Metabolism of Carbohydrates

Where is ATP present?

Every cell in the body (specifically the cytoplasm and nucleoplasm of the cell)

What is the energy currency of the body?

ATP

___ percent or more of carbs utilized by the body are used for ATP production

90

Component of ATP structure with the highest energy bond?

Triphosphate

What are the final product monomers of carbohydrate digestion? What about the final common pathway for all CHO in tissue cells?

Final product monomers are glucose, fructose and galactose with GLUCOSE being the final common pathway

Where are galactose and fructose converted to glucose during carb digestion?

Liver

Where is the largest amount of glucose phosphatase in the body? What does it do? Why?

Liver; converts glucose-6-phosphate to glucose so that the free glucose can be transported through liver membrane into the blood

What is the purpose of glucokinase?

Phosphorylation serves to capture the glucose in the cells because phosphorylated glucose (glucose-6-phosphate) cannot diffuse out of the cell

T/F - once the monosaccharides have entered the cell membrane, they dissociated from GLUT transporters

TRUE; they are only associated with the GLUT transporters when they are trying to enter the cell

This hormone increases facilitated diffusion of glucose

Insulin

How does insulin increase facilitated diffusion of glucose?

By causing a rush of GLUT carriers to the cell membrane to circulate glucose into the cell

After glucose is phosphorylated to glucose-6-phosphate in the cell, what are the two routes it can possibly take?

1) Glycolysis

2) Glycogen synthesis

Where is glycogen stored?

Liver or muscles

The MAKING of a polymer

Glycogensis

The process of glycogen breakdown to reform glucose

Glyogenolysis

T/F - glycogenolysis is the reverse of glycogensis

FALSE

In glycogenolysis, the glucose molecule on each branch of the glycogen polymer is split away by the process of phosphorylation by the enzyme of ____

phophorylase

What is phosphorylase activated by?

Epinephrine and glucagon (increased cAMP) - both of these are active in times of fasting or high activity so you need to break down your glycogen reserves via glycogenolysis

How many molecules of ATP is formed for each molecule of glucose in the glycolytic pathway?

38 ATP (2 ATP from glycolysis, 2 ATP from Citric acid cycle and 34 ATP from oxidative phosphorylation)

What are the steps of the glycolytic pathway in order?

1) Glycolysis

2) Acetyl-CoA formation

3) Citric Acid Cycle

4) Oxidative Phosphorylation

Which steps of the glycolytic pathway occur in the mitochandria?

Acetyl-CoA formation, Citric Acid Cycle and Oxidative Phosphorylation (glycolysis occurs in the cytoplasm)

What is produced from glyocolysis?

2 pyruvic acid molecules, 4 H and 2 ATP

What is produced from Acetyl-CoA formation?

2 Acetyl-CoA, 4H, NO ATP

What is produced from the Citric acid cycle?

16H and 2 ATP

What is produced from oxidative phosphorylation?

34 ATP

What creates 90 percent of the total ATP created during oxidative phosphorylation?

Oxidation of H atoms

What mechanism is used during oxidative phosphorylation?

Chemiosmotic mechanism

2 H make how many ATP in the electron transport chain

3 ATP

What enzyme utilizes H to convert ADP into ATP during oxidative phosphorylation?

ATP synthetase

In the electron transport chain, each electron is shuttled until it finally reaches what enzyme?

Cytochrome A3 (aka cytochrome oxidase)

T/F - oxidative phosphorylation can occur during low oxygen conditions

FALSE; only glycolysis can occur during low oxygen conditions

When glucose is lacking and amino acids and glycerol can be turned into glucose

Gluconeogenesis (REMEMBER - only 60 percent of amino acids in the body protein can be converted to carbs)

What increases gluconeogenesis?

Low levels of carbohydrates (because that means low levels of glucose)

T/F - monosaccharides can diffuse through the pores of the cell membrane

FALSE; monosaccharides cannot diffuse through the usual pores of the cell membrane so they must combine with PROTEIN CARRIERS (GLUT - glucose transporter or carrier) through facilitated diffusion

In the absence of oxygen, ____ is converted to lactate via the use of NADH

pyruvate (think - this is because pyruvic acid is a product of glyocolysis and that is the only process that can occur during the absence of oxygen)

How does the pentose phosphate shunt occur?

It removes one carbon atom from a glucose molecule to produce carbon dioxide and hydrogen that allow the hydrogen to eventually enter oxidative phosphorylation pathway to form ATP