Lecture 20: Glycolysis

Question 1

How much ATP does glycolysis generate

Answer 1

2 ATP

Question 2

what are the sources of glucose in the diet?

Answer 2

disaccharides (especially sucrose and lactose)
starch
glycogen

Question 3

Describe the GLUT1 transporter

Answer 3

ubiquitous but expressed highly in brain and RBCs, high affinity

Question 4

Describe the GLUT2 transporter

Answer 4

main transporter in the liver, low affinity

Question 5

Describe the GLUT3 transporter

Answer 5

main transporter in neurons, high affinity

Question 6

Describe the GLUT4 transporter

Answer 6

present in skeletal muscle, heart, adipose tissue (insulin dependent)

Question 7

What is sucrose a disaccharide of?

Answer 7

glucose and fructose

Question 8

What is lactose a disaccharide of?

Answer 8

glucose and galactose

Question 9

What are the major regulatory enzymes?

Answer 9

hexokinase
phosphofructokinase
pyruvate kinase

Question 10

What is the goal of glycolysis regulation in the muscle?

Answer 10

generate ATP during activity

ATP levels regulate glycolysis

Question 11

What is the goal of glycolysis regulation in the liver?

Answer 11

maintain blood glucose levels and provide building blocks for other pathways

Question 12

There is no _____ in the liver

Answer 12

hexokinase

Question 13

How can excess fructose consumption lead to pathological conditions?

Answer 13

actions of fructokinase and triose bypass the most important regulatory step in glycolysis, the phosphofructokinase catalyzed reaction
fructose derived G3P and DHAP are processed by glycolysis to pyruvate and acetyl CoA in an unregulated fashion
excess acetyl CoA converts to fatty acids which can accumulate in liver and body

Question 14

disruption of galactose metabolism is called what?

Answer 14

galactosemia

Question 15

classic galactosemia is an inherited deficiency in ______

Answer 15

galactose 1-phosphate uridyl transferase activity

Question 16

What causes cataracts?

Answer 16

presence of aldose reductase causes the accumulating galactose to be reduced to galactitol

Question 17

rapidly growing tumor cells metabolize glucose to lactate even in the presence of oxygen, which is called _____

Answer 17

aerobic glycolysis or the Warburg effect