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MCAT > AAMC FL 1: Bio/Biochem > Flashcards

AAMC FL 1: Bio/Biochem Flashcards

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1
Q
  • Reviewable content: If a mutation is only expressed in somatic/cancerous cells, can it be inherited by offspring?
  • Date: 6/16/2022
  • Question: 3
  • Content: 1C: Transmission of heritable info from generation to generation and the processes that increase genetic diversity
  • Skill: 2: Scientific reasoning
  • Error Description/ Category: Missed and misinterpreted important info in the passage
A

NO: Mutations that are expressed in somatic/ cancerous can’t be inherited by offspring OR at least its not v likely. These mutations would have to occur in the germ line for them to be inherited by the offspring

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2
Q
  • Reviewable content: What usually codes for a gene, an intron or an exon? Which is usually spliced out?
  • Date: 6/16/2022
  • Question: 5
  • Content: 1B: Transmission of genetic info from the gene to the protein
  • Skill: Scientific reasoning and problem solving
  • Error Description/ Category: Guessed
A
  • Exons usually code for genes, not introns, so they are not spliced out
  • Introns are non-coding sections of an RNA transcript or the DNA encoding and are .: spliced out before the RNA is translated to protein
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3
Q
  • Reviewable content: What can happen to exons at splice acceptor sites when mutations occur?
  • Date: 6/16/2022
  • Question: 5
  • Content: 1B: Transmission of genetic info from the gene to the protein
  • Skill: 2: Scientific reasoning and problem solving
  • Error Description/ Category: Guessed
A

Splice acceptor sites can allow exons to be omitted when mutations occur

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4
Q
  • Reviewable content: What are the function of chaperone proteins? What about clathrin?
  • Date: 6/16/2022
  • Question: 5
  • Content: 1A: Structure and function of proteins and their constituent amino acids
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Got correct but wanted to study the concepts
A
  • Chaperone proteins facilitate proper protein folding and inhibit the formation of non functional protein aggregates
  • Clathrin functions in the formation of vesicles for intracellular trafficking
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5
Q
  • Reviewable content: What is a nuclear localization signal?
  • Date: 6/16/2022
  • Question: 8
  • Content:2A: Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms
  • Skill: 2: Scientific reasoning
  • Error Description/ Category: Missed and misinterpreted important info in the passage
A

A sequence that tags the protein for it to be transported into the nucleus

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6
Q
  • Reviewable content: What is a signal sequence? Where are they located? Where are they normally found?
  • Date: 6/16/2022
  • Question: 8
  • Content:2A: Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms
  • Skill: 2: Scientific reasoning
  • Error Description/ Category: Missed and misinterpreted important info in the passage
A
  • Signal to a ribosome that translation need to be continued in the rough endoplasmic reticulum
  • 5’ region of a mature mRNA sequence
  • On a protein that is secreted or that will locate to the cell membrane
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7
Q
  • Reviewable content: What are two things that are absent in mature mRNA?
  • Date: 6/16/2022
  • Question: 8
  • Content:2A: Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms
  • Skill: 2: Scientific reasoning
  • Error Description/ Category: Missed and misinterpreted important info in the passage
A

Introns and promoters

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8
Q
  • Reviewable content: What is chemiosomosis?
  • Date: 6/16/2022
  • Question: 10
  • Content: 1D: Principles of bioenergetics and fuel molecule metabolism
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Got correct but wanted to study the concepts
A

The actual production of ATP in cellular respiration that involves the pumping of protons through the special channels in the mem of the mitochondria from the inner to the outer compartment -> This proton gradient is what then drive ATP synthase to produce ATP

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9
Q
  • Reviewable content: What is the only step in cellular respiration where NAD+/ NADH is neither oxidized nor reduced? Glycolysis, chemiosmosis, citric acid/ Kreb’s/TCA cycle, or the ETC?
  • Date: 6/16/2022
  • Question: 10
  • Content: 1D: Principles of bioenergetics and fuel molecule metabolism
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Got correct but wanted to study the concepts
A

Chemiososmosis

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10
Q
  • Reviewable content: During the invitation of muscle contraction, myosin binds to actin after troponin binds to what? AKA what ion plays a role in myosin- actin binding during skeletal contraction? What does it allow?
  • Date: 6/16/2022
  • Question: 12
  • Content:3B: Structure and integrative functions of the main organ systems
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Got correct but wanted to study the concepts
A
  • Ca2+ ions

- They bind to troponin and allows tropomyosin to move .: freeing the site of interaction bt actin and myosin

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11
Q
  • Reviewable content: What is the total number of fused rings present in a steroid?
  • Date: 6/16/2022
  • Question: 13
  • Content: 2A: Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Got correct but wanted to study the concepts
A

A steroid is composed of a 6-6-6-5 fused ring assembly which is a total of 4 fused rings

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12
Q
  • Reviewable content: Let’s say someone has a diseases that results in motor seizures due to massive synchronous firing of neurons in a small area of the brain. A drug for the treatment of this disease would be most effective if it caused what?
  • Date: 6/16/2022
  • Question: 14
  • Content:3A: Structures and functions of the nervous systems and ways in which these symptoms could coordinate the organ systems
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Couldn’t decide bt two answers
A

An increase in the the threshold that would make it more challenging for a neuron to fire an action potential. This would reduce the frequency of downstream neuron depolarization molecules resulting in a relief of symptoms

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13
Q
  • Reviewable content: Influx/ efflux of what ions leads to neuron depolarization and thus action potenital firing? Where are there higher concentrations of these ions in the cell? When does repolarization and hyperpolarization occur?
  • Date: 6/16/2022
  • Question: 14
  • Content:3A: Structures and functions of the nervous systems and ways in which these symptoms could coordinate the organ systems
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Couldn’t decide bt two answers
A
  • There is more sodium outside of the cell and there is less inside the cell, whereas there is more potassium inside the cell and less outside of the cell
  • Influx of sodium coming into the cell causes depolarization .: influx of potassium causes repolarization
  • Hyperpolarization can be caused by opening channels that allow positive ions to move out of the cell so efflux of potassium ions while sodium channels rest
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14
Q
  • Reviewable content: What happens to the membrane potential as depolarization occurs?
  • Date: 6/16/2022
  • Question: 14
  • Content:3A: Structures and functions of the nervous systems and ways in which these symptoms could coordinate the organ systems
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Couldn’t decide bt two answers
A

It becomes more positive or less negative since resting potential is already negative

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15
Q
  • Reviewable content: When concentrated urine is being produced, in which region of the kidney will the filtrate reach its highest concentration? Why?
  • Date: 6/16/2022
  • Question: 15
  • Content: 3B: Structure and integrative functions of the main organ systems
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Guessed but still got it right so wanted to review the concept
A

The medullary portion of the collecting duct: This is the final structure in which water reabsorption occurs, which concentrates filtrate. The medullary portion of the collecting duct is the last portion of the tubules where reabsorption can occur. In this portion the tubule that follows, there will be no more reabosrption

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16
Q

Reviewable content: What is expected in kinetic studies in terms of protein activity? What does this mean?

  • Date: 6/16/2022
  • Question: 16
  • Content: 1A: Structure and function of proteins and their constituent amino acids
  • Skill: 3: Reasoning about the design and execution of research
  • Error Description/ Category: Misinterpreted the graph and question -> Didn’t realize it said NOT
A
  • In kinetic studies, protein activity is just expected to increase w temp, assuming the protein does not thermally denature
  • This means that they are studying some other aspect (in this question it was the presence of cholesterol AKA membrane fluidity to see how it played a role in protein activity) -> They weren’t focused on temp
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17
Q
  • Reviewable content: What is the function of Na+K+ ATPase during a neuronal action potential?
  • Date: 6/16/2022
  • Question: 18
  • Content:3A: Structures and functions of the nervous systems and ways in which these symptoms could coordinate the organ systems
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Honestly just forgot
A

Restoration of the resting potential

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18
Q
  • Reviewable content: In which direction does the Na+K+ ATPase transport ions across the cell membrane upon ATP hydrolysis? Why?
  • Date: 6/16/2022
  • Question: 19
  • Content: 2A: Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Got correct but wanted to study the concepts
A
  • 3 Na+ are transported outside the cell and 2 K+ are transported inside the cell against their concentration gradient
  • Bc Na+ concentration is higher outside the cell and K+ concentration is higher inside the cell so this is done to restore the membrane potential
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19
Q
  • Reviewable content: What kinds of molecules can freely pass through the cell mem via simple diffusion?
  • Date: 6/16/2022
  • Question: 21
  • Content: 2A: Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms
  • Skill: 2: Scientific reasoning and problem solving
  • Error Description/ Category: I was overthinking and couldn’t tell if the molecule was hydrophobic or not
A

Small, non polar and uncharged molecules like O2, CO2, and water

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20
Q
  • Reviewable content: What is the activating event of a protein kinase?
  • Date: 6/16/2022
  • Question: 22
  • Content: 1A: Structure and function of proteins and their constituent amino acids
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Got correct but wanted to study the concepts
A

Phosphorylation

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21
Q
  • Reviewable content: How to active transporters work?
  • Date: 6/16/2022
  • Question: 24
  • Content: 2A: Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms
  • Skill: 2: Scientific reasoning and problem solving
  • Error Description/ Category: Missed info in the passage that said that P-GTP was an ABC transporter protein
A

They are transporter proteins w ATPase activity so they use ATP to actively transport molecules such as drugs out of cells

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22
Q
  • Reviewable content: How do microtubules aid in cell mitosis and meiosis?
  • Date: 6/16/2022
  • Question: 28
  • Content: 2C: Processes of cell divisions differentiation, and specialization
  • Skill: 2: Scientific reasoning and problem solving
  • Error Description/ Category: Got correct but just wanted to study the concept
A

Microtubules bind to chromosomes at the level of the kinetochore and regulate their migration/ movement toward opposite poles of the cell during anaphase

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23
Q
  • Reviewable content: The initial filtration step in the glomerulus of the mammalian kidney occurs primarily by what? What are the 3 pressures that work tg to regulate filtration in the glomerulus?
  • Date: 6/16/2022
  • Question: 29
  • Content: 3B: Structure and integrative functions of the main organ systems
  • Skill: 1: Knowledge of scientific principles
  • Error Description/ Category: Guessed but still got it right so wanted to review the concept
A
  • Passive flow due to a pressure difference: There are 3 pressures that work tg to regulate filtration in the glomerulus -> Capillary pressure, capsular hydrostatic pressure, and blood colloid osmotic pressure
  • The glomerular capillary pressure will force filtrate from a capillary into Bowman’s capsule and the other two forces promote movement of the filtrate in the opposite direction
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24
Q

Enzymes alter the rate of chemical reactions by doing what 3 things?

A

Co-localizing substrates, altering local pH, altering substrate shape, NOT substrate primary structure

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25
Q

Why might a new amino acid like orthinine not be likely to be found in proteins synthesized in vivo?

A

Proteins are generated during translation. In this process, mRNA triplets are read by ribosomes, and tRNA molecules provide the amino acids. Each amino acid is matched to a tRNA molecule carrying a specific anti-codon. A specific amino acid will be added only if it is recognized by its specific codon. Based on the triplet code, no codon recognizes ornithine, thus ornithine cannot integrate proteins primary structure.

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26
Q

If an amino acid isn’t found in a protein that means it isnt able to form peptide bonds: T or F

A

F: If it is an amino acid it is capable of forming peptide bonds

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27
Q

If an enzyme assay like ornthinine decarboxylase assay is said to be highly specific, what does that mean? What does it measure? What does it not measure?

A
  • They can distinguish their target enzyme activity from the many other enzymatic reactions in a cell
  • That means it is highly specific to both the reactions it catalyzes and in their choice of substrates. Therefore, specific enzyme assays like ornithine decarboxylase assay are very specific and only measures the activity of a single chemical reaction catalyzed by ornithine decarboxylase.
  • The essay measures the enzymes activity, NOT the quantity of substrate present in the cell
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28
Q

What is the molecule that enter the citric acid/ Kreb’s/ TCA cycle?

A

Acetyl- CoA

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29
Q

If the lung cells of heavy smokers would be expected to have greatly increased concentrations of cP-450, then what would this mean for the levels of cP-450 DNA and mRNA present in the cell?

A
  • cP-450 DNA is just present in the genome, so its levels do not change specifically in the lung cells
  • The levels of cP-450 mRNA should be elevated in smokers as they are almost directly related to the levels of cP-450 protein produced to get rid of the toxins and would .: need the genes in the DNA from the genome of these cells to be expressed further .: resulting in increased mRNA sequences
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30
Q

Cells that are in what stage of the cell cycle are NOT actively dividing?

A

Interphase

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31
Q

Anaphase

A

Phase of mitosis where the sister chromatids are being separated

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32
Q

Metaphase

A

Phase of mitosis in which the chromosomes are locate din the middle of the cell plate

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33
Q

Do mature erythrocytes contain DNA?

A

No they have no nucleus and .: have no DNA

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34
Q

What are examples of proteins that regulate cell division?

A

Cyclins and maturation promoting factor (MPF)

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35
Q

Animal viruses are obligate parasites, meaning that……

A

Animal viruses can only infect animal cells

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36
Q

What is a telomere? What do they contain?

A
  • Telomere refers to a distal end of a chromosome.

- Telomeres contain non-coding repeats.

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37
Q

In general, telomeres are NOT important to bacterial cells because most bacterial chromosomes:

A

Are circular

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38
Q

How are nucleotides linked together in a single strand of DNA?

A

Nucleotides are linked to one another by phosphodiester bonds between the sugar base of one nucleotide (thymine) and the phosphate group of the adjacent nucleotide (adenine) in a way that the 5′ end bears a phosphate, and the 3′ end a hydroxyl group.

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39
Q

The flux of sodium into the cytoplasm of a cell results in what? This is required for?

A
  • Membrane depolarization

- Activation of action potentials

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40
Q

When does hyperpolarization occur?

A

When the membrane potential becomes more electronegative

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41
Q

When does repolarization occur? What causes it? Are sodium channels open during this time?

A
  • Occurs after the membrane has been depolarized
  • Is due to the opening of potassium channels.
  • Sodium channels are typically closed during this period.
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42
Q

Chloride ions follow the movement of other ions?

A

Sodium ions

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43
Q

AAMC FL1 Q48 states that: Aldosterone is responsible for the conservation and elimination of which ions?

A

Conservation of sodium and elimination of potassium

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44
Q

The release is ACTH from the pituitary gland is regulated by what kind of feedback? What does this

A

-Negative feedba

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45
Q

Gluccocorticoids increase _______ ________, but suppress ______ _______, which is mediated by what?

A

-Increases protein degradation, but decreases immune function, which is mediated by white blood cells

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46
Q

Increased systemic vascular resistance, increased extracellular volume, and increased cardiac contractility can lead to what?

A

Hypertension

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47
Q

The most rapid rate of gluconeogenesis will most likely occur in the body when:

A

Gluconeogenesis becomes active when the body needs more glucose to generate energy .: It is likely to occur when glucose levels are low

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48
Q

What is gluconeogenesis?

A

Pathway for the synthesis of glucose (a carbohydrate) from other metabolic compounds such as lipids and amino acids.

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49
Q

Gluconeogenesis is increased by high levels of? What does this mean in terms of regulation?

A
  • Cortisol?

- That gluconeogenesis is most likely down regulated when cortisol is inhibited

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50
Q

What is meant by the fact that working skeletal muscles are insulin independent? How exercise affect this blood glucose levels for patients w diabetes?

A
  • Working skeletal muscle can use glucose independently from insulin availability
  • Exercise will be able to reduce the levels of glucose in both types of diabetes. (working skeletal muscle is being used more during exercise)
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51
Q

What is the endomembrane system responsible for?

A

It is the portion of the cells that is in charge of modifying proteins that will be secreted

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52
Q

Despite the effects of diabetes, the brains of diabetic patients still receive adequate nourishment. This is most likely because the brain:

A

Contains glucose transporter for the uptake of glucose that are insulin- independent

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53
Q

In diabetes mellitus, will use proteins and lipids as a source of glucose, thus increasing, rather than decreasing, leading to

A
  • An increase in appetite
  • Unexplained weight loss
  • Feelings of fatigue
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54
Q

The kidneys can reabsorb glucose at what rate? If the levels of glucose in the body is too high for the kidneys to filter as is seen in diabetes patients, what can happen?

A
  • 320mg/min

- The levels of glucose in the filtrate that are in excess will pass into urine, leading to a sweet taste.

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55
Q

Glucose transporter proteins in the liver do not require the presence of insulin to facilitate the uptake of glucose. However, insulin does stimulate the first step in the glycolytic pathway within the liver. Therefore, in liver cells, insulin most likely:

A
  • Aids glucose uptake by decreasing the cellular concentration of glucose.
  • The question states that insulin stimulates the first step in the glycolytic pathway in the liver. This will result in a decrease of the cellular concentration of glucose. To compensate for the low cellular glucose concentration, glucose uptake is increased.
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56
Q

What is the mechanism that regulates the release of corticotropin releasing hormone (CRH) form the hypothalamus

A

Negative feedback

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57
Q

In normal conditions, high levels of circulating glucose and other stressors activate the production of

A

corticotropin- releasing hormone (CRH) from the hypothalamus

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58
Q

CRH will stimulate the pituitary gland to release of ______ which will trigger ________ release from the _________ _________

A
  • ACTH
  • Cortisol
  • Adrenal cortex
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59
Q

High levels of circulating cortisol will inhibit _______ secretion (negative feedback)

A

CRH

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60
Q

High levels of circulating cortisol are the stimulus to reduce __________________________
secretion from the hypothalamus

A

corticotropin releasing hormone (CRH)

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61
Q

The gastrrointestinal epithelial cells are typically highly _____________

A

Proliferative

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62
Q

What do phosphodiester bonds link?

A

the 3ʹ carbon atom of one deoxyribose and the 5ʹ carbon atom of another deoxyribose within the DNA molecules AKA the sugar phosphate backbone of DNA

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63
Q

If H+ is a reactant in a rxn how could you manipulate pH to shift the reaction equilibrium to the right to form product?

A

You could decrease pH so that there would be more H+ ions present in solution. Increasing H+ concentration on the reactant side would shift the equilibrium to the right and favor product formation

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64
Q

Which AA contains sulfhydryl groups?

A

Cysteine (C)

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65
Q

If the ETC is shut down, what would be the major pathway for ATP production?

A

Glycolysis

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66
Q

What 3 main steps happens when a macrophage ingests foreign material?

A
  1. The material initially becomes trapped in a phagosome.
  2. The phagosome then fuses with a lysosome to form a phagolysosome.
  3. Inside the phagolysosome, enzymes digest the foreign object.
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67
Q

What is allosteric inhibition vs competitive inhibition?

A
  1. When an inhibitor inhibits enzyme activity by binding to a regulatory site other than the active site of the enzyme
  2. In contrast, competitive inhibition involves competition for binding to the active site
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68
Q

If a cell contains a v high concentration of chlorine in comparison to outside the cell, how would it maintain this? What kind of transport would need to be used?

A

In order to maintain a higher concentration of chlorine ions inside the cell, the ions must be moved into the cell against their concentration gradient, which requires energy. This process is active transport

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69
Q

If potassium ion channels are blocked, how would this affect membrane repolarization and the length of an action potential?

A

If potassium ion channels are blocked, the membrane would fail to repolarize, extending the length of the action potential and simulating excessive muscle contractions.

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70
Q

Where are secretory proteins normally produced and folded?

A

The rough ER

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71
Q

Proteins w high isoelectric points (like 9) typically have what charge at physiological pH (7)?

A

+

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72
Q

What is the isoelectric point of a protein?

A

The pH of a solution at which the net charge of a protein becomes zero

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73
Q

What happens if the solution pH is above the pI of a protein?

A

The surface of the protein will become predominantly negatively charged

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74
Q

What happens if the solution pH is below the pI of a protein?

A

The surface of the protein will become predominantly positively charged

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75
Q

What happens if the solution pH = pI of a protein?

A

Protein is neutral or has a net charge 0

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76
Q

Proteins that are translocated into the nucleus usually contain a

A

Nuclear localization sequence

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77
Q

If a protein or enzyme activates transcription factors for the target genes of another kind of protein, what this protein or enzyme likely have? Why?

A

A nuclear localization sequence bc transcription factors are found in the nucleus, meaning the protein or enzyme must enter the nucleus to activate these transcription factors and in turn, these genes

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78
Q

What does ubiquitination do?

A

Targets a protein for degradation by a proteasome

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79
Q

If reducing agents separate subunits of a protein, what does this mean the tertiary structure of the protein was held tg by? Why?

A
  1. Disulfide bonds, which implicate the thiol groups of cysteine residues
  2. Disuflide bonds are broken upon reduction
80
Q

If the insertion of a random transmem protein that the alters the permeability of the inner mem where to be inserted into the inner mem of the mitochondria, what would this cause?

A

The proton gradient across the inner membrane will dissipate

81
Q

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the reversible conversion of….

A

Glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate

82
Q

Posttranslational modification of proteins such as histone acetylation can be analyzed by what kind of blot?

A

SNOW DROP: Western blot

83
Q

Vasopressin regulates the insertion of aquaporins into the apical membranes of the epithelial cells of what renal structure?

A

Collecting duct

84
Q

What are the primary myelin-forming cells in the peripheral nervous system?

A

Schwann Cells

85
Q

What are the primary myelin-forming cells in the central nervous system?

A

Oligodendrocytes

86
Q

What is the equation for osmotic pressure?

A

Π = iMRT

87
Q

A prion is best described as an infectious ______? Why?

A
  • Protein
  • a prion is an abnormally folded protein that induces a normally folded version of the protein to also adopt the abnormal structure, which is often deleterious
88
Q

Blood from the small intestine is first transported to what organ? What does this organ do?

A

Liver, which regulates nutrient distribution and removes toxins from the blood

89
Q

Assume that a typer of bacteria immediately enters the bloodstream from the small intestine. What would be the first major organ that the blood-borne bacteria would encounter? Why?

A

Liver bc it regulates nutrient distribution and removes toxins from the blood

90
Q

In order for a child to be homozygous for a recessive disease what must the parents have if neither of them actually have the disease?

A

The child would have to inherit the two recessive alleles from their parents (1 from each), meaning if neither of them actually have the disease, they’d have to be carriers of the disease and have at least one recessive allele to give to their child. If only parent carries the recessive allele, there is no way the child can come out homozygous recessive bc they would need 2 recessive alelles

91
Q

What are neuromodulators vs releasing factors?

A
  • Neuromodulators: Do not stimulate the release of a hormone on their own, but can modulate (enhance or inhibit) the responses of the secretory cells of the gland that originally releases it
  • Releasing factors stimulate the release of the target protein on their own
92
Q

Internalization of viral particles through endocytosis is mediated by what strucutre?

A

Endosomes

93
Q

How do viruses enter host cells via endocytosis?

A

Through the fusion of the viral membrane with the host cell membrane.

94
Q

Proteases function to

A

Digest proteins into smaller fragments

95
Q

What end to amino acids get added to on a growing polypeptide chain?

A

The C terminus

96
Q

PEP is product of

A

Glycolysis

97
Q

How can you remember the reactants and productions of the citric acid/ krebs/ TCA cycle

A 
Can: Citrate
I: Isocitrate
Keep: Alpha- ketoglutarate or alpha ketoglutaric acid
Selling: Succinyl CoA
Sex: Succinate 
For: Fumarate
Money: Malate
98
Q

Under anaerobic conditions how many moles of ATP are produced by glycolysis?

A

2 moles of ATP

99
Q

Under anaerobic conditions, how many net molecules of ATP are produced by the consumption of 5 moles of glucose?

A

Under anaerobic conditions, 2 moles of ATP are produced from each mole of glucose. Thus, 10 moles of ATP would be generated from 5 moles of glucose. Since there are 6 × 1023 molecules per mole, 10 moles of ATP is equal to 6 × 1024 molecules.

100
Q

How many individual molecules are there per 1 mole

A

1 mole= 6x10^23 molecules

101
Q

The central nervous system is derived from what embryonic layer?

A

The ectoderm

102
Q

The heart, kidneys, and skeletal muscle are derived from what embryonic layer

A

The mesoderm

103
Q

Motor proteins move along what? Through interactions with what?

A

Motor proteins move along microfilaments through interaction with actin

104
Q

Lysosomes are defined as

A

membrane-bound organelles that contain hydrolytic enzymes activated by a low pH

105
Q

Microtubules are cellular structures that originate from

A

Centrosomes

106
Q

cytotoxic T lymphocytes target virus-infected cells by

A

recognizing the viral antigen presented on the cell surface of the virus- infected cells

107
Q

If something binds to the promoter on a gene, then regulation occurs at what level?

A

Transcriptional (affects mRNA synthesis), not translational,

108
Q

What part of the antibody allows for recognition of a particular antigen? Where are the found

A

-The variable portion of the antibody which is typically found on the ends of the upper v section of the Y shaped antibody

109
Q

Where in the human male reproductive system do the gametes become motile and capable of fertilization?

A

Epididymis

110
Q

Are sperm produced in, mature in, and become motile in the same structure?

A

No: Sperm is produced in the seminiferous tubules of the testes and then completes maturation and becomes motile in the epididymis.

111
Q

during normal muscle contraction, ATP is required to

A

break the bonds between the actin filament and the myosin head

112
Q

According to the cross-bridge model of muscle contraction, the muscles stiffen after death because ATP is unavailable to bind and directly release:

A

the myosin head from the actin filament.

113
Q

A homodimeric protein was found to migrate through SDS polyacrylamide gel electrophoresis (SDS-PAGE) with a mobility that matched that of a 45-kDa standard. What change in the experiment would increase the chances of observing the mobility expected for the 22.5-kDa monomer?

A

Adding a reducing agent: a reducing agent would eliminate any disulfide bridges and allow the monomers to run separately–thus leading to a migration expected for the 22.5-kDa protein.

114
Q

What are the relative potentials for force and power generation by a slow-twitch muscle fiber and a fast-twitch muscle fiber of the same diameter?

A

The fast-twitch fiber is capable of generating more power than the slow-twitch fiber, while the potential for force generation is the same bc similarly sized fibers would generate similar force, regardless of fiber type (depends on cross- sectional area which is the same for muscle fibers of the same diameter)

115
Q

Lack of oxygen shuts down what?

A

The Krebs cycle and the ETC bc the ETC only provides ATP aerobically

116
Q

Work is the product of

A

force applied over a distance an object is moved

117
Q

What do fast twitch fibers have a greater capacity for than slow- twitch fibers?

A

Greater Ca2+-pumping capacity

118
Q

Slow twitch fibers are better adapted for what than fast twitch fibers? What do they have that allows them to do this?

A

slow-twitch fibers are adapted for aerobic exercise which suggests they are likely, relative to fast-twitch fibers, to have increased capillary density, larger numbers of mitochondria, and higher levels of oxygen-binding proteins

119
Q

Pyrimidines

A

CUT the PY: C, U, and T

120
Q

Purines

A

PUR As Gold: A, G

121
Q

Convergent evolution is defined as

A

a process whereby distantly related organisms independently evolve similar traits to adapt to similar needs

122
Q

gonadotropin-releasing hormone regulates

A

pituitary gonadotropin (luteinizing hormone and follicle-stimulating hormone) secretion

123
Q

Kallman Syndrome is a disease in which gonadotropin-releasing hormone producing neurons fail to migrate from the olfactory area to the hypothalamus during embryonic development. Which endocrine axis is disrupted in individuals with Kallman Syndrome?

A

gonadotropin-releasing hormone regulates pituitary gonadotropin (luteinizing hormone and follicle-stimulating hormone) secretion. Thus, if gonadotropin-releasing hormone is not able to regulate luteinizing hormone and follicle-stimulating hormone secretion from the pituitary, the reproductive axis will remain quiescent.

124
Q

an operon containing two genes in prokaryotic cells is transcribed from

A

a single promoter upstream of the first gene in the operon

125
Q

In the heart, increased intracellular calcium levels will result in

A

enhancement of the contractile force of the heart.

126
Q

The Na+K+ ATPase is an example of what kind of active transport

A

Primary

127
Q

Primary vs secondary transport

A

Primary active transport uses a chemical energy source like ATP to move solutes against their concentration gradient. Secondary active transport, on the other hand, uses one electrochemical gradient to move different molecules against their own concentration gradients.

128
Q

Histone acetylation typically

A

promotes transcription by modifying chromatin structure and loosening it

129
Q

Fasting leads to what? Continued fasting them leads to what?

A

asting leads to glycogen breakdown and gluconeogenesis, then continued fasting leads to the production of ketone bodies by sustained fatty acid oxidation.

130
Q

If βOHB is a component of ketone bodies, when are serum levels of βOHB elevated?

A

Serum levels of βOHB are elevated when there is sustained fatty acid oxidation.

131
Q

The adrenal medulla is part of which branch(es) of the peripheral nervous system?

A

The sympathetic branch of the autonomic nervous system only because the adrenal medulla secretes epinephrine and norepinephrine in response to short-term stress. Reactions to short-term stress are mediated by the sympathetic branch of the autonomic nervous system.

132
Q

Which of the following best describes the chemical energy that is derived from the Krebs cycle? Energy is produced in the forms of:

A

ATP, which directly supplies energy for many cellular processes, and NADH, which supplies energy for the electron transport chain. ->The answer to this question is C because the Krebs cycle produces both ATP and NADH but not NAD+. ATP directly supplies energy for many cellular processes, such as muscle contraction, and NADH, which is used in the electron transport chain.

133
Q

Osmotic pressure is directly proportional to

A

Solute concentration

134
Q

What is the equation for osmotic pressure?

A

Pi=inRT

135
Q

During hypoxia, what is activated and what is attenuated? This leads to an increase in concentration of what? For glycolysis to proceed what must happen?

A
  • glycolysis is activated while mitochondrial functions (oxidative phosphorylation) are attenuated.
  • This metabolic reprogramming leads to increased concentration of NADH inside the cell.
  • For glycolysis to proceed, NADH must be converted back to NAD+ through lactic fermentation
136
Q

Phosphoglucose isomerase is involved in what cellular process?

A

Glycolysis

137
Q

Why is tubulin often used as a loading control to ascertain an equal amount of protein loading in each lane in a Western blot analysis

A

tubulin, a cytoskeletal protein, is stable under most conditions, including hypoxia.

138
Q

A restriction enzyme that has a a four-base recognition sequence, a six-base recognition sequence, and an eight-base recognition sequence would cut base pairs:

A

Palindromic sequences, every 4, 6, and 8 base pairs

139
Q

Succinate dehydrogenase is known as what complex in the ETC?

A

Complex II

140
Q

succinyl-CoA synthetase, which results in

A

the increased production of succinate

141
Q

Imprinted genes are expressed in what manner?

A

in a parent-specific manner

142
Q

During protein synthesis, new amino acids are added to which terminal?

A

C- terminal

143
Q

Certain viruses contain RNA as their genetic material. One of the ways these RNA viruses replicate themselves is to:

A

code for or carry a transcriptase that copies viral RNA:RNA viruses require a type of transcriptase (reverse transcriptase) to replicate themselves

144
Q

Large amounts of protein are found in the urine of a patient. Based on this information, which portion of the nephron is most likely malfunctioning?

A

Glomerulus: In healthy individuals, the structure of the glomerular capillaries prevents the entry of large molecules, such as proteins, into the filtrate.

145
Q

While the optimum pH value varies greatly from one enzyme to another, the optimum temperature for enzymes is normally what

A

37 degrees celsius

146
Q

What is an action that SSRIs block? What this increase?

A

-transport of released serotonin back into the presynaptic terminal AKA they block reuptake
by blocking serotonin reuptake in the presynaptic neuron.
-Blocking the reuptake of serotonin into the presynaptic neurons would increase the amount of time that serotonin is available in the synaptic cleft to bind to postsynaptic neurons.

147
Q

antidepressant drugs act to increase the amount of serotonin in the synaptic space. Therefore, the action of serotonin on postsynaptic receptors would be terminated by

A

the removal of serotonin from the synaptic space.

148
Q

What happens with osmotic pressure and fluid movement in blood if there are too many particles/ plasma proteins? What about too little like what happens during malnutrition?

A
  • Too many plasma proteins: Osmotic pressure increase, fluid enters the blood/ circulatory system too “dilute” the solutes .: increasing blood pressure
  • Too little plasma proteins: Osmoitc pressure would decrease and fluid would leave the blood/circulatory system AKA enter the body tissues to account for the higher concentration of solutes out of the blood vessel .: blood pressure decreases
149
Q

Osteoblast vs osteoclast

A

osteoblasts function to build and repair bone, osteoclasts break down bone.

150
Q

If we wanted to increase calcium levels in the blood, would we want to increase osteoblast or osteoclast activity?

A

osteoblast activity should be decreased and osteoclast activity should be increased to release stored calcium from the bone to the bloodstream

151
Q

In what order does the filtrate pass through the tubular regions of the nephron?

A
  1. Bowman’s capsule
  2. Proximal tubule
  3. Loop of Henle
  4. Distal tubule
  5. Collecting duct
152
Q

P450 acts as what? What does it do?

A

monooxygenases, where an oxygen atom is inserted into a substrate (the drug of interest), thereby resulting in the oxidation of the substrate. and reduction of the oxygen

153
Q

What happens during the phoshporylation of tyrosine?

A

Tyrosine has a nucleophilic hydroxyl group that attacks the terminal phosphate group (γ-PO32–) on ATP, resulting in the exchange of the hydrogen atom of a hydroxyl group for a phosphate group of ATP.​

154
Q

A defining characteristic of proteins that act as transcription factors is? What is not?

A
  • The defining characteristic of a transcription factor is that it has a DNA-binding domain that allows it to bind to regulatory nucleic acid sequences in a gene to alter transcription.
  • The fact that they are present in the nucleus:Transcription factors ultimately end up in the nucleus, but other proteins can exist within the nucleus that do not alter transcription.
155
Q

Where does fatty acid oxidation occur?

A

In the mitochondria

156
Q

What does the carnitine shuttle do?

A

transports fatty acids into the mitochondria for oxidization.

157
Q

What does a carboxylase do?

A

Adds carboxyl groups

158
Q

How much ATP is consumed/ produced during the preparatory and payoff phases of glycolysis, respectively?

A

Two ATP molecules consumed, four ATP molecules produced

159
Q

In what steps is ATP consumed in glycolysis?

A

In the prepatory phase where glucose is converted to glucose-6-phosphate, and fructose-6-phosphate is converted to fructose 1,6-biphosphate.

160
Q

In what steps is ATP produced in glycolysis?

A

The first two ATP molecules are produced in the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, and another two ATP molecules are produced in the conversion of phosphoenolpyruvate to pyruvate.​

161
Q

As blood passes through actively contracting skeletal muscle tissue, the affinity of hemoglobin for oxygen in the muscle tissue:

A

decreases as a result of a decrease in plasma pH. -> Affinity would decrease with a decrease in plasma pH, and during prolonged exercise, anaerobic respiration would decrease the plasma pH due to the build up of lactic acid ALSO bc of the decrease in PO2 of actively contracting muscle

162
Q

Henry’s law

A

Henry’s Law constant kH relates the solubility of a gas S to the pressure of that gas Pg above the solution and is written as S = kH•Pg.

163
Q

Where is ghrelin secreted from? The small intestine, stomach, or hypothalamus?

A

Small intestine and hypothalamus

164
Q

how many nucleotides code for an amino acid?

A

3

165
Q

When trying to determine the number of nucleotides that codes for x amino acid long sequence, what must you remember to do?

A

Add the triplet that codes for the STOP codon

166
Q

As blood glucose levels increase after a meal, levels of what will decrease?

A

Glucagon

167
Q

Because of a feedback mechanism, the levels of circulating ghrelin are

A

the opposite of the amount of weight gained. They are low when the individual gains weight (person has more energy stores when heavier) and high when the individual loses weight.

168
Q

In what order does tRNA move on the ribosome?

A

A-> P-> E: During protein translation, aminoacyl transferase functions to transfer the tRNA originally bound at the A (amino acid) site to the P (peptide) site and later to the E (exit) site of the ribosome.

169
Q

From which sites on the ribosome is the amino acid on the tRNA added to the growing peptide chain?

A

As it moves from the A site to the P site

170
Q

RT-PCR is a molecular technique that measures

A

mRNA levels of specific protein.

171
Q

Southern blot is a technique that analyzes what? Can it be used to measure the transcriptional regulation of a gene?

A
  • genomic DNA

- no

172
Q

Quantitative PCR is a technique that measures what? Can it be used to measure the transcriptional regulation of a gene?

A

the levels of DNA, not mRNA

-No

173
Q

Western blot is a technique that measures the

A

the translational levels of a protein,

174
Q

Native PAGE separates

A

molecules based on their electrophoretic mobility, relying on length, conformation, and charge.

175
Q

Gel filtration chromatography separates protein only on

A

the basis of their size.

176
Q

The inactivate X chromosome is one of the last

A

chromosomes to replicate.

177
Q

Both the active and inactive X chromosome

A

Replicate

178
Q

A negative control is the one that is performed in the conditions that

A

are not expected to give positive results.

179
Q

Extra water is normally excreted through what organs?

A

Extra water is normally excreted through skin and lungs. The skin excretes water through the process of transpiration, and the lungs use water to humidify the air that enters the body.

180
Q

The osmolarity of urine in these subjects was 958 milliosmoles/L, compared with an average blood osmolarity of 284 milliosmoles/L. The higher osmolarity of urine suggests that:

A

the kidneys are acting to conserve water: An increase in water conservation would result in higher urine osmolarity and lower blood osmolarity.

181
Q

If someone was dehydrated, the osmolarity bt the blood and urine would be?

A

Closer

182
Q

What activates osmoreceptors? What does this process trigger?

A

Osmoreceptors are activated by the increase in osmolarity of the blood. This process triggers the sensation of thirst.

183
Q

heart rate is

A

the number of heart contractions per minute.

184
Q

What is stroke volume? What happens to it during dehydration?

A

The stroke volume is the amount of blood that is pumped by the left ventricle per beat. In dehydration conditions a decrease in stroke volume will decrease, the cardiac output.

185
Q

During exercise, muscles produce ______ that goes into circulation. What will this do to the osmolarity of venous blood?

A

During exercise, muscles produce lactate that goes into circulation. The presence of lactate will increase the osmolarity of the venous blood.

186
Q

The Na+/K+ ATPase, or sodium/potassium pump is an active transporter that pumps sodium and potassium ions through the membrane _______their concentration gradient to maintain osmotic pressure.

A

Against

187
Q

When adding negatively charged groups to a protein, we are decreasing its

A

Isoelectric point

188
Q

Microglia are

A

phagocytotic innate immune cells specific to the brain.

189
Q

In the brain, B cells, Cytotoxic T cells, and Helper T cells are all

A

adaptive immune system cells and require activation by microglia in order to mount an immune response

190
Q

Tight junctions are

A

intercellular junctions that prevent the movement of solutes within the space between adjacent cells.

191
Q

How do tight junctions work in the blood- brain barrier?

A

In blood capillaries, neighboring endothelial cells form tight junctions with one another to restrict the diffusion of harmful substances and large molecules into the interstitial fluid surrounding the brain.

192
Q

An amber codon is a

A

stop codon

193
Q

Endosomes are formed to

A

transport a substance from the outside of the cell,

194
Q

Receptors destined for the cell mem will be

A

synthesized in the RER, modified in the Golgi apparatus, and transported to the membrane by transport vesicles.

195
Q

What is a test cross used for?

A

to identify if an organism that shows a dominant phenotype is a homozygous or heterozygous.

196
Q

How do you perform a test cross?

A

Cross the organism w the dominant phenotype (heterozygous or homozygous dominant) w a homozygous recessive phenotype

197
Q

If the opening of GABA receptors results in entry of chloride ions inside the cell, as chloride ions the cell membrane would become?

A

Hyperpolarized: As chloride ions have a negative charge, the entry of chloride ions into the cell will make the cytoplasm more negative thus hyperpolarizing the cell membrane.

MCAT (6 decks)

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