9/13/24 - Digestion and Metabolism (Reading 4) Lecture Questions

What is another name for Anaerobic Respiration?

When does it occur?

Incomplete Glucose Oxidation

Occurs when Oxygen is lacking

What are some reasons we may use Anaerobic Respiration?

1. Lack of Oxygen (O2)

2. Problem with Mitochondria in the cell

3. Lack Mitochondria in the cell (Ex. RBCs)

What are the inputs of Glycolysis in Anaerobic Respiration?

Outputs?

Where does it occur?

Inputs:

• 1 Glucose

• 2 ATP

• 2 NAD+

• 4 ADP

Outputs:

• 2 ADP

• 2 NADH

• 4 ATP

• H2O Byproduct

Occurs in the Cytoplasm

What is the main input of Fermentation?

What enzyme is used?

What is the main output?

2 Pyruvate

Lactate Dehydrogenase

Lactate

What happens to the Lactate after Fermentation?

Moved to Liver and converted into Glucose via Gluconeogenesis

What is Lipogenesis?

Formation of Triglycerides from Fatty Acids and Glycerol

What is Lipolysis?

Breakdown of Triglycerides into Fatty Acids and Glycerol

What steps are used to turn stored Triglycerides into Ketones?

What are Ketones used for?

1. Stored Triglycerides broken down into Fatty Acids & Glycerol through Lipolysis

2. Fatty Acids undergo Beta-Oxidation to form Acetyl-CoA

3. Excess Acetyl-Coa unders Ketogenesis to form Ketones

Ketones are an energy source that can be used by the body and the brain

Does Carbohydrate Metabolism produced more ATP than Lipid Metabolism?

No

What is the byproduct of Ketogenesis?

What happens when these byproducts and Ketones are produced?

What condition can occur as a result?

CO2

CO2 and Ketones turn the blood Acidic (lower the pH)

Ketoacidosis / Metabolic Acidosis (too much acid)

Where are excess Triglycerides stored?

In Adipose / Fat tissue or the Liver

How can we use excess Acetyl-CoA from Pyruvate Oxidation?

Can either turn it into Fatty Acids to go through Lipogenesis and form Triglycerides, or

use it to synthesize Cholesterol which is used to synthesize Steroid Hormones and Bile (by the Liver)

How can we eliminate excess Amino Acids?

1. Deaminate the amino acids (remove the —NH2) to produce Ammonia (NH3)

2. Ammonia travels to Liver, where it is converted into Urea

3. Urea travels to Kidneys and is eliminated through Urine

What is the Absorptive State?

What processes happen during this state?

How does this affect the plasma concentrations of Glucose, Fatty Acids, and Amino Acids?

Does Insulin or Glucagon dominate?

Also called the Fed State; state where the body is absorbing nutrients

Increase Glycolysis, Glycogenesis, Lipogenesis, and Proteogenesis

All concentrations would go DOWN

Insulin dominates

What processes occur in response to higher Insulin secretion within these target tissues?:

• Most tissues in general

• Adipose Tissue

• Liver and Skeletal Muscles

• Liver

Most tissues:

• MORE glucose uptake

• MORE amino acid uptake

• MORE proteogenesis

• LESS proteolysis

Adipose Tissue:

• MORE Lipogenesis

• LESS lipolysis

Liver and Skeletal Muscles:

• MORE glycogenesis

• LESS glycogenolysis

Liver:

• MORE lipogenesis

• LESS gluconeogenesis

What is the Post-Absorptive State?

What processes happen during this state?

Why is it important that these processes occur?

Does Insulin or Glucagon dominate?

Also called the Fasted State; state where there is no food intake

Increased Glycogenolysis, Gluconeogenesis, and Ketogenesis

These processes provide substrates for the body to live and prevent Hypoglycemia

Glucagon dominates

What causes Glucagon secretion?

What will happen to the level of glucose in the blood?

What will happen to the level of fatty acids in the blood?

Protein Synthesis is decreased. How does this affect the level of amino acids in the plasma?

Were any fuel storages increased?

Lower Blood Glucose levels

Increases

Increases

Increases

No, we are breaking them down

What processes occur in response to higher Glucagon secretion within these target tissues?:

• Liver

• Adipose Tissue

Liver:

• HIGH glycogenolysis

• LOW glycogenesis

• HIGH gluconeogenesis

• HIGH ketogenesis

• HIGH proteolysis

• LOW proteogenesis

Adipose Tissue:

• HIGH lipolysis

• LOW lipogenesis