amino acids

Question 1

how many standard amino acids are there?

Answer 1

20

Question 2

what is the structure of an amino acid?

Answer 2

a-carbon is bonded to a carboxyl, amino, hydrogen atom and R group

Question 3

what do amino acids vary by?

Answer 3

the R group, side chain

Question 4

why is Proline an exception to the structure?

Answer 4

its side chain is attached to the central atom and amino group

Question 5

describe the structure of hydrophobic amino acids?

Answer 5

uncharged nonpolar side chains. carbon or hydrogen.

Question 6

what amino acids are hydrophobic?

Answer 6

Glycine, alanine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan, proline

Question 7

what hydrophobic amino acids are aromatic?

Answer 7

phenylalanine and tryptophan

Question 8

what is the smallest amino acid?

Answer 8

glycine

Question 9

what is the largest amino acid?

Answer 9

tryptophan

Question 10

what are the characteristics of hydrophobic amino acids?

Answer 10

Form water-insoluble cores of proteins.

Question 11

Describe hydrophilic amino acids

Answer 11

uncharged polar side chains. R group no pos or neg charge.

Question 12

what do hydrophilic amino acids do?

Answer 12

they are on surface of proteins. by interacting with H2O they make proteins soluble.

Question 13

what hydrophilic amino acids contain a polar hydroxyl group?

Answer 13

Serine, threonine and tryosine

Question 14

what hydrophilic amino acids contain a highly polar amino functional group?

Answer 14

asparagine and glutamine

Question 15

what hydrophilic amino acid contains a sulfhydryl group?

Answer 15

Cysteine

Question 16

what can be added to amino acids with OH in the R chain?

Answer 16

Phosphate

Question 17

what amino acid can form a disulfide bond ?

Answer 17

Cysteine because it has a sulfhydryl group in the R chain.

Question 18

what can a sulfhydryl group of 2 molecules do?

Answer 18

it may oxidise spontaneously to form a disulfide compound called cystine

Question 19

what does disulfide bond between Cys do

Answer 19

stabilises the structure on many proteins

Question 20

what is an amphoteric molecule?

Answer 20

is a molecule that can act as both an acid and a base.

Question 21

describe the amino and carboxyl groups at PH7

Answer 21

carboxyl groups deprotonated- neg charge.
carboxyl groups are acidic
amino acids protonated- pos charge
amino groups are basic

Question 22

acidic amino acids

Answer 22

aspartate or aspartic acid
glutamate or glutamic acid

Question 23

what are acidic amino acids?

Answer 23

negatively electrically charged

Question 24

what are the characteristics of acidic amino acids?

Answer 24

carboxyl group dissociates to give H+ and negatively charged carboxyl group at PH7
can H-bond with water
form ionic bonds with basic amino acids

Question 25

basic amino acids

Answer 25

lysine, arginine, histidine

Question 26

what are basic amino acids?

Answer 26

positively charged . basic amino acids associate with H+ to form pos charged groups at PH7

Question 27

how are amino acids linked?

Answer 27

peptide bond

Question 28

does the formation of a peptide bond result in the loss of water

Answer 28

yes

Question 29

is the peptide bond stable

Answer 29

yes

Question 30

what are linked amino acids referred to ?

Answer 30

amino acid residues

Question 31

what is a peptide bond?

Answer 31

a chemical bond formed between carboxyl group of one amino acid and the amino group of the next amino acid

Question 32

what is the direction of the polypeptide chain?

Answer 32

will run from the amino to carboxyl end

Question 33

what is the name of the free amino group at the beginning

Answer 33

the amino terminal or N-terminal

Question 34

what is the free carboxyl group called at the end ?

Answer 34

the carboxyl terminal or C-terminal

Question 35

what does the polypeptide chain consist of ?

Answer 35

a regularly repeating part called the main chain or backbone. variable part comprised of the distinctive side chains.

Question 36

does the chain fold ?

Answer 36

yes, first amino acid could be beside last

Question 37

what does a functional protein consist of ?

Answer 37

one or more polypeptides twisted, folded and coiled into a unique shape