MCAT Bio Biochem Flashcards
1
Q
What are the two main componenets of the viral envelope.
A
Viral envelopes consist of phospholipids and glycoproteins that contribute to recognition and interaction with other cell receptors.
2
Q
Name each type of inhibition and what they all affect?
A
Competitive inhibition–> Increases Km and Vmax unchanged.
Noncompetitive inhibition–> Vmax is decreased while Km is unchanged.
Uncompetitive inhibition–> Vmax and Km both decrease.
3
Q
What is the term used to describe “catalytic efficiency”?
A
Kcat=Vmax/Km
4
Q
What is the order of scope covered from largest to smallest with Coenzymes, Prosthetic groups, and Cofactors?
A
Cofactors>Coenzymes>Prosthetic groups
5
Q
Where are action potentials summated?
A
Action potentials begin in the axon hillock before they move down the axon.
6
Q
What is hyperpolarization?
A
Hyperpolarization happens when the membrane potentail changes to a negative membrane potential due to the loss of potassium ions in the cell.
7
Q
Which neurotransmitter would cause muscle flacidity? 1) Acetylcholine 2) Glutamine 3) Epinephrine 4) GABA
A
Muscle flacidity is caused by a lack of acetylcholine released by somatic cells that causes muscles to not contract.
8
Q
What muscles would be expected to be forcefully contracting if a patient is struggling to breathe?
A
Forceful exhalation is defined as a contraction of the internal intercostal muscles to force air out, which is abnormal.
9
Q
What is pulmonary surfactant and how does it affect respiration?
A
Pulmonary surfacant in involved in the reduction of aveolar surface tension. Decreased amounts of surfactant can lead to less area for gas exchange causing difficulty breathing.
10
Q
What is ADH, Aldosterone, and ANP? What are their functions?
A
Vasopressin (ADH) is involved with water retention. So, a vasopressin receptor antagonist will cause the receptors to NOT retatain water causing large amounts of urine to be excreted. Aldosterone and ANP are also involved in either secretion of water/sodium or the retention of such. All are invloved in kidney function and urine secretion.
11
Q
How do you know the change in pressure between the Glomerular Capillaries and the Bowman Space? Hint: It is positive/negative depending on the direction of flow.
A
Pressure going into the Bowman Space (from the Glomerular) is positive and flowing into the Glomerular Capillaries is negative.
12
Q
If the anterior pituitary malfunctioned, what would be the resulting affect on the Thyroid?
A
The anterior pituitary gland creates a hormone called TSH (Thyroid stimulating horome) that stimulates the Thyroid to create T3 and T4 hormones
13
Q
What is the function of the Pineal gland? What Bodily cycle does it tie into?
A
The Pineal gland secretes Melatonin (Melatonin production is stimulated by darkness and inhibited by light).
14
Q
What would happen to the body if the concentration of aldosterone increased? (hint: It affects Sodium, Water, and Potassium.)
A
As Aldosterone concentration increases, water and salt retention will also increase, while potassium will be secreted due to stimulation of the distal ducts on the kidney nephron.
15
Q
What are the affects of LH on both men and women?
A
Increase in LH will stimulate the follicles on the ovary to undergo ovulation. However, for males, LH will bind to receptors to stimulate testosterone synthesis.
16
Q
Where are phospholipids created?
A
Phospholipids are synthesized on th surface of the smooth ER then packaged into vesicles and sent to the membrane.
17
Q
What are dyeins and what is their function?
A
dyneins–> are motor proteins that are structurally similar to kinesins, but carry cargo toward the minus end of the mircotubule, which is usually oriented toward the center of the cell. There are two other types that are found in a smaller scale that either help with cellular transport or function of filia or flagella.
18
Q
What are Kinesins and what is their function?
A
Kinesins–> are motor proteins that use ATP to power movement across microtubules and usually go towards the periphery (outside of the cell). They are also made up of four distinct subunits.
19
Q
What are Myosins and what is their function?
A
Myosins–> similar to kinesins/dyneins (need ATP) but are not involved in transport. They play a role in actin-based muscular contraction in muscle, as well as a winde rande of motility processes (including actin contraction in cleavage furrow of cell seperation). Use ATP to carry out power stroke.
20
Q
What is the fuction of actin microfilaments?
A
Actin Microfilaments (smallest of the skeleton)–> play a role in motility, cell cleavage, endocytosis/exocytosis, and muscle contraction.
21
Q
What is the function of Intermediate filaments?
A
Intermediate filaments (the middle sized in the cytoskeleton)–> provide stuctural support and other functions; major example = Keratin (findernails, etc.).
22
Q
What is the function of Mircotubules?
A
Microtubules (largest in cytoskeleton)–> Hollow cylinders composed of poolymeric tubulin dimers (alpha and beta). Contribute to chormosome movement during division and intracellular division.
23
Q
What are the three types of junctions and their functions?
A
Anchoring junctions–> involve cadherins; help keep cell/tissue in place. Gap junctions–> formed by connexin proteins, connects cells so that diffusion/communication can take place. Tight junctions–> invlove several types of proteins, are found in epithelial cells, and prevent solutes from being able to move freely between tissues (i.e. blood-brain barrier).
24
Q
In oogenesis, when does the primary occytes turn into the secondary occyte (it’s either before birth or at puberty)? When are they diploid and haploid?
A
When women are born, they are born with primary oocytes arrested in Meiosis I. When puberty occurs, those primary occytes complete meisis I and become secondary occytes that are haploid (while primary occytes are diploid).
25
What hormone is released when the egg attaches to the uterine lining and what mechanism does it stimulate?
Directly after the egg implants in the uterine lining, it releases cHG, that mimics LH, to maintain the Corpus Luteum, thus maintaining estrogen and progesterone levels to signal to the body that pregnancy is occuring.
26
What are Osteoblasts/Osteoclasts and their function?
Osteoblasts -->use hydroxyapatite to create the bone matrix. Osteoclast--> Break down the bone matrix to inject calcium and phospate into serum levels if they're low.
27
What is the difference between ligaments and tendons?
Ligaments: Are used to connect bone to bone. Tendons are used to connect muscle to bone.
28
How would you go about finding what estradiol looks like when given four different steriods to choose from?
Estradiol (a steriod and a form of estrogen) is going to have the common 4-ring that steriods normally have. Also, the -diol refers to OH (hydroxy) groups attached to the steriod. Di means two. So, it should be relatively easy to reason through.
29
What is the difference between multipotent, pluripotent, and totipotent stem cells?
Multipotent stem cells--> in various types of tissue and can develop onto various forms, unlike other types. Pluripotent stem cells--> are similar to multipotent cells but are NOT found in adults.
Totipotent stem cells--> Can give rise to embryos or placental tissue but cannot form anything else and are NOT found in adults.
30
What are sutures (related to the body) and where are they found?
Sutures are a fibrous connective tissue that are found in the skull--and only in the skull--are used to connect pieces of the skull together.
31
What is a use of vitamin D in the body?
Vitamin D is useful in the body as it allows an uptake of calcium and phosphate from the intestines.
32
What is SDS-PAGE used for?
SDS-PAGE is used to disrupt secondary and tertiary structures in proteins while also applying a negative charge across the gel--as well as the protein--to separate protein by mass or size.
33
If we had an SDS-PAGE experiment with a protein composed of 3 small subunits and 1 large one, what would the lines in the gel display?
SDS-PAGE--> separates proteins and their subunits by size or mass. Therefore, smaller subunits will travel farther through the gel, while larger subunits will travel shorter. So, if we had three small subunits and one large, one very dark long line would show up for the three small subunits, but a faded shorter line would show up for the larger subunit because it did not move as far through the gel.
34
What creates collagens in the skin?
Fibroblasts are the most internal structure of skin and are used to synthesize collagen.
35
What is the name of the fiber that connects the epithelial layer of the skin with the endothelium of capallaries?
The Epithelial layer of tissue is connected to the endothelium of the capillaries via a fiber called Fibronectin.
36
What are the general roles of the Sympathetic and Parasympathetic nervous systems?
Sympathetic NS EXCITES the body while the Parasympathetic NS CALMS the body
37
If someone had the nerves in the front of their spine severed (while the lateral and dorsal were intact) what symptoms would this person be experiencing?
Sensory (afferent) nerves are on the dorsal side of the spine--in the rear. Motor nerves are located in the ventral and lateral sides of the spine.
38
Where is Myelin produced?
Oligodendrocytes produce myelin sheathing in the CNS. However, Shwann cells produce myelin sheathing in the PNS
39
What type of neurons are found in the CNS/cerebrum? Hint: "polarity"
Multipolar neurons are dominate in the Frontal lobe/CNS/cerebrum because they allow quick and complicated neural responses.
40
What is more likely to cause a neuron to fire? 1) one EPSP 2) one IPSP or 3) Multiple EPSPs or 4) Multiple IPSPs ?
Rapid EPSPs (excitatory post-synaptic potentials) will cause a neoron to fire whereas IPSP (Inhibitory post-synaptic potentials) will hyperpolarize a neuron or inhibit its firing. Also, Myelination has nothing to do with neuron excitability.
41
What is the charge of a cell that's depolarized?
A normal cell sits at -70mV and when depolarized will move to -45mV
42
Do sodium channels close or deactivate (there is a difference) when a neuron fires? Also, this keeps them from firing again.
During the absolute refractory period of a neuron, sodium channels deactivate (not just close), which causes the neuron to be unable to fire again until it has returned to baseline.
43
What is the function of GABA and Glutamate in the neural system?
GABA is the standard inhibitory neurotransmitter. Howevere, Glutamate is the classic example of an excitatory neurotransmitter!
44
What is cell-mediated immunity?
Cell-mediated Immunity has to do with specific T cells that offer a respose that does NOT include antibodies, but uses phagocytosis, cytokines, and the release of specific lymphocytes.
45
What is DNA polymerase I?
DNA Polymerase I---> Helps connect Okazaki fragments together and remove the RNA primer.
46
What is DNA Polymerase II?
DNA Polymerase II---> Primarily involved in DNA repair
47
What is DNA Polymerase III?
DNA Polymerase III---> Is involved in the main process of DNA synthesis.
48
What is DNA Ligase?
DNA Ligase---> Joins normal DNA strand together, but can also join Okazaki fragments together
49
What is the function of Primase?
DNA Primase---> Creates an RNA primer for the lagging strand.
50
What are the three enzymes that are involved with the unwinding and stablization of DNA during replication?
The enzymes involved in the unwinding and stablization of DNA are 1) Topoisomerase (uncoils the DNA so it can be broken apart for replication) 2) Single Stranded Binding Proteins (inhibit the single strand of DNA from rebinding) and 3) Helicase (unzips the DNA for replification).
51
What does the term 'Anhedonia' mean?
Anhedonia---> The lack of feeling of pleasure.
52
If someone was sicked by a virus, recovered completely, then was sicked by a different strain of the same pathogen, what would be the immune response to the pathogen?
Resistance to a particular strain of pathogens does not confer resistance to other strains (even if they are similar). A person likely would NOT have any increased response to a new strain of a similar pathogen. (think if the general flu and something like Swine Flu).
53
What is the process of a phagosome as it ingests a foreign object?
The primary function of phagosomes is to ingest the possible pathogen and immediately kill it (due to very high acidity via proton pumps) so that the bacteria will die before it can replicate and lyse the phagosome.
54
What are restricing enzymes called and what is there function within DNA?
Endonucleases are restricting enzymes. They cleave WITHIN a nucleaic sequence where Exonucleases cleave on the ends of sequences.
55
In gel electrophoresis, is DNA postive or negatively charged and is it moving towards the anode or cathode?
Gel Electrophoresis negatively charges DNA so that it may move it towards the anode (yes, the anode)
56
What does the term Incomplete Penetrance mean?
Incomplete Penetrance---> Clinical symptomes (phenotype) may not always be expressed even though someone may have a disease causing mutation (genotype).
57
In miRNA gene silencing, a small RNA binds to a mRNA to begin degradation. This prevents translation of the mRNA. What is this called?
Hybridization. That process is describing of complementatry nucleotides
58
What part of the nervous system--specifically--causes your pupils to dialate?
The PNS, but specifically the sympathetic motor neurons.
59
If a student conducts an experiment involving harmful bacteria, what is the proper lab method to dispose of this harmful bacteria?
The proper--and best way--is to place the sample in an autoclave where the temperature exceeds 120C and 2atm, which is enough to kill almost anything.
60
Where do single and double crossovers occur on a chromosome?
Single crossovers occur on the end of chromosomal arms while double crossovers occur in segments in the middle of the chromosome.
61
When cancer cells are present, what can we expect of lactate levels? Low or High and why? What would glycolysis be doing in this case?
In cancer cells, we would expect high levels of lactate via fermentation due to lack of O2 and inhibited glycolysis.
62
How does mismatch repair occur?
Say two amino acids are connected that should not be (Like T and G), mismatch repair will cut one of those out, and replace it, most likely with a Cytoseine to match the G.
63
If a new cancer drug is being developed, what stage of the cell cycle would NOT be used for possible treatment?
G knot (Go) is the general stage of cellular arrest (it does this on its own). So, it would not be beneficial to target that phase since it's arresting the cell already.
64
What is southern blotting?
Southern blotting is used to determine the concentration of DNA in a cell. Uses gel electrophoresis too.
65
What is northern blotting?
Northern blotting is used to find cellular concentration of RNA (NOT DNA). It uses the same mechanism of southern blotting--gel electrophoresis.
66
Say you had 4 amino acids, how would you determine the amount of configurations that they could form?
Whatever the number of amino acids there are--say there are four--it would be that number (n) factorial. (example 4! which would be 4x3x2x1 = 24
67
If an organ has low circulating levels of a hormone, what will be the body's reaction to a low amount of hormone circulation in the blood?
The body will stimulate the organ to produce more of the hormone(s) in hopes to raise the levels of it present circulating in the blood.
68
In a negative inducible operon, if the repressor is already bound, what could you add to restore active trascription?
NOT an activator but an INDUCER! This would block the repressor from binding.
69
What is Western blotting?
Western blotting is accomplished through another mechanism NOT invloving gel electrophoresis. In Western blotting, we are looking for specific proteins (not amino acids or mRNA like the others).
70
What contributes--in the largest context--to DNA helix stability?
The hydrophobic effect is what contributes in the largest extent. Decreases the hydrophobic effect will only weaken the DNA helix.
71
What does Pluripotent mean?
Pluripotent cells, usually embryonic cells, are cells that can essentially become any type of cell needed. Adults do not have this cells.
72
What end--positive or negative--does polymerization in actin happen at, and why?
The rate of polymerization or depolymerization depends on how much actin is present. The positive (+) end is attatched to ATP while the negative (-) end is attatched to ADP. Polymerization occurs faster at the positive (+) end.
73
What does the term 'allosteric inhibition' mean?
Allosteric inhibition describes inhibition that occurs anywhere other than the active site.
74
If substrate and allosteric activators are increased in a solution, will the Vmax and Kcat change or stay the same? Why?
Vmax is not effected by substrate concentration (only addition of enzymes), but increase of activators will increase the reaction rate.
75
What is the difference between post-transcriptional modification and post-translational modification?
Post-transcriptional modifcation occurs before entering the cytoplasm. This happens when mRNA is created. Post-translational modification is after the actual protein or structure is created when something else is added like a phosphate or a glucose.
76
What is bacterial transformation?
Bacterial transformation is where a bacteria just takes up foreign genetic material from its' environment and inserts it into its DNA sequence.
77
What is bacterial transduction?
Bacterial transduction is where new DNA is injected into the bacteria by a virus where it inserts itself into the DNA sequence.
78
What is the difference between osmotic and hydorstatic pressure?
Hydrostatic pressure is the 'pushing' pressure exerted on a container. Osmotic pressure is the 'pulling' pressure due to the presense of solutes in solution (usually, in blood).
79
What would the effect be on ATP production if the proton gradient was disipated (in addition to lack of function of the ETC)?
The disassociation of the proton gradient would be redundunt in this context. If the ETC was already severvely hindered, the dispersion of the proton gradient wouldn't make any greater noticeable difference than what is already happening.
80
What would be the affects on the body if someone was given a Calcitonin antagonist?
Calcitonin decreases plasma Ca2+ concentration. So, decrease in Calcitonin would increase osteoclast activity, which would stimulate bone breakdown to add Ca2+ to blood plasma.
81
What is a useful way to know the developemental stages after the morula?
The mnemonic "More Blasting Gas, I'm Nervous.", which outlines the process: Morula, Blastula, Gastrula, and to Neurulation. That's going from smallest to largest portions of the embryo
82
What is the synaptoemal complex?
It is a protein based linkage that appears during meiosis and connects homologous chromosomes. Helps with crossing over and any issues would hinder crossing over from occuring or at least occuring properly.
83
What is angiogenesis and what disease will propagate under misregulation?
Angiogenesis is the creation of blood vessels and vascular pathways and is often seen in Cancer do to the large demands of tumor growth.
84
When comparing unicellular eukaryotes, like algea, to human cells, what is a large characteristical difference that will be observed?
That nearly 95% of the human genome does NOT code for protein or RNA, whereas, algea almost exclusively encodes for proteins.
85
What is the name of the cell that nourishes developing sperm in the testes?
They're called Leydig cells. They're activated by FSH.
86
If the synaponemal complex is severed in a cell, destroying the protein-DNA linkage, what bridge between the two bodies is affected?
Homologous chromosomes in prophase I will be hindered where the interactions occur and could possibly affect recombination, as well.
87
What parts of the body consist of ectoderm?
Ectoderm gives rise to skin, hair, body cavities, nervous tissue, etc.
88
What parts of the body consist of mesoderm?
Mesoderm forms bone, skeletal muscle, the heart, the urinary tract, circulatory system, reproductive system, etc.
89
What are holoenzymes and apoenzymes?
Holoenzymes are both the enzyme and coenzyme bound together, which is needed to carry out catalytic activity. Apoenzyme is refering to an enzyme without that coenzyme (or cofactor) that is needed for it to function.
90
What is the function of the G2-M checkpoint in mitosis?
This is specifically the DNA damage checkpoint prior to replication. If there is damaged DNA, then apoptosis will ususally occur.
91
What is the difference between incomplete dominance and codominance?
Codominant is something like human blood types where two things can be expressed at once. Incomplete dominance, however, is when genes blend, like a red and white flower making a pink flower or a tall and short horse making a medium sized foal.
92
Where does fatty acid synthesis--and oxidation--occur?
Fatty acid synthesis occurs in the cytosol and requires acetyl-CoA. Beta oxidation occurs in the mitochondria of the cell, however.
93
Can nucleic acids catalyze biological reactions, if so, which ones can?
Yes, they can! Between DNA and RNA, RNA is the only one that can form ribozymes (which perform enzymatic functions) and play a role in protein production and packaging.
94
What are the four steps of Beta Oxidation?
1) Oxidation 2) Hydration 3)Oxidation and finally 4)Thiolysis
95
What is the name of the process that allows the eye to transform light into an electrochemical signal so that your brain can perceive images?
The process is called Phototransduction.
96
Where are proteins produced and what does retrograde transport mean?
Proteins are produced in the ER, then sent to the golgi apparatus where they're packaged and sent out. Retrograde transport would be going backwards through this process.
97
What's the difference between proactive and reactive interference?
Proactive is done beforehand while reactive is done after-the-fact. Proactive is generally better.
98
If you had a random acid, HA, that doesn't completely disassociate in water, but does completely disassociate in blood; what would be the reasoning for that? (Equation is HA [H+] + [A-] )
So, because blood is trying to remain at equilibrium, H+ ions will continually be taken out, which allows the acid to completely disassociate and the reaction will reach equilibrium.
99
If an experiment was being conducted that initially used L-isomers of amino acids but the study wanted to try using D-isomers instead, what would be the result?
The experiment would be inhibited and nothing would result. Ribosomal protein synthesis only uses the naturally occuring L-isomer and cannot use the D-isomer.
100
What does 'Amphipathic' mean?
Amphipathic means that a molecule (i.e. a vitamin or an amino acid) contains both polar and nonpolar sections.
101
What does a promotor do in regards to an operon?
This is what actually allows transcription to begin and is upstream of the actual DNA.
102
What does an activator do in an operon?
An activator is a protein that increases gene transcription when bound to enhancers or promotor-proximial sites.
103
What does a repressor (and corepressor) do in an operon?
Repressor regions are usually already bound to the operon (but not active in repression). Corepressors bind to the repressor, which then activates the repressor. Once the repressor is created, it binds to the promotor to inhibit transcription.
104
What does an enhancer to to an operon?
An enhancer is a short segment of DNA that enhance transcription and are usually bound to activators.
105
What are the two biggest factors (physiologically, not chemically) that influence blood pressure?
The two factors that normally determine blood pressure are Cardiac Output and Resistance to Blood flow.
106
What is a frameshift mutation?
A Frameshift mutation either deletes a base pair or adds a base pair, which affects all other amino groups down the line; this usually changes the entire downstream sequence.
107
What is a nonsense mutation?
Changes to a stop codon.
108
What is a missense mutation
Missense mutation is the substitution of one DNA/RNA base pair and would change the codon from one to another.
109
What is a Silent Mutation?
A Silent mutation is changing one base pair that does NOT change the codon. So, the amino acid stays the same.
110
What type of tissue do capillaries consist of?
Capillaries consist of endothelial tissue.
111
What is Cholecystokinin?
It is a digestive enzyme found in the small intestine (peptide hormone). It catalyzes the process of digestion and inhibits things like somatostatin.
112
What are chaperone proteins and what are their functions?
Chaperone proteins are heat shock proteins and are used to facilitate proper protein folding and inhibit the formation of nonfunctional protein aggregates.
113
During the initiation of muscle contraction, mysosin binds actin after troponin binds to which ion?
Calcium!
114
When concentrated urine is being produced, in which of the following regions of the kidney will the glomerular filtrate reach its highest concentration?
The medullary portion of the collecting duct.
115
If you were told that a cellular component was located in a cholesterol rich domain, where would it be located?
Within a lipid raft of the membrane of the cell.
116
The initial filtration step in the glomerulus is done by: filtrate concentration, pressure, or active transport?
It is done by passive flow due to differences in pressure.
117
If there is not a codon for an amino acid that is in the body, is it produced in vivo? Why or why not?
No, it cannot be produced in vivo. The body can take things and synthesize them (like different amino acids) that do not have codons within the body. A codon just allows it to be replicated and produced in DNA and RNA
118
What are some long term ill affects of glucocorticoids on the body?
Glucocorticoids break down muscle within the body--in high concentrations and for extended periods of time.
119
What are the two phases of viral pathogenesis?
First, the Lysogenic phase, which is when the virus is dormant in the hosts DNA. All of the daughter cells--of the infected cell--will carry the virus genome. Next, in the lytic phase, the virus is triggered and begins to produce massive amounts of viral vectors and the cells lyse, beginning the process all over again.
120
If given a certain solute concentration in the kidneys, what would be the affect on the kidney filtration rate if blood pressure was increased due to ADH?
It would be met with an increase in glomerular filtration rate to meet the demand of greater blood pressure. This would affect the output of the substance in the urine.
121
What hormone triggers ovulation?
LH triggers ovulation. Also, when LH triggers ovulation, it spurs an increase in both estrogen and progesterone.
122
What is the largest characteristic of natural selection that allows us to determine if a species is relying on natural selection?
It doesn't have anything to do with mating frequency, but everything to do with genes propagating in higher quantities through each generation; becoming more concentrated due to production via propagation.
123
What type of bodily response is it when a bacteria starts a cytokine storm?
NOT an autoimmune response because the cytokine storm was caused by factors outside of the body. This will be a overstimulated immune response via the presence of excessive amounts of this bacteria.
124
What are defining characteristics that differenciate archaea from bacteria and eukaryotes?
Well, archaea has circular chromosomes--like bacteria--but does not have a cell wall--like eukaryotes. In almost every aspect--besides the cell wall--it's exactly like bacteria.
125
Given a small sequence of template DNA, how would you find its complementary strand?
Well, for RNA, it's the complementary strand but with uracil in the strand. Synthesizing the end of telomeres--with RNA subunits--using the complementary RNA strand.
126
How would you know where two genes were on a chromosome in relation to each other?
The percentage recombination would tell you that the closer two genes are to each other, the less likely they will be to have a recombination event. So, if the recombinant percentage is low (like 8% of something) the genes are probably very close together.
127
How many base pairs are in an amino acids with 439 residues?
To find that, multiply 439 x 3 base pairs per codon = number of nucleotides
128
What are Desmosomes?
Similar to anchoring junctions, they are found in areas of high tensile stress and are found in skin where a lot of mechanical stress is. They anchor the intermediate filaments between cells to held keep stability.
129
What is receptor-mediated endocytosis?
The process where a ligand binds to a receptor on the extracellular side, which induces the plasma membrane to bud inward. This creates a vesicle that contain both ligand and receptor.
130
How would you find the nucleotide sequence if given a generic mRNA strand of a retrovirus?
Because it's a retrovirus, we don't have to find a DNA sequence. It would be the mRNA that was given to us. The RNA is what gets translated and inserted into the DNA within the cell.
131
If we were applying the Michaelis-Menten approach to a rate experiment, how would that affect our Vmax and Km?
The Michaelis-Menten method keeps enzyme concentration constant, varying the substrate concentration, and either including or excluding the inhibitor to assess the effects of the mechanism (how something is inhibited).
132
How much does the average amino acid weigh? If given a sequence of amino acids, how would you find the weight of the protein?
Average weight of an amino acid is 110 Da. If we wanted to find the weight of a protein, we would multiply 110 Da by the amount of amino acids in the protein.
133
Where do all the hormones from the posterior pituitary come from?
Hormones from the posterior pituitary come from the hypothalamus.
134
What's the difference between pluripotent and totipotent stem cells?
Pluirpotent stem cells can give rise to endoderm, mesoderm, or ectoderm. Totipotent cells are found only in embryos and helpt differentiate into almost anything.
135
What does the 5' Cap consist of on mRNA?
Well, the first base is always a methionine and the 5' Cap will always have a methylated guanine (a purine) in it.
136
How does bacteria mainly reproduce?
Binary fission!
137
What is considered the restriction point of the cell cycle, afterwhich, the cell is commited to mitosis?
It happens at G1
138
How does an R^2 value close to 1--or close to zero--effect correlation with data?
R^2 values indicate with a regression line correlates with data well or not. A R^2 value of 1 means that the line and data are a perfect match (meaning accurate data) and an R^2 value vlose to 0 means that the data and regression line DO NOT match.
139
If asked to find the amount of a recessive alleles in a population--given the dominate allele frequency is 75%--how would you find its frequency?
The equation: 1=q+ p (alleles in population) and p^2+2pq+q^2=1 (phenotypes in population). We will then use q^2 =0.25 and solve, which equals ~6%
140
What is a conservative mutation?
A conservative mutation is one that changes amino acid residues to other similar residues like leucine to valine.
141
What type of interactions within molecules make up quaternary structures?
Hydrophobic interactions between side chains are the hallmark interaction of qaurternary structures.
142
What is glycogenolysis?
Glycogen breakdown
143
What is the main carrier of free fatty acids in blood?
Albumin is the main carrier of free fatty acids in blood.
144
What is an easy way to tell of a recessive gene is X-linked or autosomal?
One of the easiest ways to tell is see how it affects the males in subsequent generations. If it's X-linked, way more men will get it because they only have one X chromosome.
145
What does isoforms mean?
Isoforms are different structures--or proteins for example--that complete the same task. Their only variance is in their amino acid structure, even though the complete the same tasks.
146
What do systolic and diastolic pressures measure respectively?
Systolic pressure is measuring the heart muscle contracting, which pumps blood into the arteries. Diastolic pressure is measuring the heart relaxing and filling the ventricle with blood.
147
What is primary active transport?
Primary active transport uses ATP hydrolysis to move molecules against their concentration gradient.
148
What is secondary active transport?
Secondary active transport uses one molecule traveling down its concentration gradient to help another molecule travel against its concentration gradient.
149
What is convergent evolution?
Organisms--that are not related--individually evolve similar characteristics (think sharks and dolphins).
150
What do viruses carry that helps replicate their RNA inside an infected host?
Viruses use reverse transcriptase to turn their RNA into DNA so that it can be incorporated into the host's genome and then carried on through the lytic cycle.
151
How does cytochrome P450 alter the activity of drugs?
Cytochrome P450 oxidizes the druges.
152
What is the defining characteristic of proteins that act as transription factors?
Proteins that act as tanscription factors, have DNA binding domains so as to bind to the regulatory DNA sequence.
153
What is Henry's Law?
Henry's Law is something that allows us to relate the solubility of a gas to its' pressure. The equation is S=k*P.
154
What are the two factors used when attempting to create a vaccine?
The two factors are toxicity and immunogenicity. Immunogenicity is the ability for the body to induce a response to the antigen. Toxicity is if something can be turned into it's non-toxic state (toxoid) or if what's being attacked by the vaccine will produce toxins (this obviously isnt good).
155
What is RT-PCR?
Well, general PCR is just used to find the DNA composition of things. RT-PCR is used to find the mRNA/RNA composition of things.
156
What is Gel Filtration Chromatography and Native PAGE?
Gel Filtration Chromatography is separating proteins based on their size--not their charge; Natve PAGE uses their charge, conformation, and electrophoretic motility.
157
Does water appear in equilibrium reactions?
No, water is a liquid and a solvent and will not appear in equilibrium reactions.
158
At what point of embryo growth does cell division begin to slow down?
Gastrulation is when cell division begins to slow down.
159
What is truncated mRNA and how will it become truncated?
Truncated mRNA just means that it was shorted, for whatever reason, through a mutation. This often involves a mutation that created a stop codon, thus, creating a shorter amino acid sequence.
160
What are Microglia?
Microglia are innate immune phagocytes specific to the brain. Other adaptive immune cells rely on Microglia to activate them.
161
Where does the Urea cycle occur and what is its purpose?
The Urea cycle occurs in the mitochondrial matrix and cytosol. It is fueled by and creates precursors for the CAC.
162
Where does the Pentose Phosphate pathway occur? What is its purpose?
It occurs in the cytosol. The Pentose Phosphate Pathway is used in fatty acid synthesis, nucleotide synthesis, and is tied into glycolysis.
163
How much does one molecule of glucose produce through glycolysis and the CAC?
The total ATP produced is 32.
164
Just know that the sense strand is the same as the mRNA but with U replacing T in the strand.
Also, tRNA--matching strand to mRNA--is what creates the peptide sequence.
165
What is an adjuvant and what is its purpose?
An adjuvant is just something that enhances an immune response by using an additional part of the pathogen that is trying to be vaccinated against.
166
Is inflation of the lungs considered a positive or negative pressure change in the lungs?
Inflation of the lungs is considered a negative pressure change.
167
How many molecules of NADH and FADH2 are created during one round of the Krebs cycle?
It's a 3:1 ratio with 3 NADH produced and 1 FADH2 per round of the Krebs Cycle.
168
How many molecules of ATP are produced with one molecule of acetyl-CoA going through the Krebs cycle and ETC?
In total, 10 molecules of ATP will be produced from 1 molecule of acetyl-CoA.
169
Would RNA replicase be expected to be found inside of virons?
Negative-sense singl-stranded RNA replicase creates the postitive stranded RNA, which is used for infecting host cells via the original virus.
170
What is ions are flowing/not flowing at the height of an action potential?
During the height of an action potential, NA+ is not flowing but K+ is flowing OUT of the cell.
171
What does the enzyme "aldolase" do in the glycosidic pathway?
The enzyme aldolase condenses G3P and DHAP into an aldol--F-1,6-BP
172
What does glucokinase do?
Glucokinase works similarly to Hexokinase (adding a phosphate group to glucose) but has less affinity to glucose than Hexokinase and does so for immediate storage purposes in glycogen. Thus, at lower concentrations of glucose, only Hexokinase will bind to glucose.
173
What are the three enzymes located in the irreversible steps within glycolysis?
The three irreversible steps (i.e. enzymes) are Hexokinase, phosphofructokinase (Rate-limiting step), and pyruvate kinase.
174
Do enzymes alter reaction kinetics or thermodynamics?
Enzymes alter reaction kinetics NOT reaction thermodynamics. Thus, enzyme concentration will not affect equilibrium reactions.
175
What category is NAD placed in: Coenzyme or Cofactor?
NAD is technically both, however, Coenzymes are both organic and inorganic molecules, where NAD is solely organic. Thus, NAD is considered a Cofactor--specifically organic molecules.
176
How many protons are pumped out through each complex within cellular respiration?
Complex I pumps 2 protons, complex II does not pump any; complex III pumps 4 protons; complex IV pumps 2 protons, as well.
177
Which glucose transporter is insulin-dependent for cellular uptake?
GLUT4 is stimulated by insulin and causes cellular uptake of glucose.
178
What are homrone classified as?
Hormones can be classified as: Amino Acid derivatives, peptide hormones, and steriod hormones. (peptide hormones and HydroPHILLIC while steriod hormones are HydroPHOBIC)
179
What are the three regulatory enzymes of the CAC?
High concentrations of ADP will stimulate the CAC, while high amounts of ATP will inhibit the CAC.
Step 1: Citrate Synthase
Step 3: Isocitrate Dehydrogenase
Step 4: α-Ketoglutrate dehydrogenase
180
What do topoisomerase and helicase do?
Topoisomerase unwinds the helical structure of DNA, while helicase breaks the hydrogen bonds between the strands.
181
At how many weeks does an embryo become a fetus?
At 9 weeks an embryo is now considered a fetus.
182
With these three choices, Codon, Polypeptide, and anticodon, what is the proper sequence for protein translation?
Codon; then is matched by anticodon; leads to a polypeptide.
183
What does sexual reproduction do?
It increases the fitness of a species, not individuals.
184
Are mutations always bad?
Mutations are not always bad. If they lead to a greater chance of survival (like less cancer) they may be considered at least not harmful, possibly beneficial. They're also going to end up being the dominant gene if fewer of them end up dying from cancer.
185
Do mutations always get passed on to other generations?
Well, yes and no. If the mutation is acquired over an individual's lifetime, or a somatic cell (rather than germ cell), then a mutation will likely not be passed down to subsequent generations.
186
What does the term "signal sequence" mean?
Signal sequence is what a protein will use to interact with the rough ER and get inserted into the plasma membrane, for example.
187
What are nuclear factors and what is their function?
Nuclear factors are located within the nucleus of an organism and help differentiate which genes are expressed over others. Since each cell has DNA for the entire body, it's important that certain genes are inhibited while others are activated.
188
How do you calculate Kcat?
The equation to calculate Kcat is Kcat = Vmax / [E] with "E" being the enzyme concentration.
189
What shape does a sigmoidal curve have?
Sigmoidal curves have "S" shapes and are indicative of cooperative binding.
190
What's the difference between a Lewis Acid and a Lewis Base?
A Lewis Base will DONATE a pair of electrons to a covalent bond, however, a Lewis Acid is a molecule that can accept a lone-pair of electrons.
191
When given a pKa of 6.37, a base concentration of 0.2M, and an acid concentration of 2M, what's the pH of the solution?
pH=pKa+log[base/acid]
| Plugin the numbers and you'll get 6.37 - 1/10(equal to 1)= 5.37
192
When given equal quantities of two reactants and a Ksp of 4.9 x 10^-9, how would you find the concentration of one or both of the reactants?
Use the equation Ksp = [x] * [x], which would give us
4.9 x 10^-9 = x^2 then just take the square root of both sides and the concentration for either reactant is
7 x 10^-5
193
What is a nuclear localization sequence?
Just a fancy word for something that wants to find the nucleus. A nuclear localization sequence can be found in certain proteins (transcription factors) because they have to find the nucleus to inhibit transcription. Mostly in Eukaryotes.
194
What is Ubiquitination?
Ubiquitination is just a fancy word for a molecule that has been targeted for degradation.
195
When running a gel, what will reducing agents do?
Reducing agents will break any disulfide bonds within a protein. So, if there are multiple units that showed up as one band in a normal gel, they will now show up as two bands (if they're not the same size). Remember, only Cysteine can form sulfide bonds.
196
What is divergent evolution?
Divergent evolution is the accumulation of differences in species that are close together. Think of elephants versus wooly mamoths.
197
How many sodium and potassium ions are transported in/out of the cell when one ATP is hydrolyzed?
When one ATP is hydrolyzed, 3 sodium ions are pumped OUT of the cell and 2 potassium ions are pumped INTO the cell.
198
What sequences do restriction enzymes recognize?
Restriction enzymes recognize palindromes, so a sequence of TTTAAA--the same sequence forwards and backward, is what they will recognize.
199
What is Complex II of the ETC?
Complex II is Succinate dehydrogenase and acquires electrons from FADH2.
200
What is an imprinted gene?
An imprinted gene is a gene that does not follow the normal rules of inheritance but is specifically in a parent-specific manner.
201
Do any viruses carry a reverse transcriptase?
Yes, negative-sense RNA viruses carry reverse transcriptases.
202
What type of cells are found in the lungs?
Epithelial cells
203
What is the difference between heterochromatin and euchromatin? What's the difference between a histone deacetylase and a histone acetylase?
Heterochromatin is tightly packed (low expression) chromatin, but euchromatin is loosely packed (high expression) chromatin. Histone deacetylase removes an acetyl group from histones, making chromatin more densely packed; histone acetylase adds an acetyl group and increases gene expression.
204
Are Vander waal forces part of secondary, tertiary, or quaternary structures?
Yes, they are. They're part of tertiary structure stability.
205
Does insulin only stimulate cellular glucose uptake?
No, insulin stimulates things like Acetyl-CoA uptake, too.
206
What's the difference between measuring precision and accuracy?
Well, precision is measuring something multiple times to see if the result will be consistent each time, but accuracy is measuring something against a "gold standard" to see if it matches.
207
What's the equation to find Vmax?
The equation is Vmax = [Kcat]*[E] and [E] is the enzyme concentration. So, yes increasing the amount of enzyme present will increase Vmax.
208
How many ATP molecules are created from the breakdown of one glucose molecule?
Two ATP molecules are used in the breakdown and four are produced--that's a net of two ATP molecules.
209
Be careful about the wording of a question. ALWAYS double-check it. If it asks how many nucleotides does it take to get a protein (28 amino acids long) that's cleaved to become active, note that it says "cleaved to become active. How many nucleotides would it be then?
Well, it would be 84 nucleotides just for the 28 amino acids plus another 3 for the stop codon; however, because it's a CLEAVED molecule, it's probably longer so it needs a MINIMUM of 87 peptides.
210
When targeting an organism for the development of a vaccine, what would the target be?
It's not wise to target something that's relatively inaccessible (if a portion of it is implanted in a membrane) or a part of it that is the toxic functioning portioning of the molecule (builds a toxin or releases a molecule that's toxic).
211
What are the large and small subunits of the bacterial and eukaryotic ribosomes, respectively?
The large and small units of ribosomes in bacteria are 50S and 23S (total of 70S), respectively. The large and small units of ribosomes in eukaryotes are 60S and 40S (total of 80S), respectively.
212
In a ribosome, what is the order of the three sites that bind a tRNA, add an amino acid to a peptide, and then detach the tRNA, respectively?
In that order, it's site A (attach), site P (peptide), and site E (exit).
213
What's the charge of this peptide (NDAFEITKRC) at physiological pH?
Well, it has two positive (NK) amino acids and two negative (ED) amino acids, plus it has a positive N-terminus and negative C-terminus. Thus, the charge is zero at physiological pH.
214
Does the inactive X chromosome in females replicate?
Yes, it does replicate, but it is the last to do so.
215
What's the difference between Gap Junctions and Tight Junctions?
Gap junctions are channels between cells, from cytoplasm to cytoplasm. Tight junctions are basically gated channels. Think of the blood-brain barrier. Keeps certain things out for protection.
216
What are the three stop codons?
UGA, UAG, and UAA
217
What is mesoderm?
reproductive system, heart, muscle, blood vessels, bone, and connective tissue.
218
What is ectoderm?
skin, neurons, brain, mouth, anus, hair, and anything in the outermost layer.
219
What is endoderm?
digestive and respiratory system.
