Lecture 32

Question 1

What does Hexokinase catylyze?

Answer 1

Glucose to Glucose-6-Phosphate

Question 2

What inhibits hexokinase?

Answer 2

Glucose-6-Phosphate

Question 3

How does Glucose-6-Phosphate affect Hexokinase?

Answer 3

It inhibits hexokinase

Question 4

How what is G6P to Hexokinase?

Answer 4

It is a negative allosteric effector

Question 5

What does G6P inhibiting hexokinase do?

Answer 5

It reduces the rate that glucose is converted to G6P

Question 6

What kind of regulation is it for G6P to inhibit hexokinase?

Answer 6

Product inhibition

Question 7

What does PFK-1 catalyze?

Answer 7

The conversion of Fructose-6-P to Fructose-1,6-BP

Question 8

What is PFK-1 allosterically regulated by?

Answer 8

ADP/AMP and PEP

Question 9

What kind of inhibition is PEP regulating PFK-1?

Answer 9

Feedback inhibition

Question 10

What is a good indicator of the need for ATP in a cell?

Answer 10

ADP/AMP concentrations

Question 11

When do ADP and AMP concentrations increase?

Answer 11

When a cell is consuming ATP

Question 12

What is ADP and AMP to PFK-1?

Answer 12

A positive heteroallosteric effector of PFK-1

Question 13

What is ATP to PFK-1?

Answer 13

An inhibitor of PFK-1

Question 14

What is PFK-1 sensitive to?

Answer 14

The energy needs of the cell

Question 15

Why is ATP complex with it regulation of PFK-1?

Answer 15

Because it is also a substrate of PFK-1

Question 16

What is ATP to PFK-1?

Answer 16

It is a homoallosteric inhibitor (which is rare). This is because it is a substrate but it is also a product

Question 17

What does Pyruvate kinase catalyse?

Answer 17

The conversion of phosphoenolpyruvate to Pyruvate

Question 18

What would happen if pyruvate kinase is inhibited?

Answer 18

The levels of phosphoenolpyruvate will increase which then inhibits PFK-1

Question 19

What does elevated PEP signal?

Answer 19

The products of glycolysis are not being consumed

Question 20

What is F-6-P for PFK-1?

Answer 20

A positive homoallosteric effector because it is a substrate and an activator?

Question 21

How would increasing concentration of F-6-P affect the rate vs concentration graph?

Answer 21

It will shift toward the r state

Question 22

What does a sigmoidal shape on a rxn velocity vs substrate graph mean?

Answer 22

The substrate is also an activator

Question 23

What happens if AMP is added to a PFK-1 rate vs conc of F-6-P graph?

Answer 23

Because AMP is a positive heteroallosteric effector, it will shift the curve to the left because it increases the activity of PFK-1

Question 24

How does PEP affect the graph of rate PFK-1 to F-6-P conc?

Answer 24

It will shift the curve to the right because PEP is a negative hetero allosteric effector of PFK-1

Question 25

What is Pyruvate Kinase affected by?

Answer 25

ATP and Fructose-1,6-bisphosphate

Question 26

What does Pyruvate Kinase catalyze?

Answer 26

PEP to Pyruvate

Question 27

What is Pyruvate kinase inhibited by?

Answer 27

ATP

Question 28

What is Pyruvate Kinase activated by?

Answer 28

Fructorse-1,6-bisphosphate

Question 29

What kind of inhibition is ATP to Pyruvate kinase?

Answer 29

Product inhibition

Question 30

What does PFK-1 produce when activity is high?

Answer 30

Fructose-1,6-bisphosphate as a product

Question 31

Where does Fructose-1,6-bisphosphate act as an activator for Pyruvate?

Answer 31

In yeast

Question 32

What kind of activation if F-1,6-bisphosphate to pyruvate?

Answer 32

Feedforward activation

Question 33

What is ATP to Pyruvate Kinase?

Answer 33

An allosteric inhibitor, through product inhibition

Question 34

What kind of relationship is seen on the graph of Pyruvate Kinase vs conc of PEP and what does it indicate?

Answer 34

There is a sigmoidal relationship indicating that PEP is a substrate and a homoallosteric activator

Question 35

How does F1,6BP affect the pyruvate kinase vs PEP conc graph and why?

Answer 35

It shifts the graph to the left because PEP is a positive heteroallosteric activator

Question 36

How does ATP affect the pyruvate kinase vs PEP conc graph and why?

Answer 36

It shifts the graph to the right because ATP is a negative hetero allosteric effector of pyruvate kinase

Question 37

Which enzymes in glycolysis are affected by ATP?

Answer 37

PFK-1 and PK. They are both inhibited

Question 38

Which reactions in glycolysis consume ATP?

Answer 38

* Conversion of glucose to glucose-6-phosphate | * Conversion of F-6-P to F-1,6-bisphosphate

Question 39

Which enzymes are regulated in glycolysis?

Answer 39

* Hexokinase * Pyruvate kinase * Phosphofructokinase

Question 40

Which enzyme do you need to know that is not regulated in glycolysis?

Answer 40

GAPDH

Question 41

What are the high energy molecules in glycolysis?

Answer 41

ATP, NADH, 1,3-BPG and Phosphoenolpyruvate

Question 42

What are the high energy products of glycolysis?

Answer 42

ATP and NADH

Question 43

What are the high energy intermediates in glycolysis?

Answer 43

1,3-BPG and PEP

Question 44

What is Glycogen synthesized from?

Answer 44

Glucose-6-phosphate (anabolic)

Question 45

What does the breakdown glycogen use?

Answer 45

Inorganic phosphate to break glycosidic bonds

Question 46

What can glycogen be broken down into/

Answer 46

Less glycogen and glucose-1-phosphate

Question 47

What is used to the reaction to breakdown Glycogen?

Answer 47

Pi

Question 48

What happens Glucose-1-phosphate from the breakdown of glycogen?

Answer 48

It is converted to Glucose-6-phosphate which is an isomer

Question 49

How much ATP is used to generate G-6-P from glycogen?

Answer 49

No ATP

Question 50

How does Glycogen metabolism affect NET yield of ATP?

Answer 50

It increases net yield of ATP by 1 so instead of 2 ATP, 3 ATP is produced

Question 51

What is generated at the end of glycolysis?

Answer 51

Pyruvate

Question 52

What is the fate of Pyruvate aerobically?

Answer 52

It can be converted to acetyl CoA by oxidative phosphorylation

Question 53

What is the fate of Pyruvate anaerobically?

Answer 53

It can be converted to Lactate or Ethanol

Question 54

What is the difference between pyruvate and alanine?

Answer 54

Pyruvate contains a carbonyl where alanine contains an amino

Question 55

What high energy molecules are made during glycolysis?

Answer 55

ATP and NADH

Question 56

What can happen to NADH under aerobic conditions?

Answer 56

It can be oxidized to NAD+

Question 57

What can happen to NADH under anaerobic conditions?

Answer 57

NADH will begin to accumulate because there is no oxygen to oxidize it

Question 58

What can happen if NADH accumulates due to anaerobic conditons?

Answer 58

Raising the level of products from glycolysis will stop the reaction from proceeding

Question 59

How many NADH is made for every pyruvate in glycolysis?

Answer 59

1 NADH is made for every pyruvate

Question 60

What can convert the NADH back into NAD+ aside from O2?

Answer 60

Glucose

Question 61

How many NADH, pyruvate and ATP are produced at the end of glycolysis?

Answer 61

* 2 Pyruvate * 2 NADH * 2 Net ATP

Question 62

What needs to happen to NADH for glycolysis to continue?

Answer 62

It need to be reoxidized to NAD+

Question 63

What can help convert NADH to NAD+ in at the end of gylcolysis?

Answer 63

* Oxidative phosphorylation - anaerobic | * Pyruvate reduction (anaerobic)

Question 64

What are the two ways of Pyruvate oxidation to convert NADH back to NAD+ anerobic?

Answer 64

* Ethanol (yeast) | * Lactate formation in muscle/RBCs

Question 65

What does the reaction of Pyruvate NADH and an H+ produce?

Answer 65

L-lactate and NAD+

Question 66

What does Lactate Dehydrogenase do?

Answer 66

Catalyzes the conversion of pyruvate to lactate and the oxidation of NADH for glycolysis to continue

Question 67

What is the reduced form of pyruvate?

Answer 67

Lactate