proteins lec 1

Question 1

Amino acids contain

Answer 1

carboxyl and amino termini

Question 2

In ___ the __ carbon is denoted the ___

Answer 2

amino acids
central
alpha carbon

Question 3

amino acids are ___ in equilibrium with Zwitterion ions and non-ionic form

Answer 3

acids

Question 4

charges
N terminus?
C terminus?

Answer 4

N = positive
C= negative

Question 5

most/some amino acids exhibit ___ (almost exclusively ___ acids on earth)

Answer 5

most
chirality
L-amino

Question 6

types of amino acids in proteins

Answer 6

20

Question 7

amino acids contain a variable ____ denoted __

Answer 7

side chain

R

Question 8

Polar side chains vs non-polar side chains

Answer 8

Polar side:
hydrophilic 
form hydrogen bonds with -OH groups 
form C= O bonds 
form NH2 bonds

Non-polar:
hydrophobic
contains lots of carbons
includes glycine (nonchiral)

Question 9

example of polar/non-polar side chains that form hydrogen bonds with -OH groups

Answer 9

polar
Ser
Thr
Tyr

Question 10

Which type of sidechain forms C=O bonds

Answer 10

Polar

Asn
Gin

Question 11

Which type of sidechain forms NH2 bonds

Answer 11

Polar
Asn
Gin

Question 12

Which type of sidechain is found inside protein molecules

Answer 12

non-polar

Question 13

Which amino acid of the polar/non-polar side chain is nonchiral

Answer 13

non-polar

glycine

Question 14

All amino acids except ____ are chiral? True or false

Answer 14

glycine

True

Question 15

types of amino acid side chains

Answer 15

3
nonpolar
polar
electrically charged

Question 16

Electrically charged side chains

Answer 16

hydrophilic
basic side chains/positively charged (Lys, Arg, His)
acidic side chains/negativity charged (Asp, Glu)
charged or not depends on environment pH

Question 17

Asp and Glu are ___ charged

Answer 17

negatively

Question 18

Lys, Arg, His are _____ charged

Answer 18

positively charged

Question 19

Acid/base properties

when pH = pK, there are ___ amounts of ___ and _____ amino acid forms

Answer 19

equal
protonated
deprotonated

Question 20

amino acids are acids in ____

Answer 20

equilibrium with zwitterion and non-ionic forms

Question 21

if pH is greater than the pKa of the amino acid, there will be more ____ forms (_______)

Answer 21

de-protonated

shifting of the equilibrium

Question 22

histidine changes ___ slightly depending on the environment

Answer 22

pKa

Question 23

at ~7 Asp, Glu, Lys, Arg fare usually negative/positive

Answer 23

Asp- negative
Glu -negative
Lys - positive
Arg - positive

Question 24

what property of Glycine allows it to be flexible

Answer 24

size : small

Question 25

what forms disulphide linkages (-SH groups form -S-S-)

Answer 25

cysteine

Question 26

____ gives rigidity (introduces kinks to proteins)

Answer 26

proline

Question 27

problem with viruses eg ____ ? Solution?

Answer 27

HIV
The HIV surface protein amino acid sequences keep changing therefore we can’t make conventional vaccines to combat it

Target HIV enzymes for inhibition