Chemical and Mechanical Digestion

Question 1

What are the 3 layers of stomach smooth muscle fibres?

Answer 1

• Circular
• Longitudinal
• Oblique

Question 2

What are the Acid and Enzyme that work in the stomach?

Answer 2

Hydrochloric Acid and Pepsin?

Question 3

What important roles does HCL play in the stomach?

Answer 3

• Kills most microorganisms ingested with food
• Aids in breakdown of food
• Uncoils proteins exposing more of the peptide bonds for enzymatic attack
• Activates the Pepsin enzyme

Question 4

What does Pepsinogen and Pepsin do?

Answer 4

Pepsinogen combines with HCL to produce Pepsin.

Pepsin cleaves peptide bonds of proteins to yield small peptides

Question 5

What protects the stomach lining from acid damage?

Answer 5

Stomach secretes alkaline salts and a mucous carpet to protect underlying tissue

Question 6

What does the stomach absorb?

Answer 6

Alcohol and Aspirin

Question 7

Which hormones stimulates the release of pancreatic juice?

Answer 7

CCK for Pancreatic enzymes

Secretin for bicarbonate buffer from pancreas

(Both secreted by SI mucosa)

Question 8

Which hormones are produced by the pancreas?

Answer 8

Insulin & Glucagon

Question 9

What enzymes does the Pancreas secrete?

Answer 9

Pancreatic Amylase for carbohydrate digestion

Pancreatic Lipase for fat digestion

Proteolytic Enzymes for protein digestion

Question 10

Provide a Summary of Protein Digestion

Answer 10

Gastric pepsin and pancreatic proteases turn protein into small peptides.

Peptidases in the microvilli turn them into amino acids. They then go to the intestinal epithelial cells and then the blood

Question 11

Explain the digestion of complex carbohydrates and polysaccharides

Answer 11

Salivary Amylase cleaves large molecules into starch and glycogen.

The Pancreatic Amylase digests polysaccharide to disaccharides

Then BB enzymes digest disaccharides to monosaccharides

Question 12

What are the 2 reagents required for fat digestion?

Answer 12

• Pancreatic Lipase

Lipase breaks down triglycerides into FFAs and Monoglyceride

• Base Salts

Intestinal movements break up large fat droplets into smaller ones (mechanical digestion)

Question 13

What is the difference between Catabolism and Anabolism?

Answer 13

Catabolism is the break down of complex molecules and polymers energy is captured to produced ATP or given off as heat

Anabolism is the synthesis gf complex macromolecules ATP is consumed

Question 14

What is Metabolism?

Answer 14

The chemical reactions that occur in the body that are necessary to sustain life

Question 15

How does the body convert carbohydrates, proteins and lipids into energy?

Answer 15

Biochemical reactions in the body break/rearrange the bonds that hold the molecule together

Results in the transfer of electrons

Relocation of electrons releases energy which is eventually used to make ATP

Question 16

What is the difference between oxidation and reduction?

Answer 16

OIL - Oxidation is loss of electrons

RIG - Reduction is the gaining of electrons

Question 17

How does glucose move into cells?

Answer 17

Glucose passes through the plasma membrane by facility diffusion (GLuT transporters mostly perform this)

Insulin increases the insertion of GLuT4 transporters into the membrane hence increasing rate of diffusion

Question 18

What do Insulin Receptor molecules do?

Answer 18

Insulin binds to Insulin Receptors located on fat, liver and muscle cells

Binding activates GLUT4 which signals to uptake glucose into cell