Exam 2

Question 1

nucleic acids

Answer 1

-DNA and RNA polymers

Question 2

nucleotides

Answer 2

-DNA and RNA monomers

Question 3

RNA

Answer 3

-the activated genetic data for making proteins and polymerized from four monomer ribonucleotides that are named ATP, CTP, GTP, and UTP

Question 4

Main role of nucleic acids

Answer 4

-specifying the entire phenotype of organism by directing production of particular sets of RNAs and proteins and exerting diverse genetic regulatory functions

Question 5

nucleotide structures are usually linked by ___ bonds between 3’OH and 5’-OH

Answer 5

phosphodiester

Question 6

isosteric

Answer 6

meaning that the positions and the distances between the C1′ carbon atoms are very similar.

Question 7

how much space between turns of a B form helix of DNA

Answer 7

3.4 nm

Question 8

how many basepairs / helix turn in a B form helix of DNA

Answer 8

10.5

Question 9

Which of these statements about enzyme catalyzed reactions is false:
A. at saturating levels of substrate, the rate of an enzyme-catalyzed rxn is proportional to the enzyme concentration
B. if enough substrate is added, the normal Vmax of a rxn can be attained even in the presence of a competetive inhibitor
C. the rate of an in vitro reaction decreases steadily with time as substrate is depleted
D. the activation energy for the catalyzed rxn is the same as for the uncatalyzed rxn, but the equlibrium constant is more favorable in the enzyme catalyzed rxn

Answer 9

D is false

Question 10

the number of substrate molecules converted to product in a given unit of time by a single enzyme molecule at saturation is referred to as the

Answer 10

turnover number

Question 11

in the situation of a competitive inhibitor, an inhibitor

Answer 11

binds reversibly at the active site

Question 12

Phenyl-methane-sulfonyl-fluoride (PMSF) inactivates serine proteases by reacting covalently with the catalytic serine residue at the active site; this enzyme-inhibitor bond is not cleaved by the enzyme. This is an example of what kind of inhibition

Answer 12

Irreversible

Question 13

When two carbohydrates are epimers

Answer 13

they differ only in the configuration around one carbon atom

Question 14

stopped at question 6 of exam

Answer 14

j

Question 15

structure of Hb

Answer 15

• 4 polypeptides (2a and 2 B)

- 4 heme groups per tetramer

Question 16

deoxyHb

Answer 16

• T state (tense)

- heme Fe doesnt fit well into porphyrin ring, porphyrin is flexed

Question 17

when O2 binds to Hb, what happens to the heme Fe?

Answer 17

-heme Fe gets drawn into the plane of the porphyrin so ring is relaxed

Question 18

which interactions of polypeptides is least likely to move or change in Hb

Answer 18

a1B1 and a2B2

Question 19

describe Hb O2 binding curve

Answer 19

• NOT hyperbolic
• it is sigmoidal
• see Hill equation
• shows positive cooperativity

Question 20

what shifts the oxygen binding curve to the right?

Answer 20

• increasing [CO2] and [H]

- increase in temp

Question 21

What compound allosterically regulates Hb

Answer 21

2,3-BPG

-bisphosphoglycerate

Question 22

what adaptation occurs to help unloading of 02 at high temperatures

Answer 22

-BPG increases!!

Question 23

HbF

Answer 23

• fetal hemoglobin
• comprised of 2 a and 2 gamma subunits
• has a higher affinity for O2 compared to adult Hb and doesnt bind BPG as well

Question 24

Sickle cell anemia

Answer 24

• recognized as a E6V mutation of Hb B chain
• fibril assemblies only occur for deoxyHbS
• serious consequences at small blood capillaries