Lecture 15 - Glycolysis

Question 1

In glycolysis 1 molecule of […] is converted to 2 molecules of […] and generates 2 molecules of […].

Answer 1

Glucose; Pyruvate; ATP

Question 2

Sources of glucose in diet.

Answer 2

Disaccharides (i.e. sucrose and lactose), starch, and glycogen.

Question 3

Only fuel that RBCs can use.

Answer 3

Glucose

Question 4

Pyruvate and lactate can be salvaged and resynthesized to glucose via […].

Answer 4

Gluconeogenesis

Question 5

Protein transporters that uptake glucose.

Answer 5

Glucose transporters (GLUTs)

Question 6

GLUT transporter, ubiquitous but expressed highly in brain and RBCs.

Answer 6

GLUT1

Question 7

GLUT transporter, main transporter in liver.

Answer 7

GLUT2

Question 8

GLUT transporter, main transporter in neurons.

Answer 8

GLUT3

Question 9

GLUT transporter, present in skeletal muscle, heart, and adipose tissue.

Answer 9

GLUT4

Question 10

GLUT transporter, has the low affinity.

Answer 10

GLUT2

Question 11

GLUT transporters with high affinity.

Answer 11

GLUT1 and GLUT3

Question 12

GLUT transporter that is regulated insulin.

Answer 12

GLUT4

Question 13

Location of glycolysis.

Answer 13

Cytoplasm

Question 14

Two stages of glycolysis.

Answer 14

Trapping of glucose and generation of ATP.

Question 15

Step of glycolysis, traps glucose.

Answer 15

Glucose → Glucose-6-phosphate via hexokinase

Question 16

Step of glycolysis, commited step.

Answer 16

Fructose-6-Phosphate → Fructose-1,6-Bisphosphate via phosphofructokinase (i.e. consumes ATP)

Question 17

Enzymes in glycolysis, utilize ATP.

Answer 17

Hexokinase and phosphofructokinase

Question 18

Rate limiting enzyme of glycolysis.

Answer 18

Phosphofructokinase

Question 19

Enzyme of glycolysis, reduceds NAD⁺ to NADH.

Answer 19

GAPDH (i.e. NADH goes to ETC)

Question 20

ATP producing steps of glycolysis.

Answer 20

1,3-Bisphosphoglycerate → 3-phosphoglycerate via phosphoglycerol kinase and phophoenolpyruvate → pyruvate via pyruvate kinase

Question 21

Three fates of pyruvate produced in glycolysis.

Answer 21

Ethanol, lactate (i.e. regenerates NAD⁺), acetyl CoA (i.e. for further oxidation)

Question 22

Disaccharide of glucose and fructose.

Answer 22

Sucrose

Question 23

Disaccharide of glucose and galactose.

Answer 23

Lactose

Question 24

Major regulatory enzymes of glycolysis.

Answer 24

Hexokinase, phosphofructokinase, and pyruvate kinase.

Question 25

Enzyme of glycolysis, converts glucose to glucose-6-phosphate

Answer 25

Hexokinase

Question 26

Enzyme of glycolysis, converts fructose-6-phosphate to fructose-1,6-bisphosphate.

Answer 26

Phosphofructosokinase

Question 27

Enzyme of glycolysis, converts phophoenolpyruvate to pyruvate.

Answer 27

Pyruvate kinase

Question 28

Goal of glycolysis in muscle.

Answer 28

To generate ATP during activity.

Question 29

Regulator of glycolysis within muscle.

Answer 29

ATP

Question 30

Goal of glycolysis within the liver.

Answer 30

To maintain blood lgucose levels, to provide building blocks for other pathways.

Question 31

Significance of hexokinase not being present in the liver.

Answer 31

Prevents glucose from being permentantly trapped, uses glucokinase instead.

Question 32

In the liver phosphofructukinase is activated via [...] and inhibited via [...].

Answer 32

Fructose-2,6-Biphosphate; citrate

Question 33

How is pyruvate kinase regulated within the liver?

Answer 33

Allosteric effectors and covalent modification.

Question 34

Main reason excess fructose consumption can lead to pathological conditions.

Answer 34

Fructose when metabolized bypasses the most important regulatory step of glycolysis (i.e. step catalyzed by phosphofructokinase)

Question 35

Enzyme deficient in individuals with lactose intolerance.

Answer 35

Lactase

Question 36

Term, disruption of galactose metabolism.

Answer 36

Galactosemia

Question 37

Classic galactosemia is due to inherited deficiency in [...] activity.

Answer 37

Galactose 1-phosphate uridyl transferase

Question 38

Diagnostic of galactosemia.

Answer 38

Absences of galactose-1-phosphate uridyl transferase in RBCs

Question 39

As a result of galactose 1-phosphate uridyl transferase cataracts can form. This is because the enzyme aldose reductase reduces galactose to [...].

Answer 39

Galactitol

Question 40

Process, when rapidly growing tumor cells metabolize glucose to lactate even in the presence of oxygen.

Answer 40

Aerobic glycolysis/Warburg effect