Question

Please include an explanation, thanks!

1. Explain the processes of carbohydrate and protein digestion indicating the site of the gastrointestinal tract, and the enzymes involved.

2. What are the major end products of carbohydrate digestion? How is each end product absorbed?

3. What are the mechanistic differences between skeletal muscle and smooth muscle contraction?

Answer 1

1. Digestion of carbohydrates -

a. Mouth - salivary -alpha-amylase or ptyalin helps in digestion of carbohydrates in to dextrins and maltose.

b. Stomach - Hcl of gastric juice may hydrolyse some sucrose.

c. Duodenum - alpha-amylase of pancreatic juice converts starch in to maltose.

Digestion of proteins -

a. Mouth - No digestion occurs in mouth.

b. Stomach - pro-active enzymes such as pepsinogens becomes activated and acts on proteins to convert them in to free amino acids.

Ex . Pepsin, trypsin etc.

2. The major end products of carbohydrate digestion are - dextrins and maltose. These are monosaccharides and movement across the cell in to blood.

a. Simple diffusion - when conc of sugar exceeds than that of blood.

b. Active transport - absorption of sugars against their conc gradient in to blood.

3. Skeletal muscle contraction -

a. Contains troponin in thin filaments helps in contraction.

b. Cannot contract with out nerve stimulation.

Smooth muscle contraction -

a. Contains calmodulin a protein when bound to Ca+2 , activates the enzyme myosin light chain kinase helps in contraction.

b. Maintains contraction with out nerve stimulation.