unit 1 exam

Question 1

what is the hydrophobic effect

Answer 1

the favorable increase in entropy of water when it is released from nonpolar molecules

Question 2

characteristics of peptide bonds

Answer 2

partial double bond character between carbonyl carbon and amide nitrogen

Question 3

specific activity formula

Answer 3

activity/total protein (units/mg)

Question 4

number of H-bonds in alpha helix

Answer 4

(# amino acids)-4

Question 5

uses for gel electrophoresis

Answer 5

separate molecules by size; unfold protein but maintain primary structure

Question 6

does lower Kd correspond to ligand binding more or less tightly

Answer 6

more tightly

Question 7

myoglobin properties

Answer 7

oxygen storage protein
binds to heme (porphyrin ring and iron atom)
iron atom in +2 ox state
monomer
bad transporter
tertiary
hyperbolic O2 binding curve

Question 8

hemoglobin properties

Answer 8

oxygen transporter
tetramer
T state: binds less strongly to O2
R state: binds most strongly to O2

Question 9

more BPG

Answer 9

more T state

Question 10

less BPG

Answer 10

more R state

Question 11

high affinity state conditions

Answer 11

more R state, less BPG, higher pH, less O2 released
(fetal hemoglobin has less BPG)

Question 12

low affinity state conditions

Answer 12

more T state, more BPG, lower pH, more O2 released

Question 13

Michaelis-Menten assumptions

Answer 13

k-2 is negligible
[ES] is constant

Question 14

oxyanion hole purpose (chymotrypsin)

Answer 14

stabilizes transition state (2x in peptide breaking)

Question 15

hydrophobic pocket purpose (chymotrypsin)

Answer 15

substrate binding specificity

Question 16

histidine purpose (chymotrypsin)

Answer 16

gen acid/base
take H+ from ser, protonate amide, take H from H2O, protonate ser

Question 17

serine purpose (chymotrypsin)

Answer 17

covalently bonds to carbonyl carbon

Question 18

asparagine purpose (chymotrypsin)

Answer 18

H-bonds to stabilize the positive charge on histidine

Question 19

allosteric enzyme characteristics

Answer 19

feedback inhibition
reversible
binding to enzyme makes it more active for substrate
product will shut down production
non michaelis-menten behavior

Question 20

competitive inhibition m-m graph

Answer 20

constant vmax
Km increases

Question 21

uncompetitive inhibition m-m graph

Answer 21

vmax and Km decrease at same rate

Question 22

mixed inhibition m-m graph

Answer 22

vmax decreases
Km increases

Question 23

sphingolipid purpose

Answer 23

important immunogenic determinant in blood

Question 24

glycerophospholipid purpose

Answer 24

prostaglandins derived from them

Question 25

sterol purpose

Answer 25

membrane structural lipid

Question 26

Ramachondran plot purpose

Answer 26

gives possible rotations of functional groups Glycine has most possible rotations because double H group

Question 27

what is a post-translational modification?

Answer 27

covalently attaching functional groups after protein translation from ribosome ex: hydroxyproline for collagen

Question 28

how are peptides (peptide bonds) formed?

Answer 28

condensation reaction

Question 29

what kind of amino acids are on the interior of a protein

Answer 29

nonpolar hydrophobic

Question 30

Alfinsen RNase folding experiment

Answer 30

unfolded proteins, proved they were inactive, refolded, proved they were active experiment proved that the primary sequence of a polypeptide is sufficient for proper protein folding activity

Question 31

Beta-sheet characteristics

Answer 31

contain relatively few amino acid residues H bonds form between strands have a tendency to twist and are pleated

Question 32

what are the 3 main catalytic strategies

Answer 32

acid/base catalysis, covalent catalysis, metal ion catalysis

Question 33

Do larger Mr values belong to larger or smaller molecules

Answer 33

larger

Question 34

how do you count ionizable groups

Answer 34

count number of -ate, -ine, -SH, and OH groups and add 2 for the terminal NH3 and COO-

Question 35

do bacteria produce a higher ratio of saturated/unsaturated fatty acids at higher or lower temps

Answer 35

higher temps

Question 36

COVID characteristics

Answer 36

surrounded by lipid membrane that can be destroyed with soap and simple hand washing to infect another cell the virus fuses its lipid bilayer with the host cell bilayer and that process depends on viral spike protein binding to receptors on cell surface

Question 37

what is the Bohr effect?

Answer 37

binding affinity for O2 decreases at lower pH - more BPG - more T-state

Question 38

what is the most abundant protein in humans?

Answer 38

collagen

Question 39

what is keratin?

Answer 39

a fibrous protein found in hair and skin

Question 40

what is a fibrous protein?

Answer 40

highly extended protein with repeating helical or beta sheet structure