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U-world mistakes Flash cards

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MCAT flashcards
1
Q

what hormone acts on the hypothalamus to stimulate appetite?

A

Ghrelin

Ghrelin is a hormone released by cells in the stomach. It is transported to the hypothalamus, it stimulates appetite

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2
Q

what is the function of cholecystokinin?

A
  • Gut derived hormone, it promotes satiety rather than appetite.
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3
Q

what is unique about estradiol ?

A

it functions as a lipid-soluble steroid hormone,

because it influences GH secretion, it also functions as a tropic hormone

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4
Q

what is adaptive immunity broken into ?

A

Cell- mediated immunity and humoral immunity

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5
Q

What is humoral immunity?

A
  • process of adaptive immunity
  • run by B lymphocytes that secrete antibodies.
  • antibody-mediated immune response
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6
Q

describe MHC1 and MHC2

A
  • MHC 1 cells are found in non nucleated cells for effector T cells
  • MHC2 cells are found on macrophages, dendritic cells, B cells, and T cells
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7
Q

What type of cells respond to antigens by releasing toxins to induce apoptosis?

A

Natural killer and cytotoxic T cells

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8
Q

what is permeable in the ascending and descending limbs?

A

Descending limb- highly permeable to water, and low NaCl permeability.

Ascending limb- impermeable to water, but permeable to NaCl

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9
Q

what kind of polymerases are responsible for carrying out transcription

A

RNA polymerases, they bind to the DNA at the promoter region.

transcription factors are proteins that bind to the DNA near gene promoter regions and either increase transcription

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10
Q

what is the function of kinesin and dynein

A

Dynein- towards cell body

kinesis- away from cell body

both move along a MT

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11
Q

what is the mismatch repair system?

A

DNA polymerase may mistakenly put a wrong nucleotide in a newly made strand

= MMR comes in with a nuclease enzyme, takes out the wrong nucleotide, then DNA polymerase comes and incorporates teh correct one.

This happens in DNA not RNA

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12
Q

what is the function of olgiodendrocytes ?

A

form myelin sheaths around axons to reduce ion leakage, decrease capacitance, and increase AP speed along the axon

in the CNS

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13
Q

what is the function of schwann cells ?

A

Form myelin sheaths around the axons to increase speed of conduction

in the PNS

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14
Q

Lytic vs lysogenic life cycles

A

lysogenic- bactera get their DNA integrated with Viral DNA. making prophages, over a long period of time latency.

lytic cycle takes over degrades host genome and then busts out

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15
Q

what is conjugation?

A

transfer of genetic information from one bacterial cell to another cell via direct contact
F factor sex pilus

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16
Q

what is transformation?

A

Cellular uptake of foregn DNA from the environment

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17
Q

what is transduction?

A

Involves trh DNA transfer from one bacterium to another by bacteriophage

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18
Q

what is repolarization?

A

Na+ channels close, K+ channels open
(falling phase)

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19
Q

What is hyperpolarizing?

A

Excessive K+ efflux

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20
Q

What is the function of a SDS-Page?

A

It separates proteins primarily based on size. It is inversely proportional to the migration distance and molecular weight.

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21
Q

What are the IR spectrum ranges?
OH
CH
C trip bond N/C
NH

A

OH- 3200-3400
C-H stretch 2850-3100
C Tripple bond N /C tripple bond C- 2100-2260
NH-(3300-3500)
CH- alkyn stretch >3000

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22
Q

what is a competitive inhibitor ?

A

bind to enzymes active site and prevent the substrate from binding.

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23
Q

what is a noncompetitive inhibitor?

A

bind to a different site (allosteric site) on the enzyme and cause a conformational change that affects its activity.

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24
Q

what is an uncompetitive inhibitor?

A

binds to the substrate-enzyme complex and prevent the substrate from leaving the active site.

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25
Q

what does Kcat represent?

A

the rate of the catalytic reaction of an enzyme and is determined by number of substrate molecules turned into products with a certain period

26
Q

what is the difference between acetylation and deacetylation?

A

Deacetylation= decrease gene expression

acetylation= increases gene expression, trasfer of acetyl groups from acetyl co A

27
Q

how to histones associate with DNA ?

A

they associate with DNA by forming salt bridges between positively charged amino acids residues and negatively charged phosphate groups

these ionic interactions allow histones to bind tightly to DNA and prevent genes from being transcribed.

28
Q

heterochromatin vs euchromatin?

A

heterochromatin- less accessibl e

euchromatin- more accessible

29
Q

what do peptide hormones require?

A

they require secondary messengers, as they cannot cross the membranes.

these hormones bind to cell surface receptors like the G protein coupled receptor. That receptor then relays the signal from extracellular ligands by causing production of secondary messengers.

That messenger then interacts with protiens in the cytosol and nucleus causing a response.

30
Q

what is the sympathetic nervous system ?

A

fight of flight

shiv
stimulates glucose release
increased heartbeat
inhibits digestion
secretes epinephrine and norepinephrine

31
Q

how does glycogen get mobilized for glycogenolysis ?

A

epinephrine first binds to B- adrenergic receptor
( that is. GPCR) that is couped to a heterotrimeric G protein)

a signal cascade happens producing cAMP activating PKA, and that phosphorlates and activates enzymes phosphorylase kinase and phosphorylase.

phosphorylase brakes down he alpha 1-4 glycosidic bonds of gylcogen; therefore epinephrine stimulates glycogenolysis

32
Q

where does gluconeogenesis occur ?

A

liver and kidney

33
Q

what kind of function is free energy?

A

it is a state function

34
Q

what are the 4 NTPs (nucleoside triphosphates)

A
  • adenine
  • guanin
    -cytosine
  • uracil
35
Q

Difference between DNA and RNA ?

A

DNA- deoxyribonucleic acid
ATCG

RNA- Ribonucleic acid
UACG

36
Q

what makes up Purines

A

Adenine and guanine

37
Q

what makes up pyrimidines

A

Cytosine thymine uracil

38
Q

what is an anomeric carbon?

A

Carbon bonded to oxygen ring and the hydroxy group in the cyclic form

Or the carbonyl carbon of the aldehyde or ketone functional group

the carbon that has two bonds to oxygen

39
Q

what does complex 2 do in the ETC

A

Complex 2 facilitates the transport of electrons from succinate in CAC to complex 3

electrons from succinate are transferred to FAD to produce FADH2, as succinate is oxidized to fumarate.

FADH2 is reoxidized to FAD

ubiquinone or coenzyme Q, accepts electrons from the iron sulfur centers, becoming reduced to ubiquinol,

Ubiquinol then transports its electrons to complex 3

40
Q

what classification of enzyme catalyzes the reduction of ketones to alcohol

A

oxidoreductases, they use cofactors as reducing agents or oxidizing agents

41
Q

Km describes what ?

A

affinity of the enzyme substrate interaction, so the lower the km means the substrate can find the enzyme very quickly, so it gets to 1/2vmax fast

42
Q

lower km means

A

higher affinity

43
Q

higher km means

A

lower affinity

44
Q

what does michaelis menten equation measure

A

the rate of product formation in the presence of varying concentrations of substrate

45
Q

what is catalytic efficiency?

A

Measure of how well an enzyme completes reactions at low substrate concentrations

46
Q

what is a schiff base

A

when a protein forms a covalent bond to a carbonyl containing compound by nucleophilic addition of an amine to make an imine linkage

47
Q

what is the rate limiting step of pentose phosphate pathway?

A

glucose 6 phosphate dehydrogenase
(rate limiting step)

48
Q

what is parallel evolution

A

two or more closely related species continue to evolve the same characteristics to adapt to similar environments

49
Q

What is divergent evolution

A

two species descended from a recent common ancestor, but have different contrasting environments and evolve different characteristics

50
Q

What is convergent evolution?

A

2 unrelated species develop similar characteristics due to similar environments

51
Q

what is the sapir-whorf theory

A

language shapes cognition

52
Q

what is universalism

A

cognition controls language

53
Q

what is the nativist theory

A

it says humans are biologicall programmed to get a langauge and will learn whatever langauge they are exposed to in a critical period

critical period in language developement is there is a time sensitive period where the language acquistion is easier

54
Q

what is wernicke area

A

language comprehension

55
Q

what does the lingual lipase do ?

A

hydrolyzes triglycerides into free fatty acids and diglycerides

56
Q

what does salivary amylase do ?

A

hydrolyzes the polysaccharide starch into disaccharide maltose

57
Q

what is the function of pepsin

A

a proteolytic enzyme responsible for initial digestion of polypeptides into smaller peptides

58
Q

what is the occipital lobe?

A

in the occipital lobe, the primary visual cortex is associated with processing visual imports from the retinas

59
Q

SDS Page.. what is it and explain the conditions it can be run under

A
  • technique that used to separate proteins by size

does not disrupt disulfide bonds
it can be run under non reducing and reducing conditions

in non- reducing disulfide bonds remain intact

under reducing conditions a reducing agent is added in addition to SDS, to break disulfide bonds

60
Q

what is the function of lactate dehydrogenase

A

another reversible enzyme, in oxygen poor tissue, lactate dehydrogenase uses pyruvate to oxidize NADH and produce lactate and NAD+ in a process called fermentation

61
Q

what is isoelectric focusing-

A

analytic technique that can detect and distinguish proteins with mutations that affect their ionizability

MCAT decks (6 decks)

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