Carbohydrates

Question 1

___ is the first step in cellular respiration.

Answer 1

Glycolysis

Question 2

What is the most common biological role of a kinase?

Answer 2

adding a phosphate group

Question 3

What two enzymes can be used in the first step of glycolysis: Glucose –> Glucose-6-Phosphate?

Answer 3

Hexokinase (present in most tissues) or Glucokinase (used by liver and some pancreatic cells)

Question 4

When do hexokinase and glucokinase each reach maximum velocity with reference to glucose concentration, respectively?

Answer 4

Hexokinase: reaches Vmax at low [glucose] (low Km)
Glucokinase: reaches Vmax at high [glucose] (higher Km)

Question 5

What inhibits hexokinase?

Answer 5

Glucose-6-Phosphate (negative feedback)

Question 6

What induces glucokinase?

Answer 6

Insulin secreted by hepatocytes.

Question 7

1,3-bisphosphoglycerate is an important molecule, because it stimulates the production of what two molecules during glycolysis?

Answer 7

ATP and NADH

Question 8

How does 1,3-bisphosphoglycerate stimulate ATP production during glycolysis?

Answer 8

in substrate level phosphorylation (non-oxygen dependent), one of it’s phosphates is removed to create an ATP
this is the only way to make ATP in glycolysis anaerobically

Question 9

How does 1,3-bisphosphoglycerate stimulate NADH production during glycolysis?

Answer 9

during it’s production, a H ion is removed from G3P to make 1,3-bisphosphoglycerate. This H ion reduces NAD+ into NADH.

Question 10

Name the only way to make ATP anaerobically during glycolysis.

Answer 10

non-oxygen dependant substrate level phosphorylation: a phosphate is taken from 1,3-bisphosphoglycerate during this process to make an ATP

Question 11

What type of feedback describes when intermediates from earlier steps are used to activate later steps in a process?

Answer 11

Feedforward Activation

Question 12

___ is a method of regenerating NAD+ from pyruvate in a anaerobic environment.

Answer 12

Fermentation

Question 13

Pyruvate can only make ATP in the presence of oxygen, so it won’t be missed when it’s made into ___ in fermentation.

Answer 13

Lactate

Question 14

In a ___ environment, pyruvate from glycolysis will be used to regenerate NAD+ via fermentation.

Answer 14

Anaerobic

Question 15

What is literally the only way to make ATP in glycolysis?

Answer 15

Substrate level phosphorylation of 1,3- bisphosphoglycerate and PEP (phosphoenolpyruvate)

Question 16

Why do red blood cells use bisphosphoglycerate mutase to convert 1,3-bisphosphoglycerate into 2,3-bisphoglycerate

Answer 16

the red blood cells use 2,3-BPG to ensure that oxygen is released from hemoglobin in the peripheral tissues

Question 17

What is the effect that causes the decrease in oxygen affinity to hemoglobin due to 2,3-BPG (bisphosphoglycerate) in the peripheral tissues?

Answer 17

the Bohr effect