Biochemistry II - Exam 1

Increased delta H (enthalpy) does what do spontaneity?

Is delta G positive or negative?

less spontaneous

more positive

Increased delta S (entropy) does what to spontaneity?

Is delta G positive or negative?

more spontaneous

more negative

When Keq > 1

Are there more products or reactants?

more products

When Keq < 1

Are there more products or reactants?

more reactants

T/F? Enzymes have NO effect on thermodynamics

True

Enzymes ______ reactions by ______ activation energy

speed up reactions

lowering activation energy

________ inhibit enzymes

excess product

_______ stimulates enzymes

excess reactant

Which classification of enzyme moves a functional group?

mutase

Which functional group adds a phosphate?

kinase

Which functional group removes a phosphate?

phosphatase

When there is a HIGH energy charge, are we using or making ATP?

Breaking or building fat?

using ATP

building fat (synthesis)

When there is a LOW energy charge, are we using or making ATP?

Breaking or building fat?

making AtP

breaking (running glycolysis)

T/F/ Glycolysis is a process used to control blood glucose levels

FALSE

What is the "purpose" of glycolysis?

make ATP and 2 pyruvate

How many carbons does glycolysis start with?

End with?

6

3

Where does glycolysis take place?

cytosol

What are the reversible steps of glycolysis?

1, 3, 10

What is the rate limiting step of glycolysis?

3

Which steps of glycolysis is ATP consumed?

1 and 3

Which steps of glycolysis is ATP made?

7 and 10

What is the NET ATP production of glycolysis?

2

What is the gross (total) ATP production of glycolysis?

4

Which enzyme catalyzes step 1 of glycolysis?

hexokinase

Step 1 Glycolysis:

Reactant = ?

Product = ?

glucose

G6P

Which enzyme catalyzes step 2 of glycolysis?

isomerase (phosphoglucose)

Step 2 Glycolysis:

Reactant = ?

Product = ?

G6P

F6P

Which enzyme catalyzes step 3 of glycolysis?

phosphofructokinase

Step 3 Glycolysis:

Reactant = ?

Product = ?

F6P

Fructose 1, 6 bisphosphate

Which enzyme catalyzes step 4 of glycolysis?

aldolase

Step 4 Glycolysis:

Reactant = ?

Product = ?

fructose 1,6 bisphosphate

DHAP and G3P

Which enzyme catalyzes step 5 of glycolysis?

isomerase (triose phosphate)

Step 5 Glycolysis:

Reactant = ?

Product = ?

DHAP

G3P

Which enzyme catalyzes step 6 of glycolysis?

dehydrogenase

Step 6 Glycolysis:

Reactant = ?

Product = ?

G3P

1, 3 bisphosphoglycerate

What else is produced in step 6 of glycolysis?

1 NADH (2 total from 1 glucose molecule)

Which enzyme catalyzes step 7 of glycolysis?

kinase (phosphoglycerate)

Step 7 Glycolysis:

Reactant = ?

Product = ?

1, 3 bisphosphoglycerate

3 phosphoglycerate

Which enzyme catalyzes step 8 of glycolysis?

mutase

Step 8 Glycolysis:

Reactant = ?

Product = ?

3 phosphoglycerate

2 phosphoglycerate

Which enzyme catalyzes step 9 of glycolysis?

enolase

Step 9 Glycolysis:

Reactant = ?

Product = ?

2 phosphoglycerate

PEP

Which enzyme catalyzes step 10 of glycolysis?

kinase

Step 10 Glycolysis:

Reactant = ?

Product = ?

PEP

pyruvate

How does fructose enter glycolysis?

Does it avoid regulation?

converted to DHAP and G3P

yes some because it enters below step 3 (rate limiting)

How does galactose enter glycolysis?

Does it avoid regulation?

converted to G6P

enters before step 2 so it is still regulated

One fate of pyruvate is lactate production, a MODERATE production of lactic acid (lactate) would do what do glycolysis?

increase glycolysis, more NAD+ to stimulate step 6

One fate of pyruvate is lactate production, a LARGE production of lactic acid (lactate) would do what do glycolysis?

decrease glycolysis, inhibit PKF1 (step 3)

One fate of pyruvate is alcohol production where we reduce pyruvate to form _________?

Does this happen in humans?

ethanol

happens in microorganisms

One fate of pyruvate is converting it to alanine... what do we add to make this happen?

amine (NH3)

Hexokinase has a ____ km and a _____ affinity for glucose

low Km, high affinity

Hexokinase is inhibited by?

product or G6P

Glucokinase has a _____ km and a _____ affinitty for glucose

high km, low affinity

Glucokinase is indirectly inhibited by?

fructose-6-phosphate

Glucokinase is stimulated by what? (2)

insulin and fructose

Glucokinase makes G6P ONLY when glucose is __________

abundant

PFK1 is allosterically inhibited by?

ATP and citrate

An abundance of PFK1 tells us what?

we don't need to make more pyruvate

Pyruvate Kinase is inhibited by? (3)

alanine

ATP

PKA

Pyruvate kinase is stimulated by?

fructose 1-6 bisphosphate

PKA does what to the production of cAMP?

increases production

PKA _______ pyruvate kinase by _________ a kinase which turns it on or off?

inhibits

adding kinase

OFF

Insulin is secreted by pancreas in response to _________ blood glucose

HIGH (well fed)

What does insulin release stimulate?

storage and building

glycolysis

Glucagon is secreted by pancreas in response to _________ blood glucose

LOW (fasting)

What does glucagon initiate?

breakdown

decreases glycolysis

Glucagon activates what? What does this inhibit?

AMPK

inhibits synthesis

PFK2 (liver only) adds a phosphate to what? What does this make?

fructose 6 phosphate

fructose 2, 6-bisphosphate

PFK2 is inhibited by what?

glucagon

Active PFK2 means what for PKA activity?

decreased (insulin released)

Inactive PFK2 means what for PKA activity?

increases (glucagon released)

Pyruvate dehydrogenase is inhibited by what 3 things?

NAD, ATP, acetyl coA

Pyruvate dehydrogenase is activated by what?

pyruvate (blocks PDH kinase)

Ca2+ (activates PDH phosphatase)

T/F? More negative means a greater tendency for reduced form to be oxidized

True

T/F? Electrons flow from positive to negative

False - negative to positive

How many ATP are produced from 1 FADH2 typically?

2