Biochemistry 460 Lecture 26 - Glycolysis 1

Front 1

What is lactose intolerance caused by?

Back 1

It is caused by reduced levels of the digestive enzyme lactase, which is required to hydrolize the dissacharide sugar lactose to form glucose and galactose.

Front 2

What does purified lactase enzyme, which is commercially available, accomplish for its users?

Back 2

It reduces the symptoms that occur when bacteria of the Lactobacillus family convert lactose to methane and hydrogen gases in the small intestine.

Front 3

What 3 reasons causes glycolysis to be considered one of the core metabolic pathways in nature?

Back 3

Glycolytic enzymes are highly conserved amongst all living organisms. It is the primary pathway for ATP generation under anaerobic conditions. Metabolites of glycolysis are precursors for a large number of interdependent pathways, including mitochondrial ATP synthesis.

Front 4

What does Glycolysis accomplish for the cell?

Back 4

It generates a small amount of ATP which is critical under anaerobic conditions. It generates pyruvate, a precursor to acetyl CoA, lactate, and ethanol (yeast)

Front 5

What is the overall net reaction of glycolysis?

Back 5

Glucose + 2 NAD+ + 2ADP + 2 Pi --> 2 Pyruvate + 2 NADH + 2H+ + 2 ATP + 2 H2O

Front 6

What are the key enzymes in glycolysis?

Back 6

Hexokinase - commitment step in glycolysis, inhibited by glucose-6-P. Phosphofructokinase - activated by AMP and F-2,6-BP, inhibited by ATP and citrate. Pyruvate kinase - activated by AMP and fructose-1,6-bisphosphate, inhibited by ATP and acetyl CoA

Front 7

What are examples of glycolysis in real life?

Back 7

A deficiency in the hexokinase-related enzyme glucokinase, leads to a rare form of diabetes which is caused by the inability of liver and pancreatic cells to phosphorylate glucose inside cells when blood glucose levels are elevated.

Front 8

What does glycolysis generate?

Back 8

It generates a small amount of ATP

Front 9

Where does glycolysis take place?

Back 9

It takes place entirely in the cytosol

Front 10

Does glycolysis require oxygen?

Back 10

It does not require oxygen

Front 11

Does complete oxidation of glucose to CO2 and H2O require oxygen?

Back 11

Yes

Front 12

How many ATP does glycolysis yield?

Back 12

It yields 2 ATP out of the total 32 (6%)

Front 13

Coupled reactions accomplish what for glycolysis?

Back 13

Coupled reactions allow reactions that would normally have positive delta G values to instead have negative values.

Front 14

The five enzymatic reactions of glycolysis first accomplish what task?

Back 14

Using ATP as the phosphate donor, they create phosphorylated compounds that are negatively charged and cannot diffuse out of the cell.

Front 15

The five enzymatic reactions of glycolysis accomplish what after using ATP as the phosphate donor to create phosphorylated compounds?

Back 15

The aldolase reaction in step 4 splits the six carbon fructose-1,6-BP compound into two halves.

Front 16

What is reaction 2 of glycolysis?

Back 16

It is the isomerization of glucose-6-P to fructose-6-P by phosphoglucose isomerase

Front 17

What does phosphoglucose isomerase accomplish?

Back 17

It interconverts an aldose and a ketose through a multi-step pathway that involves opening and closing of the ring structure.

Front 18

What is reaction 4 of glycolysis?

Back 18

It is the cleavage of fructose-1,6-BP into glyceraldehyde-3-P and dihydroxyacetone-P by aldolase

Front 19

What is reaction 5 of glycolysis?

Back 19

It is the isomerization of dihydroxyacetone-P to glyceraldehyde-3-P by triose phosphate isomerase.