two atoms are on the same side.
What is the conservative model of replication?
The two parental strands reassociate after acting as templates for new strands, thus restoring the parental double helix.
What is the semiconservative model of replication?
The two strands for the parental molecules separate, and each functions as a template for synthesis of a new, complementary strand.
What is meiosis?
The type of cell division that reduces the number of sets of chromosomes from two to one in gametes, counterbalancing the doubling that occurs at fertilization.
What is heterochromatin?
The type of interphase chromatin that is in a highly condensed state similar to that seen in a metaphase chromatin.
What is fertilization?
The union of gametes, culminating in the fusion of their nucleic.
What is the dalton?
The unit of measurement used for atoms and subatomic particles. (neutrons and protons are about 1 dalton)
What is energy coupling?
The use of an exergonic process to drive an endergonic one.
What is bioinformatics?
The use of computational tools to store, organize, and analyze the huge volume of data that results from high-thoroughput methods.
What does it mean if an element is inert?
The valence shell is full and they are chemically unreactive.
What is the simplified version of the viral replicative cycle?
The virus enters the cell and is uncoated, releasing viral DNA and capsid proteins. Host enzymes replicate the viral genome. Meanwhile, host enzymes transcribe the viral genome into viral mRNA, which host ribosomes use to make more capsid proteins. Viral genomes and capsid proteins self assemble into a new virus particle, which exist the cell.
What is the membrane potential?
The voltage across the membrane. It acts like a battery, an energy source that affects the traffic of all charged substances across the membrane. Because the inside is - the membrane potential favors the passive transport of cations into the cell.
What is the golgi apparatus?
The warehouse for receiving, sorting, shipping, and even manufacturing. This is where proteins are modified and stored and then sent to other destinations. It consists of flattened membranous sacs - cistern - looking like a stack of pita bread.
What is induced fit?
The way that an enzyme substrate complex comes together like a clasping handshake, which brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction.
How have bacteria and archaea adapted to hot temperatures?
Their membranes include unusual lipids that may prevent excessive fluidity.
Alternative versions of genes account for variations in inherited characters. What does this mean?
There are alternative versions of a gene called alleles. The DNA at a locus can vary slightly in nucleotide sequence and can affect the function of the encode protein and thus the phenotype of an organism.
Why did Mendel chose to work with peas?
There are many varieties of pea (purple v. white flower color, etc.) They have a short generation time There is a large number of offspring from each mating. He could control mating between plants by fertilizing them himself.
What is the wobble?
There are only about 45 tRNAs which means that some can bind to more than one codon because there are 61. The versatility is possible because rules for base pairing between the third nucleotide base of a codon and the corresponding base are relaxed compared to those at other codon positions.
What is the structure of chloroplasts?
There are two membranes again with a very narrow inter membrane space. Inside, there are flattened, interconnected sacs called thylakoids. Each stack is called a granum. The fluid outside the thylakoids is the stroma which contains chloroplast DNA and ribosomes. There is the inter membrane space, the stroma, and the thylakoid space.
How does a GPCR work?
There is a GPCR, an inactive G protein, and an enzyme. The G protein acts as a switch. When GDP is bound to the protein, it is off, when GTP is bound, it is on. When the signaling molecule comes in, the receptor is activated and changes shape. This binds to the G, protein, causing a GTP to displace the GDP. This activates the G protein. This dissociates from the receptor, diffuses along the membrane and binds to the enzyme, altering it. When the enzyme is activated, it trigs the next step leading to response. When the signaling molecule is gone, the G protein hydrolyzes GTP to GDP and P. Now it's inactive, and the G protein leaves the enzyme.
What is the U tube experiment?
There is a u shaped glass tube with a selectively permeable artificial membrane separating two sugar solutions. Water molecules can pass through but sugar can't. One side has less solute and more free water. The other has more solute and less free water. Water moves from the area higher to lower free water concentration (lower to higher solute concentration).
How does anaerobic respiration work?
There is an electron transport chain but it doesn't use oxygen as the final receptor. It can use sulfate ion.
What happens if plants and their surroundings are isotonic?
There is no net tendency for water to enter, and the cells become flaccid.
What is the structure of a chloroplast?
There is typically an envelope of two membranes surrounding a dense fluid called the stroma. Inside the stroma is a group of sacks called thylakoids. Thylakoids are stacked in columns called grans. Chlorophyll lives in the thylakoid membranes of the chloroplast.
What was Stanley Miller's 1953 experiment?
There was a water mixture in a flask to mimic the sea which was heated. The vapor entered the atmosphere flask which contained a mixture of hydrogen gas, methane, ammonia, and water vapor. Sparks were discharged to mimic lightning. A condenser cooled the atmosphere, raining water and dissolved molecules into the sea flask. As material cycled through the apparatus, Miller periodically collected samples for analysis.
What is heat?
Thermal energy in transfer from one body of matter to another.
What happens when two objects of different temperature are brought together?
Thermal energy passes from the warmer to the cooler object until the two are the same temperature. Therefore, an ice cube cool a drink not by ding coldness to the liquid, but by absorbing thermal energy from the liquid as the ice itself melts.
What are piRNAs?
These also induce formation of heterochromatin, blocking expression of some parasitic DNA elements in the genome known as transposons.
What are sticky ends?
These are short extensions on either side of the cut DNA strand that can form hydrogen bonded base pairs with complementary sticky ends on any other DNA molecules cut with the same enzyme.
What are disulfide bridges in tertiary structure?
These form where two cysteine monomers, are brought close together by the folding of a protein.
What happens when a male has XYY?
These males undergo normal sexual development and do not exhibit any well defined syndrome. They tend to be taller than average.
What is calvin cycle reduction?
These molecules each get an additional phosphate group. After modification, one G3P comes out of the cycle.
What is the same among all cells?
They all are bounded by a selective barrier, called the plasma membrane. Inside all cells is a semisolid, jellylike substance called cytosol, in which sub cellular components are suspended. All cells have chromosomes, which carry genes in the form of DNA. All cells have ribosomes, tiny complexes that make proteins according to instructions from the gene.s
What kind of protein does active transport require?
They are all carrier proteins because when channel proteins are open, they allow solutes to diffuse down their concentration gradients so it wouldn't be possible to do it the opposite way.
What is the rare case of the bdelloid rotifer?
They are asexual but they live in a very dry climate where they go into a state of suspended animation where their cell membranes crack allowing entry of DNA from other rotifers. The DNA becomes incorporated into the genome of the rotifer, leading to increased genetic diversity which supports the idea that genetic diversity is advantages.
What are helicases?
They are enzymes that unwind and separate the parental DNA strands at the replication forks.
What are retroviruses?
They are equipped with reverse transcriptase which transcribes an RNA template into DNA, providing an RNA-DNA information flow, the opposite of the usual direction.
What are monohybrids?
They are heterozygous for the one particular character being followed in the cross.
How do gametes come about?
They are not produced from mitosis but rather develop from specialized cells called germ cells in the gonads.
How do chemicals flow through an ecosystem?
They are recycled within. Chemicals that plants absorb are passed to an animal that eats the plant. These chemicals are returned to the environs by decomposers, such as bacteria and fungi. Then the chemicals are again taken up by plants.
What are small interfering RNAs or siRNAs?
They are similar to miRNAs in that they can associate with the same proteins and produce similar results.
What are microRNAS or miRNAS?
They are small single stranded RNA molecules capable of binding to complementary sequences in mRNA molecules. This forms a complex with proteins and allows the complex to bind to any mRNA molecules with a complementary sequence. The complex either degrades the target mRNA or blocks its transition.
What are C4 plants?
They are so named because they preface the calvin cycle with an alternate mode of carbon fixation that forms a four carbon compound as its first product.
What are peripheral proteins?
They aren't embedded in the lipid bilayer at all; they are appendages loosely bound to the surface of the membrane, often to exposed parts of integral proteins.
What are receptor tyrosine kinases?
They belong to a major class of plasma membrane receptors characterized by having enzymatic activity. A kinase is any enzyme that catalyzes the transfer of phosphate groups. The difference between RTKs and GPCRs is that the RTK can activate different transduction pathways and cellular responses.
How do proteins aid with enzymatic activity?
They can be an enzyme with the active site exposed to substances in the adjacent solution.
How do proteins aid in transport?
They can either provide a hydrophilic channel that is selective for a particular solute or they can shuttle a substance from one side to the other by changing shape.
What are obligate anaerobes?
They carry out fermentation or anaerobic respiration. They cannot survive in the presence of oxygen.
What are anabolic pathways?
They consume energy to build complicated molecules from simpler ones; sometimes called biosynthetic pathways.
What do hormonal proteins do?
They coordinate an organisms' activities. Insulin, a hormone secreted by the pancreas, causes other tissues to take up glucose, thus regulating blood sugar concentration.
How did Meselson and Stahl experiment to find out what model of replication was correct?
They cultured e. coli in a medium containing nucleotide precursors labeled with a heavy isotope of 15N. They transferred the bacteria to a medium with only 14N. A sample was taken after the first DNA replication and then another after the second replication. They centrifuged the samples to separate DNA of different densities. They compared results and the first replication in the 14N medium produced hybrid DNA which ruled out the conservative model. The second replication produced both light and hybrid DNA, a result that got rid of the dispersive model.
What are structural promisers?
They differ in the covalent arrangements of their atoms. This includes location of double bonds.
What are noncompetitive inhibitors?
They do not directly compete with the substrate to bind to the enzyme at the active site. They impede enzymatic reactions by binding to another part of the enzyme which causes the enzyme molecule to change its shape in a way that makes the active site less effective.
What normal signals do cancer cells ignore?
They do not stop dividing when growth factors are depleted, they do not follow anchorage dependence, they do not follow density dependent inhibition. They do not stop dividing at the points in the cycle when they should, they do it randomly.
What is a light harvesting complex?
They each consist of various pigment molecules like chlorophyll a, b, or carotenoids bound to proteins.
How is gene expression altered in lens cells ad liver cells?
They each have a different set of control elements for their genes. Although both code for albumin and crystallin, their sets are so specific that the liver cells only makes albumin because of the activators it can take whereas the crystallin gene is expressed only in the lens cell because the activators bind to that one.
What are the poitns of the poly a tail and the 5' cap?
They facilitate export of the mature mRNA from the nucleus. They also protect the mRNA from degradation by hydrolytic enzymes. They help ribosomes attach to the 5' end of the mRNA once it reaches the cytoplasm.
What do glucose and most other pentoses and hexoses do in aqueous solutions?
They form rings.
What are desmosomes?
They function like rivets, fastening cells together into sheets. Intermediate filaments made of keratin anchor these in the cytoplasm. They attach muscle cells to each other.
What are monosaccharides?
They generally have molecular formulas that are some multiple unit of CH2O. The most common being glucose C6H12O6.
Why are aquaporins important to kidneys?
They have a high number because it allows them to reclaim water from urine before it is excreted. If they didn't do this, people would pee 180 L of urine a day and have to drink that much as well.
How have fishes that live in extreme cold water adapted?
They have a high proportion of unsaturated hydrocarbon tails, enabling their membranes to remain fluid.
How is the anatomy of a C4 plant different?
They have two types of cells. Bundle sheath cells - which are arranged into tightly packed sheaths around the veins of a leaf. Mesophyll cells - normal plant cells.
What do motor proteins do?
They help with movement. They are responsible for the undulations of cilia and flagella. Actin and myosin proteins are responsible for the contraction of muscles.
What are malignant tumors?
They include cells whose genetic and cellular changes enable them to spread to new tissues and impair the functions of one or more organs.
What are carbohydrates?
They include sugars and polymers of sugars.
How do inherited lysosomal storage diseases like Tay Sachs disease work?
They lack a functioning hydrolytic enzyme normally present in lysosomes. They become engorged with indigestible material, which begins to interfere with other cellular activities. The brain becomes impaired by an accumulation of lipids in the cells.
What are heterotrophs?
They obtain organic material by the second major mode of nutrition. they can't make their own food so they live on compounds produced by other organisms.
What are integral proteins?
They penetrate the hydrophobic interior of the lipid bilayer. They are mostly transmembrane proteins, which span the membrane.
What are gap junctions?
They provide cytoplasmic channels from one cell to an adjacent cell and are similar to plasmodesmata. They consist of membrane proteins that surround a pore through which ions, sugars, amino acids, and other small molecules can pass.
What do structural proteins do?
They provide support. Keratin is the protein of hair, horns, feathers, and other skin appendages. Insects and spiders use silk fibers to make their cocoons and webs. Collagen and elastin proteins provide a fibrous framework in animal connective tissues.
What distinguishes the four blood types from each other?
They refer to the variation in the carbohydrate part of the glycoproteins on the surface of the red blood cells.
What was the Hoekstra experiment with camouflage mice?
They spray painted mouse models with either light or dark color patterns that matched those of the beach and inland mice and then placed models with both partners in each of the habitats. In both habitats, the models whose pattern did not match their surroundings suffered much higher "predation" than did the camouflaged models.
What do storage proteins do?
They store amino acids. Casein the protein of milk, is the major source of amino acids for baby mammals. Plants have storage proteins in their seeds. Ovalbumin is the protein of egg white, used as an amino acid source for the developing embryo.
How do animals store sugar?
They store the polysaccharide called glycogen, a polymer of glucose that is like amylopectin but more extensively branched. It is tired mainly in liver and muscle cells.
What do fermentation, anaerobic, and aerobic bacteria all have in common?
They use glycolysis to oxidize glucose and other organic fuels to pyruvate, with a net production of 2 ATP by substrate level phosphorylation. NAD+ is the oxidizing agent that accepts electrons from food.
What were the Hershey and Chase experiments?
They used radioactive sulfur to tag the protein and radioactive phosphorus to tag the DNA. They infect bacterial e. coli with T2 phages and then centrifuged them to see where the radioactivity lay. It turned out that the pellet in the second batch was radioactive which meant that the phosphorus carried through and it was actually the DNA that was inserted into the bacteria.
How did Srb and Horowitz build on Beadle and Tatum's experiments?
They wanted to investigate the biochemical pathway for arginine synthesis in neurospora. They put wild type mold in MM, MM + ornithine, MM + citrulline, MM + arginine. This was to see where in the synthesis of arginine was the mold lacking in metabolic enzyme. The class I could grow in all but the MM control. Class II could only grow in MM citrulline and MM arginine, and class III could only grow on arginine. This proved which enzyme was not working in each class.
How did Watson and Crick discover the double helix?
They were at Cambridge University and while visiting the laboratory of Maurice Wilkins, Watson saw an X ray diffraction image of DNA. He was familiar with the pattern that helical molecules produce and saw that the DNA was helical in shape.
What experiment did Nusslein volhard and Weischaus do?
They were trying to find knight into pattern formation during embryonic development. They exposed flies to mutagenic chemicals and then mated these flies and scanned descendants for dead embryos or larvae with abnormal segmentation defects. Doing this, they identified 1200 genes that were essential for pattern formation during embryonic development.
What was Beadle and Tatum's experiment?
They worked with Neurospora crassa which they bombarded with X rays to cause genetic changes. In these survivors, they found mutants. Wild type neurospora has no food requirements. It just needs inorganic salts, glucose and biotin. Beadle and Tatum identified mutants that could not survive on the minimal medium because they couldn't synthesize certain molecules from the ingredients. Beadle and Tatum allowed them to grow on complete growth medium and took samples from the mutant growing on complete medium and distributed them to different vials that contained each minimal medium plus an additional nutrient. This would show where the particular metabolic defect was.
What are microfilaments?
Thin solid rods. They are made of actin, a globular protein. Present in all eukaryotic cells. Cortical microfilaments help support the cell's shape.
What is transduction?
This changes the receptor protein, initiating transduction. This converts the signal to a form that brings about a specific response. This sometimes happens in a single step, but more often requires a sequence of changes in a series of different molecules - a signal transduction pathway. The molecules in this are called relay molecules.
How does initiation work in a eukaryotic promoter?
This commonly includes a TATA box, a nucleotide sequence containing TATA, about 25 nucleotides upstream from the transcriptional start point. Several transcription factors, one recognizing the TATA box, must bind to the DNA before RNA polymerase II can bind. Additional transcription facts bind to the DNA along with RNA polymerase II, forming the complex. RNA polymerase II then unwinds the DNA double helix and the synthesis begins.
What are DNA microarray assays?
This consists of tiny amounts of a large number of single stranded DNA fragments representing different genes fixed to a glass slide in a tightly spaced array or grid.
What is RNAi?
This experimental approach uses synthetic double stranded RNA molecules matching the sequence of a particular gene to trigger breakdown of the gene's messenger RNA or to block its translation.
What is the alternation of generations?
This includes both diploid and haploid stages. Meiosis creates spores which grow into haploid multicellular organisms called gametophytes. These divide by mitosis to create gametes which get fertilized and form the diploid zygote. When this becomes a multicellular organism called a sporophyte, it undergoes meiosis again to create spores.
What happens when a male has XXY?
This is klinefelter syndrome, where the male has male sex organs, but the testes are abnormally small and the man is sterile. even though the extra X is inactivated, some breast enlargement and other female body characteristics are common They may have subnormal intelligence.
What happens during anaphase?
This is the shortest stage of mitosis and begins when the cohesion proteins are cleaved. The two sister chromatids part suddenly and each becomes a full fledged chromosome. They move towards opposite ends of the cell as the microtubules shorten. Because they are attached at the centromere region, the chromosomes move centromere first. The cell gets longer and by the end of anaphase, both sides have the same amount of chromosomes.
What happen at the M checkpoint?
This is the stopping point where a cell must stop until all of the chromosomes are attached to spindle fibers. If they are not, then the cell does not go through with pro metaphase until all the chromosomes are attached to spindle fibers from both poles.
What is the basic concept of glycolysis?
This occurs in the cytosol and begins the degradation process by breaking down glucose into two molecules of a compound called pyruvate.
What is chronic myelogenous leukemia?
This occurs when a reciprocal translocation happens during mitosis of cell that will become white blood cells. The exchange of a large portion of chromosome 22 with a small fragment from the tip of chromosome 9 produces a shortened chromosome 22 called the Philadelphia chromosome. Causes cancer by activating a gene that leads to uncontrolled cell cycle progression.
What is a frameshift mutation?
This occurs whenever the number of nuclides inserted or deleted is not a multiple of three. All downstream nucleotides will be improperly grouped which usually creates missense or premature termination nonsense mutations.
What is an exergonic reaction?
This proceeds with a net release of free energy. ∆G is negative because the chemical mixture loses free energy.
How does polymerase chain reaction work?
This requires double stranded DNA, a heat resistant polymerase, all four nucleotides, and two 15-20 nucleotide DNA strands that serve as primers. First the DNA is heated to separate the two DNA strands. Then it is cole to allow primers to form hydrogen bonds with ends of the target sequence. DNA polymerase adds nucleotides to the 3' end of each primer. The DNA polymerase used is called Taq polymerase which can take a lot of heat so it doesn't denature along with the protein in the beginning. Cycle 1 yields 2 molecules. Cycle 2 yields 4 molecules. Cycle 3 yields 8 molecules. At the end of this, only two match the target sequence and can be used. PCR primers are synthesized to include a restriction site at each end of the DNA fragment that matches the site in the cloning vector.
What is gel electrophoresis?
This technique uses a gel made of a polymer as a molecular sieve to separate out a mixture of nucleic acids or proteins on the base of size, electrical charge, and other physical properties. A researcher would cut the products again using the same restriction enzyme and yielding one the size of the original plasmid and one the size of the inserted DNA fragment.
What is the endosymbiont theory?
This theory states that an early ancestor of eukaryotic cells engulfed an oxygen using non photosynthetic prokaryotic cell. The engulfed cell formed a relationship with the host becoming an endosymbiont. after evolution, they merged into a single organism, a eukaryotic cell and mitochondria. The same applies to chloroplasts.
How is a trycylglycerol made?
Three fatty acid molecules are each joined to glycerol by an ester linkage, a bond formed by a dehydration reaction between the hydroxyl group and a carboxyl group.
What are the three types of junctions in animal cells?
Tight Junctions Desmosomes Gap Junctions
What is the lagging strand?
To elongate the other new strand of DNA in the mandatory 5'-3' direction, DNA pol III must work away from the replication fork. This happens in the lagging strand. In contrast to the leading strand, the lagging strand is synthesized discontinuously as a series of segments called okazaki fragments.
What is the role of the cytoskeleton?
To give mechanical support to the cell and maintain its shape. Important to animal cells which lack cell walls. It also helps in cell motility.
What do humans use receptor mediated endocytosis for?
To take in cholesterol. Cholesterol travels in the blood in particles of low density lipoproteins. LDLs bind to the LDL receptors on plasm membranes and then enter the ell by endocytosis. They act as ligands, a term for any molecule that binds specifically to a receptor.
What are mutant phenotypes?
Traits that are alternatives to the wild type.
What are the three things that cause cancer in proto-oncogenes?
Translocation or transposition: gene moved to new locus under new controls. New promoter stimulates protein in excess. Gene amplification: there are multiple copies of the gene which makes protein in excess. Point mutation within a control element causes excess. Within a gene causes hyperactive or degradation resident protein.
What are the six major functions of proteins in the plasma membrane?
Transport Enzymatic activity Signal transduction Cell-cell recognition Intercellular joining Attachment to the ECM
What do transport proteins do?
Transport of substances. Hemoglobin, the iron containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body. Other proteins transport molecules across membranes.
What are channel proteins?
Transport proteins that function by having a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane.
If hydrophilic substances can't pass through, how do they get to the other side?
Transport proteins.
What happens when a female is XXX?
Trisomy X's are healthy and have no unusual physical features other than being slightly taller than average. They are at risk for learning disabilities but are fertile.
What are ions?
Two atoms where one is more electronegative and strips an electron completely away from the partner resulting in two oppositely charged atoms.
What happens in telophase?
Two daughter nucleic form in the cell. Nuclear envelopes arise from the fragments. Nucleoli reappear. The chromosomes become less condensed. Any microtubules are depolymerized.
What is the electrochemical gradient?
Two forces drive diffusion, both the chemical force (ion concentration gradient) and the electrical force (membrane potential).
What is a disaccharide?
Two monosaccharides linked.
What is a molecule?
Two or more atoms held together by covalent bonds.
What's the law of independent assortment?
Two or more genes assort independently - that is, each pair of alleles segregates independently of each other pair of alleles - during gamete formation.
In secondary structure, what is the B pleated sheet?
Two or ore segments of the polypeptide chain are lying side by side and are connected by hydrogen bonds between parts to eh two parallel segments of the polypeptide backbone.
What reaction happens when the DNA polymerase adds nucleotides to the new strand?
Two phosphate groups break off as a pyrophosphate molecule.
What is the shape of two carbons with three single bonds each to the same atom?
Two tetrahedral groups. (Ethene)
How many steps are there to photosynthesis?
Two. Light reactions and the calvin cycle.
What are the stop codons?
UAA, UAG, UGA.
Where are intermediate filaments found and how is their structure slightly different?
Unlike microfilaments and microtubules, which are found in eukaryotic cells, these are only found in some animal cells. They are slightly more permanent than the others and don't get reassembled in various parts of the cell.
How does temperature affect an enzyme?
Up until a certain point, it speeds up the reaction because it increases the number of collisions between substrates and active sites. But above that certain point, the thermal agitation disrupts the hydrogen bonds that stabilize the active shape of the enzyme and the protein molecule denatures.
What is cyclic electron flow?
Uses photosystem I but not photosystem II. the electrons cycle back from ferredoxin Fd to the cytochrome complex and continue on to a P700 chlorophyll in the PS I reaction center complex. No production of NADPH and no release of oxygen. But it does make ATP.
How was this hypothesis proven wrong?
Van Niel worked with bacteria that made carbohydrates from CO2 but didn't release O2. He then saw a group of bacteria that used hydrogen sulfide H2S instead of water and created sulfur as a byproduct. CO2 + 2H2S -> CH2O + H2O + 2S He figured that bacteria split H2S and used the hydrogen atoms to make sugar. General: CO2 + 2H2X -> CH2O + H2O + 2X Scientists later used a heavy isotope tracer of O18 and proved the hypothesis correct.
What is the transformation from liquid to gas called?
Vaporization or evaporation.
What is genomic imprinting?
Variation in phenotype depending on whether an allele is inherited from the male or female parent. It seems to be an addition of a methyl group to cytosine nucleotides of one of the alleles. This silences the allele. However, it can activate the expression of the allele.
How does cytokinesis happen in plant cells?
Vesicles derived from the golgi move along microtubules to the middle of the cel where they coalesce, producing a cell plate. Cell wall materials carried in the vesicles get inside the cell plate as it grows. It gets bigger until it fuses with the surrounding membrane. Two daughter cells result.
What are transport vesicles?
Vesicles in transit from one part of the cell to another.
How does a product move through the golgi apparatus?
Vesicles move from the ER to golgi, ad they coalesce to form new cis golgi cistern. Golgi cistern move in a cis to trans direction. vesicles form and leave golgi, carrying specific products to other locations or to the plasma membrane for secretion.
What are bacteriophages or phages?
Viruses that infect bacteria.
What are emerging viruses?
Viruses that suddenly become apparent.
What happens in the light reactions?
Water is split, providing a source of electron and protons and giving off O2 asa by product.
What is the basal body?
What typically anchors the cilium or flagellum to the cell. It is structurally very similar to a centriole with microtubule triplets in a 9+0 pattern.
What is ocean acidification?
When CO2 dissolves in seawater, it reacts with water to form carbonic acid, which lowers ocean pH. This is because CO2 has been trapped in ice which is now melting because of fossil fuel emission. As seawater acidifies, the extra hydrogen ions combine with carbonate ions (CO3 2-) to form bicarbonate ions thereby reducing the carbonate ion concentration. This could cause the concentration to decrease by 40% by 2100
What is polydactyly?
When a baby is born with extra fingers or toes. One out of 400 babies and is a dominant allele.
What is a haploid cell?
When a gamete contains a single set of chromosomes.
What is a hydrogen bond?
When a hydrogen atom is covalently bonded to an electronegative atom, the hydrogen atom has a partial positive charge that allows it to be attracted to a different electronegative atom nearby.
What is evaporative cooling?
When a liquid evaporates, the surface of the liquid that remains behind cools dow. This is because the "hottest" molecules, those with the greatest kinetic energy, are the most likely to leave as gas.
What is the process of termination of translation?
When a ribosome reaches a stop codon on the mRNA, the A site of the ribosome accepts a release factor, a protein shaped like a tRNA, instead of an aminoacyl tRNA. The release factors promotes hydrolysis of the bond between the tRNA int he P site and the last amino acid of the polypeptide, thus freeing the polypeptide from the ribosome. With two GTP, he two ribosomal subunits and the other components of the assembly dissociate.
What would cause an aqueous solution to have an imbalance of H+ or OH- concentrations?
When acids dissolve in water, they donate additional H+ to the solution.
What is a polar covalent bond?
When an atom is bonded to a more electronegative atom, the electrons of the bond are not shared equally.
What is the operator?
When an e. coli cell must make tryptophan for itself because the nutrient medium lacks this amino acid, all the enzymes for the metabolic pathway are synthesized at one time. The switch is a segment of DNA called an operator.
Even though women inherit two copies of the X chromosomes, why don't they express double the genes as male?
When an embryo is female, one of the X chromosomes in all of the cells becomes inactivated. It condenses into a compact Barr body, which lies along the inside of the nuclear envelope. Most of the genes of the X chromosome that forms the barr body are not expressed. In the ovaries, the barr body chromosomes are reactivated in the cells that give rise to eggs. The Xs are inactivated randomly giving women a mosaic of the active X's from both parents. If a female is heterozygous for a sex linked trait, half her cells will express one allele, while the others do the opposite.
When is there a 50% frequency of recombination?
When any two genes are located on different chromosomes and thus cannot be linked.
What is a Lewis Dot Structure?
When element symbols are surrounded by dots that represent the valence electrons.
When does an electron have its greatest potential energy?
When its farther from the nucleus.
What is facilitated diffusion?
When many polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane.
What is pleiotropy?
When most genes have multiple phenotypic effects.
What is synapsis?
When the DNA breaks are closed up so that each broken end is joined to the corresponding segment of the non sister chromatid. Thus paternal chromatid is joined to a piece of maternal chromatid beyond the crossover point and vice versa.
What is transition state?
When the molecules have absorbed enough energy for the bond to break, the reactants are in an unstable condition known as the transition state.
How does ATP give off energy?
When the terminal phosphate group is hydrolyzed, it leaves as inorganic phosphate and leaves a molecule of ADP. This releases 7.3 kcal of energy per mole hydrolyzed. ∆G = -7.3
What is the start point?
Within the promoter of a gene there is the transcription start point (the nucleotide where RNA synthesis actually begins) which typically extends several dozen or more nucleotide pairs upstream from the start point.
What is sexual reproduction?
When two parents give rise to offspring that have unique combinations of genes inherited from the two parents.
What are trans fats?
When vegetable oils are hydrogenated which not only produces saturated fats but also unsaturated fats with trans double bonds.
What is prophage?
When viral DNA is integrated into the bacterial chromosome.
What is cotransport?
Where a transport protein (a cotransporter) can couple the "downhill" diffusion of the solute to the "uphill" transport of a sec on substance against its own concentration gradient.
What are the mesophyll cells?
Where most chloroplasts are found. They are the tissue in the interior of the leaf.
What is endocytosis?
Where the cell takes in molecules and particulate matter by forming new vesicles from the plasm membrane.
What is nondisjunction?
Where the members of a pair of homologous chromosomes do not move apart properly during meiosis I or sister chromatids fail to separate during meiosis II.
What is epistasis?
Where the phenotypic expression of a gene at one locus alters that of a gene at the second locus. In labs, black coat color is dominant to brown. For a lab to have fur color, the second gene determines whether or not pigment will be deposited (E). If the lab is homozygous for ee, then the coat is yellow regardless of the Bb, bb or BB genotype.
What can this be used to determine?
Whether or not a process will be spontaneous or not. If ∆G is negative, then the process is spontaneous. If ∆G is positive, it is not spontaneous.
What is tertiary structure?
While secondary structure involves interactions between backbone constituents, this is the overall shape of a polypeptide resulting from interactions between the side chains of the various amino acids.
What kind of inactivation are ncRNAs responsible for?
X inactivation. Transcripts for the XIST gene located on the chromosome to be inactivated bind back to and coat that chromosome, and this binding leads to condensation of the entire chromosome into heterochroamtin.
Is bulk transport across the membrane considered active transport?
Yes, because it requires energy.
How does the cyclic Amp cycle work positively in the cell?
cAMP begins to aciculate when glucose is sarce. CAP, the regulatory protein, is an activator, a protein that binds to DNA and stimulates transcription of a gene. When cAMP binds to this, CAP assumes active shape and attaches to a specific site upstream of the lac promoter. This increases affinity of RNA polymerase for the promoter. By facilitating the binding of RA polymerase to the promoter and increasing the rate of transcription, the attachment of CAP to the promoter directly stimulates gene expression = positive gene regulation.
How does one find how many grams to weigh of a substance in order to get one mole?
grams x 1 mol/molecular mass.
What are multifactorial disorders?
heart disease, diabetes, cancer, alcoholism, certain mental illnesses, and other diseases. the hereditary component is polygenic.
What are homeotic genes?
ones that control pattern formation in the late embryo, larva, and adult.
What is the pH of a solution defined as?
pH = -log[H+]
What is a common misconception in the term controlled experiment?
that scientists control the experimental environment to keep everything strictly constant except the one variable being tested. They usually do that by eliminating the unwanted variables by canceling out their effects by using control groups.
How do phospholipids react around water?
the heads are typically hydrophilic and the tails are hydrophobic. So when they get in water, they aggregate into double layered structures called bilayers.
What is the metaphase chromosome 700 nm level of packing?
the looped domains coil and fold, further compacting the chromatin to produce the metaphase chromosome. Particular genes always end up located at the same places in metaphase chromosomes, indicating that the packing steps are highly specific and precise.
What is the Gibbs Free Energy equation?
∆G = ∆H-T∆S
What do the parts of this equation stand for?
∆H is total change in enthalpy (total energy) T is temperature in Kelvin (C+273) ∆S is the change in entropy