AP Bio - Semester 1 Final

Which enzyme, DNA polymerase III or RNA polymerase, does not require a primer to begin synthesis?

RNA polymerase

receptor tyrosine kinase

Step 1 -before signaling molecule binds, receptors are individual polypeptides -each has an extracellular ligand-binding site, an alpha helix spanning membrane, and intercellular tail with multiple tyrosines Step 2 -binding of signaling molecule causes two receptor polypeptides to associate closely with each other, forming a dimer (dimerization) Step 3 -dimerization activates tyrosine kinase region of each polypeptide -each tyrosine kinase adds a phosphate from ATP molecule to a tyrosine on the tail of other peptide Step 4 -fully activated receptor protein is recognized by specific relay proteins in cell -each protein binds to specific phosphorylated tyrosine, changing structure that activates bound protein -each activated protein triggers a transduction pathway (cellular response)

glycolysis

Step 1 -energy investment: glucose in, 2 ATP used and made 2 ADP and 2 phosphate Step 2 -energy payoff: 4 ADP and 4 phosphate in and make 4 ATP; 2 NAD+, 4 electrons, and 4 hydrogen ions make 2 NADH and 2 H+; 2 pyruvates and 2 H2O are formed Net Energy -glucose -> 2 pyruvate + 2 H2O -4 ATP formed + 2 ATP used -> 2ATP -2 NAD+ + 4 e- + 4 H+ -> 2 NADH + 2 H+

citric acid cycle

Step 1 -pyruvate's carboxyl group (-COO-) (already fully oxidized, little chemical energy) is removes and given as CO2 Step 2 -remaining 2-carbon fragment is oxidized, forming acetate; enzyme transfers extracted e-'s to NAD+, storing energy in form of NADH Step 3 -CoA (sulfur-containing compound) is attached to acetate by an unstable bond that makes attached acetyl group very reactive

transcription initiation

Steps 1) a eukaryotic promoter commonly includes a TATA box around 25 nucleotides upstream from the transcriptional start point 2) several transcription factors, one recognizing the TATA box, must bind to the DNA before RNA pol II does 3) additional transcription factors bind to the DNA along with RNA pol II, forming transcription initiation complex; DNA double helix unwinds, and RNA synthesis begins and start point on the template strand

chromosome replication and distribution

Steps 1) before duplication each chromosome has 1 DNA 2) after replication, chromosome is 2 sister chromatids (connected by sister chromatid cohesion along lengths), each containing a copy of DNA 3) mechanical processes separate sister chromatids into 2 chromosomes and distribute to 2 daughter cells

HeLa cells

(Interview and Except from Rebecca Skloot, The Immortal Life of Henrietta Lacks) cells taken from the cervix of a women named Henrietta Lacks during her cancer treatment. These cells are the first known "Immortal" cells and have been used to cure diseases such as polio

taxonomic classification

(biggest to smallest) (mnemonic device: Does King Phillip Come Over For Great Sex) -Domain -Kingdom -Phylum -Class -Order -Family -Genus -Species

DNA

(deoxyribonucleic acid) A complex molecule containing the genetic information that makes up the chromosomes

polyribosome

(polysome) group of several ribosomes attached to and translating the same mRNA

Explain the physical events of crossing over

(prophase I) replicate homologous pair and become physically connected along their lengths by the syraptonemal complex; crossing over between 2 sister chromatids is completed; the 2 homologs slightly pull apart but held together by chiasmata

How many chromosomes are in a human somatic cell?

(somatic cell: all body cells except sperm and egg) -46

What specifically happens to a cell during the process of apoptosis?

*aka: cell suicide *protects nearby cells from damage from a cell leaking out its contents -cellular agents chop up DNA and fragment organelles and other cytoplasmic components -cell shrinks and becomes lobed -cell's parts are packaged up in vesicles that are engulfed and digested by specialized scavenger cells

Seven Essential Factors of Living Organisms (RAREHOG)

*has to have all 7 to be alive -Reproduction (ex: hereditary, DNA) -Adaption (ex: evolution) -Response to environment (ex: food chain) -Energy (ex: photosynthesis, cellular respiration) -Homeostasis (ex: regulation) -Order (ex: cells) -Growth and development (ex: embryo developing fingers)

lac operon

*see pg 2 ch 18 RG for better diagram

signaling pathway cell regulation

*see pg 9 ch 18 RG or pg 375 for diagram (1) growth factor binds to (2) receptor in the plasma membrane. Signal is relayed to (3) G protein called Ras passed to signal (4) a series of protein kinases. Last kinase activates (5) transcription activator that turns on one or more genes for proteins that stimulate the cell cycle. If a mutation makes Ras or any other pathway components abnormally active, excessive cell division and cancer may result.

unsaturated fatty acid

- has a double bond which creates a kink, can't stack to form solids -ex: olive oil and canola oil

Here is the abbreviated ring structure of glucose. Where are all the carbons?

- on the corners and one "branch"

What is the operator? What does it do?

-(bacterial) sequence of nucleotides near start of an operon to which an active site repressor can attach -with bound repressor, prevents RNA pol from attaching to promoter and transcribing genes of operon; controls access of RNA pol to genes

An event that is certain to occur has a probability of __, while an event that is certain not to occur has a probability of __.

-1 -0

chromosome

-1 DNA molecule and associated proteins -chromatid: 2 DNA molecules stuck together -centromere: specialized region where 2 chromatids attach -chromatin: loosely packaged DNA and protein histones used for transcription

A female who carries an allele for colorblindness, but is not color-blind, mates with a camel who has normal color vision. What is the probability that they will have a sone who is color-blind?

-1/4 *see figure 15.6 in book/pg 3 ch 15 RG

The calvin cycle must be turned 3 times. Each turn will require a starting molecule of ribulose biphosphate, a five-carbon compound. This means we start with ___ carbons distributed in three RuBPs. After fixing three carbon dioxides using the enzyme ____, the calvin cycle forms six G3Ps with a total of ___ carbons. At this point the net gain of carbons is ___, or one net G3P molecule.

-15 carbons -rubisco -3

What is the difference between a first messenger and a second messenger?

-1st messenger: ligand -2nd messenger: any small, non-protein, water-soluble, or ion component of a signal transduction pathway

Explain the law of segregation

-2 alleles for each gene separate -F1 -> 4 haploid gametes

G2 of interphase

-2 centrosomes have been formed by replication of z -(animal cells) each centrosome features 2 centrioles -chromosomes (duplicated during S phase) can't be seen individually because haven't condensed yet

Telophase

-2 daughter nuclei formed -nuclear envelopes form from fragments -nuclei reappear -chromosomes become less condensed -mitosis complete

How many nucleotide bases are there? How many amino acids?

-4 bases -20 nucleotides

Make an electron distribution diagram of carbon. -How many valence electrons does carbon have? -How many bonds can carbon form? -What type offends does it form with other elements?

-4 valence -4 bonds -covalent bonds

How many chromosomes are in human cells? What is a chromosome?

-46 -condensed DNA strand and associated proteins

Three turns of the calvin cycle nets one G3P because the other five must by recycle to RuBP. Explain how the regeneration of RuBP is accomplished.

-5 G3P molecules are rearranges into 3 RuBP molecules by last steps of calvin cycle -cycle uses 3 ATP

The net production of one G3P requires ___ molecules of ATP and ___ molecules of NADPH.

-9 ATP -6 NADPH

DNA nitrogenous bases

-Adenine -Guanine -Thymine -Cytosine

What molecules make up the rungs?

-Adenine -Guanine -Thymine -Cytosine

RNA nitrogenous bases

-Adenine -Guanine -Uracil -Cytosine

three domains

-Bacteria (prokaryotic): bacteria -Archaea (prokaryotic): archea -Eukarya (eukaryotic): plants, animals, fungi, protists

Consider the following materials that must cross the membrane. For each, tell how it is accomplished.

-CO2: straight through membrane (phospholipids) -glucose: carrier protein specifically for glucose -H+: straight through membrane -O2: straight through membrane -H2O: aquaporins

All sugars have the same to functional groups. Name them.

-Carbonyl (C=O) -Hydroxyl (--OH)

cyclic electron flow

-Cyclic electron flow is thought to be similar to the first forms of photosynthesis to evolve. In cyclic electron flow no water is split, there is no production of NADPH, and there is no release of O2

What is the TATA box? How do you think it got this name?

-DNA sequence in eukaryotic promoters crucial in forming the transcription complex -sequence of thymine-adenine-thymine-adenine (TATA)

What are the monomers of DNA and RNA? Of proteins?

-DNA: A, T, C, G -RNA: A, U, C, G -proteins: amino acids

Name and describe three human sex-linked disorders

-Duchenne Muscular Dystrophy: progressive weakening and loss of muscle tissue -Hemophilia: absence of one or more blood-clotting proteins; excessive bleeding -Color Blindness: inability to see certain colors, usually linked with Y chromosome

Summarize what happens at each checkpoint

-G1: if cell receives go-ahead signal at this point, cell cycle continues (regulated by Cdk) -G2: sufficient MPF accumulates, G2 is passed and mitosis is promoted (MPF initiates process that destroys own cyclin) -M: kinetochores attached to spindle fibers (metaphase), activate separase, allows sister chromatids to separate and anaphase to follow

List the three places in the light reactions where a proton-motive force is granted.

-H+ from H2O -pumped across membrane complex -remove H+ from storm when NADP+ -> NADPH

Use four examples to compare how chemiosmosis is similar in photosynthesis and cellular respiration.

-H+ gradient -ATP produced -ETC -use ATP synthase

linear electron flow

-H2O is the source of electrons for linear electron flow?This compound is also the source of O2 in the atmosphere. -As electrons fall between photosystem I and II, the cytochrome complex uses the energy to pump H+ ions. This builds a proton gradient that is used in chemiosmosis to produce ATP. -In photosystem II, the excite electron is eventually used by NADP+ reductase to join NADP+ and H+ to form NADPH. *NADPH and ATP produced will be used in the Calvin cycle

Use figure 9.11 to help you answer the following summary questions about the citric acid cycle

-How many NADHs are formed?: 3 per pyruvate -How many total carbons are lost as pyruvate is oxidized?: 2 per pyruvate -The carbons have been lost in the molecule carbon dioxide. -How many FADH2 have been formed?: 1 per pyruvate -How many ATPs are formed?: 1 per pyruvate

electron distribution diagram for sodium

-How many valence electrons does it have?: 1 -How many protons does it have?: 11

Differences between prokaryotic and eukaryotic cells

-Mode of reproduction: pro- binary fission euk- mitosis and meiosis -Number of chromosomes: pro- 1 euk- multiple (depends on organism) -shape of chromosome: pro- circular euk- linear pairs

Show the normal, downhill route most electrons follow in cellular respiration: glucose->____->____->oxygen

-NADH -electron transport chain (ETC)

The diagram covers only one pyruvate, although two pyruvate are formed from a single glucose. How many molecules of the following are formed from the breakdown of glucose?

-NADH = 6 -FADH2 = 2 -ATP = 2

At this point, you should be able to account for the total number of ATPs that could be formed from a glucose molecule. To accomplish this, we have to add the substrate-level ATPs from glycolysis and the citric acid cycle to the ATPs formed by chemiosmosis. Each NADH can form a maximum of ___ ATP molecules. Each FADH2, which donates electrons that activate only two proton pumps, makes ___ ATP molecules.

-NADH: 3 -FADH2: 3

As a review, note that the light reactions store chemical energy in ___ and ___, which shuttle the energy to the carbohydrate-producing ___ cycle

-NADPH -ATP -Calvin

What are the three key roles of cell division?

-Reproduction, ex: unicellular organism divides, creates a whole new organism -Growth/Development, ex: sexually reproducing organisms to develop from a single cell -Repair: new skin cells replace after a cut

Who proposed the fluid mosaic model of membrane structure? When? Describe this model

-S.J. Singer and G. Nicolson in 1972 -membrane is a mosaic of proteins drifting laterally in a fluid bilayer of phospholipids

Adenine paris with ____. Cytosine pairs with____. *DNA

-Thymine -Guanine

Explain how proteins are targeted for degradation

-Ubiquitin tag is attached which marks protein for destruction, proteasome see the tag -recycling cyclin to allow healthy cell cycle

Now, refer back to your definition of a compound and fill in the following chart.

-Water: molecule; not a compound; molecular formula: H2O; structural formula: H-O-H -Carbon dioxide: molecule; not a compound; molecular formula: CO2; structural formula: O=C=O -Methane: molecule; compound; molecular formula: CH4; structural formula: see page 3 of ch 2 reading guide -O2: molecule; not a compound; molecular formula: O2; structural formula: O=O

RNA processing only occurs in eukaryotic cells. The primary transcript is altered at both ends and section in the middle are removed.

-What happens at the 5' end?: receives a 5' cap after transcription of first 20-40 nucleotides -What happens at the 3' end?: poly-A tail (50-250 more adenine added)

Galapagos Finches evolutionary tree

-What is indicated by each "twig"?: an adaptation causing differences, but still linked to each other -What do the branch points represent?: a mutation (that persisted) -Where did the "common ancestor" of the Galapagos finches originate?: thought to have originated from the Caribbean Islands

Mendel's law of segregation

-What is the F2 phenotypic and genotypic ratio?: 3:1 -Which generation is completely heterozygous?: F1 -Which generation has both heterozygous and homozygous offspring?: F2

There are two types of reactions in metabolic pathways: anabolic and catabolic

-Which reaction release energy?: catabolic -Which reactions consume energy?: anabolic -Which reactions build up larger molecules?: anabolic -Which reactions break down molecules?: catabolic -Which reactions are considered "uphill"?: anabolic -What type of reaction is photosynthesis?: anabolic -What type of reaction is cellular respiration?: catabolic -Which reactions require enzymes to catalyze reactions?: anabolic

Why are cells so small? Explain the relationship of surface area to volume

-a smaller object has greater ratio of surface to volume -volume grows > surface area

What is pleiotropy? Explain why this is important in diseases like cystic fibrosis and sickle-cell disease.

-ability of a single gene to have multiple effects -responsible for multiple symptoms associated with hereditary diseases

Enzymes use a variety of mechanisms to lower activation energy. Describe four of these mechanisms

-acting as template for substrate orientation -stressing substrates and stabilizing transition state -providing favorable microenvironment -participating directly in catalytic reaction

Explain the difference between an allosteric activator and an allosteric inhibitor.

-activator: stimulates -inhibitor: slows down/stops

What did Oswald Avery determine to be the transforming factor? Explain his experimental approach

-active DNA -broke open heat-killed pathogenic bacteria and extracted cell contents; used specific treatments for each molecule; tested each treated sample for its ability to transform live nonpathogenic bacteria

five nitrogenous bases

-adenine: purine, DNA and RNA -guanine: purine, DNA and RNA -cytosine: pyrimidine, DNA and RNA -thymine: pyrimidine, DNA -uracil: pyrimidine, RNA

How does a hormone qualify as a long-distance signaling example?

-aka endocrine signaling (animals) -specialized cells release hormone molecules, travel through the circulatory system to target cells in other parts the body (animal) -travel in vessels or diffuse through the air as a gas (plant) -going through these things, they travel father than other signals -electrical signal travels the length of a nerve cell

Primary protein structure

-amino acid sequence -explanation: level referring to the specific sequence of amino acids -ex: transthyretin transports vitamin A

One function of lysosomes is intracellular digestion of particles engulfed by phagocytosis. Describe this process of digestion. What human cells carry out phagocytosis?

-amoebas and other protists eat by engulfing smaller organisms/food particles (phagocytosis) -macrophages (white blood cell) is a human cell that carries out phagocytosis

What are two benefits of multistep pathways like the protein kinase chain in figure 11.9?

-amplification of signal -better regulation

For aerobic respiration to continue, the cell must be supplied with oxygen -- the ultimate electron acceptor. What is the electron acceptor in fermentation?

-an organic molecule -ex: pyruvate or acetaldehyde

Here is a molecule of starch, which shows 1-4 glycosidic linkages. Translate and explain this terminology in term of carbon numbering

-angle of bonds makes polymer helical -number one carbon of first glucose joins with the number four carbon of the other

Consider what would happen if ponds and other bodies of water accumulated ice at the bottom. Describe why this property of water is important.

-aquatic life wouldn't be able to survive winter/cold temperatures -only a few top inches would melt -this property creates a top layer of insulation so the water below doesn't freeze and aquatic life can survive in the cold

Prokaryote reproduction does not involve mitosis, but instead occurs by binary fission. This process involves an origin of replication. Describe binary fission

-asexual reproduction where a cell's size doubles then divides in half to produce 2 identical daughter cells with the same DNA -origin of replication: site where DNA replication begins consisting of specific sequence of nucleotides

carbon

-atomic mass: 12 -atomic number: 6 -electrons: 6 -neutrons: 6

helium

-atomic number: 2 -atomic mass: 4.003

What occurs in histone acceleration? How does it affect gene expression?

-attachment of acetyl groups to certain amino acids of histone proteins, transcription is easier -promotes loose chromatin structure (permitting transcription), acetyl groups attached to lysine in histone tails neutralize positive charges and histones no longer bind to neighboring molecules *deacetylation can repress transcription

Secondary protein structure

-backbone -explanation: segments of a peptide chain repetitively coiled and folded patterns of the polypeptide backbone of a protein due to hydrogen bond formation -ex: alpha helix's coil or beta pleated sheet

Describe the action of difference types of chemical mutagens

-base analogs are chemical similar to normal DNA bases, but pair incorrectly during DNA replication -other chemical mutagens interfere with correct DNA replication by inserting themselves into DNA and distorting the double helix

Anaphase

-begins when cohesion proteins are cleaved (allows sister chromatids to part suddenly) -separated sister chromatids move toward opposite ends of cell a kinetochore microtubules shorten -cell elongates as nonkinetichore microtubules lengthen outward -at end, 2 cell ends have = and complete collections of chromosomes

Distinguish between a benign tumor and a malignant tumor

-benign: noncancerous, remains at original site -malignant: impairs functions of other organs, invade other parts of body

List three important facts about the promoter here

-binding site for RNA polymerase -determines where transcription starts -determine which of the two DNA strands in helix is the template

How does a repressor protein work?

-binds to operator and blocks attachment of RNA pol to the promoter, preventing transcription of genes -specific to operator, no effect on other operons

hierarchy of life

-biosphere: all environments -ecosystem: all living and non-living components in an area -community: array of organisms in an ecosystem -population: all individuals of a species in an area -organisms: individual living things -organs: body parts made of two or more tissues -tissues: group of cells -cells: unit of structure and function -organelles: various functional components that make up cells -molecules: chemical structures of two or more atoms

The muscle cells of a dog have 78 chromosomes. Fill in the correct chromosome number in a: bone cell, sperm, haploid, somatic cell, zygote

-bone: 78 -sperm: 39 -haploid: 39 -somatic: 78 -zygote: 78

Compare the lac operon and the trip operon.

-both: code for an allosteric repressor protein that can switch on/off -trp: inactive by itself, requires tryptophan as corepressor to bind to operator (inducible) -lac: active by itself (repressible)

Explain which has more potential energy in each pair

-boy at the top of a slide/boy at the bottom: top because he has the potential to slide down -electron in the first energy shell/electron in the third energy shell: third because distance and attraction to positives in nucleus -water/glucose: glucose because it has more electrons

Explain what is meant by a scientific theory by giving the three ways your text separates a theory from a hypothesis or mere speculation.

-broader than a hypothesis -general enough to lead to specific, testable hypothesis -supported by more evidence

Explain the symptoms of phenylketonuria, and describe how newborn screening is used to identify children with this disorder

-can't properly metabolize amino acid phenylalanine, can cause mental retardation if amino acid and by-product build up to toxic levels -can identify carriers

The large molecules of all living things fall into just four main classes. Name them.

-carbohydrates (macromolecule) -lipids -proteins (macromolecule) -nucleic acids (macromolecule)

What is the function of ribosomes? What are their two components?

-carry out protein synthesis -made of rRNA and protein

The second receptor described is receptor tyrosine kinase (ch 11 pg 3). Explain what a kinase enzyme.

-catalyzes the transfer of phosphate groups -catalyzes transfer of phosphate group from ATP to amino acid and tyrosine on a substrate protein

What occurs in meiosis? How is the chromosome number of daughter cells different?

-cell division that produces reproductive cells in sexually reproducing organisms (nonidentical daughter cells) -1/2 number of chromosomes as parent cells, only get one set

What does MPF trigger? What are some specific activities that it triggers?

-cell passage past G2 checkpoint into M phase -mitosis

labeled prokaryotic cell

-cell wall: rigid structure outside palm membrane -plasma membrane: membrane enclosing the cytoplasm -bacterial chromosome: only prokaryotes have -nucleoid- region where the cell's DNA is located (not membrane enclosed) -cytoplasm: interior of prokaryotic cell -flagella: locomotion organelles of some bacteria

components of mitotic spindle

-centrosomes -microtubules

Metaphase

-centrosomes at opposite poles of cell -chromosomes convene on metaphase plate -for each chromosome, kinetochores of sister chromatids are attached to kinetochore microtubules coming from opposite poles

Peter Agre received the Nobel Prize in 2003 for the discovery of aquaporins. What are they?

-channel protein in membrane of plant, animal, and microorganisms cells that specifically facilitates osmosis -allows hydrophilic polar molecules to get through the membrane quickly

Describe at least three typed of post-translational modifications

-chemical modification of amino acids by attaching sugars, lipids, phosphate groups, etc -enzymes may remove one or more amino acids from leading end of polypeptide chain -two or more polypeptides may come together, becoming subunits of protein with a quaternary structure

List the three main kinds of work that a cell does. Give an example of each.

-chemical work: the pushing of endergonic reaction; ex: synthesis of polymers from monomers -transport work: pumping substances across a membrane against spontaneous movement; ex: Na+ and K+ pump -mechanical work: beating of cilia, muscle cell contraction, chromosome movement during cell reproduction

What are two forces that drive the diffusion of ions across the membrane? What is the combination of these forces called?

-chemical: ion concentration gradient -electrical force: effect of membrane potential on ion's movement -electrochemical gradient

Two key terms chemiosmosis and proton-motive force. Relate both of these terms to the process of oxidative phosphorylation.

-chemiosmosis: energy stored in H+ gradient across membrane used to drive cellular work -proton-motve force: force formed by pumping H+ across membrane during chemiosmosis

List two specific cancer treatments and tell how each treatment works

-chemotherapy: chemicals attack cells, specifically cells that are reproducing -radiation: small wavelengths directed towards cancer damages DNA

A hedgehog has 90 chromosomes in its somatic cells

-chromosomes inherited from each parent: 45 -chromosomes in each gamete: 45 -chromosomes in each somatic cell of offspring: 90

Found within the nucleus are the chromosomes. They are made of chromatin. What are the two components of chromatin? When do the thin chromatin fibers condense to become distinct chromosomes?

-coil up to distinguish as separate structures -chromatin: complex of proteins and DNA

Darwin's Origen of Species

-contemporary species arose from descent with modification of common ancestors -natural selection

What is a thymine dimer? How might it occur? How is it repaired?

-covalently linked thymine bases adjacent to DNA strand, cause DNA to buckle and interfere with replication -UV rays -nuclease removes damage, DNA pol fills missing nucleotides, ligase seals end of new DNA to old

Intracellular receptors are found in the ___ or ___ of the cell, where they bond to chemical messengers that are ___ or very small, like nitric oxide.

-cytoplasm -nucleus -hydrophobic

Notice that glycolysis occurs in the ___ of the cell. What is the relationship concerning glycolysis and oxygen?

-cytosol -oxidation takes away chemical energy (not sure, I don't know)

Which type of energy does water behind a dam have? A mole of glucose?

-dam: potential (altitude above sea level) -glucose: potential (arrangement of atoms)

Telophase I (meiosis)

-daughter cells are haploid

Describe how the following can affect membrane fluidity: -decreasing temperature -phospholipids with unsaturated hydrocarbon chains -cholesterol

-decreasing temp: solifies (when cold enough), varies for different types -phospholipids w/ unsat: more fluid (can't pack together as closely) -cholesterol: high temps- less fluid by restraining phospholipid movement, hinders close packing of phospholipids, lowers solidifying temp, **temperature buffer

Monomers are connected in what type of reaction? What occurs in this reaction?

-dehydration reaction -a water molecule is removed so two molecules can bonds together

What is a Barr body? Why do human females show a Barr body in their cells?

-dense object along inside of nuclear envelope in female mammal cells; highly condense, inactivated X chromosome -so females and males have one copy of most X-linked genes

How to deoxyribose and ribose sugars differ?

-deoxyribose doesn't have oxygen on 2nd carbon -ribose has oxygen on 2nd carbon

What is the difference between an aldehyde and a ketone sugar?

-depends on placement of carbonyl group and six of carbon skeleton -aldehyde: formed when alcohol is partially oxidized -ketone: when fats are broken down for energy

sex chromosome

-determines an individual's sex -2 in human cells

Make an electron distribution diagram of water. Which element is most electronegative? Why is water considered a polar molecule?

-diagram on page 4 of ch 2 reading guide -more electronegative: oxygen -polar because the electrons are pulled to the more electronegative element (oxygen)

Sucrose

-disaccharide -formed by: glucose + fructose -found where: table sugar

Lactose

-disaccharide -formed by: glucose + galactose -found where: milk

Maltose

-disaccharide -formed by: glucose + glucose -found where: malt sugar

two main types of scientific inquiry

-discovery science, ex: Goodall's chimpanzee behavior studies -hypothesis-base (applies to scientific method), ex: predicting a lion will attack a gazelle

What is a karyotype? How is it prepared? What are there things that can be determined from a karyotype?

-display of chromosome pairs of a cell arranged by size and shape -prepared from isolated somatic cells treated with mitosis stimulating drug, grown in future for several days -size of chromosome, centrosome position, pattern of stained bands

How do different sets of activators come to be present in two cells?

-distribution of cytoplasmic determinants: maternal substances in the egg that influence early development; unevenly distributed in the cytoplasm of egg so different cells end up with different amounts of molecules as the cells divide -different inductive signals: signals to embryonic cell from theory embryonic cells in the vicinity, signals cause changes in target cell down a noticeably differentiated path

Cytokinesis

-division of cytoplasm is usually well under way in late telophase, 2 new cells form shortly after -(animal cells) involves formation of cleavage furrow -(plant cells) cell plate

Prophase

-each duplicated chromosome appears as 2 identical, joined sister chromatids -mitotic spindle begins to form -centrosomes move away from each other

Explain the law of independent assortment

-each pair of allele segregates independently of each other during gamete formation

synaptic (local signaling type)

-electrical signals trigger chemical, affects only target cells -specific ex: neuron firing into a muscle cell, causing it to contract

Is photosynthesis endergonic or exergonic? What is the energy source that drives it?

-endergonic (ΔG) -(sun) light->chemical->sugar

four important functions of fats

-energy storage -cushion vital organs -isolates the body -reservoir of fuel

What are Chargaff's rule? How did he arrive at them?

-equivalences of A to T and C to G in any species is about the same; around the same ratios of each -tested DNA from several different species

How does a prokaryotic ribosome differ from a eukaryotic ribosome? What is the medical significance of this difference?

-eukaryotic: larger in structure, different molecule composition -prokaryotic: smaller, different molecule composition -certain antibiotics can inactivate bacterial ribosomes without inhibiting ability of eukaryotic ribosomes

A major difference between prokaryotic and eukaryotic cells is the location of their DNA. Describe this difference.

-eukaryotic: nucleus bounded by double membrane in nucleus -prokaryotic: nucleoid not membrane enclosed (DNA in nucleoid)

Is cellular respiration an endergonic or exergonic reaction? What is ΔG for this reaction?

-exergonic (-ΔG)

What are three important functions of the 5' cap and the poly-A tail?

-facilitate export of mature mRNA to nucleus -help protect mRNA from degradation by hydraulic enzymes -helps ribosomes attach to 5' end of mRNA once mRNA reaches cytoplasm

What are the two main was of controlling metabolism in bacterial cells?

-feedback inhibition -regulation of gene expression

What are the components of the mitotic spindle? What is the source of these components?

-fibers made from microtubules and associated proteins -from centromere

At which end do the kinetochore microtubules shorten during anaphase? supporting data

-from kinetochore side (not polar) -tested on cell and notices change in length from kinetochore and not pole

Hormonal proteins

-function: coordination of organism's activities -ex: insulin helps regulate concentration of blood sugar

Enzymatic proteins

-function: selective acceleration of chemical reaction -ex: digestive enzymes catalyze hydrolysis of food polymers

Storage proteins

-function: store amino acids -ex: ovalbumin is protein of egg white, used as an amino acid for developing an embryo

Structural proteins

-function: support -ex: collagen and elastin provide fibrous framework in animals

Transport proteins

-function: transport of other substances -ex: hemoglobin transports oxygen from lungs to their body parts

What are linked genes? Do linked genes sort independently?

-genes located close enough together on a chromosome that they tend to be inherited together -not usually

In the 1800s the most widely favored explanation of genetics was blending. Explain the concept of blending, and then describe how Mendel's particulate (gene) theory was different.

-genetic material contributed by parents mixes like blue and yellow make green -parent pass on discrete heritable units that retain separate identities in offspring

What is the meaning of genome? Compare your genome to that of a prokaryotic cell.

-genetic material of an organism or virus -prokaryotic: single long DNA molecule -eukaryotic (yours): multiple DNA molecules (around 2m of DNA)

The starting product of glycolysis is a six-carbon sugar ____, and the ending product is two ___ carbon compounds termed ____.

-glucose -three -pyruvate

The carbohydrate produced directly from the calvin cycle is not glucose, but the three-carbon compound ____. Each turn of the calvin cycle fixes one molecule of CO2; therefore, it will take ___ turns of the calvin cycle to net one G3P.

-glyceraldehyde 3-phosphate (G3P) -3

What are the building blocks of fats?

-glycerol -3 fatty acids

Here is a figure (pg 5 ch 5 RG) that shows the structure of a phospholipid. Label the sketch to show the phosphate group, the glycerol, and the fatty acid chains. Also indicates the region that is hydrophobic and the region that is hydrophilic.

-head: phosphate group, hydrophilic, polar -head and neck: glycerol -tails: fatty acid chains, hydrophobic, non polar

Gene expression can be regulated by modifications of the chromatin. Distinguish between heterochromatin and euchromatin as to their structure and activity.

-heterochromatin: highly compressed, genes not usually expressed -euchromatin: less condensed form of a eukaryotic chromatin that is usually available for transcription

The root words of hydrolysis will be use many times to form other words you will learn this year. What does each root word mean?

-hydro: water -lysis: break

Large molecules (polymers) are converted to monomers in what type of reaction?

-hydrolysis, splits molecules by adding water

Give one example that vary in their pharmacological effect.

-ibuprofen: targets pain and inflammation -albuterol: targets asthma

miRNA gene regulation

-if miRNA and mRNA bases are complementary all along their length, the mRNA is degraded (left) -if the match is less complete, translation is blocked (right)

Explain what is meant by epigenetic inheritance

-inheritance of traits not transmitted by mechanisms not directly involving the nucleotide sequence -drosophila

Many factors can affect the rate of enzyme action. Explain each factor listed here.

-initial concentration of substrate: more substrate means more reactions -pH: without denaturing enzyme, optimal pH allows greatest number of molecular collisions and fastest reactants->products -temperature: without denaturing enzyme, optimal temperature allows greatest number of molecular collisions and fastest conversion reactants to products

activation energy (EA *subscript A)

-initial investment of energy for starting a reaction -energy required to contort react molecules so bonds can break -What effect does an enzyme have on EA?: lowers it -Is ΔG positive or negative?: negative -How if ΔG affected by the enzyme?: unaffected

Describe what happens to the centrosome during interphase and then prophase.

-interphase: single centrosome replicates to make 2 (stay together in nucleus) -prophase: 2 centrosomes move apart; mitotic spindle attaches

saturated fatty acid

-isn't kinked, can stack to form solids -ex: butter and bacon grease

Explain the difference between kinetochore and nonkinetochore microtubules

-kinetochore: attach to kinetochores on chromosomes and move chromosomes -non: push against each other and lengthen cell, not attached

Distinguish between the leading and lagging strands during DNA replication

-leading: 5' -> 3', synthesizes continuously -lagging: 3' -> 5', synthesizes discontinuously

List and describe 3 major functions of smooth ER.

-lipid synthesis -carb metabolism -detoxification of drugs and poisons

For each of the following, is the cell diploid or haploid?

-liver cell: diploid -egg: haploid -skin cell: diploid -somatic: diploid -gamete: haploid -zygote: diploid -sperm: haploid -sex cell: haploid

Frederick Griffith's experiment

-living S cells: dead mouse -living R cells: living mouse -heat-killed S cells: living mouse -mix of heat-killed S cells and living R cells: dead mouse -> living S cells found in blood, can reproduce

bound ribosome

-location: attached to endoplasmic reticulum or nuclear envelope -product: proteins that are destined for insertion in membrane

free ribosome

-location: cytoplasm -product: sugar breakdown (1st steps)

The endoplasmic reticulum makes up more than half the total membrane system in many eukaryotic cells. Use this sketch (p 4 ch 6 RG) to explain the lumen, vesicles, and the difference between smooth and rough ER.

-lumen: continuous compartment enclosed by ER -transport vesicles: vesicles in transit around the cell -smooth ER: metabolism -rough ER: secrete proteins

What is a lysosome? What do they contain? What is their pH?

-membrane-enclosed sac of hydraulic enzymes found in cytoplasm of animal cells -neutral pH

What is meant by membrane fluidity? Describe the movements seen in the fluid membrane.

-membranes move and aren't completely rigid/still -held together by hydrophobic interactions (weak) -lipids and proteins can move laterally -solidifies when cold enough -cholesterol (animal) affects fluidity (keeps from solidifying/falling apart at extreme temps to a point)

What is DNA methylation? What role may it play in gene expression?

-methyl groups added to certain DNA bases, making that section of DNA inactive (too tight to transcribe) -blocks transcription; proteins bind to methylated DNA and recruit enzymes to demethylate them and the the gene back on

What is genomic imprinting, and how is it maintained?

-methylation permanently regulates maternal or paternal allele of particular genes at start of development -specialized tissues keep chemical record during embryonic development -mother/father's methylation due to smoking (?)

Prometaphase

-microtubules from centrosomes can get in nuclear area because nuclear envelope is fragmented -chromosomes more condensed -each 2 chromatids has a kinetic hare with attached kinetochore microtubules

Use two key difference to explain how chemiosmosis is different in photosynthesis and cellular respiration.

-mitochondria: high energy electrons in ETC from organic molecules (food) -chloroplasts: photosystems capture light energy to drive electrons from water for ETC

-By what process are the damages cells in a wound replaced? -By what process are eggs formed? -By what process does a zygote develop into a multicellular organism? -In which process are identical daughter cells produced? -Which process reduces chromosome number in daughter cells?

-mitosis -meiosis -mitosis -mitosis -meiosis

What is mitosis? How is it different from cytokinesis?

-mitosis: division of nucleus (identical daughter cells) -cytokinesis: division of cytoplasm and other organelles

What is facilitated diffusion? Is it active or passive? Two examples

-molecules diffuse through membrane by going through transport proteins -passive -ex channel: allow water through -ex carrier: glucose transport

What are three mechanisms for converting a proto-oncogene to and oncogene?

-movement of DNA within genome -amplification of a photo-oncogene -point mutations in a control element or in the proto-ongene (promoter/enhancer that controls proto-oncogene, increase expression; in coding sequence)

Describe active transport. What type of transport proteins are involved, and what is the role of ATP in the process?

-moving a solute against the concentration gradient, requiring energy -carrier proteins -ATP transfers terminal phosphate group directly to transport protein to change its shape

Name two types of somatic cells in your body

-muscle -bone

What mechanism is involved in the beginning of tumor growth? Discuss oncogenes and proto-oncogenes

-mutations in the genes that normally regulate cell growth and division in somatic cells -oncogene: found in viral/cellular genomes that are involved in triggering molecular events that can lead to cancer -proto-oncogene: normal cellular gene that has potential to become and oncogene

Darwin's Evolution Theory

-natural selection: genetic mutations that were helpful we passed on and ones that weren't helpful weren't passed because they organism wouldn't reproduce

For an exergonic reaction, ΔG is negative or positive?

-negative (-ΔG)

nucleic acid

-nitrogenous base: hexagon (+ attached pentagon if present) -phosphate group: yellow -sugar: pentagon

What is the Go phase?

-nondividing state occupied by cells that have left the cycle -if cell doesn't receive go-ahead signal it exits the cell cycle

Describe the means by which Hershey and Chase established that only the DNA of a phage enters and E. coli cell. What conclusions did these scientist draw based on these observations?

-nonradioactive E. coli infected by labeled T2, tested samples shortly after to see if DNA or protein had entered and was capable of reprogramming the bacteria -phage DNA entered, protein didn't; DNA must be carrying genetic info

Consider the following reaction: C6H12O6 + C6H12O6 -> C12H22O11

-not balanced; it's missing a molecule of water: 1 H2O on product side -dehydration reaction -C6H12O6 is a monomer -when two monomers are joined a molecule of water is always removed

autosome

-not directly involve in determining sex; not a sex chromosome -44 in human cells

Explain what is meant by 5' and 3' ends of the nucleotide

-numbers assigned to carbons in sugar -5' end: exposed phosphate -3' end: exposed -OH of sugar

paracrine (local signaling type)

-numerous cells simultaneously receive and respond to growth factors produced by cells in their vicinity -specific ex: development- compounds that stimulate nearby target cells to grow and divide

What is a hydrocarbon? Name two. Are hydrocarbons hydrophobic or hydrophilic?

-organic molecule consisting of carbon and hydrogen -ethane and propane -hydrophobic

Tertiary protein structure

-overall shape -irregular contortions because of side chains involved in hydrophobic interaction, ionic bonds, hydrogen bonds, and disulfide bonds -ex: hydrophobic interaction

Quaternary protein structure

-overall structure -overall structure results from aggregation of polypeptide subunits -ex: collagen's triples helix

Fermentation allows for the production of ATP without using either ___ or any ___.

-oxygen -electron transport chain

Metaphase I (meiosis)

-pairs of homologous chromosomes line up on metaphase plate to be separated (from their pairs)

How did Hershey and Chase "label" viral DNA and viral protein so that they could be distinguished? Explain why they chose each radioactive tag in light of the chemical composition of DNA and protein.

-phages grown with ^35S and ^32P -sulfur in protein, not DNA -phosphorus is in DNA, not protein

Why is the count about 36 or 38 ATP molecules rather than a specific number?

-phosphorylation and redox aren't directly coupled to each other -- ration of NADH to ATP isn't whole number -varies depending on the type of electron shuttle -use of proton-motive force generated by redox

Photosystem I is referred to by the wavelength at which its reaction center best absorbs light, or P____; photosystem II is also known by this characteristic, or P___.

-photosystem I: P700 -photosystem II: P800

telomere

-pink parts on picture Explain telomere erosion and the role of telomerase: -telomere erosion: postpone erosion of genes near DNA ends -telomerase: catalyzes lengthening of telomeres in germ cells

three components of an operon

-promoter: where RNA pol binds to begin transcription -operator: on/off sequence in/after promoter -operon genes: functionally related genes controlled by the same operator

What is a release factor? By what mechanism is termination accomplished?

-protein shaped like aminoacyl tRNA that binds directly to stop codon in A site -hydrolization, releasing polypeptide through E site of large ribosomal subunit

Distinguish between the structure of pyrimidines and purines. Explain why adenine bonds only to thymine.

-pyrimidines: one organic ring -purines: two organic rings -adenine is about two ties as wide as thymine, so thymine has to be smaller for the helix to be a uniform width

photosystem

-reaction center complex: after receiving excite electrons from light-harvesting complex, two special chlorophyll A molecules donate these electrons to the primary electron acceptor so they can go in the ETC -light-harvesting complex: functions in gathering light to raise electrons to an excited state so they can go to the reaction center complex -primary electron acceptor: shares reaction center complex with pair of chlorophyll A molecules and accepts electrons from them

-What happens to chromosome number in meiosis? -During which division is the chromosome number reduced? -What is the purpose of meiosis? -How many times does the cell divide in meiosis? -How many times do the chromosomes duplicate? -How many daughter cells are formed? -What is the chromosome number? -What are homologs (homologs chromosomes)? -What occurs in synapsis? -What is crossing over?

-reduced by half -meiosis I -lower chromosome number in gamete (2->1) -2 -0 -4 -n -pair of chromosomes with the same length, centromere position, and staining pattern -pairing and physical connection os replicated homologs during prophase I -reciprocal exchange of genetic material between non sister chromatids during prophase I

Explain how Mendel's simple cross of purple and white flowers did the following:

-refuted blending: reappearance of white in F2 generation is evidence that the white gene hadn't been destroyed or drowned by the purple -determined dominant and recessive characteristics: white factor didn't disappear in F1 generation but didn't show -demonstrated the merits of experiments that covered multiple generations: analyzing thousands of genetic crosses from F2 equals deduced 2 principle of heredity: law of segregation and law of independent assortment

Explain how using pea plants allowed Mendel to control mating; that is, how idd this approach let Mendel be positive the exact characteristic of each parent?

-removes immature stamens of plant before they produced poll; dusted pollen from another plant on altered flowers, resulted in plant embryos *reproductive organs are in flower, reproduces with itself

three ways in which RNA differs from DNA

-ribose (not deoxyribose) -uracil (not thymine) -single strand

In the 1960s, the Davson-Danielli model of membrane structure was widely accepted. Describe this model and then cite two lines of evidence that were inconsistent with it.

-sandwich model: phospholipid bilayer between two layers of proteins -electron microscope pictures -surface os membrane adheres less strongly to water than to a biological membrane

Change the structure, change the function... now we are going to look at testosterone and estradiol. Notice how similar these two molecules are, and yet you know what a vastly different effect each has. Label each molecule in the sketch below, and circle the differences.

-see page 2 of ch 4 reading guide

What is the SRY gene? Where is it found, and what does it do?

-sex determining region of Y -found on Y chromosome -required for development of testes

What is represented by R? How many are there?

-side chain -variable group (can be anything), number varies with every amino acid ****see pg 8 ch 5 RG for chart

How is allosteric regulation somewhat like noncompetitive inhibition? Different?

-similar: can inhibit -different: allosteric can stimulate, special enzymes with 2+ subunits

What is cotransport? Explain how understanding it is used in our treatment of diarrhea.

-single ATP-powered pump that transports a specific solute can indirectly drive active transport of several other solutes -patients drink high concentration glucose and salt, taken up, causes flow of water that rehydrates

What are three properties of RNA that allow it to function as an enzyme?

-single stranded: can base-pair with a complementary region elsewhere in the same molecule, gives molecule 3-D structure for catalytic functions -some bases contain functional groups that may participate in catalysis -ability to hydrogen-bond with other nucleic acid molecules adds specificity to its catalytic function

What are snRNPs? What two typer of molecules make up a snRNP?

-small nuclear ribonucleoproteins, recognize splice sites -RNA and protein molecules

Consider coffee to which you have added sugar. Which is the solvent? The solute?

-solvent: coffee -solute: sugar

How does a somatic cell compare to a gamete in terms of chromosome number?

-somatic: 2n -gamete: n

Membran carbs are important in cell-cell recognition. What are two examples of this?

-sorting of cells into tissues and organs -rejection of foreign cells

Name two type of gametes

-sperm -egg

cholesterol

-steroid

This diagram (ph 6 ch 11 RG) uses testosterone, a hydrophobic hormone, to detail how intracellular receptors work. At each arrow, add an explanation of what is happening in the cell.

-steroid hormone (testosterone) passes through plasma membrane -testosterone binds to receptor protein in cytoplasm, activating it -hormone receptor complex enters nucleus and binds to specific genes -bound protein acts as a transcription factor (stimulates transcription of gene->mRNA) -mRNA translated into specific protein

two categories of polysaccharides

-storage, ex: starch and glycogen -structural, ex: cellulose and chitin *glycosidic linkages are different

Carboxyl (COOH)

-structure: -C=O | OH -ex: acetic acid -physical properties: acidic properties, found in ironized charge of 1- cells

Carbonyl (CO)

-structure: -C=O -ex: acetone -physical properties: ketone and aldehyde may be structural isomers, 2 groups also bound in sugars

Methyl (CH3)

-structure: -CH3 -ex: 5-methyl cytidine -physical properties: addition to methyl group to DNA/molecules on DNA affects gene expression, arrangement of methyl groups in male/female sex hormones affects their shapes and function

Hydroxyl (OH)

-structure: -OH -ex: ethanol -physical properties: polar, can form hydrogen bonds with H2O molecules to help dissolve organic compounds

Sulfhydryl (SH)

-structure: -SH -ex: cysteine -physical properties: 2 sulfur groups can react (forming a covalent bond to stabilize protein structure), cross-linking of cysteine in air proteins maintains curl/straight

Describe the structure of DNA relative to each of the following -components of backbone -components of rungs

-sugar, phosphate -nitrogenous bases (A, T, C, G)

Prophase I (meiosis)

-synapsis: pairing and physical connection of replicated homologous chromosomes -crossing over: reciprocal exchange between non sister chromatids -chiasmata: X shaped region representing homologous chromatids that have exchanged genetic material through crossing over

What is a ligand? What do ligand have to do with receptor-mediated endocytosis?

-term for any molecule that binds specifically to a receptor site of another molecule -LDLs are the ligands

qualities of a scientific hypothesis

-testable -falsifiable: has to be able to be proven wrong

What is meant by induced fit? How is it shown in this figure (pg 4 ch 8 RG)

-the enzyme changes shape to better fit the substrate -see figure

Explain why ice floats. Why is 4 degrees celsius the critical temperature in this story?

-the freezing causes the molecules to be farther apart, making it less dense than water -4 degrees C is when water is at its greatest density

Explain the statement that only the green cells of a plant are the autotroph while the rest of the plant is heterotroph

-the non-green cells depend on organic molecules exported from the leaves through the veins -green cells have chloroplasts that perform light reaction and produce their own food

If a fat is composed of 3 fatty acids and 1 glycerol, how many water molecules will be removed from it?

-through hydrolysis 3 water molecules will be removed and create Ester linkages between the glycerol and each fatty acid

Given that the DNA of a certain fly species consists of 27.3% adenine and 22.5% guanine, use Chargaff's rules to deduce the percentages of thymine and cytosine

-thymine: 27.3% -cytosine: 22.5%

Each activated protein in the figure (pg 5 ch 11 RG) above triggers a signal ____ pathway leading to a ____ cellular response.

-transduction pathway -cellular

Briefly describe major functions of membrane proteins

-transport: hydrophilic channel across membrane (selective to a particular solute) -enzymatic activity: active site exposed to substances in adjacent solution -signal transduction: receptor with specific binding shape for chemical messenger -cell-cell recognition: glycoproteins serve as ID tags specifically recognized by membrane proteins of other cells- -intercellular joining: membrane proteins of adjacent cells may hook together in various kinds of junctions -attachment to cytoskeleton and ECM: elements of cytoskeleton bound to membrane proteins, maintains shape and stabilizes location of certain membrane proteins; proteins that can bind to ECM molecules can coordinate extracellular/intracellular changes

Which of these events occur in Down syndrome? What are four characteristics of Down syndrome?

-trisomy -characteristic facial features, short structure, correctable heart defects, developmental delays

What is a trans fat? Why should you limit them in your diet?

-unsaturated fat containing one or more trans double bonds (unsaturated -> saturated in theory) -there's no enzyme to digest them, so they cause blockages

Explain why oxygen is the ultimate electron acceptor. Oxygen stabilizes the electrons by combining with two hydrogen ions to form what compound?

-very electronegative -H2O

Distinguish between the virulent and nonvirulent strains of Streptococcus pneumoniae studied by Frederick Griffith

-virulent: living S, mix of heat-killed S cells and living R cells -nonvirulent: living R cells, heat-killed S cells

What is membrane potential? Which side of the membrane is positive?

-voltage across a membrane -outside is positive

Why can you not digest cellulose? What organisms can?

-we don't have enzymes that digest cellulose -some prokaryotes and fungi can digest cellulose

Study this figure (pg 6 ch 8 RG) feedback inhibition

-what is the substrate molecule to initiate this metabolic pathway?: threonine -what is the inhibitor molecule?: isoleucine -what type of inhibitor is it?: noncompetitive -when does it have the most significant regulatory effect?: 1st step in pathway -what is this type os metabolic control called?: feedback inhibition

Scientists expected to find one aminoacyl-tRNA synthase per codon, but far fewer have been discovered. How does wobble explain this?

-wobble is base-pairing flexibility rules where the 5' nucleotide of tRNA anticodon can hydrogen-bond to one or more base at 3' of codon -different amino acid sequence can make the same amino acid

What is another term for a fertilized egg? What is the chromosome number in a fertilized egg?

-zygote -diploid, 2n

transcription initiation complex

1) activator proteins bind to distal control elements grouped as an enhancer in the DNA. This enhancer has three binding sites 2) A DNA-binding protein brings bound activators closer to the promoter. General transcription factors, mediator proteins, and RNA pol are nearby 3) the activators bind to certain mediator proteins and general transcription factors, helping them form an active transcription initiation complex on the promoter *see ph 5 ch 18 RG or pg 360 in book for better diagram

aminoacyl-tRNA syntheses joining a specific amino acid to a tRNA

1) active site binds to amino acid and ATP 2) ATP loses two phosphate groups and joins amino acid as AMP 3) appropriate tRNA covalently bonds to amino acid, displacing AMP 4) tRNA charged with amino acid is released by enzyme

translation elongation

1) anticodon of the incoming anicoacyl tRNA base-pairs with complementary mRNA codon in the A site; hydrolysis of GTP increase accuracy and efficiency 2) rRNA of large ribosomal subunit catalyzes formation of a peptide bond between new amino acid in A site and carboxyl end of growing polypeptide in P site; removes polypeptide from tRNA in P site and attaches it to amino acid on tRNA in A site 3) ribosome translocates tRNA in A site to P site, at the same time, empty tRNA in P site is moved to E site, where it's released; mRNA moves along with its bound tRNAs, bringing next codon to be translated into A site

Explain how Meleson and Stahl confirmed the semiconservative mechanism of DNA replication.

1) bacteria cultured in ^15N 2) bacteria transferred to ^14N 3) DNA sample centrifuged after 20 minutes (first repetition) 4) DNA sample centrifuged after 40 minutes (second repetition) Conclusion: heavy ^15N found in strands as the semiconservative model predicted

sodium-potassium pump

1) cytoplasmic Na+ binds to pump 2) Na+ binding causes phosphate from ATP to bind to protein 3) causes protein to change shape and release Na+ 4) new shape take in K+ from extracellular fluid and release phosphate 5) loss of phosphate causes protein to go back to original shape 6) K+ is released and Na+ is able to bind

The transport vesicle formed from the rough ER fuse with the Golgi apparatus. Use this sketch to label the cisterna of the Golgi, and its cis and trans faces. Describe what happens to a transport vesicle and its contents when it arrive at the Golgi.

1) golgi pinches off transport and other vesicles 2) lysosome is available for fusion with another vesicle for digestion 3) transport vesicle carries protein to plasma membrane for secretion 4) plasma membrane expands by fusion of vesicles; proteins are secreted from cell

Steps that occur in the synthesis of a new strand

1) helicase unwinds parent double helix 2) single stranded binding protein stabilizes 3) leading strand synthesizes 5' to 3' by DNA pol III 4) primes synthesizes RNA primer for Okazaki fragments 5) DNA nucleotides added to RNA primer on the Okazaki fragments 6) DNA pol I switches RNA to DNA 7) DNA ligase bonds Okazaki fragments

Explain the multistep model of cancer development by using the specific example of colorectal cancer.

1) loss of tumor-suppressor gene APC or other 2) activation or Ras oncogene 3) loss of tumor-suppressor gene DDC 4) loss of tumor-suppressor gene p53 5) additional mutations *it takes multiple mutations for cancer

Use this figure (pg 6 ch 6 RG) to explain how the elements of the endomembrane system function together to secrete a protein and to digest a cellular component.

1) nuclear envelope is connected to rough ER, continuous with smooth ER 2) membranes and proteins produces by ER flow as transport vesicles to golgi 3) golgi pinches off transport and other vesicles that make lysosomes, specialized vesicles, and vacuoles 4) lysosome is available for fusion with another vesicle for digestion 5) transport vesicle carries proteins to plasma membrane for secretion 6) plasma membrane expands by fusion of vesicles; proteins are secreted from cell

Use the following figure to explain how proteins are targeted for the ER

1) polypeptide synthesis begins 2) SRP binds to signal peptide, halting synthesis 3) SRP binds to receptor protein; receptor is part of translocation complex (with membrane pore and signal-cleaving enzyme) 4) SRP leaves and peptide synthesis resumes, translocation at the same time 5) signal-cleaving molecule enzyme cuts off signal peptide 6) rest of compound polypeptide leaves ribosome and folds into final form

translation initiation

1) small ribosomal subunit binds to mRNA; initiator tRNA with anticodon (UAC) base-pairs with start codon (AUG), tRNA carries Met amino acid 2) arrival of large ribosomal subunit completes initiation complex, (initiation factors bring components together), GTP provides energy for assembly initiator tRNA in P site, A site is available to next tRNA bearing amino acid`

spliceosome

1) snRNPs and other proteins form a spliceosome on pre-mRNA with introns and exons 2) within spliceosome, snRNA base-pairs with nucleotides at specific sites along the intron 3) spliceosome cuts pre-mRNA, releasing intron and splicing exons together; spliceosome comes apart releasing mRNA with only exons

Use this figure (p 2 ch 4) to identify the three types of isomers. For each type, give a key character and an example.

1) structural-differ in covalent partners, C5H12 2) geometric- differ in arrangement about double bond, rhodosphin 3) enantiomers- mirror image, albuterol and ibuprofen

The flow of genetic information is from DNA->RNA->protein. Use this figure (pg 11 ch 5 RG) to explain the process.

1) synthesis of mRNA in the nucleus 2) movement of mRNA into cytoplasm 3) synthesis of protein

Study this figure of Stanley Miller's experiment (p 1 ch 4 RG) to simulate conditions thought to have existed on the early earth. Explain the elements of this experiment, using arrows to indicate what occurs in various parts of the apparatus.

1) the water in the "sea" is evaporated into the "atmosphere" 2) mix of H2, CH4, NH3, and water vapor 3) sparks to mimic 4) condenser cooled "atmosphere", rains water and dissolved molecules into "sea" flask 5) collected samples for analysis

proteasome

1) ubiquitin attached to protein by enzymes in cytosol 2) tagged protein is recognized by proteasome, which unfolds protein and sequesters it within a central cavity 3) enzymatic part of proteasome cut protein into small peptides that can be further degraded by other enzymes in the cytosol

What is the probability that a couple will have a girl, a boy, a girl, and a boy in this specific order?

1/2 x 1/2 x 1/2 x 1/2 = 1/16

What is the concentration of each ion in pure water at 25 degrees C?

10^-7M (one 10 millionth of a mole H ions/liter of pure H2O)

Mendel's model consists of four concepts

1st concept: alternative versions of genes account fro verities in inherited characters 2nd concept: for each character, an organism inherits two alleles, one from each parent 3rd concept: if the two alleles at a locus differ, than the dominant allele determines appearance 4th concept: law of segregation- two alleles for a heritable character separate during gamete formation and end up in different segments

sexual reproduction

2 parents, 2 games combined, genetically different daughter cells

How many different aminoacyl-tRNA syntheses are there?

20

What percentage of the genes of a typical human cell is expressed at any given time?

20%

How many chromosomes in a human gamete?

23

How many nucleotides are required to code for these 20 amino acids?

3

How many DNA molecules are in each of your somatic cells?

46 (chromosome = one long, linear DNA)

What is the direction of synthesis of the new strand?

5' -> 3'

formula for photosynthesis

6 CO2 (carbon dioxide) + 6 H2O (water) + light energy -> C6H12O6 (glucose) + 6 O2 (oxygen)

Of the 64 codons, how many code for amino acids?

61; UAA, UAG, UGA

So, the language of DNA is a triplet code. How many unique triplets exist?

64

Explain what has happened to the six-carbon molecules found in the original glucose molecule.

6C (glucose) -> 3C (pyruvate) -> CO2 (release when pyruvate -> acetyl CoA)

blood types

A -genotype: I^A I^A or I^A i -phenotype: A -appearance: triangles on cell B -genotype: I^B I^B or I^B i -phenotype: B -appearance: circles on cell AB -genotype: I^A I^B -phenotype: AB -appearance: circles an triangels O -genotype: ii -phenotype: O -appearance: just cell

codon

A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.

What is the start codon?

AUG -- met

What is the formula for a hexose sugar?

C6H12O6

Explain the important events that occur in the carbon fixation stage of the calvin cycle.

CO2 attached to 5 carbon sugar (RuBP) (rubisco catalyzes 1st step), product is unstable 6 carbon sugar that splits into 2 G3P

Explain how alcohol fermentation starts with glucose and yields ethanol. Be sure to stress how NAD+ is recycled.

CO2 from pyruvate becomes acetaldehyde, which is reduced by NADH to ethanol, this regenerates NADH->NAD+

G protein-linked receptor

Components -G protein-coupled receptor: signal in plasma membrane that responds to binding of signaling molecule by activity G protein -G protein: GTP binding protein that relays signals from membrane signal receptor to other transduction proteins in the cell -Enzyme: changes shape and activity from G protein (temporarily), generates cellular response, make G protein inactive by changing GTP to GDP Step 2 -appropriate signaling molecule binds to extracellular side of receptor -receptor is activated and changes shape -cytoplasmic side binds to G protein, to replace it -G protein is activated Step 3 -activated G protein dissociates from receptor, diffuses along membrane, binds to enzyme -enzyme shape and activity is changed -activated enzyme can trigger the next step in the pathway leading to cellular response Step 4 -changes in G protein and enzyme are only temporary -G protein also functions as a GTPase enzyme (hydrolyzes bound GTP to GDP and inactivates) -G protein (inactive) is available for reuse

ion channel receptor

Components -ligand: binds and opens gate -ions: go through gate (with the gradient) -closed gate: prevents ions from going through -ligans-gated ion channel receptor: receives ligand and opens gate to let ions through Step 1 -ligand binds to receptor and gate opens -specific ions can flow through channel and change particular ion concentration in cell (possibly directly affecting activity of cell) Step 2 -ligand dissociates from receptor and gate closes, ions no longer enter cell

base-pairing

DNA -thymine -- adenine -guanine -- cytosine RNA -uracil -- adenine -guanine -- cytosine

Write the central dogma of molecular genetics, as proclaimed by Francis Crick

DNA -> RNA -> protein

What are the two chemical components of chromosomes?

DNA and protein

All genes are not "on" all the time. Using the metabolic needs of E. coli, explain why not.

E. coli relies on its host for nutrients, if it isn't getting a certain nutrient, the gene to make the enzyme that digests said nutrient is turned off, until the host eats the nutrient, then the gene to make the enzyme is turned on

The rough ER is studded with ribosomes. As proteins are synthesized, they are threaded into the lumen of the rough ER. Some of these proteins have carbohydrates attached to them in the ER to form glycoproteins. What does the ER then so with these secretory proteins?

ER membrane keeps them separate from proteins that are produced by free ribosomes and will remain in cytosol

The two electron carrier molecules that feed electrons into the electron transport system are

FADH2 and NADH

In phase two, the reduction stage, the reducing power of NADPH will donate electrons to the low-energy acid 1,3-biphosphoglycerate to form the three-carbon sugar ___.

G3P

Amino (NH2 or NH3)

H | -structure: -N --H -ex: glycine -physical properties: acts as base (can pick up H+ ions), ionized with charge of 1+ (under cellular conditions)

Explain the overall concept of how ATP synthase uses the flow of hydrogen ions to produce ATP.

H+ flowing down gradient enters stator, enter binding sites in rotor -- changing shape of subunit so rotor spins within membrane, each H+ makes a complete turn then leaves through another stator into mitochondrial matrix, rotor spinning causes rod with knob (stays still) at bottom to spin too, turning rod activates catalytic sites in knob for ADP + Pi -> ATP

Now it is time to put all elements of transcription together. Write an essay

Initiation consists of transcription factors binding to a promoter, often a TATA box around 25 nucleotides up from the start point. The RNA pol II binds to the DNA and RNA synthesis starts on the template strand. In elongation the polymerase moves down the DNA strand from 5' to 3' end. A termination signal causes the polymerase to detach from the DNA and release the transcript, known as termination. A copy of the previous gene has been created.

Who performed the experiments that elucidated the correct mechanism of DNA replication?

Matthew Meleson and Franklin Stahl

mitosis vs. meiosis

Mitosis -role in animal: growth repair, reproduction -DNA replications: 1 -divisions: 1 -daughter cells: 2 -chromosomes in daughter: 2n Meiosis -role in animal: gamets, genetic diversity -DNA replications: 2 -divisions: 2 -daughter cells: 4 -chromosomes in daughter: n

The step that converts pyruvate to acetyl CoA at the top of the diagram also occurs twice per glucose. This step accounts for 2 additional reduced ___ molecules and two carbon dioxide molecules.

NAD+

In cellular respiration, electrons are not transferred directly from glucose to oxygen. Each electron is coupled with a proton to form a hydrogen atom. Following the movement of hydrogens allows you to follow the flow of electrons. The hydrogens are held in the cell temporarily by what electron carrier?

NAD+ (coenzyme) -coenzyme: organic nonprotein helper for catalytic reactions

Phosphate (PO4)

O || -structure: O -- P --O | O- -ex: glycerol phosphate -physical properties: contributes to negative charge to molecule that it's part of, has potential to react with water (releasing energy)

ribozyme

RNA molecules that function as enzymes

Name the enzyme that uses the DNA template strand to transcribe a new mRNA strand.

RNA polymerase

Use as many words from the list above to describe why a carrot left on the counter overnight would become limp.

The carrot becomes flaccid from diffusion, specifically osmosis. The water uses passive transport to go with the concentration gradient, from the hypertonic inside to the hypotonic outside. This causes plasmolysis and the carrot gets close to being isotonic with the air.

Explain the potential influence of the environment on phenotypic expression

The outcomes of a genotype is held in the norm of reaction (phenotype range that depends on environment where the genotype is expressed), however the norm of reaction doesn't always have an effect. Multifactorial phenotypes are when phenotypes are influenced by multiple genes and environmental factors

What was the first codon--amino acid pair to be identified?

UUU -- Phe

Who built the first model of DNA and shared the 1962 Nobel Prize for discovery of its structure?

Watson and Crick

testing fetus genetic disorders

What are the strengths and weaknesses of each test? -amniocentesis: strength: amniotic fluid (can bemused to detect enzymatic/development issues not in cells) and fetal cells; weakness: several weeks, late in pregnancy -CVS: strength: fast and early in the pregnancy; weakness: no amniotic fluid collected

human anueuploidies

XXY -sex: male -physical traits: Klinefelter syndrome- male sex organs, testes abnormally small, sterile, some breast enlargement and other female characteristics XXX -sex: female -physical traits: Trisomy X- no unusual physical features, slightly taller than average; at risk for learning disabilities; fertile XO -sex: female -physical traits: Turner syndrome- phenotypically female; sterile; secondary sex characteristics developed with estrogen replacement; normal intelligence XYY -sex: male -physical traits: normal sexual development; usually taller than average; lots of testosterone (facial hair, personality impacts, etc)

Are scientific hypotheses proved?

Yes, they can be proved wrong or right depending on your quantitative and/or qualitative data

How did Meleson and Stahl create "heavy" DNA for their experiments?

^15N instead of ^14N

Using ^18O as the basis of your discussion, explain how we know that the oxygen released in photosynthesis comes from water.

^18O is a heavy isotope used as a tracer, only O2 released from H2O was labeled with ^18O

catalyst

a chemical agent that speeds up reactions without being consumed by the reaction

glycosidic linkage

a covalent bond formed between two monosaccharides by a dehydration reaction

Huntington's disease

a degenerative disease of the nervous system, caused by the lethal dominant allele that has no obvious phenotypic effect until the individual is about 35-40 years old; uncontrollable body movements and degeneration of nervous system

What happens in Tay-Sachs disease? Explain the role of lysosome in Tay-Sachs

a lipid-digesting enzyme is missin or is inactive and becomes impaired

ligand

a molecule that binds specifically to another molecule, usually a larger one

nuclear matrix

a network of fine filaments that provides structural support and may be involved in the regulation of genetic activity

emergent property

a property the system/collection has but individual doesn't -ex: heart is made of heart cells but the heart cells don't pump blood -ex: salt is salty but sodium and chloride aren't

allosteric regulation

a regulatory molecule binds to one site and affects a separate site; can inhibit or stimulate

compound

a substance consisting of 2 or more different elements

element

a substance that can't be broken down to other substances by chemical reactions

hypothesis

a tentative answer to a well-framed question; an explanation on trial

negative feedback

accumulation of end product that slows the process (brings back to normal)

Explain the correlation between an absorption spectra and an action spectrum.

action spectrum shows chlorophylls in absorption spectra correlate closely to the action spectrum

Why are cancer cells immortal, but most body cells have a limited life span?

active telomerase in cancerous cells

addition rule

adding individual probabilities; add when question says OR -ex: rolling snake eyes: 1/6 + 1/6 = 2/6 = 1/3

What activates a G protein?

addition of GTP (replacement of GDP)

DNA polymerase III

adds DNA nucleotides to new strand

cellular respiration

aerobic and anaerobic respiration respiration break down organic molecules for the production of ATP

What commonly held idea was rendered obsolete by the discovery of ribozymes>

all biological enzymes were proteins

What are alleles?

alternative forms of a gene for a single trait -ex: brown eyes or blue eyes

high specific heat

amount of heat that must be absorbed/lost for 1 gram of a substance to change its temperature by 1 degree C -water's high specific heat: 1cal/gram/degree C -alcohol: 6cal/gram/degree C

electron shells

an energy level of electrons at a characteristic average distance from the nucleus of an atom

protein phosphatases

an enzyme that removes phosphate groups, dephosphorlyzing from proteins, often functioning to reverse the effect of protein kinase -inverse of protein kinase

protein kinase

an enzyme that transfers phosphate groups from ATP to a protein, phosphorylating the protein -inverse of protein phosphatases *figure on page 7 of ch 11 RG Explain what is occurring in the cell at each arrow: 1) relay molecule activates protein kinase one 2) activate protein kinase from ATP to an inactive molecule of protein kinase two, activating the second kinase 3) activate protein kinase two catalyzes phosphorylation of protein kinase three 4) active protein kinase three phosphorylates protein that brings cell's response to signal 5) protein phosphate (PP) enzymes catalyze removal of phosphate groups from proteins, making them inactive and available for reuse

controlled experiment

an experiment designed to compare an experimental group with a control group (constant factors in both groups)

matter

anything that takes up space and has mass

atomic mass

approximation of the total mass of an atom

Which type of reproduction will result in genetically identical offspring?

asexual

independent assortment of chromosomes

at metaphase I, homologous pais are positioned on the metaphase plate, 1st meiotic division results in each pair sorting maternal and paternal homologs into daughter cells independently of other pairs; each daughter cell represents one outcome of all possible combinations

What is the common control point of gene expression for all organisms?

at transcription

adhesion

attraction between different kinds of molecules, sticks to other things

Which two domains consist of prokaryotic cells?

bacteria and archaea

missense mutation

base-pair substitution that results in a codon that codes for a different amino acid

chromosome theory of inheritance

basic principle in biology stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns

Use morphine and endorphins as examples to explain why molecular shape is crucial in biology.

because morphine and endorphins have similar shapes, morphine able to bond to brain cells and relieve pain and alter mood like endorphins do naturally

cohesion

binding together of like molecules, often by hydrogen bonds, sticks to itself

noncompetitive inhibitor

binds to another part of enzyme, causing it to change shape so the active site is less effective at catalyzing conversion

competitive inhibitor

block substrates from entering active sites by mimicking the shape of the substrate

Why is the genetic code said to be redundant but not ambiguous?

both GAA and GAG specify glutamic and redundancy for less harmful mutations, neither specifies any other amino acid (no ambiguity for mix ups)

Explain the important role played by the peroxisomes

break down fatty acids into smaller molecules that can be transported to the mitochondria

What is the function of the electron transport chain in cellular respiration?

breaks fall of electrons to oxygen into several energy releasing steps; slows down

energy

capacity to cause change

What four elements make up 96% of all living matter?

carbon (C), oxygen (O), hydrogen (H), and nitrogen (N)

Explain the Calvin cycle, utilizing the term carbon fixation in your discussion

carbon fixation incorporates CO2 from the air, fixed carbon used with NADPH and ATP to make sugar

Exercise will result in the production of CO2, which will acidify the blood. Explain the buffering system that minimizes blood pH changes.

carbonic acid (H2CO3) is formed, which dissociates to create a bicarbonate ion (HCO3-) (removes H ions) and hydrogen ion (H+) (dissociates carbonic acid)

cystic fibrosis

caused by recessive chloride channel protein allele; excessive secretion of mucus and vulnerability to infection, fatal if untreated

Besides packaging secretory proteins into transport vesicles, what is another major difference of the rough ER?

cell membrane factory, grows in place by adding membrane proteins and phospholipids to its own membrane

exocytosis

cell secrete certain biological molecules by fusion of vesicles with the plasma membrane

endocytosis

cell takes in biological molecules and particles by forming new vesicles from plasma membrane

pinocytosis

cellular drinking

phagocytosis

cellular eating

structural polysaccharide that comprises plant cell walls

cellulose

polypeptide

chain of amino acids

What two molecules make up the "uprights"?

chains of alternating sugar and phosphate molecules

point mutation

change in gene at single nucleotide pair

mutation (in terms of genetics)

change in nucleotide sequence of an organism or virus's DNA

carrier protein

change shape to allow certain molecules/atomic ions through

structural polysaccharide that gives cockroaches their crunch

chitin

Sketch a chloroplast and label its outer membrane, inner membrane, inner membrane space, thylakoids, granum, and stroma.

chloroplasts aren't considered part of endomembrane system

deletion

chromosomal fragment is lost

Acid precipitation is increasing. Explain its sources.

coal burning power produce more oxides, burning of fossil fuels

What can you say that all calico cats are females?

coloring requires presence of two different alleles (one black and one orange); normally only females can have bother because they have two X chromosomes

dipeptide

combination of two amino acids with a peptide bond

In a DNA double helix, a region along one DNA strand has this sequence of nitrogenous bases: 5'-TAGGCCT-3'

complementary strand: 3'-ATCCGGA-5'

chromatin

complex of DNA and associated protein molecules

isomer

compounds with the same formulas but different structures -ex: p 2 ch 4 RG

Describe the structure of a eukaryotic ribosome.

contains large subunit and small subunit, each made of proteins and one or more tRNAs

cytokinesis in animal cell

contractile ring of actin microfilaments associated with molecules of the protein myosin; actin microtubules interact with myosin molecules causing ring to contract and cleavage furrow to appear

What controls the cell cycle?

control checkpoints where "stop" and "go-ahead" signals can regulate the cycle

What is a cell cycle checkpoint?

control point where stop and go-ahead signals can regulate cycle

transformation (cancer)

conversion of a normal animal cell to a cancer cell

What is the function of the chloroplasts?

convert solar energy to chemical energy in photosynthesis

peptide bond

covalent bond between the carboxyl group on one amino acid and the amino group on another formed by a dehydration reaction

Kinases drive the cell cycle, buy they must be activated by attachment of a ___

cyclin (cyclin dependent kinase)

The activity of cyclin-dependent kinases (CDks) rises and falls. Why?

cyclin partner concentration varies

qualitative data

descriptions, observed not measured -found in field sketches

central vacuoles in plants

develops smaller vacuoles, transport solutes, cell sap (solution inside vacuole), composition from cytosol

How can alternative RNA splicing result in different proteins derived from the same initial RNA transcript?

different sequences are treated as exons and introns

passive transport

diffusion of substances across biological membrane (no energy required)

osmosis

diffusion of water across a selectively permeable membrane

trisomy

diploid cell has 3 copies of a particular chromosome, not two

monosomy

diploid cell has only one copy of a particular chromosome, not two

gene

discrete unit of hereditary information consisting of a peace's nucleotide sequence in DNA

solvent

dissolving agent of a solution (water is the most versatile solvent known)

What determines the chemical behavior of an atom?

distribution of its electrons and number of electrons in its valence shell

hydrophobic

doesn't like water (aversion to water)

What type of bond is seen in O2? Explain what this means.

double covalent bond, oxygen can bond with itself

What is the shape of DNA called?

double helix

What is the semiconservative model of replication?

each new double helix will have one strand from parent and one newly made

Mendel's law of independent assortment

each pair of alleles separates independently of every other pair of alleles during gamete formation

female gamete

egg

nonpolar covalent bond

electrons are equally shared between 2 atoms of similar electronegativity

polar covalent bond

electrons are unequally shared and pulled closer to the more electronegative (+) and farther from the other (-)

positive feedback

end product speeds up the production (furthers change)

products

end result of a reaction

potential energy

energy that matter possesses as a result of its location or spatial arrangement; energy that can be used

What occurs in nondisjunction?

error in meiosis or mitosis where members of homologs or sister chromatids fail to separate properly from each other

In probability, what is an independent event?

event's outcome is unaffected by previous trials

nuclease

excise damaged area of DNA

exon

expressed region that exit nucleus

Even though all cells of an organism have the same genes, there is differential gene expression. What does this mean?

expression of different sets of genes by cells with the same genome

duplication

extra segment (can be identical)

Why is the tail of a phospholipid hydrophobic?

fatty acids are hydrophobic and nonpolar

F1 generation

first filial generation

What are some of the things that will result in a final-from functional protein?

folding, chemical modification of amino acids, enzymatic removal, rearrangement

How did Watson and Crick's model explain the basis of Chargaff's rules?

for a double helix to work adenine has to pair with thymine, and guanine has to pair with cytosine, so it's the same diameter

achondroplasia

form of dwarfism; heterozygous individual have phenotype; recessive allele is much more prevalent that the corresponding dominant allele

food vacuoles

formed by phagocytosis

Where are the gametes of an animal produced?

from germ cells in gonads -female: ovaries -male: testes

glucose + ________ form sucrose

fructose

monosaccharide commonly called "fruit sugar"

fructose

random fertilization

fusion of male gametes with female gametes produces different zygote with around 70 trillion diploid combinations; millions of different combinations

What is the definition of a sex-linked gene?

gene located on a sex chromosome (usually X) resulting in a distinctive pattern of inheritance

What happens when a repressor is bound to the operator?

gene not transcribed because RNA pol can't bind, operon is off

Explain what is meant when a gene is said to have multiple alleles

genes can exist in more than 2 forms of alleles

What are regulatory genes?

genes that code for a protein (ex: repressor) that control the transcription of another gene/group of genes

transformation (bacteria)

genetic alteration of bacterial cell due to transfer of foreign DNA

two monomers of this form maltose

glucose

storage polysaccharide produced by vertebrates; stored in your liver

glycogen

has 1-4 glucose linkages

glycosidic

hypertonic

greater solute concentration (specify which side of membrane) -ex: outside solution is hypertonic

gamete

haploid reproductive cell

amphipathic molecule

has both hydrophobic and hydrophilic regions

Describe Nirenberg's experiment in which he identified the first codon

he synthesized artificial mRNA by linking identical RNA nucleotides containing uracil at their bases; one codon in repetition: UUU

Explain how hydrogen bonding contributes to water's high specific heat.

heat must be absorbed fro hydrogen bonds to break; heat is released when hydrogen bonds form

Three types of phosphorylation are covered in the text, and two of those occur in cellular respiration. Explain how the ETC is utilized in oxidative phosphorylation.

helps protons get to lower energy level so they can go to final electron acceptor (oxygen) and go through ATP synthase

incomplete dominance

heterozygote's phenotype is intermediate between homozygous individuals for each allele (mix); neither one are dominant, mix to make a new trait

single stranded binding protein

holds DNA strands apart; stabilizes

crossing over

homologs move slightly apart, chiasmata and attachments hold homologs together, move to metaphase plate, breakdown proteins allows homologs with recombinant chromatids to separate; allows new genetic combos and randomizes genes

What are other examples of steroids?

hormones, sex hormones

What two ions form when water dissociates?

hydronium ion (H3O+, represented as H+) and a hydroxide ion (OH-)

channel protein

hydrophilic channel certain molecules/atomic ions can pass through

Lipids include fats, waxes, oils, phospholipids, and steroids. What characteristic do all lipids share?

hydrophobic

What is demonstrated when you see beads of water on a waxed car hood?

hydrophobic wax and water can't combine

density-dependent inhibition

if cell is crowded, it won't divide; cells stop dividing when in contact with other cells

Describe how Englemann was able to form an action spectrum long before the invention of a spectrophotometer

illuminated filamentous alga with light passed through a prism, exposed different parts of alga to different wavelengths, use aerobic bacteria to see which parts of alga were releasing most O2 (photosynthesizing most), bacteria most around alga with violet-blue or red light

transcription factors

in the cell they control which genes are turned on (which genes are transcribed into mRNA)

In what body system are ligand-gated ion channels and voltage-gated ion channels of particular importance?

in the nervous system (quick responses)

frameshift mutation

insertion or deletion of nucleotides that alter the frame of the genetic message, the triplet grouping of bases on mRNA that is read during translation Identify two mechanisms by which frameshift may occur -base-pair substitutions -base-pair insertions or deletions

snRNPs band together in little snRNP groups to form spliceosomes. How do spliceosomes work?

interact with certain sites along the intron, releasing intron and joining the two exons that flanked the intron

All of these sugars have the same chemical formula: C6H12O6. What term did you learn in chapter 3 for compounds that have the same molecular formulas but different structural formulas?

isomers

A G protein is also a GTPase enzyme. Why is this important?

it hydrolyzes its bound GTP to GDP

Why is glycolysis an appropriate term for this step of cellular respiration?

it means "sugar splitting" which is what happens

translocation

join non homologous chromosome; switch segments

DNA ligase

joins DNA fragments together; seals free ends

calorie

kcal-energy content of food; amount of heat energy required to raise the temperature of 1 gram of water by 1 degree celsius; amount of heat energy 1 gram of water releases when cooled by 1 degree Celsius

Which of the two fatty acid chains of the phospholipid is unsaturated?

kinked one, kink is due to a double bond

"milk sugar"

lactose

Summarize how water's high specific heat contributes to the moderation of temperature. How is this property important to life?

large body can absorb lots of heat during the day (in summer) and only raise a few degrees; cool during the night or winter and warm air; can stabilize ocean temperatures

Although it is not an enzyme, hemoglobin shoes cooperativity in binding O2. Explain how hemoglobin works at the gills of a fish.

less likely to bind to O2 and will release it where it's needed

genome

library of genetic instructions an organism inherits

hydrophilic

likes water (affinity for water)

flaccid

limp, no pressure from water

glycolipid

lipid with covalently attached carbs

solution

liquid that is a completely homogenous mixture of two or more substances

heterotroph

live on compounds produced by other organisms, "other-feeding"

polymer

long molecule consisting of many similar building blocks, linked with covalent bonds

hypotonic

lower solute concentration (specify which side of membrane) -ex: outside solution is hypotonic

autophagy

lysosomes use hydrolytic enzymes to recycle the cells own organic material

Posttranscriptional control includes regulation of mRNA degradation. Explain how this affects translation

mRNA are degraded in cytoplasm a few minutes after synthesis in bacteria (hours/days/weeks in euk), allowing patterns of protein synthesis to change quickly in response

enzyme

macromolecule (protein) that acts as a catalyst

malt sugar; used to brew beer

maltose

When do synapsis and crossing over occur?

meiosis prophase I

mRNA

messenger RNA -description: modified single strand of nucleotides complementary to DNA -function: carries message of genes (what proteins to make)

What is awls the first amino acid in the new polypeptide?

methionine (Met)

In animal cells, the assembly of spindle microtubules starts at the centrosome. What is another name for the centrosome?

microtubule organization center (MTOC)

Sketch a mitochondria and label its outer membrane, inner membrane, inner membrane space, cristae, matrix, and ribosomes.

mitochondria aren't considered part of endomembrane system

polar molecule

molecule with opposite charges on different ends of the molecule -why is water considered a polar molecule?oxygen is polar negative and hydrogen is polar positive

What are the monomers of all carbohydrates?

monosaccharides and simple sugars

anchorage dependence

most animal cells much be in contact with a solid surface in order to divide

diffusion

movement of molecules of any substance to have even ratios in available space

multiplication rul

multiply probability of on event by the probability of the other event; multiply when the question says AND -ex: probability of rolling a 2 and a six: 1/6 x 1/6 = 1/36

Dominant alleles are not necessarily more common than recessive alleles in the gene pool. Explain why this is true

natural selection determines how common an allele is in a gene pool

If you could not regenerate ATP to some other molecule by phosphorylating ADP, how much ATP would you need to consume each day?

nearly your body weight

To summarize, if energy is released, ΔG must be what?

negative (-ΔG)

electron

negative charge

electron

negative charge; same number of protons and electrons (atomic number = number of protons)

Feedback inhibition is a recurring mechanism throughout biological systems. In the case of E. coli regulation tryptophan synthesis, is it positive or negative inhibition?

negative, rate decreases as product increases

anion

negatively charged ion

nuclear lamina

net-like array of protein filaments that maintains shape

List the three components of a nucleotide.

nitrogenous base, deoxyribose, phosphate group

neutron

no charge

cytokinesis in plant cell

no cleavage furrow; vesicle from golgi moves along microtubules to middle of cell, produce a cell plate, cell plate fuses with plasma membrane -cell plate formed from vesicles from the golgi moving along the cytoskeleton and coalesce in the middle

intron

noncoding segments of nucleic acid between coding regions

cofactors

nonprotein, inorganic catalytic helpers -ex: ionic forms of zinc, iron, copper

peripheral proteins in fluid mosaic model

not embedded in lipid bilayer, loosely bound to membrane surface (often to exposed part of integral)

anticodon

nucleotide triplet at one end of tRNA that recognizes a particular complementary codon on an mRNA molecule

atomic number

number of protons (unique to each element); subscript to the left on symbol

quantitative data

numerical, can be measured -would be presented in a data chart and could be graphed

Tumor-suppressor genes help prevent uncontrolled cell growth. One that is found mutated (and therefore nonfunctional) in more than 50% of human cancer cells is p53. Describe the double whammy that results from mutation of p53.

numerous cell-cycle-inhibiting processes will be affected, leading to a higher likelihood of uncontrolled cell growth and possibly cancer

You already know that some materials, such as olive oil, will not dissolve in water. In fact, oil will float on top of water. Explain this property in terms of hydrogen bonding.

oil is hydrophobic due to non polar bonds between carbon and hydrogen, which state electrons almost equally

isotope

one for several atomic forms of an element, each with the same number of protons, but different number of electrons; different atomic forms of the same element -ex: C12 radioactive tracers

In sexually reproducing organisms, why are there exactly two chromosomes in each homologue?

one from each parent

aneuploidy

one or more chromosomes are present in extra copies or are deficient in number

coenzymes

organic catalytic helpers -ex: vitamins

Give the formula with name for the catabolic degradation of glucose by cellular respiration.

organic compounds (C6H12O6) + oxygen (O2) -> carbon dioxide (CO2) + water (H2O) + energy (ATP + heat)

polyploidy

organism possesses more than two complete sets; result of accident in cell division

monohybrid cross

organisms heterozygous for one character -ex: Tt x Tt

dihybrid cross

organisms heterozygous for two characteristics -ex: TtRr x TTRr

P generation

parent generation

fermentation

partial degradation of sugars that occurs without oxygen

integral proteins in fluid mosaic model

penetrate hydrophobic core of lipid bilayer, many are transmembrane

Name a human enzyme that functions well in pH 2 (acidic). Where is it found?

pepsin, located in stomach

Enzymes are globular proteins that exhibit at least tertiary structure. On this figure, identify and explain each interaction that folds this portion.

pg 10 of ch 5 RG -top: hydrophobic interactions and van der Waals interactions -second: hydrogen bond -third: disulfide bond -bottom: ionic bond

complete dominance

phenotype of heterozygote and dominant heterozygote are indistinguishable

codominance

phenotypes of both alleles are exhibited in the heterozygote because both alleles are equally expressed

In many cellular reactions, a phosphate group is transferred from ATP to some other molecule in order to make the second molecule less stable. The second molecule is said to be _____.

phosphorylated

What are the two categories of mutagens?

physical and chemical

What is controlled by homeotic genes?

placement and spatial organization of body parts in animals, plants, and fungi by continually developmental fate of groups of cells

nonsense mutation

point mutation changes codon for amino acid into a stop codon and causes translation to stop prematurely

hydrogen bonding in water

polar positive hydrogen and polar negative oxygen are attracted to each other on H2O molecules -one water molecule can form 4 hydrogen bonds

Quantitative variation usually indicates

polygenic inheritance

free energy

portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system -difference between end final energy and initial free energy

proton

positive charge; atomic number = number of protons

cation

positively charged ion

What is the function of the mitochondria?

powerhouse of the cell

In eukaryotes, what is the pre-mRNA called?

primary transcript; only called this in the nucleus before modification

gene expression

process by which DNA directs the synthesis of proteins

Review meiosis. When does crossing over occur?

prophase I

glycoprotein

protein with one or more carbs covalently attached (more common than glycolipid)

Why did researchers originally think that protein was the genetic material?

proteins are a class of macromolecule with great heterogentity and specificity of function

When cell signaling causes a response in the nucleus, what normally happens?

proteins become transcription factors, certain genes are chosen, then transcribed

contractile vacuoles

pump excess water out of cell

Explain how lactic acid fermentation starts with glucose and yields lactate. Be sure to stress how NAD+ is recycled

pyruvate is reduced by NADH to form lactate, NADH->NAD+

heat of vaporization

quantity of heat a liquid must absorb for 1 gram of it to go from liquid to gas -helps moderate earth's climate, sweating/evaporative cooling, steam burns

X inactivation maintains the proper gene dosage. How is the X chromosome inactivated?

randomly and independently in each embryonic cell present and the time of X inactivation

substrate

reactant an enzyme acts on

chemical shorthand for photosynthesis

reactants: 6CO2 + 6H20 -> products: C6H12O6 + 6O2 -carbon dioxide molecules: 6 -glucose molecules: 1 -elements in glucose: 3

A photosystem is composed of a protein complex called a ___-___ complex surrounded by several ___-___ complexes.

reaction-center light-harvesting

Explain the concept of reading frame.

reading symbols of a language in correct groupings

Describe what you think is important to know medically about the behavior of recessive alleles.

recessive alleles can lead to disorders; if a couple both carry the recessive allele, their kids could have a genetic disorder

Explain why the dihybrid cross detailed in figure 14.12 has 4 white mice instead of the 3 that would have been predicted by Mendel's work

recessive traits must be homozygous to show

sickle cell disease

recessively inherited blood disorder where a single nucleotide change in beta globin gene causes hemoglobin to aggregate, changing read blood cell shape and causes multiple symptoms

What do geneticists call the offspring that show these new combinants (unlinked)?

recombinant types or recombinants

data

recorded observations

The most important part of the spectrum in photosynthesis is visible light. What are the colors of the visible light? -Notice the colors and corresponding wavelengths and the explain the relationship between wavelength and energy

red, orage, yellow, green, blue, indigo, violet -longer: less energy -shorter: higher energy

concentration gradient

region where density of chemical substance decreases (high->low)

What is the crucial role of noncoding RNAs?

regulation of gene expression by molecules

kinetic energy

relative motion of objects, moving

When the terminal phosphate bond is broken, a molecule of inorganic phosphate Pi is formed, and energy is _____.

released -For this reaction: ATP + Pi, ΔG = negative (-7.3kcal/mol) -Is this reaction endergonic or exergonic?: exergonic

topoisomerase

relieves strain caused by unwinding

DNA polymerase I

removes RNA primer and replaces with DNA

repair enzymes

repair genetic damage

essential element

required by an organism in everyday life to survive and reproduce

trace element

required by an organism in only minute quantities

active site

restricted region of the enzyme molecule that binds to the substrate

rRNA

ribosomal RNA -description: molecules that make up a ribosome -function: reads DNA; ribosome structure

List all the structures of the endomembrane system.

ribosome, cell membrane, mitochondrion, smooth endoplasmic reticulum, centrioles, golgi apparatus, rough endoplasmic reticulum, nuclear envelope, nucleus, nucleolus -functions: protein synthesis, transport proteins to membranes and organelles or out of cell, metabolism and movement of lipids, detoxification of proteins

The enzyme responsible for carbon fixation in the calvin cycle, and possible the most abundant protein on earth, is ___.

rubisco

homologous chromosomes

same length, same centromere position, and same staining pattern

isotonic

same solute concentration on both sides of membrane

Why are supernatural explanations outside the bounds of science?

science can't support or falsify supernatural explanations, observations and experimental results must be repeatable

F2 generation

second filial generation

What are Okazaki fragments? How are they welded together?

segments of lagging strand synthesized discontinuously, DNA ligase welds them together

inversion

segments orientation if reversed

autotroph

self sustained, "self-feeders"

cell cycle

sequence of events from division of its parent cell to its own division Phases -G1: (interphase) normal cell function and growth -S: (interphase) synthesis of DNA -G2: (interphase) preparation for cell division -M: mitotic phase - mitosis and cytokinesis

signal transduction pathway

series of steps linking a mechanical or chemical stimulus to a specific cellular response Steps: 1) reception: target cell's detection of a signaling molecule from outside; a chemical signal is detected when the signaling molecule binds to receptor on cell's surface 2) transduction: binding of signaling molecule changes the receptor protein, starting the transduction; converts signal to a form for specific cellular response; sometimes 1 step, sometimes multiple 3) respronse: transduced signal triggers a specific cellular response; response can be any cellular activity; helps ensure crucial activities occur in the right cell at the right time for coordination of cells and organelles

What was the role of Rosalind Franklin in the discovery of the double helix?

she took an x-ray diffraction image (x-ray crystallography) of DNA, which produced an X shape, which means it's a helix

What is the consequence of alternative splicing of identical mRNA transcripts?

single gene can encode one or more polypeptides, depending on which segments are treated as exons during RNA processing

asexual reproduction

single parent, non-sexual, usually genetically identical daughter cells

During meiosis I, homologous chromosomes separate. What separates during meiosis II?

sister chromatids

promoter

site when RNA polymerase can bind to DNA and begin transcription

origins of replication

site where DNA replication begins

What type is the RNA in a snRNP?

small nuclear RNA

Explain what occurs in the light reactions stage of photosynthesis. Be sure to use NADP+ and phosphorylation in you discussion

solar energy converted to chemical energy, light absorbs by chlorophyll (transfers electrons and H+ to NADPH+), NADP+ become NADPH, ATP is produced by photophosphorylation

functional group

specific configuration of atoms commonly attached to carbon skeletons of organic molecule and usually involved in chemical reactions

locus

specific place along the length of a chromosome where a given gene is located

male gamete

sperm

metastasis

spread of cancer cells to distant locations from their original site

What event is coded for by UAA, UAG, and UGA?

stop signals

Carbon chains form skeletons. List here the types of skeletons that can be formed.

straight, branched, closed ring

transcription unit

stretch of DNA that is transcribed into and RNA molecule

Take a moment to place the chloroplast in the leaf by working through figure 10.3.

stroma: dense fluid within chloroplast thylakoid: flattened membranous sac in chloroplast; interconnected; contain "machinery" used to convert light energy to chemical energy

Here is a list of the types of bonds and interactions discussed in this section. Place them in order from the strongest to the weakest: hydrogen bonds, van der Waals interactions, covalent bonds, ionic bonds

strong<- ionic, covalent, hydrogen, van der Waals ->

kinetochore

structure of proteins attached to centromere that links each sister chromatid to the mitotic spindle

eukaryotic cell

subdivided by internal membranes into various membrane-enclosed organelles

acid

substance that increases hydrogen ion concentration, pH less than 7 (7 is neutral; pure water); H+>OH- -2: gastric juice -6: urine

solute

substance that is dissolved

base

substance that reduces hydrogen ion concentration, pH greater than 7 (7 is neutral; pure water); OH->H+ -13: bleach

monomer

subunit that is the building blocks of a polymer

-ose

sugars, carbs, and proteins

transcription

synthesis of RNA using a DNA template (before translation) -template: DNA -product synthesized: RNA -location in eukaryotic cell: nucleus Steps 1) initiation: after RNA pol binds to promoter, DNA strands unwind, and pol initiates RNA synthesis at start point on template strand 2) elongation: pol moves downstream, unwinding DNA and elongating RNA transcript 5' to 3'; after transcription, the DNA strands re-form a double helix 3) termination: eventually RNA transcript is released and pol detaches from DNA

translation

synthesis of polypeptide using genetic information encoded in an mRNA, change of "language" from nucleotides to amino acids (after transcription) -template: nucleotides -product synthesized: amino acids -location in eukaryotic cell: cytoplasm

primase

synthesizes RNA primer

receptor-mediated endocytosis

take in cholesterol for membrane and other steroid synthesis

DNA is double stranded, but for each protein, only one of these two strands is used to produce an mRNA transcript. What is the coding strand called?

template strand

Discuss how CO2 emissions affect marine life an ecosystems.

the CO2 dissolves, reacts with H2O, and forms H2CO3, producing protons and balance between 2 ions (HCO3- and CO3^2-); calcification is directly effected by CO3^2-

prokaryotic cell

the DNA in the cell isn't separated from the rest of the cell by enclosure in a membrane-bound nucleus

Explain how the splice sites are recognized

the RNA parts of snRNP base-pair to specific sites on the intron

What is ta key difference between receptor tyrosine kinases and G protein-coupled receptors?

the ability of a single ligand-binding event to trigger so many pathways

electronegativity

the attraction of a particular kind of atom for the electrons of a covalent bond

ATP (Adenine Tri Phosphate)

the bond at CH2 is likely to break, releasing a phosphate -hydrolysis breaks the bond -made of: ribose sugar, nitrogenous base adenine, chain of 3 phosphate groups

How can a base-pari substitution result in a silent mutation?

the change can still create the same amino acid, this there is no noticeable change

Why are many unsaturated fats liquid at room temperature?

the double bond makes it so they can't stack evenly, so they slide around

ionic bond

the electron(s) is/are pulled to the other element's valence shell to complete the shell (even number of electrons = complete) -ex: Sodium (Na) and Chlorine (Cl), Cl steals an electron from Na

DNA is DNA is DNA

the genetic code is universal

Explain why water is a fine solvent.

the polarity of it, polar negative parts (oxygen) attract polar positive parts of other molecules, polar positive parts (hydrogen) attract polar negative part of other molecules allowing the water molecule(s) to pull apart other molecules

What do we mean when we say the two strands of DNA are antiparallel?

the strands run in opposite directions 5' -> 3' 3' -> 5'

Why is height a good example of polygenic inheritance?

there is no either-or classification of height, characters vary in popularity in gradients along continuum

Recall that enzymes are globular proteins. Why can extremes of pH or very high temperatures affect enzyme activity?

they can denature them, which causes them to be unable to function

Why does alcohol abuse increase tolerance to other drugs such as barbiturates?

they induce proliferation of smooth ER and its associated detox enzymes, this increasing detoxification rate

Even slight change in pH can be harmful! How do buffers moderate pH change?

they minimize changes in concentrations of H+ and OH-

When are the nucleoli visible? What are assembled here?

through the electron microscope as a mass of densely strained granules and fibers adjoining part of the chromatin

How does a bacteriophage destroy a bacterial cell?

to phage attached to the cell, inserts its DNA, takes over cellular machinery, and goes through lytic cycle to destroy cell

What was the purpose of Griffith's studies?

to prove DNA can transform bacteria

What is the purpose of meiosis?

to reduce chromosome number from 2 to 1; genetic diversity

Alternate version of the same gene, like purple an white flower color, are termed

traits

What comprises a transcription initiation complex?

transcription facts and RNA pol II bind to promoter

repressible operon

transcription is usually on but can be inhibited/repressed when a small molecule binds to a regulatory site -ex: trp operon

tRNA

transfer RNA -description: anticodon and one end and an amino acid on the other end -function: transfers amino acids from cytoplasm to mRNA and ribosome What binds at each attachment site?: specific anticodon binds at one end and corresponding amino acid at the other end

How many times does the citric acid cycle occur for each molecule of glucose?

twice (one molecule of glucose makes 2 pyruvate)

Describe the nuclear envelope. How many layers is it? What connects the layers?

two layers with space between, perforated by pores

molecule

two or more atoms held together by covalent bonds

Why are the strands of DNA said to be antiparallel?

two sugar-phosphate backbones have opposite 5'->3' arrangement 5'->3' 3'->5'

epistasis

type of gene interaction where one gene alters the phenotype affects of another gene that is independently inherited

In humans, how was that term been modified?

typically sex-linked traits are X-linked genes

Explain how protein structure is involved in enzyme specificity.

unique 3-D shape (due to the amino acid sequence) allows only certain shapes of substrates to land

operon

unit of genetic function consisting of a promoter, operon, and coordinately regulated culture of genes whose products function in a common pathway

genes

units of inheritance that transmit information from parents to offspring

helicase

untwists and separates parent strands

energy coupling

use of an exergonic process to drive an endergonic one

What is the role of the electron transport chain in forming the H+ gradient across the inner mitochondrial membrane?

uses exergonic flow of electrons from NADH and FADH2 to pump H+ across membrane (matrix to inter membrane space)

inducile operon

usually off but can be induced on by interaction between molecules and regulatory proteins -ex: lac operon

Which is the only subatomic particle that is directly involved in the chemical reactions between atoms?

valence electrons

What was collected in the samples fro chemical analysis? What was concluded from the results of this experiment (Stanley Miller's-p1 ch 4 RG)?

varied organic molecules throughout the tubes

turgid

very firm, caused by pressure from water uptake

van der Waals interactions

weak attractions between molecules that result from localized charge fluctuations; individually weak but together are somewhat strong -can stick a gecko to the ceiling

hydrogen bond

weak chemical bond, formed when the slightly positive hydrogen atom of a polar bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule

dynamic equilibrium

when a forward reaction equals the rate of reverse reaction, so relative concentrations of the reactants and products don't change with time; not equal in concentration, but concentrations have stabilized

plasmolysis

when a plant, bacteria, or fungi cell shrivels in a hypertonic solution and the plasma membrane pulls away from the cell wall; can lead to wilt and/or death

evaporation

when molecules move fast enough to overcome attraction and depart liquid and enter air as gas -helps moderate earth's climate, sweating/evaporative cooling, steam burns

Explain why pyruvate is a key juncture in metabolism.

without pyruvate, aerobic cellular respiration (then the citric acid cycle) and fermentation wouldn't occur

Are transport proteins specific? Cite an example that supports your response.

yes, they only allow certain molecules, like water, through, while not letting others pass