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MCAT > B/B > Flashcards

B/B Flashcards

1
Q

cellular Cl- transport

A

[Cl-] outside cell > [Cl-] inside cell

  • to move against the gradient, it requires ATP
  • ACTIVE TRANSPORT (ion channel)
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2
Q

The precursor of EGP is translated from a transcript that has had one nontemplated nucleotide added to the open reading frame. This change does not create or eliminate a stop codon. Compared with the protein sGP, which is produced from the unedited transcript, EGP most likely has the same primary:

A

A) amino-terminal sequence as sGP, but a different primary carboxy-terminal sequence.

  • We always read amino acid sequences from N- terminal (amino) to C-Terminal (carboxy).
  • C terminal is modified post-translationally not the N.
  • A frameshift doesn’t always have to create or eliminate a
  • The addition of one nucleotide to the open reading frame of EGP results in a frameshift mutation and an aberrant carboxy-terminal domain
  • The frameshift will most likely affect areas after the mutation near the C-terminal but most likely did not affect the areas before the mutation near the N-terminal.
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3
Q

lysosomes

A

membrane-bound organelles that contain hydrolytic enzymes activated by a low pH. These enzymes are capable of degrading many kinds of biomolecules.

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4
Q

microtubules

A

cellular structures that originate from centrosomes

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5
Q

Variable region of an antibody

A

Regions 1 and 3 (“caps” on the chains”) correspond to the variable portion of the light and heavy chains, respectively, of an antibody.
- The variable region of an antibody will enable recognition of a particular antigen, such as HER2, which typically has elevated expression in breast cancer tumors.

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6
Q

Muscle contraction after death

A

during normal muscle contraction, ATP is required to break the bonds between the actin filament and the myosin head.

After death, no new ATP is generated, so the myosin head cannot be released from the actin filament, resulting in stiffening of muscles

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7
Q

phagocytosis

A

because when a macrophage ingests foreign material, the material initially becomes trapped in a phagosome. The phagosome then fuses with a lysosome to form a phagolysosome. Inside the phagolysosome, enzymes digest the foreign object.

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8
Q

Where are secretory proteins synthesized?

A

the rough endoplasmic reticulum

- fold into their tertiary structure there too

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9
Q

Ubiquitination

A

targets a protein for degradation by a proteasome

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10
Q

transmembrane domains

A
  • cross the phospholipid bilayer

- As a result, these domains are most likely to have a high proportion of hydrophobic residues (non polar)

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11
Q

thiol group

A

R-S-H

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12
Q

bonds between protein subunits

A
  • reducing agents separate subunits that are linked together by disulfide bonds, which implicate the thiol groups of cysteine residues.
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13
Q

How are posttranslational modification of proteins such as histone acetylation analyzed?

A

Western blotting (protein)

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14
Q

vasopressin

A

regulates the fusion of aquaporins with the apical membranes of the collecting duct epithelial cells

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15
Q

Schwann cells

A

myelin-forming cells in the peripheral nervous system

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16
Q

Osmotic pressure Π relation:

A

Π = iMRT

where i is the van’t Hoff factor, M is the concentration of solute, R is the gas constant, and T is the temperature.

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17
Q

prion

A

an abnormally folded protein that induces a normally folded version of the protein to also adopt the abnormal structure, which is often deleterious (infectious)

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18
Q

blood from the small intestine is transported first to the . . .

A

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

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19
Q

endosomes

A

mediate internalization of viral particles through endocytosis
- endocytosis through the fusion of the viral membrane with the host cell membrane

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20
Q

ectoderm

A

nervous system, epidermis, dermis, hair, nails, eyes, and ears

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21
Q

mesoderm

A

muscle, cardiac and skeletal systems, blood, kidney, and spleen

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22
Q

endoderm

A

glands, lining of the digestive system and respiratory system, liver, pancreas, respiratory system

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23
Q

Motor proteins on microfilaments

A

move along through interaction with actin

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24
Q

cytotoxic T lymphocytes

A

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

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25
Q

Where sperm are produced

A

the seminiferous tubules of the testes

26
Q

where sperm complete maturation and become motile

A

epididymis

27
Q

for every 1 molecule of NADH, __ molecules of ATP are produced

A

2.5 ATP/1 NADH

28
Q

for every 1 molecule of FADH2, __ molecules of ATP are produced

A

1.5 ATP/1 FADH2

29
Q

Pentose phosphate pathway

A

The first phase of the pathway, known as the oxidative phase, results in the production of two NADPH molecules and a molecule known as ribulose-5-phosphate. The second phase of the pathway, known as the non-oxidative phase, can result in multiple possible outcomes depending on the energy needs of the cell. The pathway can produce glycolytic intermediates to feed into glycolysis, or ribose-5-phosphate to feed into nucleotide synthesis.

It’s important to note that the PPP does not produce any NADH–the type of electron carriers required for oxidative phosphorylation and ATP synthase. Rather, it produces NADPH–an important electron carrier in fatty acid synthesis.

30
Q

transmission of mutations

A

only occurs in germ cell lines, NOT somatic

Ex) a mutation only expressed in tumor cells won’t be passed down to kids

31
Q

chaperone proteins

A

facilitates proper protein folding and inhibits the formation of nonfunctional protein aggregates

32
Q

Cell adhesion molecules

A

Cell adhesion molecules (CAMs) are proteins located on the cell surface involved in binding with other cells or with the extracellular matrix (ECM) in the process called cell adhesion. In essence, cell adhesion molecules help cells stick to each other and to their surroundings.

transmembrane glycoproteins
Ex) selectins, integrins, syndecans, and cadherins

*maintaining multicellular structure, signal transduction, pathogenesis of infectious organisms.

33
Q

Clathrin protein

A

Protein that maintains the vesicles for transportation in and out of a cell

Clathrin-coated vesicles are found in all eukaryotic cells, but they are particularly enriched in the brain, where they play a major role in the formation of neurotransmitter-containing pre-synaptic vesicles required for synaptic nerve transmission.

Pathogenic viruses and bacteria can gain entry into their target cell by making use of the host’s clathrin-dependent endocytic machinery, producing molecules on their surface that mimic endogenous ligands to the host’s cell receptors, thereby inducing the host’s intracellular

34
Q

signal sequence

A

sequence that the signal recognition particle (on ribosomal ER) recognizes; translation occurs and pushes protein into lumen of ER

  • Transmembrane proteins enter the endomembrane system by docking at the rough ER
    (1) After translation, the signal sequence is removed
    (2) These proteins are then sent through the Golgi apparatus to the plasma membrane
35
Q

Posttranslational modifications:

A

• Foldingbychaperones
• Formation of quaternary structure
• Cleavage of proteins or signal sequences
• Covalent addition of other biomolecules
(phosphorylation, carboxylation, glycosylation, prenylation)

36
Q

NAD+/NADH

A

NAD+ is reduced to form NADH

NADH oxidized to form NAD+

37
Q

initiation of muscle contraction

A

Free Ca2+ in the cytosol binds to troponin, which pulls tropomyosin away from actin’s myosin-binding site. This allows myosin to bind to actin

38
Q

When concentrated urine is being produced, in which of the following regions of the kidney will the glomerular filtrate reach its highest concentration?

A

Medullary portion of the collecting duct

glomerular filtrate is most concentrated in the medullary portion of the collecting duct,

39
Q

measure the activity of the Na+K+ ATPase

A
  • Measuring the rate of ATP hydrolysis
  • Measuring the rate of ADP production
  • Measuring the change in ion concentration within the liposome
40
Q

Na+K+ ATPase function during an action potential

A

restore the resting membrane potential by moving the ions against their concentration gradients

41
Q

Na+K+ ATPase transports

A

3 sodium ions out of the cell and 2 potassium ions into the cell with each ATP hydrolyzed

3-2-1 Nokia
3 Na Out
2 K In
1 Atp

42
Q

transcription factors

A

bind DNA and subsequently recruit RNA polymerase

43
Q

simple diffusion

A
  • does not require a transporter
  • Small, nonpolar molecules passively move from an area of high concentration to an area of low concentration until equilibrium is achieved
44
Q

Facilitated diffusion

A
  • uses transport proteins to move impermeable solutes across the cell membrane
  • large, polar molecules
45
Q

ABC transporter protein

A

uses ATP to actively transport antitumor drugs out of the cell

46
Q

lipid rafts

A

cholesterol rich domains of the plasma membrane

47
Q

The initial filtration step in the glomerulus of the mammalian kidney occurs primarily by:

A

passive flow due to a pressure difference

the initial filtration in the glomerulus occurs as blood pressure forces the fluid from the glomerulus into the lumen of Bowman’s capsule

48
Q

Enzymes alter the rate of chemical reactions by

A

co-localizing substrates.
altering local pH.
altering substrate shape.

49
Q

enzyme specificity

A

enzymes are highly specific both in the reactions that they catalyze and in their choice of substrates

  • therefore they catalyze only a single chemical reaction or occasionally a set of closely related reactions
50
Q

increased protein levels likely has increased

A

mRNA sequences that code for the protein

51
Q

a cell arrested during Interphase would..

A

they would not divide but would, from a metabolic perspective, continue to function normally

Interphase is the phase of the cell cycle between cell divisions and is the phase in which the cell obtains nutrients, grows, reads its DNA, and conducts other “normal” cell functions

52
Q

prokaryotic DNA

A

circular and therefore does not have the repetitive, non-coding nucleotide sequences called telomeres that occur in eukaryotic DNA

53
Q

nucleotides are linked to one another by

A

phosphodiester bonds between the sugar base of one nucleotide and the phosphate group of the adjacent nucleotide in a way that the 5’ end bears a phosphate, and the 3’ end a hydroxyl group.

54
Q

glucocorticoids

A

act on skeletal muscle causing the breakdown of muscle proteins

Therefore, if a patient is given too high a replacement dose of glucocorticoids, this will result in muscle weakness

55
Q

when is gluconeogenesis activated

A

when carbohydrate stores are low

56
Q

endomembrane system

A

a system of membranous components that includes the membranes of the nucleus, the endoplasmic reticulum, the Golgi apparatus, lysosomes, endosomes, vesicles, and the cell membrane

57
Q

fuel for brain cells

A

glucose is the main fuel for brain cells

since the brains of diabetic patients receive an adequate amount of glucose, the brain must use an insulin-independent mechanism for glucose uptake

58
Q

the symptoms of diabetes mellitus

A

frequent urination and catabolism of fatty acid as well as proteins as alternative energy sources.

  • high blood glucose results in excretion of excess sugar into the urine, hence sweet-tasting urine
  • the catabolism of fatty acids and proteins results in weight loss and feelings of fatigue respectively
59
Q

dna semi-conservative replication

A

DNA replication is semi-conservative.
After the first round of cell division the genome mass in each bacterium will be 5.45 fg (one DNA strand will contain 15N 5.4 fg and the other strand 14N 5.5 fg)
Following the second round of cell division, half of the bacteria will have a genome mass of 5.4 fg (14N exclusively) and the other half a mass genome of 5.45 fg (14N in one DNA strand and 15N in the other).

60
Q

CoA components

A

adenosine 3,5 diphosphate
B alanine
b-mercaptoethyllamine

  • Coenzyme A ends is S-H
  • Acetyl-CoA ends is S-COR

MCAT (4 decks)

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