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UWorld wrong answers - but that ill get right next time, YAY! > UWorld mix Aug 7th > Flashcards

UWorld mix Aug 7th Flashcards

1
Q

isomers that differ in their connectivity are called

A

consitutuional isomers

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2
Q

isomers that can be the same with rotation around bond

A

conformational

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3
Q

isomers that you would need to break bond to ake the same

A

configurational

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4
Q

configurationa isomer that is due to resticted movment (ie doube bond)

A

geometric, cis-trans isomer

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5
Q

do conformational isomers fall under diasterosomers?

A

no, it goes constitutional or steriososmers

and then steriosomers can be conformational or configurational and the configurational can be geometic, diasteriomers or enantiomers

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6
Q

describe one way geometric isomers can be seperated?

A

by GC bc they have different bp’s

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7
Q

is proline polar or non-polar

A

non-polar

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8
Q

are the acidic and basic amino acids hydrophilic?

A

yes, they are charged

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9
Q

tyrosine and cystine are a point of confusion

A

they both have polar bonds,

on own polar (SH bond)
when cysteine is S-S bonded - hydrophobic

tyrosine hydrophobic is the consensus- but can kinda be both

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10
Q

methionine

A

non-polar bc methyl attached to it

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11
Q

tyrosine

A

kaplan says relativley polar bc OH

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12
Q

how to determine R and S if H is in line with plane (not out, not in)

A
  1. pretend you are looking at it from side ( see if can figure it out
  2. rotate it, when we rotate the outy- stays put - think like your holding the massage spide thing from the top and rotate the other 3 prongs
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13
Q

tryptophan

A

non-polar - funky one with 2 righgs, aromatic

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14
Q

phenols with strong oxidizing agent

A

turn into quinones ( which are phenols but with the H’s removed and double c=o bonds) and only 2 double bonds on the ring - so usually not aromatic

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15
Q

ubiquinone(electron carrier) can be reduced to

A

ubiquinol (has OH)

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16
Q

how can alcohols serve as protecting groups

A

by reacting them with aldehydes or ketones they turn them to ketals and acetals which will protect the aldyhede and ketones - to remove them react with acid

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17
Q

why react alcohol with mesylate or tosylate?

A

so they attach to OH and become a leaving group - used for Nu subsitution (bc Oh is normally not that great)

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18
Q

sketcher synth

A

aldehyde, NH4Cl, and CN

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19
Q

irreversible rxns tend to be under _______ control and these favour

A

kinetic, low temp and the most favourable product is the one with the lowest activation energy

  • the lowest activation energy reaction will yeild the most productive
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20
Q

reversible rxns tend to be under ________ which favours

A

thermodynamic control, high temps

  • under these conditions all products form readily, and the most stable product will be favoured
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21
Q

how do you determine the most stable product

A

the lowest delta G

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22
Q

at 298K which products would be favoured

A

this is a low temp = irreversible rxn under kinetic control (this was stated in the passage- I missed it ) —> the product that is favoured will be the one with the lowest activation energy

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23
Q

when passage reads the reaction is irreversible what can we infer

A

that they are under kinetic control, so when deciding which product is favoured - look for activation energies

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24
Q

unit reaction rate is measured in

A

concentration of reactants used up or concentration of products produced over time

so a high rxn rate = fast rate

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25
Q

how is rate constant k related to T and activation energy

A

with Arrenhius equation

k= Ae^-Ea/RT

but get rid of negative expo by putting it in the denominator

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26
Q

when temp increases what happens to k

A

k increases exponentially

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27
Q

when Ea decreases what happens to k

A

k increases exponentially

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28
Q

when catalyst is added what happens to k

A

lower Ea, lower denominator = greater k = faster rate

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29
Q

what is the relevance of an equivalence point

A

at this point exactly enough (equal molar quantity) of base has been added to completly neutralize acid

  • so if 50ml of 0.1M H2CO3 t titrated with 2M NaOH, then the mols of acid are 0.005, meaning that we need 0.005 mols of acid at the first equivalence poiint
  • we are told 2M NaOH is the titrant –> so need 0.025ml to make 0.005
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30
Q

adiabatic

A

no heat exange

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31
Q

interferon

A

peptide signal that interfers with virual replication

  • they induce production of RNaseL which cleaves RNA in cels to reduce the ability for virus to replicate
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32
Q

how can the host stop viral replication

A

by stropping viral transcription and translation –> this is what interferons do

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33
Q

what enzyme synthesises new DNA strand in replication euk and prok?

A

pro- DNA polymerase III

euk - DNA polymerase a,g,e

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34
Q

what enzyme removes RNA primer?

A

pro- DNA polymerase 1

euk- RNase H

then filled with DNA polymerase 1 (pro) and DNA polymerase g (euk)

35
Q

monocistronic vs polycistronic

A

eukaryotic mRNA is monocitronic meaning that each mRNA translates to only one protein

but in prokatyotes, DNA is polycistronic, so starting translating at different parts on mRNA molecule can result in dif proteins

36
Q

what is eukaryotes mRNA

A

Monocistronic mRNA is a mRNA that encodes only one protein and all eukaryotic mRNAs are monocistronic

37
Q

what enzyme activates tRNA

A

aminoacyl-tRNA synthetase (requires ATP)

38
Q

what organic chem rxn happens when tRNA is activated

A

CA (on aminoacid) + OH on tRNA 3’ end = an ester!

39
Q

sequence on the 3’ end of tRNA

A

CCA

40
Q

the activated tRNA has stored energy in its eter bonf- what does this power

A

translater - peptide bond later on

41
Q

where is rRNA synthesized

A

in the nucleolous

42
Q

ribozymes

A

enzymes made of rna instead of proteins

ribozymes help catalyze peptide formation

43
Q

how doe you read anticodond

A

5’ to 3’ but this looks backwards - so just be careful with these questions

44
Q

how to remeber stop codons

A

U Are Annoying
U Go Away
U Are Gone

45
Q

nonsense vs missense

A

this nonsense has to STOP

missense is one aa for another

46
Q

in eurkaryotes what enzyme is the main player in RNA transcription

A

RNA polymerase II - binds to TATA

47
Q

DNA polymerase III

A

in e.coli - primary enzyme for DNA replication (equivalent to DNA poly age in eukaryotes)

48
Q

which RNA in eukaryotes transcribes mRNA

A

RNA poly II ( 1 synth rRNA, 3 synth tRNA and some rRNA)

49
Q

differences in DNA polymerase and RNA polymerase (one MAIN one)

A

RNA does NOT proofread

also doesnt need an RNA primer … duh

50
Q

antisense stranf vs sense strand terminology refers to

A

antisense is the template strand so antiparallel and complmentary

and the sense strand –> is identica to the mRNA (exept it has thyamine - mRNA has uracil ) but it doest do anything during transcription- just gets pulled apart and seperated

51
Q

is uracil or thymine heavier

A

thymine- bc it has one extra methyl group

52
Q

affliction

A

something that causes pain or suffering

53
Q

the first base transcribed from DNA to RNA is denoted?

A

+1 ( there is no zero) - TATA is usually around -25

54
Q

what is mRNA called before it is processed?

A

hnRNA -the primary transcript

55
Q

before hnRNA can leave the nucleous what has to happen

A

3 things so that it can survive the cytoplasm and interact with ribosome

  • poly A tail, 5’ cap and intron splicing
56
Q

introns

A

stay in the nucleus

57
Q

what enzymes splice

A

snuRPs/ snRNA complex

58
Q

whats the 5’ cap

A

7-methylguanylt triphosphate cap - protect from degradation

59
Q

poly A tail

A

like time bomb as sooon as it leaves the tail will start getting degraded so the longer the tail the better

60
Q

what is still left at the end of hnRNA processing? why?

A

UTRs- untranslated regions of mRNA on both the 5’ and 3’ end

  • bc ribosome initiated translation at the start codon and end at stop
  • roles in stability, translation ect..
61
Q

where does translation get its energy from

A

GTP is required for each step: initiation, elongation and temination

62
Q

eukaryotes subunits

A

40S + 60S = 80S

63
Q

prokaryotes subunits

A

50S + 30S = 70S

64
Q

where does translation occur

A

in the cytoplasm

65
Q

in pro where does small ribosome bind

A

Shine-Dalgarno sequence which is in the 5’ UTR

66
Q

in euk where does the small ribosome bind

A

to the 5’ cap

67
Q

RNA –> protein - what way does ribosome read the mRNA? how does this ocmpare to the reading of RNA polymerase

A

ribosome reads 5’ to 3’ —> synth protein from N to C terminal

whereas NA poly and DNA poly READ 3’ to 5’ bc they synthesize 5’ to 3’

68
Q

whats in the A site

A

the next amino acid to be added (determined by the mRNA codon in the A site bottom

  • order is APE
69
Q

whats in the P site

A

the tRNA with the growing peptide chain
also where the first methionine binds
the polypeptide chain is passed from P to A with peptidyl transferase (GTP)

70
Q

when ribosome comes across a stop codon

A

a release factor binds to A site – this causes a water molecule to be added chain to hydrolyze the chain from tRNA

71
Q

prenylation

A

adding lipid groups to proteins

72
Q

Alternative Splicing vs. Monocistronic

A

so eukarytes are monocisronic meaning that one gen codes for one primary hnRNA under control of one promotor - however alternative splicing can cause many different ISOFORMS of that protein to come about

whereas prokaryotes have many genes under the contro of one promotore (lac) byut dont have mRNA proccessing

73
Q

does prokaryotic mRNA get processed

A

In prokaryotes, there is a little or no processing of mRNA transcripts. Prokaryotic mRNA is degraded very rapidly from 5′ end. Therefore, to rescue from degradation it is translated before being finally transcribed.

74
Q

operator site

A

non-transcribable region of DNA that a repressor protein can bind

75
Q

promotor region

A

for RNA polymerase to bind

76
Q

reguator gene

A

code from protein known as repressor

77
Q

inducible system

A

repressor bound tight to operator, negative control

need an inducer to remove the roadblock

78
Q

example of an inducable system

A

lac operon –> repressor is bound but lactose can act as an inducer and remove the roadblock

with help of CAP ( a TF)

79
Q

CAP

A

is a TF used in e.coli,

low glucose- need to use diff fuel source, low glucose= high cAMP which binds to CAP- change shape and it can now bind to the promoter region of gene- further increase transcription of lactase genes

CAP binding increases transcription - this is called positive control

80
Q

repressible system

A

usually always on, but when corepressor binds, the repressor binds to the operator and stops transcription
- Trp operon
when tryptophan is high it acts as a corepressor and a binds to repressor causing it to bind to operant site and thus turns off cells own supply of tryptophan

81
Q

histone acetylases

A

coactiators

open up DNA bc they add an acetyl group to lysine whihc decreases positive charge on protein- lessens its attraction to DNA so it open up

82
Q

histone deacetylases

A

deactivate DNA (close it up)

83
Q

DNA methylation

A

silencing

during development - methylation plays an important role in silencing genes that are no longer needed

UWorld wrong answers - but that ill get right next time, YAY! (20 decks)

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