Biology
How does inhaling work?
Increase the volume, dec the pressure creates a negative pressure allowing air to flow in
A virologist obtains a purified sample of genetic material from a newly discovered virus. The virologist injects the genetic sample into the cytoplasm of healthy yeast cells in culture. Within hours, the cells die and free viral particles are detected in the growth medium. This new virus is most likely a:
(+) RNA virus. The genetic material must be positive-sense RNA. Upon entering the yeast cell, the viral RNA would be treated like host mRNA and quickly processed by yeast ribosomes. This would result in the production of all necessary viral proteins, including those required for RNA replication. In this way, new viral particles could be synthesized and released into the growth medium despite the initial absence of viral accessory proteins
Transposons
(jumping genes) short strands of DNA capable of moving from one location to another within a cell's genetic material 50% of human genome inc genetic diversity
resting membrane potential
-70mV
Genotype vs. Phenotype
-Genotype : Collection of alleles -Phenotype : Physical expression of alleles
9% of individuals within a population of butterflies are resistant to milkweed toxins, a trait which arises from a recessive allele. If these butterflies reproduce exclusively within their population, genetic mutations do not occur, and natural selection does not play a role, what is the predicted frequency of the recessive allele after 10 generations?
0.30 If 9% of individuals have the recessive phenotype, then the frequency of the homozygous recessive genotype is 0.09. This means that q2 = 0.09. Taking the square root of this value gives us q = 0.3, which is the frequency of the recessive allele in the population. Note that the allele frequencies should remain the same regardless of how many generations have passed, since the population is not evolving.
How many viable gametes can a primary oocyte produce?
1 Correct Answer Each primary oocyte will undergo meiosis I and II, but during each meiotic division, only one cell is kept and the other is eventually lost as a degenerate polar body.
centimorgans (map units)
1 centimorgan = distnace associated with 1% change in recombination frequency Maxes out at 50%
A coding sequence of DNA reads 3'-ATTTGCGTAGC-5'. After mutation, its complementary strand reads 5'-TAAACGCTACG-3'. Which of the following answer choices describes a sequence of mutations that could have potentially led to this new sequence?
1) Substitution 2) Substitution Substitution mutations replace a single nucleotide base at one position along the DNA strand with another base of a different type. The strand before mutation reads: 3'-ATTTGCG-TA-GC-5'. Therefore, its complementary strand before mutation reads 5'-TAAACGC-AT-CG-3'. The strand after mutation reads 5'-TAAAGCG-TA-CG-3'. Therefore, the eighth and ninth DNA bases were substituted - adenine for thymine, and thymine for adenine.
coagulation cascade
1. Clotting factors 2. Prothrombin --> thrombin 3. Fibrinogen --> Fibrin --> platelet plug
Steps of Translation
1. Initiation 2. Elongation 3. Termination
Bacteria Growth Patterns
1. Lag Phase: bacteria adapt to a new enviorment, growth lags 2. exponential phase: population multipliues rapidly 3. stationary phase: maximum population is reached, growth is limited by nutrients and space 4. Death phase: resources are depleted, bacteria begin to die
menstrual cycle (3 cycles)
1. Ovarian 2. Uterine 3. Hormone
Main types of DNA mutations
1. Subsitution 2. insertion 3. deletion
Basic tenets of the cell theory
1. all organisms are composed of one or more cells 2. the cell is the most basic unit of life 3. All cells arise from pre-existing cells Modern versions of the theory explain that genetic info encoded by DNA is trasmitted from cell to cell
Eukaryotic cells (3 major functional features)
1. membrane bound nucleus (besides RBC with no nucleus) 2. presense of organelles 3. mitotic division
substitution mutation (types)
1. silent 2. missense 3. nonsense
The carrier frequency for cystic fibrosis, an autosomal recessive disorder, in the Ashkenazi Jewish population is 1 out of every 24 individuals. A baby born to a couple from this demographic is tested for this mutation. A family history reveals that the mother's father was afflicted with cystic fibrosis. What is the approximate probability that the father is a carrier and the child will also be a carrier of this disease?
1/50 Since the mother's father expresses the autosomal recessive trait, he must have two copies of the mutation and will pass one on to his daughter, making her an obligate carrier. The husband has a 1/24 chance of also being a heterozygote. If both parents are carriers, there is a 50% chance that the child will be one as well (along with a 25% chance that the child will have cystic fibrosis, and a 25% probability that the child will be homozygous dominant). Since we want the probability of the father being a carrier AND the child being a carrier, multiply (1/24)(1/2) = 1/48, which is closest to choice C.
Which of the following patterns can be used to identify X-linked dominant patterns of inheritance?
100% of the daughters of an affected father and a non-affected mother will display the phenotype. X-linked dominant patterns can be distinguished from X-linked recessive patterns because in X-linked dominant patterns, 100% of the daughters of an affected father will have the phenotype in question (the father gives his X chromosome to all of his daughters and to none of his sons).
Meiosis occurs in ______ rounds of division
2 Meiosos I Meiosis II
Anaphase I
2 chromosomes in a homologus pair are seperated each daughter cell has 1/2 the amt of chromosomes (23) but each with the sister chromatids still attached
sister chromatids
2 identical copies of a chromosome joined together at the centromere
haploid cells contain
23 chromosomes 1n half set of chromosomes
How long is the cell cycle time?
24 hrs
Equation to find the number of combos possible for genes?
2^n n = number of genes present
Na+/K+ ATPase
3 Na+ out per 2 K+ in -uses 1 ATP
Codon
3 base sequence on mRNA
5' ACTG 3' Give the other stand
3' TGAC 5' but must be expressed starting with 5' 5' CAGT 3'
DNA polymerase reads in the _______ direction and synthesizes in the _______ direction
3' to 5' 5' to 3'
Which of the following is the sense DNA strand from which the following RNA strand was obtained: 3'-AUCGCUUA-5'?
3'-ATCGCTTA-5' The sense, or coding, DNA strand has a sequence identical to that of the RNA transcript, except that thymine is replaced by uracil in RNA. Both the sense strand and the RNA transcript are complementary to the antisense, or template, strand from which the RNA was transcribed. Therefore, the correct sequence is the same as that of the RNA molecule but with T in place of U.
20% of adenine, what is the percent of the rest of the base pairs
30 C 30 G 20 T 20 - A
Lymphocytes
30% WBC T cells B cells NK cells
How many chromosomes do humans have?
46 (23 pairs)
how many possible combonations of codons are there?
4^3 = 64
Pentose Sugar
5 carbon sugar RNA = Ribose (2 OH groups) DNA = Deoxyribose (1 OH and 1 H)
DNA directions
5' to 3' on one side of strand 3' to 5' on the other strand
An orchid breeder crosses two types of orchids, one that is tall with a petite bloom and one that is short with a large bloom, with the goal of obtaining a tall orchid with a large bloom. The first cross yields all short flowers with petite blooms. What is the expected yield of tall orchids with large blooms if bred from the first generation?
6.25% The first cross yields only short flowers with petite blooms, indicating that these are the dominant traits. The parent flower that was tall with petite blooms must have been homozygous recessive for height and homozygous dominant for bloom size. The parent flower that was short with large blooms must have been homozygous dominant for height and homozygous recessive for bloom size. All of the first generation flowers are heterozygotes for both traits, so if you were to cross two of these progeny, you could expect a result that follows normal Mendelian ratios for a dihybrid cross: 9:3:3:1. Here, the "1" represents the 1/16, or 6.25%, that will display both recessive traits, tall orchids with large blooms, which is this orchid breeder's goal.
Neutrophils
60% of leukocytes track down forgein pathogens like bacteria phagocytosis
A man with blonde hair, blue eyes, and fair skin has a daughter with a woman with dark hair, brown eyes, and dark skin. (Assume that hair, eye, and skin color are each dependent on a single gene.) Based on their differences in these three traits, how many possible phenotypic combinations are possible for their child?
8 We are given no information regarding dominance or recessivity, so we must take all potential allelic combinations into account. Three genes are present, with two possibilities each; thus, we can use 2n to find that there are eight different combinations.
Suppose that a population of deer is in Hardy-Weinberg equilibrium and that all deer within this population have either straight or curved horns, and curved horns are dominant to straight horns. The frequency of the allele for curved horns is 0.7. What percentage of the deer have straight horns?
9% First, we need to find the frequency of the straight horns allele (q) within the population. From the question stem, we know that p = 0.7. Plug this into the equation p + q = 1 to obtain 0.3 for q. From the Hardy-Weinberg equation, we know that q2 is the percentage of deer that are homozygous recessive, so we can simply square 0.3 to get the correct answer: 0.09 or 9%.
Interphase
90% of cell cycle Cell growth, organelle dupilcation, protein synthesis, and DNA replication
Dihybrid crosses ratio
9:3:3:1
Immigration vs. Emigration
> immigration-Migration into a place (especially migration to a country of which you are not a native in order to settle there) ----------------------- > emigration-migration from a place (especially migration from your native country in order to settle in another)
Gene
A DNA sequence that codes for a protein that produces a given trait
If a man has type A blood, what type of antigens do his blood cells present when donated to another individual?
A antigens Correct Answer An antigen is any substance that causes an immune response and the production of antibodies against the antigen. If a person with A type blood donates blood to a person with B type blood, the donor's blood would be rejected.
Chaperone proteins:
A chaperone assists in the folding and formation of the secondary protein structure.
mutagen
A chemical or physical agent that interacts with DNA and causes a mutation. physcial agents - ionizing radtion - UV light Chemical agents - reactive oxygen species
Codominance
A condition in which neither of two alleles of a gene is dominant or recessive. type AB blood
Binary fission
A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size (identical daught cells) 1. prokaryotic parent cell 2. circular chromosome is replicated 3. cell growth occurs 4. new cell wall grows and segragates 5. two chromosomes are pulled toward either half of the cell 6. parent cell splits into two daughter cells
reporter gene
A genetic marker included in recombinant DNA to indicate the presence of the recombinant DNA in a host cell.
PCR (polymerase chain reaction)
A laboratory technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides.
spliceosome (snRNPs)
A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons.
Which of the following is the definition of the fertility rate of a population?
A measure of how many children an average woman would have if the current age-specific birth rates applied over the entire course of her life Correct Answer This is the definition of the fertility rate. The fertility rate is presented as the number of lifetime births per woman based on a projection of current age-specific birth rates. Essentially, it's a measure of how many children an average woman would have if the current age-specific birth rates applied over the entire course of her life. This measure can provide a snapshot of the rate of reproduction in an understandable way.
semipermeable membrane
A membrane that allows some molecules to pass through but does not allow other molecules to pass through.
relative refractory period
A period after firing when a neuron is returning to its normal polarized state and will fire again only if the incoming message is much stronger than usual
TATA box
A promoter DNA sequence crucial in forming the transcription initiation complex.
Morula
A solid ball of cells that makes up an embryo; in humans, this stage occurs within four days of fertilization.
glycoproteins on erythrocytes
ABO blood type and Rh factor
A patient presents to the emergency room with acute hypertension. Which of the following drugs could be used to treat this condition? Select all that apply.
ACE inhibitor or Renin substrate analog
Adrenocorticotropic hormone (ACTH) is released by the anterior lobe of the pituitary gland in response to corticotropin-releasing hormone (CRH), which is secreted by the hypothalamus. ACTH acts on the adrenal cortex to stimulate the production of glucocorticoids. Cortisol, an important glucocorticoid, promotes glucose release from the liver to increase blood glucose levels. Which of the molecules described can be classified as tropic hormones? Select all that apply.
ACTH CRH Cortisol is not a tropic hormone because it does not act on an endocrine organ. Instead, it directly promotes a physiological response within the liver.
membrane resistance
Ability to keep charges seperate High MR = effective AP transmission
Aneuploidy
Abnormal number of chromosomes results from non-disjunctions
Place the following events that occur during muscle contraction in order from first to last:
Acetylcholine binds the postsynaptic receptor Influx of sodium ions from the extracellular environment Release of calcium from the sarcoplasmic reticulum Conformational change of tropomyosin Binding of myosin to Actin
Which of the following choices best explains why trypsin is secreted from the pancreas as an inactive zymogen?
Active proteases can damage essential cellular proteins. Correct Answer Active proteases do not have an "off" switch and will cleave any protein they come across that fits their specifications. Because pancreatic proteases are housed in the pancreas, this presents an imminent threat to pancreatic proteins. This solution is simple: proteases like trypsin are stored as zymogens, which are only activated when they are released into the duodenum.
Nitrogenous bases in DNA
Adenine, Guanine = Purines Thymine, Cytosine = Pyrimidines
Nitrogenous bases in RNA
Adenine, Guanine = Purines Uracil, Cytosine = Pyrimidines
4 nucleotides in DNA
Adenine, Thymine, Guanine, Cytosine
Which of the following hormones are secreted by the adrenal cortex? Select all that apply.
Aldosterone, Cortisol, Estrogen
residual volume
Amount of air remaining in the lungs after a forced exhalation
expiratory reserve volume
Amount of air that can be forcefully exhaled after a normal tidal volume exhalation
inspiratory reserve volume
Amount of air that can be forcefully inhaled after a normal tidal volume inhalation
Nondisjunction
An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other. can result in aneuploidy = abnormal amounts of chromosomes
From an evolutionary perspective, which of the following organisms is best described as 'fit'?
An organism that generates a large number of progeny Reproduction, particularly the generation of reproductively viable progeny, is the primary evolutionary measure of fitness
Which of the following phenomena allows tumor cells to satisfy the increased metabolic demands associated with rapid growth and division?
Angiogenesis Correct Answer Angiogenesis refers to the formation of new blood vessels. Tumor cells often secrete factors that promote angiogenesis to recruit blood to the tumor site, which provides a steady supply of oxygen and nutrients.
The humoral immune response results in the production of what large protein structures that will bind to specific antigens and mark them for immune destruction?
Antibodies
Voltage gated Ca+ channels
At the terminal when depolarizaiton arrives, Ca+ channels open, Ca2+ comes in, creates a chemcial cascade, allows for exocytosis of NT
Virus replication
Attach, invade, copy, release
Humoral response = ______ Cell mediated response = ______
B cells T cells
What is the most common form of DNA
B-DNA
Homozygous dominant/recessive
BB or bb
Gram-positive bacteria
Bacteria that have a thick peptidoglycan cell wall, and no outer membrane. They stain very darkly (purple) in Gram stain.
cells involved in innate immunity
Bacteria, B cells, T cells, Neurtophil, macrophage, dendrtic cell, Basophil
Which of these events is most directly responsible for the release of neurotransmitter molecules from synaptic vesicles at the axon terminal?
Influx of extracellular calcium Correct Answer Membrane depolarization at the axon terminal causes voltage-gated calcium channels to open, resulting in calcium influx. This increase in intracellular calcium causes conformational changes in calcium-sensitive vesicle docking proteins, ultimately leading to release of neurotransmitter molecules.
Which of the following immune cells releases histamine during an allergic reaction?
Basophils
Heterozygous
Bb (carrier) these are carriers of recessive gene but dominant is trait is overpowering
Post-transcriptional silencing is theorized to prevent some gene expression in response to stress. Which of these modifications could prevent functional mRNA from being translated?
Binding to miRNA Correct Answer MicroRNA is responsible for post-transcriptional silencing. These short, non-coding RNA molecules bind to mRNA, signaling its destruction or promoting degradation of its protective post-transcriptional modifications.
What happens when a cyclin level is high?
Binds and Activates cyclin dependent kinases (CDK)
demographic transition: stage 4
Birth and death rates low and balanced, population levels off
Osteoclasts
Bone-destroying cells
Pancreas (Endocrine mechanisms
Both a exo and endocrine Endo - insulin and glucagon exo - bile and digestove enzymes
Dispersive DNA replication
Both copies of genome are composed of scattered pieces of old and new DNA
BRCA 1 and BRCA 2 genes
Breast Cancer. Code for proteins involved in repair of double stranded DNA breaks 40% - 80% lifetime risks of breasts. 15%-65% for ovarian cancer mutations exhibit chromosomal rearrangements
How are ventricular muscle cells connected?
By intercalated discs Correct Answer Cardiac muscle consists of individual cells connected by intercalated discs to work as a single functional organ. Note that the prefix "inter-" means "between."
Myelination in CNS and PNS
CNS neurons are myelinated by oligodendrocytes Peripheral nerves are myelinated by Schwann cells
Calcium Hormone Regulators
Ca2+ is necessary for bine development, muslce contraction, signal transduction PTH - parathyroid Hormone Calcitonin Vitamin D (D3 = regulates Ca2+ homeostasis and absorbtion from GI tract)
Hormones that dec Ca2+
Calcitonin
The pentose sugar contained in RNA differs from that contained in DNA in terms of its substitution at which carbon?
Carbon 2 DNA and RNA differ by which type of 5-carbon sugar they contain. RNA's 5-carbon sugar ribose has a hydroxyl group at carbon 2, while DNA's 5-carbon sugar deoxyribose does not a hydroxyl group at its carbon 2 position.
Which of the following best describes the process of gas exchange in the alveoli?
Carbon dioxide and oxygen move down a concentration gradient to diffuse from the bloodstream to the alveoli and from the alveoli to the bloodstream, respectively. Gas exchange across the alveoli occurs via passive diffusion for both carbon dioxide and oxygen. Carbon dioxide moves out of the bloodstream and into the alveoli to be expelled by the body during exhalation. Oxygen moves out of the alveoli and into the bloodstream where it is transported by its carrier protein, hemoglobin, throughout the body to be consumed by cells.
Which of the following best describes how the concentration of carbon dioxide in the blood affects the pH?
Carbon dioxide reacts with water to form carbonic acid, which exists in equilibrium with bicarbonate. Carbonic acid exists in equilibrium with its conjugate base, bicarbonate, and the protons that are lost from carbonic acid circulate in the bloodstream, thereby lowering the pH.
Each of the terms below is an organ that plays a role in the chemical digestion of macronutrients. Match each organ with the macronutrient(s) it digests. Small Intestine
Carbs, Proteins, and lipids
Types of bacteria
Catagorized by shape Coccus = sphere shaped Bacillus = rod shaped Spirillum = spiral shaped
Large Intestine parts
Cecum Colon Rectum
Mitosis
Cell division resulting in 2 identical copies of a cell occurs in somatic (body cells) Does not occur in sperm/egg cells
Where is the electron transport chain located in prokaryotes?
Cell membrane
Telophase I
Cell splits they are now haploid cells, but the chromosomes will still be paired with their identical copies
Which of the following best describes cleavage division?
Cells divide to create smaller cells so that there is no overall change in volume. Correct Answer After the zygote is formed, it undergoes a series of divisions in which new, smaller cells are formed but the total volume occupied by all the cells does not change because the daughter cells are smaller than the parent cell.
What are at the poles of the cells?
Centrosomes - structures composes of 2 centrioles made up of microtubule fibers
post-translational modification
Changes to the new protein that may be critical to its final function, like folding, phosphorylating glycosylating, or lipidating
What determines if DNA is in the heterochromatin or Euchromatin state?
Charged attractions between DNA (phosphates = neg) and histone (AA = +) proteins
Metaphase I
Chromosomes line up in 23 pairs. arrangement is random.
Metaphase
Chromosomes line up in the middle of the cell on the metaphase plate Must pass M checkpoint
autosomes
Chromosomes that are not directly involved in determining the sex of an individual.
sex chromosomes
Chromosomes that determine the sex of an individual
2 types of transpsons
Class I Transposons - Copy and Paste. (Trascribed into RNA then code a reverse transcriptase enzyme. the a DNA copy is made that can be intserted anywhere. Class II Transposons - Cut and Paste (composes a splicing enzymes that splices the DNA out, then allows it to go somewhere else)
Sickle-cell disease involves the production of abnormally shaped red blood cells. Individuals homozygous for sickle-cell disease develop this debilitating condition, but heterozygotes exhibit enhanced resistance to malaria. This has been proposed as an explanation for the close overlap between regions with a high prevalence of sickle-cell disease and areas with endemic malaria. What mechanism best explains the fact that homozygosity causes a potentially devastating illness whereas heterozygosity is associated with improved fitness?
Codominance Sickle-cell trait exhibits codominance. In heterozygotes, both normal and abnormal forms of hemoglobin are expressed; enough normal hemoglobin molecules are produced to ensure functionality (although heterozygotes have been excluded from certain physically demanding jobs, such as fighter pilots) while enough abnormal hemoglobin molecules are produced to interfere with the life cycle of the parasite that causes malaria.
Transmission of the F factor, a plasmid that contains genes for a sex pilus, is facilitated by which process?
Conjugation
Which type of genetic exchange allows for the largest increase in genetic diversity in a population of prokaryotes?
Conjugation
Which of the following recombinant processes depends on the F factor plasmid? Solution: The correct answer is C. Bacteria can exchange genes by three processes: conjugation, transformation and transduction. The process of conjugation involves production of a special conjugation pilus (sex pilus) by one bacterium and transfer through it of DNA to another bacterium. It requires special genes for the pilus and these are usually present on a plasmid, a separate extragenomic strand of DNA not incorporated
Conjugation Bacteria can exchange genes by three processes: conjugation, transformation and transduction. The process of conjugation involves production of a special conjugation pilus (sex pilus) by one bacterium and transfer through it of DNA to another bacterium. It requires special genes for the pilus and these are usually present on a plasmid, a separate extragenomic strand of DNA not incorporated into the bacterium's own DNA. This plasmid is referred to as the fertility or F factor. Conjugation is a feature of Gram-negative bacteria. It confers the advantages of sexual reproduction on the bacterium. The plasmid benefits by being able to move from one host bacterium to another through the conjugation pilus. Conjugation is the process described in the stem, so choice C is correct. Choice A and B are the other two processes that do not require a plasmid. In transformation bacteria take up DNA from their surroundings, the media in which they are immersed. Transduction is the process whereby genes are transferred by a virus. Choice D is also incorrect; translocation, is a general term used in biology to describe movement from one place to another (genes on a chromosome, proteins in a cell, sap in a tree).
How are centromeres an example of reptitive non coding DNA?
Contain blocks of repeting blocks of DNA heavy in G-C pairs
How are telomeres an example of reptitive non coding DNA?
Contain repeting codons of DNA made up of TTAGGG these cap the ends of chromosomes
Hemoglobins binding to O2 is ________
Cooperative
Stress Hormone Regulators
Cortisol - long term Epi and Norepi - short term
Testicular Thermoregulation
Cremaster muscle contracts to draw in the testes closer to the body Dartos muscle contracts to wrinkle the scrotal sac
Cytoplasm
Cytoplasm is defined as everything else, besides the nucleolus in external membrane, living inside the cell it includes all other organelles in the cytosol cytosol is a dense gel like aqueous solution that comprises the liquid found inside cells
Peptide hormone synthesis
DNA --> mRNA --> preprohormone --> prohormone --> hormone
Roles of DNA and RNA
DNA = stores and transmits genetic info RNA = decodes DNA to make proteins
Which of the following enzymes possesses a 3′-to-5′ exonuclease activity?
DNA Polymerase
Proofreading and Repairing DNA
DNA polymerases proofread newly made DNA, replacing any incorrect nucleotides 3' to 5' Exonuclease avtivity
S Phase
DNA replication all 46 chromosomes are replicated
Central Dogma of Molecular Biology
DNA--> mRNA--> protein--> traits
Structure of a neuron
Dendrites = input Terminal = output Soma = cell body - contains the nucleus and other cellular componets axon = rapid rely of signals Axon Hillock = end of soma
Steroid hormone
Derived from cholesterol and have a 4 rings Hydrophobic --> need a carrier protein to be in the blood, so they are protected diffuse the membrane then go to DNA to repress or stimulate transcription take time to manifest becuase they act on transcription
Cytokinesis
Division of the cytoplasm during cell division mediated by actin and myosin proteins to create a ring to create a cleavage furrow
bacteria
Domain of unicellular prokaryotes that have cell walls containing peptidoglycan
alleles: dominant, recessive
Dominant = one copy required to express a trait recessive: two copies required
In respiration, O2 diffuses ________________
Down its concentrations gradient
3 parts to the small intestine
Duodenum, Jejunum, Lleum
Where might ribosomes be found? Select all that apply.
ER and Cytoplasm
During the menstrual cycle, which layer of the uterus changes thickness in anticipation of implantation?
Endometrium Correct Answer The endometrium is the innermost layer of the uterus and provides a site for implantation and nourishment of a fertilized ovum.
Mitochondria (Mitochondrion; singular)
Energy Powerhouse of the cell CAC, beta oxidation, and oxidative phosphorylation takes place here
Spindle checkpoint (M checkpoint)
Ensures the chromosomes are correctly attached to microtuble fibers that will pull them to each pole of the cell
Sexual Development Hormone Regulators
Estrogen and Testosterone
Heterochromatin
Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed. It is the Centromere In M phase, DNA is packed as heterochromatin
RNA interference (RNAi)
Eukaryotics gene expression miRNA or siRNA is turned into a RNA induced silencing complex. Then there is cleavge of the target mRNA, ruining the RNA
Suppose that a very large population of geese contains several different alleles for feather color, such that geese may have either white, black, or brown feathers. Through a chance natural disaster, the white allele is suddenly lost from this population and all future geese are black. Which of the following mechanisms could be responsible for fixation of the black allele?
Evolutionary bottleneck
Graded potentials are
Excititaory post synaptic potentials - EPSP = depolarize Inhbitory post synaptic potentials - ISPS = hyperpolarize
spindle fibers
Extend from both centosomes to form the mitotic spindle. They attach to the kinetochores which allows them to pull apart the chromatids at a later stage
True or false: Adjacent nucleotides in single-stranded DNA are connected by linkages between nitrogenous bases.
FALSE This statement is false. The sugar-phosphate backbone of nucleic acids consists of phosphate esters formed between deoxyribose sugar hydroxyl groups and phosphate groups. Adjacent nitrogenous bases are not directly connected to each other in single-stranded DNA. Instead, nitrogenous bases interact via hydrogen bonding between two complementary strands in double-stranded DNA.
True or false: During prophase I, crossing over often occurs between sister chromatids as well as between homologous chromosomes.
FALSE Crossing over occurs between homologous chromosomes (not sister chromatids), though it is observed during prophase I of meiosis. If segments of genetic material were to be exchanged between sister chromatids, no change would occur, as these chromatids are genetically identical.
Hormone cycle of menstration
FSH Inc --> inducing follicular development Estrogen levels rise, stimulating the devoplment of uterine endometrium LH triggers ovulation, ruptured follicle forms the corpus luteum progesterone helps maintain the readiness of the uterine endometirum for implantation
Which of the following hormones are released in response to gonadotropin-releasing hormone?
FSH and LH
True or false: A single antibody can recognize all antigens in the body.
False
True or false: In humans, linked genes are always inherited together.
False Linked genes tend to be passed to offspring together significantly more often than unlinked genes. However, crossover events may occur between linked alleles, causing them to recombine, or to be inherited separately.
True or false: Heterochromatin will increase in abundance during the synthesis phase of the cell cycle.
False This statement is false. Heterochromatin is the tightly-packed, condensed form of chromatin. It would be unlikely to predominate during the synthesis (replication) phase of the cycle, as the DNA must be easily accessible to DNA polymerase and other enzymes during this phase. Euchromatin predominates during the S phase.
True or false: Single nucleotide polymorphisms necessarily result in differences in the amino acid sequence of a protein.
False This statement is false. Single nucleotide polymorphisms (SNPs) that occur within coding regions may result in different amino acids being encoded at that position, or two SNPs in the same codon may still encode the same amino acid. Furthermore, many SNPs fall in non-coding regions of the genome and thus do not affect the amino acid sequences of proteins.
True or false: The components of the peripheral nervous system are bathed in cerebrospinal fluid.
False, it is the CNS
stabilizing selection
Favors an intermediate phenotype
Which of the following proteins has the most integral role in blood clotting?
Fibrin
Fluid Balance Hormone Regulators
Fluid Loss Atrial Natriuretic Peptide Fluid Retention Aldosterone ADH Too little Fluid - less fluid availible to exert pressure on vessel walls - low blood osmolarity - dehydration too much fluid - too much poressure - high blood osmolarity
cerebrospinal fluid
Fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system. secreted by ependymal cells
neurons spend most of their time in what cell cycle phase?
G0
Lysosomes
Garbage disposal of the cell these are membrane bound vesicles that contain enzymes that can hydrolysis polymers. They operate at a pH of 4.5 to 5. Due to this if a lysosomes ruptures, the enzymes cannot destroy the cell, because the physiological pH is 7 material from outside the cell enters the lysosomes through endocytosis material from inside the cell enters through autophagy
All of the following are cell types found in the stomach that secrete key molecules involved in digestion parietal cells secrete what
Gastric acid
Which of the following best explains the pH difference between the stomach and the duodenum?
Gastric acid from the stomach is neutralized by bicarbonate in the duodenum. Correct Answer The pancreas secretes a bicarbonate solution that neutralizes the acidic chyme entering the duodenum from the stomach. This mechanism ensures a duodenal pH around 6-7, which is the ideal environment for pancreatic enzymes to function in.
The diagram below depicts the positions of four genes on chromosome 7, drawn to scale. Which gene would most likely display the highest recombination frequency relative to gene A?
Gene E Genes that are farther apart on a particular chromosome are more likely to be separated by a crossover event than are closely-positioned genes. Here, genes A and E are the most distant of the genes shown.
How to determine genetic linkage?
Genetic crosses depends on where genes are and if they get recombinated during meiosis
Meiosis occurs in ______ cells?
Germ cells ovaries and testes
Biologists have argued that the gastrointestinal tract can be viewed as an outgrowth of the immune system. Which of the following answer choices correctly identify immune functions of the digestive system? Select all that apply.
Glands in the mouth produce saliva, which contains an enzyme that kills bacteria. Saliva contains lysozyme, which catalyzes the destruction of bacterial cell walls. The stomach is extremely acidic, making it inhospitable to many pathogens. The stomach typically has a pH in the range of 1.5 to 3, which kills many microorganisms on contact. One notable exception is H. pylori, which has evolved to survive in this acidic environment. However, the question says "many pathogens," not "ALL pathogens".
Which of the following hormones act to raise blood glucose levels? Select all that apply.
Glucagon Cortisol Epi GH
Blood Glucose Hormone Regulators
Glucagon, Insulin Cortisol, Epi, Norepi
Which of the following are examples of covalent post-translational modifications? Select all that apply.
Glycosylation Glycosylation refers to the addition of carbohydrate moieties, which is often catalyzed in the Golgi apparatus. This is a very common post-translational modification for proteins. Phosphorylation Kinase enzymes covalently link high-energy phosphate groups to specific amino acid residues on proteins after translation. Therefore, phosphorylation is a covalent post-translational modification.
Which of the following best describes how the respiratory system is involved in immune defense?
Goblet cells in the trachea produce mucus to trap incoming bacteria. Goblet cells in the trachea produce mucus to trap airborne bacteria. The bacteria filled mucus is then moved up and out of the trachea by ciliated epithelial cells lining the lumen of the trachea.
What hormone is released during puberty
Gonadotropin - releasing hormone is released by hypothalmus then goes to the ant. pit. to release LH and FSH
Castration is a common procedure in animal husbandry. One such instance is the removal of the testes from a stallion, a male horse, producing what is called a gelding. What part of the reproductive tract is lacking in a gelding?
Gonads Correct Answer The testes are the gonads in males. This is a consistent trait across all of the class Mammalia. Gonads are the site of gamete production. In this case, for male gonads called testes, the gametes being produced are called sperm.
Penicillin is an antibiotic that targets peptidoglycan. Would penicillin be more effective in treating an infection of Gram-positive or Gram-negative bacteria?
Gram-positive Since Gram-positive cells have a peptidoglycan-rich cell wall, penicillin would be effective in treating infections resulting from Gram-positive cells.
sex-linked inheritance
Inheritance of a genetic trait located on the sex chromosomes
innate vs adaptive immunity
Innate immunity: An individual's genetically predetermined resistance to certain diseases. Nonspecific and response to injury or infection Adaptive immunity: Ability of the body to react to specific microbial infection. ANTIGEN SPECIFIC
HPA Axis
Interaction between the nervous and endocrine systems to produce the body's response to stress. Elevated levels of one of these hormones may lead to depression utilizes multpile tropic hormones coordinated the activity of several endocrine organs vulnerable to dysregulation by overstimulation
plasma membrane proteins
Intergral lipid anchored peripheral glycoproteins
What is the key difference between benign and malignant tumors?
Invasive capacity Correct Answer Benign tumors are expected to remain localized in one area. Malignant tumors, on the other hand, are characterized by their ability to metastasize to other locations in the body.
PURe As Gold
Guanine and Adenine are Purines
Somatostatin
Halts digestive hormones stalls stomach emptying halts release of pancratic hormones inhibits release of growth hormone
Phosphate Group
Has negative charge can have more than one phosphate attached
Hypertonic
Having a higher concentration of cell than another solution. cell shrinks
cooperative binding in hemoglobin (HOW IT WORKS)
Hemoglobin changes conformation depending on the concentration of O2 in the enviorment in low O2 = hemoglobin is in the T state (Tense) = low aff for O2 When it binds O2 = hemoglobin is in the R state (relaxed) = high aff for O2 this allows for proper diffusion of O2 on and off of hemoglobin
Why does backflow of blood in the heart occur when valves are absent?
Higher pressure in the ventricles and lower pressure in the atria Correct Answer The ventricles are larger and more muscular than the atria and therefore can create more pressure. A fundamental concept involving fluids is that they flow from areas of high pressure to low pressure. Valves are neat structures which prevent blood from reentering the lower pressure atria.
What are the proteins around which chromatin condenses?
Histones
Hormones vs. Neurotransmitters
Hormones move slower because they move through the bloodstream while neurotransmitters travel through synapses
cytoplasmic resistance
How much the cytoplasm impeds the flow of ions High CR = Low conduction High Neuron size = low CR
hybrid breakdown
Hybrid is fertile, but when they breed the next generation is sterile.
Which types of interactions are DNA capable of forming?
Hydrophobic - adjacent base paoirs on top of eachother Hydrogen - hold base pairs toegther Phosphodiester - sugar phosphate backbones NOT peptide
Bone is primarily comprised of collagen and what other non-cellular component?
Hydroxyapatite Correct Answer Hydroxyapatite, Ca5(PO4)3(OH), is the mineral component of bone. Hydroxyapatite serves as a storage deposit for calcium and phosphate in bone.
Question 8 The loop of Henle utilizes a countercurrent multiplier mechanism in which the direction of blood flow in the vasa recta is opposite the direction of filtrate movement through the renal tubule. What is the purpose of this system?
It maintains a concentration gradient between the loop of Henle and the vasa recta. Correct Answer Water is reabsorbed into the vasa recta in the descending limb of the loop of Henle and ions are reabsorbed in the ascending limb. These actions depend on concentration gradients between the loop of Henle and the vasa recta, which is maintained by the countercurrent multiplier system. If blood in the vasa recta were to flow in the same direction as the filtrate in the loop of Henle, their solute concentrations would quickly equalize and the flow of water and solutes between them would stop.
A human adult male runs outside, stark naked, on a cold, windy day. While inspecting his scrotum, what will he find?
It will be pulled closer to his body, due to action of the cremaster muscle. Correct Answer A key function of the scrotum is to regulate the temperature of the testes and keep them slightly below core body temperature, or at the ideal temperature for the development and maturation of sperm. The cremaster muscle can shorten the distance between the testes and the body by contracting. On a cold day, an unclothed human adult male would find that his scrotum has moved closer to his body in order to retain more heat.
majority of our DNA is ______
Junk but allow us to maintin structural intergrity of telomers, centomeres DNA forensics promote genetic diveristy
Relative to the extracellular environment, a cell contains the most of which of the following ions?
K+_
From what organ is erythropoietin released, and what is this hormone's primary function?
Kidney, stimulation of red blood cell development Erythropoietin is a hormone secreted by the kidneys in response to cellular hypoxia. It increases the production of red blood cells (erythrocytes) in bone marrow.
Which of the following interventions will correct a blood pH of 7.6?
Hypoventilating Correct Answer A blood pH of 7.6 is higher than its normal value of 7.4, so it is too basic. This condition in known as alkalemia. To correct for alkalemia, we need to increase the concentration of protons to lower the pH back to 7.4. Breathing more slowly, hypoventilation, will promote the build up of carbon dioxide in our blood. An increased concentration of carbon dioxide will increase the concentration of carbonic acid, which loses a proton to form bicarbonate. These protons from carbonic acid will make the blood more acidic and drive it back down to its normal value of 7.4.
Hypotonic
If solution has a lower concentration of solute water will move into the cell
G1 checkpoint (restriction point)
If the cell receives a go-ahead signal at the G1 checkpoint, it will complete interphase and go on to divide If it does not, it can exit the cycle and switch to a nondividing state called the G0 phase
RNA viral genomes
Immediately translated into protein in the host cytoplasm reverse trancscribed to DNA by reverse transcriptase (retroviruses)
Match the environmental condition with the corresponding pattern of gene expression of the lac operon.
Lactose metabolism genes are not expressed when only glucose is available and are strongly expressed when only lactose is available. When both glucose and lactose are available, lactose metabolism genes are expressed, but not strongly.
Which digestive organ hosts the largest community of bacteria in the human body?
Large intestine
Monocytes
Largest by size differnceitate: - macrophage - dendritic cells
Conservative DNA replication
Leaves the original DNA molecule intact and generates a completely new molecule.
What is Z-DNA
Left handed DNA looser than A and B DNA
Match each of the following conditions with its effects on the hemoglobin dissociation curve: at high pH the curve will shift left or right?
Left shift
Match the cell type with the corresponding gonadotropic hormone that activates it. Luteinizing hormone Follicle stimulating hormone
Leydig cells are activated by luteinizing hormone (LH), causing them to produce testosterone in males. In females, an LH surge causes ovulation. Follicle stimulating hormone (FSH) acts on the Sertoli cells to promote spermatogenesis in males. In females, FSH stimulates follicle growth.
locus
Location of a gene on a chromosome
An angiotensin II receptor antagonist would be expected to promote which of the following physiological effects?
Low blood pressure. Correct Answer Angiotensin II is a downstream product of the renin-angiotensin-aldosterone system, which regulates blood pressure and volume. Angiotensin II stimulates aldosterone release from the adrenal cortex. Aldosterone promotes sodium reabsorption from the distal tubule and collecting duct of the nephron. As plasma osmolality increases, water follows its gradient from the kidney filtrate into the bloodstream by osmosis, increasing blood volume and pressure. Since an angiotensin II receptor antagonist would block the activity of angiotensin, we would expect blood pressure and volume to remain low. D Low blood volume. Correct Answer An angiotensin II receptor antagonist would prevent aldosterone release, which in turn would lead to low blood pressure and volume. See explanation for choice C.
Calcitonin
Lowers blood calcium levels
MHC1 and CD8 T cells
MHC1 is found on all cells Killer T cells = CD8
MCH2 and CD4 T cells
MHC2 = antigen presenting cells Helper T cells = Cd4
Nucleolus
Makes ribosomes
List the following terms in the correct order to properly describe nutrient exchange between the mother and the fetus via the placenta: fetal CO2, indirect exchange, umbilical vein, maternal O2, and umbilical artery.
Maternal O2 Indirect exchange Umbilical vein Fetal CO2 Umbilical artery
Platelets are derived from:
Megakaryocytes Platelets are cellular fragments derived from megakaryocytes. Platelets are responsible for blood coagulation or clotting in the circulatory system. An interesting fact about platelets is that they contain ribosomes and do synthesize some proteins, yet have no nucleus in which to produce mRNA.
Germ cells under go _____ to produce ___ and ____ via ______ and _______
Meiosis Ova and sperm oogenesis and spermatogenesis
Which of the following is produced to protect the skin from harmful UV radiation?
Melanin Correct Answer Melanin is a substance produced by melanocytes in the epidermis that causes skin pigmentation, and it absorbs ultraviolet light.
Peroxisomes
Membrane bound peroxides accumulate in peroxisomes o peroxisomes play major role in metabolism for very long chains of lipids by breaking them down into medium chain lipids that are transported to the mitochondria for further processing o also play a role in detoxification of substances like ethanol - in the liver
Glycoproteins
Membrane carbohydrates that are covalently bonded to proteins. involved in cell recognigtion and communitcation processes types: Histocompatability complex antigens of ABO blood type system
Place the following events of the uterine cycle in order, starting from the beginning of the cycle (which coincides with the first part of the follicular phase in the ovarian cycle):
Menstruation occurs Estrogen levels rise The uterine endometrium thickens The uterine endometrium is prepared for implantation The uterine lining is sloughed off again if implantation does not occur
Every protein translated in eukaryotes begins with:\
Met
Which of the following physiological functions are regulated by the thyroid gland?
Metabolic rate The thyroid gland regulates the metabolic rate by secreting the thyroid hormones T3 and T4. When the thyroid gland is hypoactive, reduced levels of T3 and T4 lead to a reduced metabolic rate. In contrast, hyperthyroidism leads to abnormally high levels of T3 and T4 and an increase in the metabolic rate. Calcium absorption The thyroid gland regulates calcium absorption by secreting the hormone calcitonin, which reduces blood calcium concentration.
Which of the following cellular components would LEAST likely be found in an erythrocyte?
Mitochondra and nuclues
Which of the following organelles contains only maternal DNA?
Mitochondria The mitochondria contain their own DNA and all of the mitochondria in your cells today were once part of the oocyte and therefore maternal. The sperm does not contribute any mitochondria during the fertilization event.
endosymbiotic origin theory
Mitochondria can self-replicate they contain their own DNA (mtDNA) it is inherited maternally and undergoes binary fission
Mitosis vs. Meiosis
Mitosis: one division forming 2 identical cells (clones); Meiosis: two divisions forming 4 genetically different cells
Molecular clock
Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently
Osmolarity
Molarity of ALL solute particles 1 mol NaCl = 2 osmols
Which leukocyte is the largest?
Monocytes
Which white blood cell can differentiate into macrophages and dendritic cells?
Monocytes
Membrane potential of Ions (relative amounts for K+, Cl-, Na+, Ca2+)
More K+ Less Ca2+, Cl-, Na+
What is A-DNA
More condensed Dehydrated form DNA and RNA hybrid helices
All of the following are cell types found in the stomach that secrete key molecules involved in digestion Epithelial cells secrete what
Mucus
Evolutionary System
Must fufill 3 criteria 1. Variation 2. Reproduction 3. Differential reproduction due to selective pressure
In which direction are peptides synthesized by ribosomes?
N to C terminus
merocrine, apocrine, holocrine
NOT ENDOCRINE they are exocrine
reploarization
Na+ channels close, K+ channels open, K+ rushed out, hyperpolarizes the cell, K+ close, Na+K+Atpase brings concentrtations gradient back to normal
Group selection
Natural selection applied to the group level inclusive fitness
Inflation of the lungs in mammals is accomplished by:
Negative pressure pumping action
trp operon
Negative repressible - expression repressed by binding of repressor An abundant supply of trp represses transcription default is the ON position
Neuroendocrine Integration
Nervous system and endcrine work together Hypothalmus release tropic hormones from pituituary gland (HPA Axis) Pos and Neg feeback
The most abundant leukocyte is:
Neutrophils
Bacterial Respiration
No mitochomdria, but they use an ETC on the cell membrane
Is a single genetic mutation likely to give rise to cancer?
No, cancer usually results from many accumulated mutations over time. Correct Answer Although tumorigenesis typically begins with a single mutation in a gene that regulates cell growth and division, a cell usually does not become cancerous until it accumulates many mutations in critical genes related to these processes.
A newly proposed candidate for an antibiotic targets flagellin, the primary structural component of bacterial flagella. Does this medication pose a significant risk of attacking human cells as well?
No; human flagella are not composed of flagellin. Eukaryotic and prokaryotic flagella have entirely different structures. In eukaryotes, a flagellum is primarily composed of a bundle of linked microtubules. The actual protein flagellin is only a component of prokaryotic flagella.
Prophase
Nuclear envelope breaks down Nucleoli disappear DNA condenses into tightly packed chromatin
Telophase II
Nuclear membrane reforms, cytoplasm divides, 4 daughter cells formed that are genetically unique from the rest
Match each term with its definition. Nucleosome Centromere Linker DNA 30-nm fiber
Nucleosome A core of 8 histone proteins wrapped in DNA Centromere The region of the chromosome that joins two sister chromatids Linker DNA Sequences between nucleosomes 30-nm fiber A condensed chromatin structure Nucleosomes are formed by DNA wrapped twice around a core of 8 histone proteins. Centromeres are the central regions of chromosomes that join two sister chromatids, and this is also where spindle fibers attach during cell division. Linker DNA describes the stretches of DNA linking two nucleosomes, giving the appearance of "beads on a string." Nucleosomes are condensed further into 30-nm chromatin fibers, which are a type of condensed chromosome structure.
Repetitive DNA
Nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome. The repeated units may be short and arranged tandemly (in series) or long and dispersed in the genome.
Anaerobes
O2 is not reuqired for metabolis obligate anaeribes cannot survive in the presense of O2
A researcher is studying a bacterium and finds that it requires oxygen in order to survive. In which of the following classes does this bacterium belong?
Obligate aerobe This bacterium requires oxygen to survive, which means it is an obligate aerobe.
in the capillaries RBC travel ______
One by one to allow for gas exchange
independent assortment
One of Mendel's principles that states that genes for different traits can segregate independently during the formation of gametes
Peptide Hormones
One or more chains of polar AA Hydrophlilic --> diffuse freely, unprotected in blood use secondary messengers
temporal summation
One or more presynaptic neurons transmit impulses in rapid-fire order potentials add up in close time
single nucleotide polymorphism (SNP)
One-nucleotide DNA sequence variation carried by 1% percentage of a population.
Thymus
Organ wehre T cells mature
Capsid
Outer protein coat of a virus
Reproductive Organs
Ovaries and Testes repsond to LH and FSH from anterior pituitary develop secindary sex characteristics
How is an egg transfered from the ovaries to be fertilized by sperm (PENISSS)
Ovary fallopian tube sperm meets egg uterus
Which of the following correctly describes the movement of oxygen during gas exchange in the lungs?
Oxygen from the alveoli diffuses into the alveolar capillaries and binds to hemoglobin in the bloodstream to be transported through the circulatory system to all the cells in the body.
Which of the following are hormones released by the posterior pituitary?
Oxytocin and Vasopressin (ADH)
synapsis
Pairing of maternal and paternal chromosomes
In which of the following ways is oxygen transported out of the alveoli and into the bloodstream? Select all that apply.
Passive transport Correct Answer Oxygen is transported out of the alveoli and into the bloodstream via passive diffusion down its concentration gradient. No energy is required for oxygen to diffuse out of the alveoli and into the bloodstream to be consumed by cells.
Depolarization
Peak = + 40 mV Na+ channels cannot open again after a period of time
Anaphase
Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell Sister chromatids are pulled apart
componets to the blood
Plasma Buffy Coat Red Blood Cells
The humoral component of the adaptive immune system involves which of the following cell types? Select all that apply.
Plasma cells B cells
Biotechnology: types of vectors
Plasmids bacteriophages
RNA silencing occurs at which stage of gene expression
Post-transcription Correct Answer RNA silencing is the process by which miRNA or siRNA targets a complementary mRNA sequence for destruction after transcription has occurred.
The endometrium is highly vascularized, and the sloughing off of the endometrium is consequently accompanied by an observable vaginal discharge of blood, tissue and fluid. What part of the ovarian cycle does the observance of such a discharge correspond to?
Pre-ovulatory phase Correct Answer The thinning of the endometrium by the sloughing off of existing tissue is a hallmark of menses, or menstruation. The preovulatory phase of the ovarian cycle overlaps in time with both menses and the proliferative phase of the uterine cycle.
types of active transport
Primary - ATP hydroysis, redox, light powers solute movement against a gradient (Sodium potassium pump) Secondary - Active and Passive. Active transport is generates a concentration gradient that powers the passive trasnport. They are usually coupled.
Arrange these steps in the development of the human female gamete in the correct order:
Primordial germ cells Oogonia Primary oocyte Secondary oocyte Arrest in metaphase II Fertilized ovum
Exocytosis
Process by which a cell releases large amounts of material controlled by ca2+ ions
convergent evolution
Process by which unrelated organisms independently evolve similarities when adapting to similar environments
What is the hormone called that causes a decrease in LH through negative feedback and thereby leads to the degeneration of the corpus luteum?
Progesterone Correct Answer Progesterone has a negative feedback effect on the secretion of luteinizing hormone (LH) by the anterior pituitary and is secreted by the corpus luteum.
Estrogen and progesterone are two important regulatory hormones in both the uterine and the ovarian cycle. Which of the following are some of their functions?
Progesterone prevents loss of existing endometrium. Correct Answer Progesterone is necessary for the maintenance of existing endometrium. It is also a key hormone released by the corpus luteum at first and - during the later stages of pregnancy - by the placenta. Estrogen encourages proliferation of the endometrium. Correct Answer Estrogen is key to the proliferation of the endometrium, an important step in the uterine cycle.
DNA Repair options
Proofreading Mismatch Repair Base Excision Repair Nucleotide Excision Repair
The primary oocyte spends most of its existence in which phase of meiotic division?
Prophase I Correct Answer The primary oocyte is arrested in prophase I until puberty. After the commencement of puberty, a small number of primary oocytes resume oogenesis and develop into secondary oocytes. These secondary oocytes in turn freeze their development at metaphase II. At ovulation, a secondary oocyte is released. If fertilization occurs, then meiosis II is completed.
Select all of the statements below that correctly complete the following sentence. The 5' cap on an mRNA transcript:
Protects from degredation facilites nuclear export provides a recognigtuon site for ribosomal attachmebnt
Which class of large biological molecules do prions belong to?
Proteins
Intergral proteins
Proteins that go all the way through the membrane transmembrane proteins hydrophilic head, and hydrophobic spanning part Types: Proton pumps Ion Channels G protein coupled receptors
Which of the following is a function of seminal vesicles?
Providing nutrients necessary for the survival of spermatozoa Correct Answer The secretions from the seminal vesicles provides nutrients necessary for the survival of spermatozoa.
Nitrogenous Base types
Purines (2 rings) - adenine and guan Pyrimidines (1 ring) - Cytosine and Thymine
reverse transcriptase
RNA to DNA
viral infection
RNA viruses must first be reverse transcribe their genetic material into DNA
saltatory conduction
Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane.
Which of the following processes take place within the proximal convoluted tubule (PCT) of the nephron?
Reabsorption of metabolically valuable solutes Correct Answer The PCT facilitates reabsorption of metabolically useful solutes such as glucose, amino acids, vitamins, and certain ions. During reabsorption, these molecules are removed from the filtrate within the renal tubule and reintroduced into the bloodstream.
Eukaryotic Gene Expression - methods of gene control
Refer to sheet RNA interference promoters transcription factors Enchancers Silencers DNA modification
Topoisomerase (DNA Gyrase)
Relaxes the DNA double helix from the tension the opening helix is creating
base excision repair
Removes 1 base small scale repairs occur during non repilication
nucleotide excision repair
Removes multiple bases larger scale repairs occur during non repilication
Telomeres
Repeated DNA sequences at the ends of eukaryotic chromosomes.
Ribosomal RNA (rRNA)
Ribosomal RNA synthesized in nucleoli some molecules act as ribozymes siRNA and miRNA inhibit gene expression
Most DNA is _______ handed
Right
Match each of the following conditions with its effects on the hemoglobin dissociation curve: at high CO2 concentration the curve will shift left or right?
Right shift
Rough vs Smooth ER
Rough - covered in ribosomes which are site for protein synethsis smooth - no ribosomes § involved in lipid metabolism, the production of steroid hormones, and detoxification § produce the phospholipid components of membranes throughout the cell
Every heartbeat is initiated with an action potential beginning at the:
SA Node
Key functions of heart pysiology
SA node with pacemaker cells Gap junctions allowing for cells to have coordinated contractions AV node Bundle of His and Purkinje Fibers
saturated vs unsaturated fatty acids in the membrane
Saturated = no double bonds, high melt points = less fluidity unsaturated = contain double bonds (usually in Cis), lower melting points = more fluidity
Which of the following answer choices best characterizes the transport mechanism through which glucose molecules move into enterocytes from the lumen of the small intestine?
Secondary active transport Correct Answer Secondary active transport couples the movement of an ion down its concentration gradient with the movement of a solute against its gradient. First, a sodium-potassium pump uses energy to generate an electrochemical gradient that maintains a low sodium concentration inside the cell. Although this "active transport" step does not directly involve glucose, it is a key preparatory step for glucose transport. Because the concentration of sodium is much higher outside of the cell, it easily flows back into the cell through a sodium-glucose symporter protein.
Genetic Drift is not a _____________
Selective pressure; occurs by random chance
Azoospermia
Semen containing no sperm
How to remeber the path of semen... SEVEN UP
Seminiferous tubules epididymis vas deferens ejaculation duct Nothing Urethra Penis
Order the following events according to the sequence of parasympathetic signal conduction.
Signal originates in cervical or sacral spinal cord Action potential travels down long axon Action potential reaches ganglion Action potential travels down short axon Acetylcholine released at target tissue
Micelles
Simple composed of a single layer of lipids in solution can reduce the surface tension of a solution = Surfactant
STR (short tandem repeats)
Simple sequence DNA containing multiple tandemly repeated units of two to five nucleotides.
RNA is usually ___ stranded state
Single
Single vs. double crossover
Single-crossover events affect only the ends of chromosome arms, while double-crossover events can affect segments in the middle of chromosome arms. A double-crossover event is one in which chromosomal arms of homologous chromosomes cross over in two different places along the arm. This results in a section in the middle of each chromosome being exchanged. Both single and double only occur in MEIOSIS and only affect one arm of each chromosome. Occurs in prophase I
Testes
Site of spermatogensis place where production and maturation of male gametes secrete Androgens
incomplete dominance
Situation in which one allele is not completely dominant over another allele blended phenotype
parasympathetic nervous system ______ HR and the sympathetics NS _______ HR
Slows Speeds up
Okazaki fragments
Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.
Place the following events in the order in which they occur during the course of a typical action potential, starting immediately after threshold voltage is reached.
Sodium channels open Potassium channels finish opening Sodium channels inactivate Cell becomes hyperpolarized Potassium channels close
The voluntary movement of skeletal muscle is part of which division of the nervous system?
Somatic Correct Answer The somatic nervous system is part of the peripheral nervous system that is associated with voluntary muscle control, and skeletal muscle is the only muscle type under voluntary control.
What stem cell types are naturally found in adults?
Somatic Stem Cells
Which of the following hormones inhibits digestive processes?
Somatostatin Somatostatin is the main inhibitory hormone in the digestive system. It inhibits all of the major pro-digestion hormones (gastrin, CCK and secretin), slows stomach emptying, and prevents the release of growth hormone, insulin, and glucagon.
Identify the correct sequence for the development of motile sperm from precursor cells:
Spermatogonial stem cells Spermatogonia Primary spermatocytes Secondary spermatocytes Spermatids Spermatozoa
Epididymis
Storgae and further maturation of spermatzoa
DNA strands that have more G-C base pairs tend to be _______
Stronger becuase they have 3 hydrogen bonds opposed to 2
How are nucleic acids held toegther... what is the backbone?
Sugar phoshate backbone.
Transporter types
Symporter - moves solutes in same directions Antiporter - moves solutes in opposite directions
DNA polymerase
Synthesizes DNA adds nucleotides sequentially in the 5' to 3' direction, but reads it in 3' to 5' direction
metabolic rate Hormone Regulators
T3 and T4 Insufficent = Hypothyroidism - fatigue, weight gain, depressed HR Too much = Hyperthyroidism - weight loss, inc appetite, rapid HR
Major Histocompatibility Complex (MHC)
Target host infected cells
Male Gonads
Testes
The Goldman equation, used in cell membrane physiology to determine the reversal potential across a cell's membrane by taking into account all of the ions that are permeant through that membrane, is most closely related to which of the following equations?
The Nernst equation Correct Answer The Nernst equation is used to model electrochemical cells, and can be applied to cell membranes in a similar way to the Goldman equation, both of which are concerned with the concentration and flow of ions.
How does a codon recognize the correct anticodon?
The anticodon binds to the codon via corresponding RNA sequences. An anticodon is part of a tRNA molecule. It is able to bind to a corresponding codon because it possesses a complementary RNA sequence.
Nucleus
The basic function of the nucleus is to compartmentalize and store genetic information by linear chromosomes
Human fingers are originally webbed when they first develop. How does the body create individual fingers from this webbed structure?
The cells of the web undergo apoptosis, resulting in the separation of fingers observed at birth. Correct Answer The cells of the webbing undergo apoptosis: they shrink in size, their nuclear DNA is degraded, and they separate into small, membrane-wrapped fragments. Finally, nearby phagocytic cells engulf these pieces.
True or false: A female of reproductive age likely forms at least one corpus albicans per month.
The corpus albicans is the degenerate scar tissue from a corpus luteum. The corpus luteum is comprised of the cells of a ruptured ovarian follicle. In a female of reproductive age, on average, one follicle ruptures during every menstrual cycle. After this ruptured follicle forms the corpus luteum, if fertilization does not occur, the corpus luteum becomes the corpus albicans.
Uterine cycle
The cycle that prepares the uterus for the growth of an embryo.
Metaphase II
The duplicated chromosomes move to the centre of the cell. Each centromere attaches to two spindle fibres instead of one. Line up in a single file line
pituitary gland
The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands. has an anterior and posterior lobe that both recieve input from the hypothalmus
Prophase II
The first phase of meiosis II. Prophase II is identical to mitotic prophase, except that the number of chromosomes was reduced by half during meiosis I.
Place the following events of the ovarian cycle in order, starting from the beginning of the cycle: Ovulation occurs, the follicle becomes the corpus luteum, the follicular phase begins, the corpus luteum decays, FSH levels spike, and estrogen rises sharply.
The follicular phase begins Estrogen rises sharply FSH levels spike Ovulation occurs The follicle becomes the corpus luteum The corpus luteum decays
The frequency with which __________ of two genes occurs is _____ to the distance between the two genes in _______.
The frequency with which recombination of two genes occurs is equal to the distance between the two genes in centimorgans.
A trait is expressed in all individuals who carry a certain gene, but causes symptoms that vary in intensity depending on diet and exercise. What can be said about the penetrance and expressivity of this trait?
The gene is 100% penetrant and variably expressive. Since this trait appears to some extent in everyone who has the gene, it is 100% penetrant. Variations in symptom severity always imply that a condition displays variable expressivity, meaning that some people express it more than others.
Which white blood cells has granules that stain blue with basic dyes?
The granules in basophils stain blue.
Euchromatin
The less condensed form of eukaryotic chromatin that is available for transcription.
Hardy-Weinberg equilibrium
The mathmatical relationship between allele and phenotype frequencies used to model stable gene pools helps us to put a percentage to the number of homozygous (dom or rec) and heterzygoes
absolute refractory period
The minimum length of time after an action potential during which another action potential cannot begin.
Nephrons within the kidney facilitate reabsorption of several small molecules. Reabsorption within the renal tubule is best defined as:
The movement of molecules from the filtrate into peritubular capillaries surrounding the nephron. Correct Answer Reabsorption within the renal tubule refers to the reuptake of metabolically valuable small molecules that were filtered out of the bloodstream in the renal corpuscle. These ions, vitamins, and nutrients pass out of the renal tubule and into the surrounding peritubular capillaries to reenter the bloodstream.
wild-type allele
The non-mutant form of a gene, encoding the normal genetic function. Generally, but not always a dominant allele. Default w+w+
dependency ratio
The number of people under age 15 and over age 64 compared to the number of people active in the labor force
Penetrance
The percentage of individuals with a particular genotype that actually displays the phenotype associated with the genotype.
Placenta
The placenta indirectly connects the circulatory systems of the mother and the fetus to facilitate nutrient exchange from the mother to the fetus and waste exchange from the fetus to the mother. This is the correct answer. The placenta indirectly connects the circulatory system of the mother and the fetus so that nutrients can be passed from the mother to the fetus and waste products can be passed from the fetus to the mother.
Gastrulation
The process by which a blastula develops into a gastrula with the formation of three embryonic layers Ectoderm, Mesoderm, Endoderm
demographic transition
The process of change in a society's population from a condition of high crude birth and death rates and low rate of natural increase to a condition of low crude birth and death rates, low rate of natural increase, and a higher total population.
genotypic ratio
The ratio of genotypes that could appear in offspring 1:2:1
G2 phase
The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.
What is the site on an antigen that is recognized by an antibody?
The site on an antigen recognized by an antibody is known as the epitope.
spatial summation
The sum of multiple synapses firing at different locations at one time to create a net effect. potentals are closley locted
Vital capacity
The total volume of air that can be exhaled after maximal inhalation.
A scientist is attempting to characterize a novel bacterial operon. Genes on this operon generally are not transcribed due to a repressor protein that binds to the operator. However, the scientist discovers that the addition of a molecule that binds the repressor activates transcription. How is the operon regulated?
This operon is regulated by negative induction. Correct Answer Negative control involves the binding of a repressor to block transcription, while positive control includes an activator protein that binds and stimulates transcription. The operon discussed in this question is controlled by a repressor, making this negative control. Secondly, this operon is "switched on" by an inducer, indicating an induction system.
What is the 'proof-reading' activity of DNA polymerase called?
This proofreading mechanism is termed a 3′-5′ exonuclease activity.
True or false: Most cancers arise from a single deleterious mutation in a critical gene.
This statement is false. A cell typically becomes cancerous only after accumulating many mutations in important genes that together allow the cell to evade normal controls on cell division and growth. A single mutation is almost never enough to cause cancer.
True or false: Each tRNA molecule corresponds to a specific mRNA codon.
This statement is false. A single tRNA molecule may correspond to more than one codon, as multiple codons (mostly those different only at the third position) may encode the same amino acid, and thus be recognized by the same tRNA molecule.
True or false: A zygote gets half of its DNA, as well as half of its mitochondria, from the sperm and half from the egg.
This statement is false. A zygote does get half of its DNA from the sperm and half from the egg, but all of its mitochondria come from the egg. The sperm does not contribute any mitochondria to the zygote. Therefore, all the mitochondria in all of your cells today came from your mother, not your father
True or false: The umbilical arteries carry oxygenated blood from the mother to the fetus.
This statement is false. Arteries carry blood away from the heart and veins carry blood towards the heart. The umbilical veins carry oxygenated blood from the mother to the fetus. The fetal tissues consume the oxygen and then the umbilical arteries carry deoxygenated blood away from the fetus, back to the mother.
True or false: A hormone that is released by the anterior pituitary and acts on the mammary glands to stimulate milk production can be classified as a tropic hormone.
This statement is false. By definition, tropic hormones regulate the release of other hormones. Since the hormone described here is directly causing a non-hormonal response, i.e. the production of milk from mammary glands, it cannot be classified as a tropic hormone. Many, but not all, of the hormones released by the anterior pituitary are tropic hormones. (The hormone described here matches the description of prolactin, but identifying the hormone was not necessary for answering the question.)
True or false: Calcitonin increases the concentration of calcium in the bloodstream.
This statement is false. Calcitonin reduces the concentration of calcium in the bloodstream by reducing calcium absorption in the intestines, promoting calcium storage in bone, and increasing urinary excretion of calcium.
True/false: Dietary fatty acids enter the bloodstream immediately after absorption in the small intestine.
This statement is false. Fatty acids do not immediately enter circulation after absorption. After they are absorbed by enterocytes, they are packaged into chylomicrons and shunted into lacteals. Lacteals are small lymphatic vessels that drain into larger lymphatic vessels, which eventually empty into the bloodstream.
True or false: If 25% of a population in Hardy-Weinberg equilibrium has a recessive phenotype, then the frequency of that recessive allele within the population is 5%.
This statement is false. If 25% of a population in Hardy-Weinberg equilibrium shows a recessive phenotype, then the frequency of the homozygous recessive phenotype is 25%. This is the q2 variable from the Hardy-Weinberg equation. To find the frequency of the recessive allele, q, we simply take the square root of 0.25, which is equal to 0.5. Therefore, the frequency of the recessive allele within the population is 50%.
True or false: In DNA transcription, the sense strand is transcribed.
This statement is false. In DNA transcription, the template or antisense strand is transcribed, resulting in mRNA that corresponds directly to the sense ("coding") strand, with the substitution of U for T.
True or false: The negative side effects of aging are, in part, likely due to an increase in the rate of mutagen-induced DNA mutations.
This statement is false. It is true that an increase in the rate of DNA mutations as we age is thought to be one of the primary factors related to the negative side effects of aging. However, this question relies on an understanding of the difference between mutagen-induced and spontaneous DNA mutations. Mutagens are generally environmental agents that can damage our DNA and induce mutations. For example, exposing a person to UV light will induce DNA mutations. However, there is no reason to believe that a person is exposed to more mutagens as they age. However, spontaneous DNA mutations are mutations that result from natural biological processes such as errors in DNA repair. Spontaneous mutations increase as we age, because errors in processes such as DNA repair increase as we age.
True or false: The four hemoglobin subunits are connected together in part by peptide bonds.
This statement is false. Quaternary structure is maintained by the association between hydrophobic domains on adjacent subunits. Ionic interactions (salt bridges) confer structural specificity and additional attractive force. Peptide bonds are the basic bond of primary structure, holding together adjacent amino acids.
True or false: Promoters may occur thousands of base pairs away from the transcription start site of target genes.
This statement is false. Regulatory elements such as enhancers may be thousands of base pairs away from the start site of target genes, but promoters tend to be in close proximity upstream of target genes.
True or false: Sexual differentiation is determined by the SRY gene on the X chromosome
This statement is false. Sexual differentiation in developing fetuses is determined by the SRY gene, which is found on the Y chromosome, not the X.
True or false: A greater number of graded potentials will increase the likelihood of an action potential occurring.
This statement is false. The question stem asks about "graded potentials," which can refer to both excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs). Enough graded potentials must accumulate to push the membrane potential past a certain depolarization threshold in order to generate an action potential. However, not all graded potentials cause depolarization. EPSPs cause depolarization and will help push the membrane potential towards the threshold, but IPSPs cause hyperpolarization and will push the membrane potential farther away from the threshold.
True or false: Although its primary role is nutrient breakdown, the stomach also functions in the absorption of several key macronutrients.
This statement is false. The stomach produces gastric acid and several key enzymes involved in nutrient digestion, but it does not directly absorb any of the major macronutrients (proteins, carbohydrates, fats, and nucleic acids)
True or false: Recessive phenotypes must skip generations
This statement is false. This pattern is common, and if you see a pedigree for a recessive mutation on the MCAT, it is very likely that it will show skipped generations - but it is not a requirement. Generation skipping depends on the specific genotypes of the parents and on the role of chance.
Tropic hormones directly induce physiological changes within non-endocrine tissues.
This statement is false. Tropic hormones act on endocrine cells and usually stimulate the release of other hormones. Only non-tropic hormones initiate changes within non-endocrine cells.
True or false: Acetylation activates genes by attaching acetyl groups directly to DNA nucleotides.
This statement is false. While acetylation does tend to activate genes, it does so by attaching acetyl groups to histone proteins around which DNA winds, not to DNA nucleotides themselves.
True or False: within the context of blood-tissue exchange, the pressure is higher in the arterioles compared to the venules.
This statement is true. An arteriole is a smaller blood vessel than an artery, connecting and branching out from an artery and ultimately leading to the capillaries. Venules connect the capillaries to the veins. Arteries and arterioles are highly elastic and surrounded by smooth muscle to withstand the high pressures generated by the heart. The pressure in the veins and venules is generally much lower than in the arteries and arterioles. In order from greatest to lowest pressure: arteries > arterioles > capillaries > venules > veins.
True or false: A receptor tyrosine kinase (RTK) initially has the capability to bind to its ligand, insulin. However, after a substitution mutation, the RTK's active site is able to bind to insulin-like growth factor (IGF). This mutation must have been a gain-of-function mutation.
This statement is true. Because the RTK protein receptor, located in the membrane of a cell, gains the ability to bind to a second ligand, it must have undergone a gain-of-function mutation. The definition of a gain-of-function mutation is any mutation which causes a protein to have new or enhanced functionality. The definition of a loss-of-function mutation is any mutation which causes a protein to have reduced functionality.
True or false: The cell membrane receptor for insulin is still likely to bind its ligand after a conservative mutation alters an amino acid which codes for part of the insulin receptor's active site.
This statement is true. Conservative and non-conservative mutations are two types of missense mutations - DNA mutations which alter the amino acid that a 3-letter sequence of DNA codes for. A conservative mutation is a missense mutation which results in the production of a new amino acid bearing similar properties to the original amino acid (e.g. valine to leucine). Non-conservative mutations are missense mutations which result in the production of a new amino acid bearing very different properties to the original amino acid (e.g. valine to aspartic acid). The active site of a protein receptor is highly specific to the charge distribution and shape of its corresponding ligand. Because the mutation to the insulin receptor is conservative, the shape of its active site is likely conserved, and thus its ability to bind to its ligand stays intact.
True or false: Differential reproduction results in natural selection, which is a mechanism through which evolution occurs.
This statement is true. Differential reproduction occurs when certain traits are more favorable than others within a population and these traits are reproduced more frequently. Since natural selection is the process through which favorable traits are selected and maintained within a population, differential reproduction results in natural selection. Natural selection in turn drives evolution, since selection for favorable phenotypes causes the population to evolve in that direction over time.
True or false: An action potential propagating down an axon requires nodes of Ranvier to maintain its strength.
This statement is true. Due to the inability of ions to pass through a myelin sheath, the charge difference between the inside and outside of an axon decays as the depolarization travels along a myelinated portion of the axon. As the depolarization reaches a node of Ranvier, it again causes voltage-gated sodium channels to open, 'replenishing' it to full intensity, before rapidly conducting down the next myelinated region, towards the next node of Raniver.
True or false: Proteolytic processing is a post-translational modification that allows cells to regulate the activity of specific proteins.
This statement is true. During proteolytic processing, inactive precursor proteins called zymogens are cleaved and activated. This is a regulatory step that prevents hormones and other enzymes from being prematurely activated in the wrong environment or under the wrong conditions.
True or false: Incomplete dominance occurs when the simultaneous expression of two alleles modifies the phenotypic qualities gained from each allele.
This statement is true. In contrast to incomplete dominance, codominance is where two dominant alleles are expressed simultaneously, with each phenotype functioning normally. Incomplete dominance requires a blending of two distinct phenotypes into a third phenotype. For offspring to be displaying incomplete dominance, the phenotypes of each expressed allele will end up qualitatively different.
True or false: The cell-mediated immune response targets host tissue, not foreign pathogens.
This statement is true. The cell-mediated immune response, or the T cell branch, does not directly target pathogens in the way that the humoral response or various components of the innate response do. Instead, cytotoxic T cells target host cells that have been infected by the pathogen in question, destroying them to prevent the cell's internal machinery from being used to further spread the infection.
True or false: The reproductive organs secrete different hormones in males and females but respond to the same anterior pituitary hormones.
This statement is true. The ovaries predominantly release estrogen whereas the testes release testosterone. However, the ovaries and testes both respond to LH and FSH, which are released from the anterior pituitary.
True or false: The somatic nervous system is responsible for voluntary movement.
This statement is true. The somatic nervous system is one of the two branches of the peripheral nervous system. It controls voluntary action while the other branch, the autonomic nervous system, controls involuntary responses such as pupil dilation.
True or false: The adrenal cortex secretes steroid hormones.
This statement is true. The steroids secreted by the adrenal cortex can be subdivided into 3 classes: the glucocorticoids, mineralocorticoids, and cortical sex hormones.
A virus invades a cell and rapidly produces antisense RNA that is complementary to a gene's promoter sequence. What will happen to transcription?
Transcription of the gene will decline. Correct Answer This question requires you to understand the complementary DNA strands involved in transcription. One strand is the sense (coding) strand, while the other is the antisense (template) strand. mRNA is transcribed directly from the antisense strand, giving it the same base sequence as the sense strand. Thus, if a virus produces antisense RNA complementary to a gene's promoter sequence, the viral RNA will hybridize that sequence, blocking transcription from occurring.
mRNA to protein is what process?
Translation
Tropic vs. non-tropic hormones
Tropic act on another endocrine gland stimulate the release of another endocrine gland regulates other endocrine cells or gland Non-tropic act on non-endocrine tissues Brings about physiological response
cross bridge cycle
Tropomyosin = covers binding sites on actin troponin = binds calcium which moves tropomyosin
True or false: Both aneuploidy and chromosomal deletions can reduce gene expressivity.
True
True or false: The main purpose of the larynx is to house the vocal cords.
True
True or false: Unlike the start codon, stop codons do not encode an amino acid.
True
Which of the following statements are true of the trp operon? Select all that apply.
Tryptophan binds the repressor. Correct Answer In the trp operon, tryptophan binds to the repressor. The repressor binds the operator. Correct Answer The repressor binds to tryptophan and subsequently binds the operator. The presence of tryptophan blocks the genes for its synthesis. Correct Answer When tryptophan binds to the repressor which subsequently binds to the operator, it begins to block the expression of the genes within the trp operon.
A neurobiologist uses an electrode to induce a local depolarization at a point in the middle of the non-myelinated axon of a resting neuron. The neurobiologist has already confirmed that this voltage, when applied to a point on the cell body, is sufficient to induce the generation of an action potential. Which of the following is the most likely result of the researcher inducing a local depolarization along the axon?
Two action potentials will be generated, moving in opposite directions along the axon. Correct Answer Retrograde (backwards) conduction is typically prevented by the inactivation of sodium channels. However, we are told that this neuron exists in a resting state. Therefore, its channels are not inactivated, and there is no reason why bidirectional conduction would not be possible, generating two separate action potentials (one propagating forward, the other propagating backwards)
stop codons?
UAA, UAG, UGA
Archea
Unicellular prokaryotes that are found in extreme environments. use whatever energy source they can
Match each of the following features of the human genome with its definition. Variable number tandem repeat Short tandem repeat Single nucleotide polymorphism Transposon
Variable number tandem repeat Non-coding DNA repeats 10-100 base pairs in length Short tandem repeat Non-coding DNA repeats 2-6 base pairs in length Single nucleotide polymorphism Variation in one base pair at a specific genomic location Transposon Mobile DNA sequence Variable number tandem repeats (VNTRs) and short tandem repeats (STRs) are repetitive, non-coding DNA sequences comprised of short repeats, with VNTRs approximately 10-100 base pairs in length and STRs approximately 2-6 base pairs in length. Single nucleotide polymorphisms (SNPs) are variations in the identity of just one nucleotide at a specific location in the human genome. Transposons, or transposable elements, are mobile DNA sequences that can "jump" to new positions within or between chromosomes.
Which of the following answer choices correctly characterizes the relationship between villi, microvilli, and enterocytes?
Villi are finger-like projections of the small intestine's epithelial surface, and each villus contains many enterocytes. Each enterocyte contains many microvilli. Correct Answer Enterocytes are the epithelial cells that make up the small intestine. Because villi are tiny folds of the small intestine's epithelial surface, each villus is composed of hundreds of enterocytes. Microvilli are microscopic hair-like extensions of each enterocyte's cell membrane.
Provirus
Viral DNA that inserts into a host genome and lays dormant until a signal arrives to lysis the cell
You are running as fast as you can as you near the end of a one-mile foot race. What volume of air is mostly likely moving in and out of your lungs?
Vital Capcity
Which of the following essential vitamins can be eliminated through the urinary system? Select all that apply.
Vitamin B and C
hemizygous
X only one copy of the allele is present
Arrange the following stages of early embryonic development in the proper order from earliest to latest: morula, zygote, gastrula, and blastocyst.
Zygote Morula Blastocyst Gastrula The correct order is zygote, morula, blastocyst, and gastrula. The zygote is formed during a fertilization event when the sperm and egg nuclei are combined to make one diploid cell from the two haploid gametes. This zygote then begins to undergo cleavage division as it travels down the Fallopian tubes to the uterus. After the 4th round of cleavage division, when the zygote is at the 16-cell stage, it becomes known as the morula. The morula continues to divide and develops a fluid-filled cavity called a blastocoel. The outer layer of cells surrounding the blastocoel are known as the trophoblast. At this point, the morula is now known as the blastocyst. The blastocyst will implant itself in the uterus, where the trophoblast will differentiate to form the placenta, and an inner cell mass at one pole of the blastocoel will undergo gastrulation: the formation of the 3 primary germ layers (endoderm, mesoderm, and ectoderm). Once this process of gastrulation begins, the blastocyst is known as the gastrula.
zymogen
Zymogens are inactive precursors of enzymes
Gonadotropin releasing hormone (GnRH) is secreted by the:
`hypothalamus. Correct Answer Only the hypothalamus secretes Gonadotropin releasing hormone (GnRH) and releases it into a portal vein system that communicates directly with the anterior pituitary.
hypophyseal portal system
a blood vessel system that directly connects the hypothalamus with the anterior pituitary
gender schema
a cognitive framework that organizes information relevant to gender
Water and solute molecules are continuously reabsorbed into the vasa recta surrounding the loop of Henle. The concentration gradients that drive this process are primarily maintained by:
a countercurrent multiplier system. Correct Answer The loop of Henle operates through a countercurrent multiplier system. In this system, blood flows through vessels of the vasa recta in the opposite direction as filtrate moving through the loop of Henle. This prevents solute concentrations from equalizing in the two compartments, driving the continuous reabsorption of water and solutes.
Test Cross
a domominant phenotype of unknown genotype is crossed with a homozygous recessive organism RR and rr --> all heterozygous offspring
Virion
a fully formed virus that is able to establish an infection in a host cell
At a relatively low oxygen partial pressure, hemoglobin has:
a lower affinity for oxygen than does myoglobin, because hemoglobin exhibits cooperativity. Correct Answer Within tissues that are metabolically active, the partial pressure of oxygen is relatively low. Under these conditions, hemoglobin exhibits a low affinity for oxygen, which facilitates its release into the tissues. Myoglobin, a monomeric protein, does not exhibit cooperativity. Its affinity for oxygen is similarly high regardless of its surrounding environment.
GABA
a major inhibitory neurotransmitter polarizes NT
gain of function mutation
a mutation that confers new or enhanced activity on a protein Mutations tend to be dominant
Acrosome reaction
a necessary and irreversible step in fertilization, which is triggered by sperm receptor, in which the sperm's and ovum's membranes fuse and the sperm penetrates the zona pellucida.
complete dominance
a relationship in which one allele is completely dominant over another
The lac and trp operons are both regulated by:
a repressor. Correct Answer Gene expression is inhibited in the presence of a repressor for both the lac and trp operons, which are prokaryotic sequences.
Nucleosome
a structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of 8 histones.
A geneticist is studying a particular species of flowering tree. He notes that a certain specimen displays the dominant trait (pink flowers), but is unsure of whether this specimen is homozygous dominant or heterozygous. The geneticist should conduct:
a test cross, in which he breeds the specimen in question with a homozygous recessive organism. A common strategy used to find the genotype of an unknown organism is to conduct a test cross, or a cross with a known homozygous recessive organism. If there are offspring exhibiting the recessive trait, then we know the unknown specimen is heterozygous.
Virulence
ability to spread and harm the host
Colon
absorbs and turns food into feces aborbs vitamins
How is EUCHROMATIN FORMED?
acetylated, removing the postive charge from the histone. thus allowiung for transcription Performed by Histone Acetyltransferase
neuromuslcar junction hormone for muscle contractions
acetylcholine binds nicotinic receptor
Inhalation is ____ while exhalation is _____.
active and passive
what is cholesterols role in membrane fluidity
acts as a moderatory for when temperatures change. Keeps the extremes from occuring At low temps = cholesteral promotes membrane fluidity at high temps = cholesterol reduces membrane fluidity ex. when the layer gets cold, the cholesterol keeps the phosphlipids structure
Vitamin D
acts as hormone that regulates calcium and phosphate concentrations in the blood major form = calcitriol
Where is cortisol released from?
adrenal cortex
What is epi and nor epi released from
adrenal medulla
Semen
alkaline nutrient fiilled liquid carries sperm through reproductive tract
A band of sarcomere
all thick and thin filaments
DNA ligase
an enzyme that eventually joins the sugar-phosphate backbones of the Okazaki fragments forming phosphdiester binds
Disruptive selection is best defined as:
an evolutionary pressure favoring extreme phenotypes over intermediate phenotypes. Disruptive selection is a type of natural selection that selects for extreme phenotypes and selects against intermediate phenotypes. For example, disruptive selection occurs when both black and white fur color are favored in a population of dogs, but grey fur color is selected against.
posterior pituitary
an extension of the hypothalmus recieves neural input common hormones: ADH and Oxytocin
cooperative binding
an interaction in which binding of a ligand at one site on a molecule influences the binding at another site
DNA melting is reversilbe and the process of it coming back together is called _______
annealing
Thyroid
anterior releases T3, T4, Calcitonin
DNA is a _______ parallel and a ______. Held together by _____, _____, and ______.
anti double helix phosodiester and hyrogen binds and hydrophobic interactions
antigen
any recognizable componet of a pathogen
Flagella
appendage that protrudes from the cell and allow it to move can also have sensory found in both prokaryotes and eukaryotes but are structurally distinct § eukaryotic flagella flap back and forth powered by ATP § prokaryotic flagella use Rotary motion powered by proton gradients - composed of protein known as flagellin o Characterized by what is known as a 9 + 2 structure § in outer ring of nine pairs of microtubules surrounding inner ring of two microtubules
pulmonary artery carries ______ and the pulmonary vein carries _______
artery = deoxy blood vein = oxy blood
bottle neck effect (genetic drift)
artifically inc or dec allele frequency ex. natural diaster
G2 checkpoint
asses if DNA replication has occured properly, go ahead signal triggers mitosis
involuntary muscles are controlled by the _____
autonomic nervous system
22 pairs of chromosomes are ________
autosomes
Arteries carry blood ____ from the heart
away
major groove and minor groove of DNA
binding sites for transcription factors
Both the adrenal cortex and the adrenal medulla synthesize hormones that affect:
blood glucose levels. Correct Answer The adrenal cortex secretes glucocorticoids like cortisol in response to stress. Cortisol works to increase blood glucose levels. The adrenal medulla synthesizes the catecholamines epinephrine and norepinephrine, which mediate the "fight or flight" response within the sympathetic nervous system. Epinephrine and norepinephrine have many physiological effects, one of which is to liberate glucose into the bloodstream.
Osteoblasts
bone forming cells
lipid-anchored proteins
bound to single or multiple lipid molecules types: G proteins
Inbreeding
breeding betwen individuals that are closley genetically related can lead to deleteriious mutations
Outbreeding
breeding with and passing alleles between unrelated members of the same species
viral genome
can be either DNA or RNA ssDNA dsDNA ssRNA dsRNA
point mutation
can be subsitiion, deleltion, or insertion a change that occurs to a single nucleotide
facultative anaerobes
can live with or without oxygen
Helicobacter pylori is a bacterium that has evolved to thrive in the harsh acidic environment of the human stomach. H. pylori infections are asymptomatic in 80% of cases, but can sometimes cause serious conditions like gastritis, gastric ulcers, and stomach cancer. What makes this microorganism so dangerous? H. pylori:
can penetrate the mucosal lining of the stomach. Correct Answer H. pylori can burrow under the protective mucous layer that coats the stomach lining to reach endothelial cells. Once there, these bacteria can irritate stomach tissue, giving rise to a variety of gastric disorders.
Unchecked mitosis leads to ______
cancer
the mouth enzymes breaks down _____ and ______
carbs and fats
Each of the terms below is an organ that plays a role in the chemical digestion of macronutrients. Match each organ with the macronutrient(s) it digests. oral cavity
carbs and lipids
What does blood plasma contain
carried ions, proteins, gases, and nutrients
Endosomes
carry and sort material brought into the cell Early endosomes Late endosomes Lysosomes
what do red blood cells do
carry gases (O2 and CO2) have no nucleus --> high energy eff and low life span produced in red marrow from EPO hormone
Chondrocytes are primarily responsible for synthesizing:
cartilage Correct Answer Chondrocytes are the cells responsible for synthesizing collagen and proteoglycans to create and maintain cartilage.
loss of function mutation
causes a complete or partial loss of function mutations tend to be recessive
What are platelets and what is their job?
cell fragments essenstial to coagulation create the coagulation cascade for a platelet plug
G1 phase
cell size and volume or cytoplasm increase actively synthesizes proteins and molecules to prepare for division
M line of sarcomere
center of sarcomere
A ganglion is a cluster of cell bodies primarily located outside of the:
central nervous system. Correct Answer While most cell bodies are located within the central nervous system, some clusters of cell bodies, termed ganglia, are located outside of it as well, in the peripheral nervous system. The common exception to this are the basal ganglia, which, while called ganglia, are not true ganglia, as they are located in the brain.
Genetic Drift
change in the gene pool due to random chance Bottleneck effect random errors in the genome accumulate at a fixed rate
Aquaporins
channel proteins that facilitate the passage of water
Ion channels
channel proteins that transport ions specific to the ion and a result of changes in voltage
Sterols
cholesterol modulates the fluidity of plasma membranes have a 4 ring structure
Fatty acids absorbed by enterocytes enter circulation after being packaged into:
chylomicrons. Correct Answer Chylomicrons are lipoproteins particles made of triglycerides, phospholipids, cholesterol, and proteins. They are synthesized in enterocytes and diffuse into lacteals, which empty into venous circulation. Once in the bloodstream, chylomicrons can deliver the dietary lipids they carry to cells throughout the body.
Sphinogomyelin
cluster with cholesterol molecules to form lipid rafts.
Types of Dominance
complete dominance, incomplete dominance, codominance
When writing a complimetary sequence, it must be _______ and _______ to the given DNA strand
complimentary and anti parallel
Electric synaptic transmission
connected by gap junctions speeds up transmission, but removes modulation and amplification
Cecum function
connects SI to LI appedix pertrudes off of it
Chromatin Fiber
consists of coiled nucleosomes which form a larger diameter fiber.
H zone of sarcomere
contains thick filaments of myosin only
I Zone of Sarcomere
contains thin filaments only
Ligand Gated Transporters
contibute to the action potential to help or inhibit trigger many NT
nonsense mutation
creates a non function protein by coding for a stop codon
Dihybrid crosses
crosses that examine the inheritance of two different traits
Backcrossing
crossing of a hybrid with one of its parents or an individual genetically similar to its parent, in order to achieve offspring with a genetic identity which is closer to that of the parent
Ethnicity
cultural background
Centrioles
cylindrical structures made primarily of tubulin that help organize the meiotic spindle and are an important constituent of the centrosome
cytoplasm vs cytosol
cytoplasm = the contents within the cell membrane cytosol = the fluid everthing moves around in inside the cell
CUT the PY
cytosine, uracil, and thymine are pyrimidines
Stage 1: demographic transition
death rate and birth rate are high stable pop
demographic transition: stage 2
death rate dec, birth rate remains high
demographic transition: stage 3
death rate slowly dec , birth rate slows
Genetic code = _____
degenerate becuase more than one codon can code for the same AA
A frame shift is caused by ______ mutations.
deletion and insertion
the pulmonary artery carries _______
deoxygenated blood to the lungs
Hair follicles are located physically in the _________, but hair consists of _________ cells.
dermis; epidermal Correct Answer Hair are composed of epithelial cells being pushed outward by a dividing lower layer, and as they get further from the nutrient supply, they die and are keratinized. The follicle itself, however, is located physically in the dermis, where it is protected from bacterial infections.
polygenic
describes a characteristic that is influenced by many genes
natural selection
describes how favorable traits are favored in a population over time
Organogenesis
development of fetal organs
sex-linked disorders
dieseases that are determined by genes found on the sex chromosomes. particularly the X chromosome
facilitated diffusion (passive transport)
diffusion that is facilitated by transmembrane channels transporters are specific to solutes respond to certain stimuli NO ATP - flows down the gradient thermodynamically favorable
parent cells are _____ cells
diploid
Extended exposure to the decreased partial pressure of oxygen present in high-altitude environments results in an increase in the production of 2,3-BPG. Compared to hemoglobin taken from those living at low altitudes, hemoglobin from the blood of an individual who has lived at high altitude for several months would most likely:
display a lower affinity for oxygen and a corresponding right-shifted dissociation curve. Correct Answer 2,3-BPG reduces the affinity of hemoglobin for oxygen, which facilitates more effective oxygen delivery to the tissues. This corresponds to a rightward shift in the dissociation curve. In the presence of this compound, at a given partial pressure of oxygen, a comparatively low percentage of hemoglobin will be saturated with oxygen.
aerotolerant anaerobes
do not utilize oxygen but can survive and grow in its presence
Vas Deferens
duct that connects epidiymis to penis for ejaculaton
Histones and DNA interact primarily through:
electrostatic interactions
z-line of sarcomere
end of sarcomere
Endocytosis
engulfing of small particles by the cell membrane
Pinocytosis
engulfment of fluid and soluble material
Phagocytosis
engulfment of large solid particles typically by phagocyes of the immune system
cortical reaction
enzymes prevent any other sperm from binding to the egg
Cells that undergo mitosis regularly and quickly
epitheial cells on digestive tract skin cells
Red blood cells are called _______
erythrocytes
vitamin C
essential for collagen synthesis
Vitamin A
essential for vision
Coevolution
evolution of two species in response to eachother symbiosis
Glutamate
excitatory neurotransmitter neuron depolarization elicts action potentials
gender script
expectations for each gender
Negative control (Operon)
expressed UNLESS repressor is present
Positive control (Operon)
expressed when activator is present
Telomerase
extends telomeres RNA dependent DNA polymerase extends end parts of chromosomes
The most common location for fertilization of a secondary oocyte by a spermatozoon is in the:
fallopian/uterine tubes. Correct Answer Commonly, sperm is deposited in the vaginal cavity during intercourse and then travels through the vaginal canal to enter the uterus, and from there through the fallopian/uterine tubes where it may fertilize a secondary oocyte (or several, in the case of dizygotic twins / polyzygotic multiplets). Fertilization is by no means exclusive to this location, but the overwhelming majority of viable human zygotes are created in this way.
Saturation kinetics of facilitated diffusion
fast at first then slows down
Compared to smaller neurons, larger neurons are:
faster at conducting signals and harder to depolarize. Correct Answer Larger neurons have more area to store charge along their membranes and, therefore, they have a higher membrane capacitance, making them harder to depolarize. At the same time, larger neurons have lower cytoplasmic resistance than smaller ones, making them faster at conducting signals
Which of the following molecules enter enterocytes in the small intestine via passive diffusion? Select all that apply.
fatty acids
directional selection
favors an extreme phenotype in one direction
disruptive selection
favors extreme phenotypes over intermediate ones
Chromosomes XX is a ______
female
Sexual orientation during pregancy is always _________
female
zygote
fertilized egg
Microglia
first line of defense for infect on the CNS phagocytes
ovarian cycle
follicular phase, ovulation, luteal phase releases an egg from the ovaries
Astrocytes
form blood brain barrier help provide enough glucose for the brain
Turmorgenesis vs. oncogenesis
formation of tumors - non malignant formatin of cancer - disregulated gene expressiomn
Hormones released by the hypothalamus into the hypophyseal portal system directly stimulate the release of other hormones:
from the anterior lobe of the pituitary gland but not from the posterior lobe. Correct Answer The hypothalamus is physically connected to the anterior lobe of the pituitary gland via a system of blood vessels at the base of the brain called the hypophyseal portal system. The hypothalamus secretes a number of tropic hormones into the hypophyseal portal system, which then regulate the secretion of other tropic hormones from the anterior pituitary. The hypothalamus regulates the posterior lobe of the pituitary gland through a totally separate mechanism.
Osteon
functional unit of compact bone
Nephron
functional unit of the kidney composed of renal corpuscle and renal tubule
Digestive Hormones
gastrin, secretin, cholecystokinin
Factrors influencing evolution
gene flow randim chance migration mutation seletive pressure
Seminal Vescicles
generates nutrients for the semen
Tumor supressor genes
genes protecting against abnormal cell growth whose impaired function can promote cancer If mutated or down regulated it can cause cancer gene P53 is the gene involved
We all have the same ____ but different _____. But this does not hold true for the sex chromosomes
genes; alleles
translocation mutation
genetic material from one chromosome is exchanged with material from another if balanced it is harmless
Operon
genetic system prokaryotes use to regulate the expression of specific genes
What is the major benefit to meiosis
genetic variabilty and confers evolutionary advantage
The Y chromosome contains very few genes of interest. Most important is the SRY gene, which activates male differentiation. During an error in replication, a father's X and Y chromosome underwent crossing over, causing the SRY gene to be left on the X chromosome. If this man passes his Y chromosome to his progeny, the child will be:
genetically male and phenotypically female. This child has a Y chromosome, so he will be genetically male. However, he is missing the gene responsible for male activation and differentiation and will therefore develop similarly to a female.
phospholipid structure
glycerol + 2 fatty acids + phosphate group
fetal hemoglobin
greater affinity for oxygen than adult
An operon is a(n):
group of genes regulated and transcribed together. Correct Answer An operon is a coordinated unit of DNA that contains genes that are regulated and transcribed together.
meiosis creates _________ cells
haploid gametes
Pathogenic bacteria
harm their hosts through different mechanisms reproduce intracellularly reproduce outside of host cells secrete damaging toxins
Heme Group
has a Fe2+ which binds O2 SO we can hold 4 O2 per hemoglobin, and each RBC has thousands of hemoglobin
Spleen (immunity)
has sections of "white pulp" rich in lymphocytes important sites of B cell activiation
amino acid derivatives
have mixed properties of peptide and steriod, can also be amipathic
amphipathic
having both a hydrophilic region and a hydrophobic region
Inflammation signals
heat, pain, redness, swellng \cytokines
What enzyme unwinds and unzips DNA?
helicase
wobble hypothesis
helps explain degeneracy in the genetic code
Bile Function
helps with fat absorption BILE IS NOT AN ENZYME
C-T have a _______ Tm
higher
During the upslope of a typical action potential, membrane permeability to sodium is:
higher than at rest, because voltage-gated sodium channels open during the upslope. Correct Answer During the upslope of the action potential, voltage-gated sodium channels open, resulting in sodium influx down its concentration gradient and into the cell.
human chorionic gonadotropin (hCG)
hormone produced by the placenta to sustain pregnancy by stimulating the ovaries to produce estrogen and progesterone
How does the body detect if there is a pregancy occuring and doesnt cause a period
human chorionic gonadotropin (hCG) gets released, maintianing the corpus luteum which produces progesterone
B cells
humoral immunity
hybrid sterility
hybrid offspring mature but are sterile as adults postzyotic barrier Mules
degradation in synaptic cleft
hydrolytic enzyme breaks down NT
Which of the following endocrine organs are involved in the pathway that results in sperm maturation in the testes?
hypothalamus anterior pituitary
What coordinated the neuroendocrine integration
hypothalmus
Positive-negative feedback (adaptive Immunity)
if either fails then could lead to autoimmunty
semi-conservative replication
in each new DNA double helix, one strand is from the original molecule, and one strand is new How DNA is replicated
In which of the following ways are repetitive and non-coding DNA sequences thought to be useful?
inc genetic diversity accelerate evolution serve as attachment sites for proteins during cell division cap ends of chromosomes
Behavioral researchers are interested in the family-rearing habits of a species of bird. They are surprised to discover that distantly related birds of the same species will guard each other's nests when eggs or hatchlings are present. The evolutionary explanation for this behavior would be:
inclusive fitness. Inclusive fitness is the idea that the propagation of alleles can be enhanced by enhancing the survival of the entire species, or at least of relatives. Evolutionary biologists suspect that different species display innate altruistic behavior to varying degrees due to this.
Certain traits are known as polygenic, meaning that multiple genes are implicated in their expression. In humans, height is once such trait. Height is genetically determined, in combination with some environmental factors, but human height falls along a wide continuum. This fact is most consistent with which pattern of inheritance?
incomplete dominance
When the concentration of carbon dioxide in the blood is low, the pH is likely to:
increase. Correct Answer Carbon dioxide reacts with water to form carbonic acid and participates in an equilibrium between carbonic acid and bicarbonate ions plus dissociated protons. Note how elevated carbon dioxide production directly translates to increased concentrations of H+, which acidifies the blood and decreases the pH. Likewise, a decrease in the carbon dioxide concentration in the blood would result in a decrease in the concentration of dissociated protons, which corresponds to an increase in the pH.
autosomal dominant
inheritance pattern of a dominant allele on an autosome at least one parent must be dominant
siRNA and miRNA _________
inhibit gene expression by interfereing with mRNA sequences
Cholecystonin
inhibits appetite
Unlike acetylation, DNA methylation:
inhibits transcription. Correct Answer DNA methylation inhibits transcription.
The purpose of the TATA box is to:
initiate transcription via binding to TATA-binding protein. Correct Answer The TATA box of the promoter binds TATA-binding protein, which then associates with RNA polymerase to initiate transcription in eukaryotes.
p53 protein:
initiates apoptosis when DNA is irreparably damaged. p53 is a tumor suppressor protein that is encoded by the TP53 gene. It has two major functions: to initiate DNA repair as needed, and to initiate apoptosis when the DNA damage is too extensive. Loss of function mutations in p53 allows cells to evade these checks on cell cycle progression, leading to cancer.
Minerals
inorganic substances required, but NOT synthesised in the body
peripheral proteins
interact only briefly with the membrane types: enzymes hormones
Ganglia are:
intermediate junctions between the central nervous system and target organs. Correct Answer Ganglia serve as intermediates that translate the neural impulse of the central nervous system into actionable commands for the target organs. Each ganglion is flanked by pre and postganglionic neurons, whose specific properties vary between the sympathetic and parasympathetic nervous systems.
Male Genitalia
internal and external reproductive organs external = penis and scrotum
mutant allele
is a variant that arises when a gene undergoes a mutation, or change. w w
The corpus luteum:
is comprised of cells of the ruptured follicle after ovulation. Correct Answer The corpus luteum is formed by the cells of the ruptured ovarian follicle. is responsible for the production of estrogen. Correct Answer The corpus luteum produces both estrogen and progesterone. is responsible for the production of progesterone. Correct Answer The corpus luteum produces both estrogen and progesterone.
As filtrate moves up the ascending limb of the loop of Henle:
it becomes increasingly less concentrated as more ions are reabsorbed. Correct Answer The ascending limb of the loop of Henle is permeable to ions but not water. Sodium and potassium ions flow out of the ascending limb. Therefore, as the filtrate moves up the ascending limb, it becomes less and less concentrated.
External Genitalia of females
labia minora and majora, clit, vulva
Single- Standed DNA Binding Proteins
latch onto newly seperated strands and hold them apart
Extrusion
leaves the host cell intact similar to exocytoiss
RNA is ____ stable than DNA
less
Glycolipids
like phospholipids but w/ carb group instead of phosphate but still share an amphiathic structure Key Componets glycerol or sphingosine backbone lipid modified with cards involved in cell signalling and adhesion process
nucleosomes are connected by
linker DNA
Liposomes
lipid bilayers inclosing a spherical shape used in labs to deliver materials to target cells and test cell membrane perm
composition of plasma membrane
lipids and proteins phospholipids
Dehydration results in:
low blood volume and low blood pressure. Correct Answer Dehydration results from insufficient fluid intake or excessive fluid loss and causes blood volume to decrease. Because there is a lower volume of blood within the circulatory system to exert pressure on the walls of vessels, blood pressure decreases as well.
Bacteriophage Replication
lytic cycle and lysogenic cycle
Thick filaments crosslink at which structure within the sarcomere?`\
m line
One characteristic of prokaryotic, but not eukaryotic, transcription is that:
mRNA does not undergo post-transcriptional modification. Eukaryotic mRNA is produced in the nucleus, but must be exported to ribosomes in the cytoplasm for translation. To prepare a transcript for this process, it is modified by the addition of a 5' cap and a 3' poly(A) tail; additionally, its introns are spliced out by cellular machinery. Prokaryotic mRNA transcripts are not modified in this manner.
Which of the following statements is correct regarding the directionality of mRNA and polypeptide synthesis?
mRNA is synthesized 5' to 3' and polypeptides are synthesized from N to C terminus. During transcription, RNA polymerase reads the DNA strand in the 3' to 5' direction, synthesizing the complementary RNA strand in the 5' to 3' direction. During translation, the ribosome reads the mRNA sequence in the 5-prime to 3-prime direction and synthesizes a polypeptide sequence from its N-terminus to its C-terminus.
Osteocytes
maintain bone
main functions of the lymphatic system
maintinging fluid balance collecting and returning interstitual fluid to circulation transporting cells and biomolecules within lymph producing lymphocytes
depolarization
makes membrane pot more pos
Chromosomes XY are ______
males
Goals of Genetic Engineering
mass protein production alterations to genetic code
T cells
mature in thymus prodiuced in bone marrow
Total Lung Capacity (TLC)
maximum amount of air contained in lungs after a maximum inspiratory effort
Graded potentials
may be either a depolarization or a hyperpolarization a neuron
Our breathing is controlled by what?
medulla oblongata
Hyperpolarization
membrane potential becomes more negative
Centrosome
microtubule organizing center
Small intestine is lined with _______ which _______ the Surface area of the intestine
microvilla which inc the SA
Mesoderm
middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems
osmotic pressure
minimum amount of pressure that prevents further osmosis
Prions
misfolded proteins that cause other proteins to misfold and aggregate toegther, harming the cellular function
endosymbiotic theory
mitochindra originated when a cyanobacterium was engulfed by an early eukaryotic cell
How are mitochondria situated in the cell
mitochondria are separated from the rest of the cytoplasm by two membranes comprised of a phospholipid bilayer the structure of the mitochondria can therefore be subdivided into the outer membrane, Inter membrane space, the inner membrane, in the mitochondrial matrix Mitochondrial matrix = citric acid cycle Oxidative Phosphorylation = Protein complexes embedded in the inner membrane of the mitochondrion The electron transport chain causes a buildup of protons in the intermembrane space resulting in a proton gradient used to power the ATP synthase
Chemotherapy targets what?
mitosis
lipid rafts
modulate membrane fluididty
Which of the following molecules are taken up by enterocytes in the small intestine? Select all that apply.
monosaccarides amino acids fatty acids
Larger neurons = (terms of depolarization)
more area to store charge = harder to depolarize
X-linked recessive
more common than dominant disorders rare for women to be affected by an x linked recessive becuase they have 2 XX copies. for males, it is the opposite; more likely to be affected becuase boys have one X (XY) males inherit the X from their mom, so if mom is recessive males will be affected
Higher membrane capacitance =
more difficult to change the mem pot
Simple diffusion
movement of a solute from an area of high concentration to an area of low concentration types gases small uncharged molecules
Oncogenes
mutant genes promoting abnormal cell growth leading to cancer normally expressed as proto-oncogenes but when mutated it becokmes an oncogene code for growth factors, GF receptors, transcription factors, protein kinases, other signalling molecules
Spontanous mutations
mutations that occur without exposure to mutagens arise during DNA replication
Neuroglobin is a newly characterized oxygen binding protein that does not bear structural homology to hemoglobin or myoglobin, but it is believed to provide a temporary reserve of oxygen during periods of neural ischemia. Despite its unique structure, the binding curve for neuroglobin most likely resembles that of:
myoglobin. Correct Answer Since we are provided with minimal structural information, it must be inferred that the oxygen binding curve of neuroglobin must resemble that of myoglobin due to their similar functions (i.e. acting as a reserve of oxygen for metabolically active tissue).
Lac operon
negative inducible operon - expression induced by removal of repressor Glucose vs. Lactose - can turn on or off depedning on what is availible E.Coli prefer glucose, so there is a usually a blocker repressing trasncription by RNA poly
The trp operon is a ___________________ operon.
negatively repressible Correct Answer The trp operon is negatively repressible. It is considered under negative control because it involves a repressor, and repressible because environmental conditions prevent the genes from being expressed.
Granulocytes
neutrophil, basophil, or eosinophil
De novo mutations
new mutations
Silent mutation
no change to the protein doesnt change the phenotype
Criteria for a stable gene pool
no mutation random mating No gene flow large population size no natural selection
nodes of ranvier function
nodes have a channel abundance myelin depletes the AP, but the nodes replenish the AP and allow it to be fast
Telophase
nuclear envelope and nucleoli reforms for each daughter cell cytokinesis
nucleoside
nucleotide without a phosphate group (so just pentose sugar and base)
Where does DNA replication occur?
nucleus
In the human cell, nucleic acids can be found in:
nucleus mitochondria cytoplasm
glial cells provide:
nutrients structure insulation defense for the neuron
intermediate filaments
o A broad category of proteins that provide structural support it is involved in cellular adhesion processes o keratin
Endoplasmic Reticulum
o An organelle that extends out from the nuclear membrane o composed of cisternae, which are flat round or tube-like structures that are enclosed by double membranes Rough ER and Smooth ER
Microfilaments
o Composed of two strands of actin polymers and play a role in cell motility as well as endocytosis and exocytosis o contribute to the process of cell cleavage during division o play a role in muscle contraction
Cilia
o Involved in cell motility and formed by microtubules o Characterized by what is known as a 9 + 2 structure § in outer ring of nine pairs of microtubules surrounding inner ring of two microtubules o Relatively small projections that help move substances along the cell surface § respiratory tract
Golgi apparatus
o Modifies and packages proteins into membrane bound vesicles o composed of chambers of cisternae
Microtubules
o slightly wider than microfilaments o comprised of a polymeric dimer of proteins § Alpha tubulin § beta tubulin o hope to maintain the structure of the cell and make up Celia and flagella o facilitate intracellular transport o make up miotic spindles, to support chromosome separation during mitosis and meiosis
obligate aerobes
obligate aerobes = oxygen required for metabolism
Voltage gated channels
open and close in response to changes in membrane potential
Vitamins
organic substances required, but insifficently produced in the body need in diet
transgenic organism
organisms whose genomes have been modified
Knockout organisms
organisms whose had one or more genes has been deleted
Ectoderm
outermost germ layer; produces sense organs, nerves, and outer layer of skin
Internal Genitalia of females
ovaries, fallopian tubes, uterus, cervix, vagina
Hardy-Weinberg equilibrium Allele frequency equation
p + q = 1 %A and %a
P and Q arms on sister chromatids
p top q bottom
Hardy-Weinberg equilibrium Phenotype frequency equation
p^2 + 2pq + q^2 = 1 % long arm (AA, Aa) % short arm (aa) the 2pq = the amount that are heterozygous p = dominatn 1 = recessive
The functions of histones include:
packaging DNA Histone packaging refers to the coiling of DNA around these proteins. organizing DNA. organizing DNA Histones organize DNA into nucleosomes. Participating in a mechanism for modulation of gene expression Histone acetylation is a mechanism that allows for variable gene expression in cells.
homologous chromosomes
pair of maternal and paternal of the same chromosomes Not identical can contain differnt alleles of the same gene
Glucagon is released by:
pancreatic alpha cells in response to low blood glucose levels. Correct Answer Glucagon is produced by pancreatic alpha cells when the concentration of glucose within the bloodstream becomes too low. It promotes glucose synthesis and release from storage.
hormones that promote bine growth and ca+ uptake
parathyroid (PTH) Calcitriol
insertion mutation
part of a chromosome breaks off and inserts itself into a second chromosome
loss of function mutations
partially or entirely prevents a protein from functioing properly
Viruses are always _______
pathogenic
A family has a history of inherited female sterility. A woman who is concerned about whether or not she has this phenotype is concerned about the trait's:
penetrance. Penetrance is the idea in genetics that for an individual who contains a certain genotype, there is a certain likelihood that the corresponding phenotype will or will not be expressed. If a woman is concerned about whether she will or will not have a trait, she is concerned about the trait's penetrance.
All of the following are cell types found in the stomach that secrete key molecules involved in digestion Chief Cells secrete what
pepsinogen --> pepsins to break down proteins
How is heterochromatin formed?
perfomed by the histone deacetylase enzyme deacetylation --> heterochromatin allows the + on the histone to be shown
Autosomal pattern of inheritance
phenotypical characteristics that are inherited via the autosomes from parents regardless of parents sex affect males and females evenly
Nucleotide parts
phosphate, pentose sugar, base
What do CDKs do?
phosphorylate and activate target proteins that will promote the activity of a particular phase of the cell cycle
Blood's greatest component by volume is what?
plasma
recombinant plasmid
plasmid that has had a particular gene inserted into it using restriction enzymes
Stem cells that give rise to cell types of one of the three primary germ layers are:
pluripotent. Correct Answer Pluripotent stem cells can develop into the 3 germ layers known as the endoderm, mesoderm, and ectoderm.
lymph nodes
pockets that have high concentrations of B and T cells
end replication problem
polymerase cannot replicate the 5' (beginning) end of the new strand because that's where the primer was. DNA strands lose 50-200 bases per replication contributes to cell aging the telomerase in (germ cells, stem cells, and cancer) can act against this.
demographic transition: stage 5
population decrease very low birth and low death
Oogenesis
porduction of female gametes ovaries circultate estrogen and progestoerone
The first apple to ripen on an apple tree releases small amounts of ethylene gas, which causes nearby apples to begin ripening and producing more ethylene gas. This is an example of:
positive feedback because it amplifies a physiological process. Correct Answer Apple ripening is under positive feedback regulation because because the ripening of one apple rapidly causes other nearby apples to begin ripening. Positive feedback works to intensify a response until a defined endpoint is reached.
Pancreas
posterior to the stomach Alpha Cells - Glucagon - secreted in repsonse to low blood glucose, promotes gluconeogensis, and glycgenesis Beta Cells - Insulin - secreted in response to high blood glucose, promotes uptake of glucose Delta Cells - Somatostatin (GHIH) - reduces stomach acid secretion and blocks release of other digestive enzymes to slow digestion
heterogeneous nuclear RNA (hnRNA)
precursor to mRNA
Cyclin
present at every stage in the cell cycle low during other phases, but high during the corresponding phase
postzygotic barriers
prevent a formed zygote from being viable or fertile
prezygotic barriers
prevent a zygote from forming
Myelination funciton
prevents effluc of ions Inc membrane resistance, Inc charge seperation, dec capacitance
adrenal medulla
produce EPi and nor Epi
ependymal cells
produce and circulate cerebrospinal fluid
Primary oocytes
produced before birth during menstration, one follicle release a mature ovum
antibodies
produced by B cells recognizes a single antigen binding marks the pathogen distinguish between self and non self
Immune Cells
produced in bone marrow WBC or leukocytes nucleated
Estrogen and progesterone in adulthood
produced in ovaries during menstration produced in the placenta later in pregancy
Gallbladder
produces bile
Spermatogenesis
produces mature sperm 4 spermatids are fomred Formation of a tail loss of excess cytoplasm formation of acrosomal cap
Hematopoiesis
production of red and white blood cells in bone marrow
basophils and mast cells
promote inflammation, release histamine
The collecting duct of the nephron:
promotes water reabsorption to increase filtrate osmolarity. Correct Answer Water is reabsorbed in the collecting duct, which reduces filtrate volume and ultimately increases its osmolarity.
Phases of Mitosis
prophase, metaphase, anaphase, telophase
an antibody is a protein, carb, or lipid
protein
gain of function mutation
protein takes on a new function that wasnt there initaly.
Each of the terms below is an organ that plays a role in the chemical digestion of macronutrients. Match each organ with the macronutrient(s) it digests. stomach
proteins
stomach is involved in what type of diagestions of what
proteins and B12
Zymogens are activated by:
proteolytic processing. Certain proteins are proteolytically processed, which means that they are cleaved at specific sites. The cleavage of a precursor protein (also called a zymogen) causes it to become active. This regulatory step prevents hormones and other enzymes from being prematurely activated within the body.
Cytoskeleton
provides structural support and helps cell move made up of microfilaments, microtubulues, and intermediate filaments
anterior pituitary
recieves hormonal signals through the Hypophyseal portal system then releases tropic hormones
What does surfactant do?
reduces surface tension
founder effect (genetic drift)
reduction in genetic diversity due to a small group founding a new colony allele frequency may shift, but not due to selective pressures
Symbiosis
relationship between two or more organisms that benefits, harms, or has no effect on one or both parties Mutalism - both organisms benefit commensalism - benefits one party without affecting the other parasitism - one benefits while the other is harmed
Fitness is ____
relative to situation
parathyroid glands
release parathyroid hormone (PTH) opposes the effect of Calcitonin PTH inc Ca2+ concentration in blood
Memory T cells
rembered immunity
deletion mutation
removal of a section of genes on a single chromosome
Mismatch repair
repair enzymes correct errors in base pairing occurs immediatley after DNA repliucation and through G2 phase can distinguish between old and new strands of DNA Old strrands of DNA are methylated
missense mutation
replace with a differnt stop codon 1. conservative --> function is paritally conserved (small impact) 2. nonconservative --> totally new proetin (large impact)
active transport
requires ATP to move a solute against a concentration/electrochemical gradient
G0 phase
resting phase of the cell cycle in which the cell continues to function but does not divide can last indefintly non-mitotic
inversion mutation
reversal in the directionality of a segemnt of DNA on a single chromosome usually harmless
Match each of the following conditions with its effects on the hemoglobin dissociation curve: at high temp the curve will shift left or right?
right shift
As hemoglobin's affinity for oxygen diminishes, a typical oxygen-hemoglobin dissociation curve shifts to the:
right. Correct Answer A decrease in the affinity means that hemoglobin would require more oxygen pressure to bind, shifting the curve to the right.
Leydig Cells
secrete testosterone
Leptin
secreted by fat cells = supresses appetiate
Ghrelin
secreted by specialized cells in the pancrease and upper stomach when stomach is empty, stimulates appetite
Heart - Hormones
secretes Atrial Natriuretic Peptide Regulates fluid balance opposes Aldosterone and ADH released in response to high BP Lowers BP by incresing fluid loss
Liver functions
secretes bile detoxifies compounds metabolizes drugs and meds stores glycogen and triglycerides mobilizes glucose and FA
Endocrine
secretes directly into circukation
The ovarian follicle:
secretes estrogen and progesterone
Pancreas functions
secretes fluids with digestive enzymes Has endocrine and exocrine functions
Exocrine
secretion via ducts acts locally
Pineal Gland
sectres melatonin
duplication mutation
segment of DNA is copied on a single chromosome
Mendel's Laws and descriptions
segregation: allele pairs will segregate randomly from each other into gametes independent assortment: Alleles for separate traits are independently inherited. But complicated by genetic recombination dominance: recessive alleles will be masked by domanint alleles
Spermiogenesis occurs in the:
seminiferous tubules. Correct Answer Recall that the seminiferous tubules produce non-motile but fully developed spermatozoa, which are transported to the epididymis. Spermiogenesis is completed in the seminiferous tubules, although further maturation to achieve motility happens in the epididymis.
Eukaryote replication
several orgins of relication DNA replication produces an identical sister chromatid that is connected to the OG DNA molecule at centrosome
Expresstivity
severity of phenotype
Meiosis
sexual reproduce to produce gametes
Sperm
short for spermatozoa haploid gametes that fertilize the egg
paralell evolution
similar changes in the phenotype between two geographically isolated taxa (species, genera, etc.)
Osmosis (passive transport)
simple diffusion of solvents (water)
types of passive transport
simple diffusion, osmosis, facilitated diffusion NO ATP nededed solutes move down concentration gradient can move AGAINST the osmotic gradient. Meaning = osmotic pressure can influence the movement
All amino acid-derived hormones are derived from a _____ amino acid.
single
Anaphase II
sister chromatids separate
Adrenal Cortex
sit on top of kidneys release corticosteroids 1. Glucorticoids - Cortisol (sugar) 2. mineralocorticoids - Aldosterone (salt) 3. Sex Hormones - Androgens and Estrogens (sex) Sugar, Salt, Sex!
Bone marrow
site of hematopoiesis
Epitote
site where an antigen is recognizged by an antibody
Which of the following are physical or chemical barriers used by the innate immune system?
skin lysozome mucous
Plasmids
small circular DNA fragments of non essential genes in prokaryotes can code for: antibiotic resisitance and virulence factors
Viroids
small simple RNA particales that infect plants single stranded RNA sequences that lack a capsid or envelope Bind to complimentary RNA sequences in plants to silence gene expression no capisid
Race formation theory
social, economic, and political forces that results in socially-constructed racial identity; sometimes real, sometimes defined by history
voluntary muscles are controled by the _____
somatic system
postitive sense RNA viruses
ssRNA viruses contain mRNA that can be directly translated into proteins
Negative sense RNA viruses
ssRNA viruses if the RNA is complementary to the mRNA and must be copied into mRNA by the RNA replicase before translation
AUG is what kind of codon?
start codon - Methiondine
Prokaryotic Replication
starts from a single point and proceeds in two directions until the entire chromosome is copied
blunt ends and sticky ends
stick ends are prefered becuase they can be ligated back together more effectivly
Rectum
stores feces
Myoglobin
stores oxygen in muscle cells like hemoglobin but only one subunit and no cooperative binding myoglobin has a higher aff for O2 than hemoglobin
skeletal muscle
striated due to sarcomeres multinucleated red = slow twitch white = fast twitch
Sertoli Cells
support spermatogenesis
Satellite cells
surround neuron cell bodies in PNS
Prophase I
synapsis occurs forming tetrads of the same chromosomes but may have differnt alleles crossing over occurs at chiasmata. DNA is recombined so that it is unique to the offspring
A neuronal propagation will end with the release of neurotransmitters into the:
synaptic cleft. Correct Answer Neurotransmitters are released into the synaptic cleft, the space between the synapse of one neuron and the dendrites of the next.
Vitamin K
synthesized by bacteria in the large intestine essential to clotting
Steriod synthesis
synthesized in the ER and diffuse to the blood stream
Primase
synthesizes a short RNA primer that has a short 3' hydroxyl group that acts as the start point for the new strand
lymphatic system
system of vessels that help transport fluids and immune cells throughout the boidy
What are the two circulations of the Heart ?
systemic circulation and pulmonary circulation
blood pressure is measured as ______/_______
systole/diastole
Steroid hormones induce physiological changes within cells that:
take effect slowly and last a long time. Correct Answer Since steroid hormones influence transcription, their effects usually take a while to manifest but tend to last a lot longer compared to the effects of peptide hormones.
Reuptake
taken back up and broken down
VNTR (variable number of tandem repeats)
tandem (next to each other) repeats of a short DNA sequence (9 to 80 base pairs) with varying numbers of repeats among individuals
Eosinophils
target parasitic infection acid loving red stain
Receotor - mediated endocytosis
targeting specific molecules for injestion - engulfment
melting temperature (Tm)
temperature at which half of a sample of double-stranded DNA becomes single stranded by overcoming hyrogen bonds and hydrophobic interaction
In comparison to single crossovers, double crossovers:
tend to result in product chromosomes in which the ends come from the same parent chromosome. Double crossover events typically involve two distinct double-stranded breaks at separate chiasma. These events can create product chromosomes in which the ends originate from the same parental chromosome, but the central region arises from the opposing chromosome.
genetic linkage
tendency for genes located close together on the same chromosome to be inherited together
Hemoglobin
the O2 binding molecule in RBC has 2 alpha and 2 beta subunits each with a heme group
membrane fluidity
the degree to which phospholipids can move around laterlly lower temp = less fluidity
Select all that apply to complete the following sentence. The use of recombination frequency to estimate the distance between two genes becomes less accurate as:
the distance between the genes in question becomes larger. Recombination frequency can typically be used to roughly estimate the physical distance between genes. However, the maximum frequency (even for unlinked genes) is 50%, so the farther apart two genes are located on the same chromosome, the poorer this estimate. Additionally, the existence of double crossovers typically skews the predicted results, as two genes that are separated by two crossover events may still look as though they were close enough to be inherited together. & the probability of a double crossover increases. The greater the probability of a double crossover event, the farther apart two genes are. The farther apart two genes are (>50%), the poorer double crossover events are as an estimation of gene distance.
Endoderm
the inner germ layer that develops into the lining of the digestive and respiratory systems
threshold potential
the membrane pot where Na+ voltage gated channels open in a domino effect at ~55 mV
Gene Flow
the movement of alleles due to migration between populations NOT an example of genetic drift
relative deprivation
the perception that we are worse off relative to those with whom we compare ourselves
A botanist conducts a cross of two plants, each of which has a genotype of RrZz. The botanist would likely suspect that genes R and Z are linked if:
the phenotypic ratio of the offspring deviates significantly from 9:3:3:1. When deciding whether two genes are linked, first assess the phenotypes of the offspring of any relevant crosses conducted. If offspring phenotypes differ significantly from the expected Mendelian ratio, the genes may well be linked. The situation here represents a dihybrid cross, which typically leads to a phenotypic ratio of 9:3:3:1 (9/16 offspring display both dominant traits, 3/16 display the first dominant trait but are recessive for the second, 3/16 display the second dominant trait but are recessive for the first, and 1/16 offspring are recessive for both traits).
Phenotypic ratio
the ratio of phenotypes produced by a cross 3:1
SRY gene
the sex determining region of the Y chromosome in males. Encodes the testis-determining factor, which turns the primordial gonads into the testes
Red bone marrow is:
the site of erythropoiesis. Correct Answer Erythropoiesis is the synthesis of red blood cells. Both red and white blood cell production occurs in red bone marrow.
Epigenetics
the study of environmental influences on gene expression that occur without a DNA change
mRNA
the template for protein synthesis
restriction enzymes
they recognize and cleave highly specific recognition sites on DNA that is usually palindromic prokaryotic DNAases
Gram-negative bacteria
thin layer of peptidoglycan, surrounded by a lipopolysaccharide outer membrane. They will stain pink instead of deep purple.
When determining the concentration of a solvent, it is the ______ of solutes dissvoled not which ones.
total
Veins carry blood ____ the heart
toward
Inclusive fitness
traits passed on that promote the survival of the group ex. altruism and empathy
DNA to mRNA is what process?
transcription
A protein added to a cell culture localizes to the nucleus and causes a cell to differentiate into a more specialized cell type. This protein is most likely a(n):
transcription factor. Correct Answer Transcription factors direct the transcription of a set of specific genes. This plays a critical role in cell differentiation.
In prokaryotes, _________ & _______ occur simutaneously in Prokaryotes
transcritpion and translation
tRNA
transers AA to growing polypeptide chain
horizontal gene transfer
transfer of genes to an existing bacteria how bacteria achive genetic variablity despite asexual repro NOT the same as reproduction (No new organism is created)
Mechanisms of horizontal gene transfer
transformation - bacterium absorbs DNA from the enviorment transduction - Gene trasnfer mediated by viruses that infect bacteria (bacteriophages). Helps to inc microbio varabilty. IMPORTANT TO BIOTECHNOLOGY conjugation - a special plasmid (fertility factor) is trasnfered between cells. F+ bacterium has a fertility factor. F- lacks the fertility factor. major cause of antibiotic resistance
DNA viral genomes
translocates to the nuclues transcribed by the host cells RNA polyermase
Transposition mutation
transposons moving whereever usually harmless
True or false: Bile salts are amphipathic molecules that associate with lipids in the aqueous environment of the duodenum.
true
Diploid cells contain
two complete sets of chromosomes 2n 46 chromosomes
autosomal recessive
two copies of an abnormal gene must be present in order for the disease or trait to develop recessive genes can skip generations, but the child can be affected if it inherts a recessive from each parent
What are epinephrine and norepinephrine derived from
tyrosine and they inc blood glucose levels
Enteric NS
under autonomic control --> unconscious
smooth mucles
uninucleated lacks sarcomeres nom striated
cardiac muscle
uninucleated straited contracts synchronously by gap junctions can beat wothout brain input
Svedberg unit
unit for sedimentation rate, how fast particle settles (sediments)
Retroviruses
use reverse transcriptase to copy their RNA genome into DNA
reverse transcriptase (enzyme)
used in reverse transcriptase PCR where an RNA template is revere transcribed into a complmentary DNA for PCR amplification
Gram staining
used to speerate bacteria into two catgeogies based on the structure of their cell walls gram postive gram negative (E. Coli)
Blood pressure is highest in the aortic arch, shortly after blood leaves the heart. Blood pressure is lowest in the:
vena cava. Correct Answer Blood leaving the heart is under high pressure, but as it travels through the body, the pressure drops. Blood pressure is lowest just before returning to the heart, in the vena cava.
bacteriophages
viruses that infect bacteria
There is a marked delay between the initiation of sodium influx and the initiation of potassium efflux. This delay occurs because:
voltage-gated potassium channels exhibit slower kinetics than their sodium counterparts. Correct Answer Once the neuron reaches its threshold voltage, opening of sodium and potassium voltage-gated channels is initiated. The conformational change required for the opening of the potassium channels occurs more slowly than that required for the sodium channels, permitting a robust increase in intracellular cation concentration without an opposing increase in extracellular cation concentration.
During the depolarization phase of an action potential:
voltage-gated sodium channels are open and activated, and potassium channels are closed. Correct Answer Depolarization is the direct result of sodium influx, which occurs due to increased membrane permeability to sodium. This is only possible if voltage-gated sodium channels are open and in an activated state. Potassium channels do not fully open until the repolarization phase of the action potential.
Tidal Volume (TV)
volume of air inhaled or exhaled in a normal breath
The entire externally visible set of female genitalia is collectively called the:
vulva. Correct Answer The external female genitalia are collectively known as the vulva.
feces consists of:
water indigestiable material
M phase
when cell division occurs through mitosis or meiosis
Isotonic
when the concentration of two solutions is the same
Divergent Evolution
when two or more species sharing a common ancestor become more different over time
what does the buffy coat carry
white blood cells - leukocytes and platelets
How does LH and FSH work in females
work on ovaries to produce estrogen and progesterone to regulate reproductive cylce
Both cortisol and epinephrine:
work to elevate circulating blood glucose levels. Correct Answer Both cortisol and epinephrine work to liberate glucose from storage to elevate blood glucose levels.
How does LH and FSH work in males
works on testes to create mature sperm and testosterone
Leading Strand vs. Lagging Strand
works toward replication fork works away from replication fork; both always move in the 5' ➝ 3' direction
What features of the nucleus allow it to carry out its function?
§ the nuclear membrane is a double membrane composed of two phospholipid bilayers § nuclear pores our protein complexes that cross the nuclear membrane and allow selective transport of larger molecules
osmotic pressure equation
Π = iMRT; Π = Osmotic pressure; i = # of particles per molecule of dissolved substrate M = TOTAL concetration of solutes R = Ideal gas constant; T = temprature
