TA Questions

Question 1

Carbohydrate Absorption Order

(11 things)

Answer 1

1. •Large Polysaccharides
2. •Ptyalin digests polysaccharides 5% of carbs- hydrolysis
3. •Residual ptyalin digests polysaccharides
4. •pH lowers and disrupts enzyme activity
5. •Pancreatic amylase/bicarbonate/sodium secretion
6. •Maltose, lactose, sucrose, glucose polymers
7. •Lactase, sucrose, maltase, and dextrinase – brush boarder oligosaccharidases
8. •Glucose, Galactose, Fructose (purposefully left out- due to next question)
9. •Sodium ions exit basolateral side of epithelial cells via active transport
10. •Sodium ion levels inside the epithelial cell drop
11. •Facilitated Diffusion: Sodium + Transport Protein + Glucose or Galactose

Question 2

Fructose + Glucose

vs.

Glucose alone

Answer 2

SGLT1 channel can only operate at max 1g glucose/minute.

Adding fructose via another channel can increase carb oxidation!!!

(delays fatigue and decreases percieved exertion)

Question 3

Similarities: Carb & Protein Digestion

Answer 3

1. Digestion is done via Hydrolysis
2. Most Digestion done via pancreatic enzymes (Trypsin, Chymotrypsin, Carboxypolypepidase, Proelastase)
3. Pancreatic enzymes do not fully digest products (dipeptides, disaccharides)
4. Membrane enzymes continue to break down products (aminopolypeptidase and dipeptidases)
5. Transport driven by Sodium co-transporter (some Amino Acids and Glucose/Glactose)
6. Fructose and some Amino Acids use facilitated diffusion without sodium

Question 4

Differences: Carb & Protein Digestion

Answer 4

Carbs:

1. Low pH of the stomach turns on digestive enzyme of protein (pepsin) – vs turns off digestive enzyme of carbohydrates
2. Monosaccharides are the only form that can pass into cell- small peptides can pass through
3. Uses Hydrogen Co-transporter
4. Enzymes within the cell continue to digest dipeptides and tripeptides

Question 5

Fat Absorption

Answer 5

1. monoglycerides and fatty acids pass through the apical side of the epithelial cells via: Passive diffusion**- or incorporated into the membrane – or **carrier mediated transport
2. Bile micelles get recycled to be used again
3. Smooth Endoplasmic Reticulum takes up the monoglycerides and fatty acids within the cell and they become chylomicrons
4. chylomicrons are exported to lymphatic capillary
5. Short and medium chain fatty acids can be absorbed directly into the blood
6. Small amounts of short and medium chain fatty acids are absorbed directly into portal blood because short chain FAs are water-soluble and not converted to TAGs by ER
7. Direct diffusion of short chain fatty acids from intestinal epithelial cells go directly into the capillary blood of the intestinal villi