Biochemistry

Question 1

What are the 4 groups attached to an amino acid?

Answer 1

-amino group
-carboxylic acid group
-hydrogen atom
-an R group

Question 2

What does the R group determine?

Answer 2

the chemistry and function of that amino acid

Question 3

Oddities in chirality

Answer 3

-all amino acids are chiral expect glycine

Question 4

Nonpolar, nonaromtic amino acids

Answer 4

glycine
alanine
valine
leucine
isoleucine
methionine
proline

Question 5

Aromatic amino acids

Answer 5

tryptophan
phenylalanine
tyrosine

Question 6

Polar amino acids

Answer 6

serine
threonine
asparagine
glutamine
cysteine

Question 7

Acidic (negatively charged)

Answer 7

aspartate, glutamate

Question 8

Basic (positively charged)

Answer 8

lysine
arginine
histidine

Question 9

Amino acid at low PH:
at high pH:

Answer 9

-fully protonated
-deprotonated

Question 10

pH=pI

Answer 10

neutral (zwitteron)

Question 11

pI:
charged side chain-
acidic-
basic-

Answer 11

-around 6
-below 6
-above 6

Question 12

How do we form a new peptide bond?
How do we break one?

Answer 12

condensation or dehydration (releases water)
hydrolysis

Question 13

Explain different protein structures:

Answer 13

1- linear amino acid sequence stabilized by peptide bonds
2-local structure of neighboring amino acids stabilized by hydrogen bonds
3-3-d shape stabilized by hydrophobic interactions, h-bonding, acid-base interactions
4- interaction between peptides with multiple subunits

Question 14

What factors can denture a protein?

Answer 14

heat and increasing solute concentration, urea

Question 15

What is an enzyme?

Answer 15

biological catalysts that are unchanged by the reactions they catalyze and are reusable

Question 16

6 types of enzymes:

Answer 16

-oxidoreductases: catalyze oxidation-reduction reactions, involve transfer of electrons
-transferases: move a functional group from one molecule to another
-hydrolayses: catalyze cleavage with addition of water
-lyases: catalyze cleavage without addition of water
-isomerases: catalyze interconversion of isomers
-ligases: join two large biomolecules

Question 17

how do enzymes work?

Answer 17

stabilize the transition state, providing a favorable microenvrinoment

Question 17

how do enzymes work?

Answer 17

stabilize the transition state, providing a favorable microenvrinoment or bonding with substrate molecules

Question 18

Cofactor vs coenzyme

Answer 18

metal cation
organic

Question 19

Saturation kinetics:

Answer 19

as substate concentrado increases, the reaction rate does as well until a maximum value is reached

Question 20

Cooperative enzymes curve:

Answer 20

sigmoid because change in activity with substrate binding

Question 21

What factors can effect enzyme activity?

Answer 21

temperature, pH
also salt concentration (salinity)

Question 22

Feedback inhibition

Answer 22

catalytic activity inhibited by preens of high levels of product later in pathway

Question 23

Reversible inhibition:

Answer 23

Competitive: Km increase, Vmax same
Noncompetitive: Km same, Vmax decreases
Mixed: Km increased/decreased Vmax decrease
Uncompetitive: Km and Vmac decrease

Question 24

Irreversible inhibition:

Answer 24

allosteric: sites can be occupied by activators which can increase activity
phosphorylation: alter activity
zymogens: secreted in inactive form and activated by cleavage