B/B MCAT 01

Question 1

serine, threonine, tyrosine, asparagine and glutamine all classify as?

Answer 1

polar neutral amino acids

Question 2

lysine, arginine, histidine are classified as

Answer 2

positively charged or basic amino acids

Question 3

when pH solution is less than the pka of a functional group, then the functional group is?

Answer 3

protonated

Question 4

when pH solution is greater than the pka of a functional group, then the functional group is?

Answer 4

deprotonated

Question 5

In isoelectric focusing, proteins are separated based on their?

Answer 5

isoelectric point

Question 6

A higher Km means that the substrate’s affinity is ?

Answer 6

low, because a greater amount would be needed to arrive at Vmax

Question 7

where does an uncompetitive inhibitor bind?

Answer 7

ENZYME-SUBSTRATE COMPLEX

Question 8

where does a non-competitive inhibitor bind?

Answer 8

allosteric site

Question 9

how does uncompetitive inhibitor affect Vmax and Km?

Answer 9

it lowers them

Question 10

how does a non-competitive inhibitor affect Vmax and Km?

Answer 10

It increases Vmax and does not change Km

Question 11

all amino acids are chiral except?

Answer 11

glycine

Question 12

all chiral amino acids have S configuration except?

Answer 12

cysteine

Question 13

what do hydrolases do?

Answer 13

they catalyze cleavage with the addition of water

Question 14

which inhibitor can inhibit enzymes equally both in the presence of a bound substrate and in its absence?

Answer 14

non-competitive inhibitor

Question 15

what inhibition occurs when there is an unequal affinity to the enzyme and enzyme-substrate complex? Here Km increases or reduces and Vmax decreases

Answer 15

mixed inhibition and binds allosteric site

Question 16

what occurs when an inhibitor binds only the enzyme-substrate complex and reduces both Vmax and Km?

Answer 16

uncompetitive inhibition

Question 17

examples of cell adhesion molecules include?

Answer 17

cadherins, integrins and selectins

Question 18

Is protein shape maintained when using NATIVE PAGE?

Answer 18

yes, but results are difficult to compare because the mass to charge ratio is different for each protein

Question 19

d and l forms of the same sugar are called?

Answer 19

enantiomers

Question 20

diastereomers in sugars include?

Answer 20

epimers and anomers(alpha and beta)

Question 21

what does chargaff’s rule state?

Answer 21

amount of purines(A ,G) = pyrimidines(C, T, U) ; A=T and C=G

Question 22

what kind of chromatin is dense, transcriptionally silent?

Answer 22

heterochromatin

Question 23

what kind of chromatin is less dense, transcriptionally active?

Answer 23

euchromatin

Question 24

what enzymes unwound DNA at the origin of replication?

Answer 24

helicases

Question 25

organisms that contain cells from two different lineages are called?

Answer 25

chimeras

Question 26

nonsense (truncation) mutations produces _ codons?

Answer 26

premature stop codon

Question 27

missense mutations produce what kind of codon?

Answer 27

a codon that codes for a different amino acid

Question 28

what is an open reading frame?

Answer 28

stretch of DNA that has a start and stop codon

Question 29

what do frameshift mutations do?

Answer 29

result from nucleotide deletion/addition and change the reading frame of subsequent codons

Question 30

the shine dalgarno sequence is present in

Answer 30

prokaryotes