amino acids

Question 1

component of plant cell wall and collagen (muscle fiber)

Answer 1

4-hydroxyproline

Question 2

found in collagen (muscle fiber)

Answer 2

5-hydroxylysine

Question 3

modified cysteine (selenium in place of sulfar) found in few proteins

Answer 3

seleno cysteine

Question 4

all amino acids are ______
proteins only contain __ amino acids
all amino acids, except glycine have a ______

Answer 4

chiral
L
chiral center

Question 5

all amino acids found in proteins are ___

the D and L form of amino acids is basd on the D and L forms of ______

Answer 5

L form

glyceraldehyde

Question 6

all amino acids absorb light in ______

only __, ___, and ___ absorb UV

Answer 6

infrared

Phe, Tyr, Trp

Question 7

three amino acids that have absorbance at 280 nm are the ________
the measured absorbance of tryptophan is as much ___ times that of tyrosine

Answer 7

Aromatic R groups

tryptophan

Question 8

at acidic pH, the carboxyl group is protonated and the amino acid is in the ____ form

Answer 8

cationic

Question 9

at neutral pH, the carboxyl group is ______but the amino group is _______
the net charge is 0
such ions are called ________

Answer 9

deprotonated
protonated
zwitterions

Question 10

at alkaline pH, the amino group is ___ and the amino acid is in the _______

Answer 10

neutral

anionic

Question 11

a-carboxyl group is much more ____ than in carboxylic acids

a-amino group is slightly less ____ than in amines

Answer 11

acidic

basic

Question 12

amio acids with uncharged side chains, such as glycine, have two _____
it can act as a _____ in two pH regies

Answer 12

pka values

buffer

Question 13

this is the characteristic pH at which the net electric charge is zero

Answer 13

isoelectric point