Nutrition - Protein, Lipids - Skildum

Question 1

What converts pepsinogen to pepsin?

Answer 1

H+

Question 2

What converts trypsinogen to trypsin?

Answer 2

Enteropeptidase

Question 3

What converts chemotrypsin to chymotrypsin?

Answer 3

Trypsin

Question 4

What converts proelastase to elastase?

Answer 4

Trypsin

Question 5

Trypsin converts procarboxylpeptidases to what?

Answer 5

Carboxypeptidases

Question 6

Trypsin cuts behind what AA?

Answer 6

Arginine and Lysine

Question 7

In cystic fibrosis, secretion of what is deficient due to blockage of pancreatic duct? What happens to protein and nutrients needed in GI tract?

Answer 7

In patients with cystic fibrosis, secretion of proteases is deficient because of blockage of the pancreatic duct. Malabsorption of protein an other nutrients can result.

Question 8

Which of these can be transported into gut epithelial cells?
Tripeptides
Dipeptides
Amino acids

Answer 8

All of them.

Question 9

How are AA transported across intestinal epithelial cells?

Answer 9

Amino acids are transported across intestinal epithelial cells using secondary active transport.

Question 10

Describe the specificity of AA transporters in GI tract?

Answer 10

Amino acid transporters have overlapping substrate specificity.

Question 11

Describe the pathophysiology of Hartnup disease. What mutation is involved? What symptoms would you expect?

Answer 11

Inherited mutations in the SLC6A9 transporter (Bo) result in Hartnup disease. This condition results in the symptoms of pellagra because tryptophan is not absorbed or resorbed and can not be used to synthesize niacin.

Pathology: “3 D’s.” Dementia, Dermatitis, and Diarrhea

Question 12

Describe the pathophysiology of cystinuria. What is the primary presenting symptom?

Answer 12

Inherited mutations in SLC7A9 (B0+) or SLC3A1 (rBAT) cause cystinuria. Patients develop kidney stones.

Question 13

What is the oxidized form or cysteine?

Answer 13

Cystine

Question 14

The balance between protein synthesis and degradation is sensitive to what?

Answer 14

The balance between protein synthesis and degradation is sensitive to the metabolic state in the cell.

Question 15

What is the relationship between mTORC1 and AMPK? Which is upstream in their relationship?

Answer 15

The mTORC1 complex activates protein synthesis and inhibits autophagy.
Activation of AMPK inhibits protein synthesis and promotes autophagy.

AMPK is upstream.

Question 16

What is the role of PLP and what is seen with deficiency?

Answer 16

transaminations, deaminations, carbon chain transfers

seizures, diarrhea, anemia, EEG abnormalities

Question 17

What is the role of FH4 and what is seen with deficiency?

Answer 17

One carbon transfers

Magaloblastic anemia

Question 18

What is the role of BH4 and what is seen with deficiency?

Answer 18

Ring hydroxylations (e.g. Phe –>Tyr)

Seizures, developmental delays

Question 19

What are two fatty acid derivatives that cause contraction of LES?

Answer 19

Prostaglandins and Thromboxanes

Question 20

Bile salts do what to fat?

Answer 20

They micellate the fats and increase their surface area.

Question 21

The hormones secretin and cholecystokinin promote secretion of what?

Answer 21

The hormones secretin and cholecystokinin promote secretion of bile and lipases into the lumen of the gut.

Question 22

What are the products of pancreatic lipase?

Answer 22

The products of pancreatic lipase are two fatty acids and 2-monoacylglycerol.

Question 23

What are the products and substrates of cholesterol esterase?

Answer 23

cholesterol ester –> fatty acid + cholesterol

Question 24

What are the products and substrates of Phospholipase A2?

Answer 24

phospholipid –> fatty acid + lysophospholipid

Question 25

Fatty acids are re-esterified to 2-monoacylglycerol to make what in intestinal epithelial cells?

Answer 25

Fatty acids are re-esterified to 2-monoacylglycerol to make triacylglycerol in intestinal epithelial cells.

Question 26

What is the major apoprotein for chylomicrons?

Answer 26

ApoB-48 is the major apoprotein of chylomicrons.

Question 27

How is ApoB created and what is the unedited form?

Answer 27

RNA editing. The unedited transcript produces full length ApoB-100 in hepatocytes.

Question 28

What do chylomicrons receive from HDL once they enter the blood?

Answer 28

After chylomicrons enter the blood, they receive ApoCII and ApoE from high density lipoprotein (HDL).

HDL’s function is to maintain cholesterol and apoprotein homeostasis.

Question 29

What is LPL activated by?

Answer 29

Lipoprotein lipase (LPL) is an extracellular lipase in the capillary beds of muscle and adipose tissue. It is activated by ApoCII.

Question 30

What is the role of the chylomicron?

Answer 30

Transport DIETARY fat.

Question 31

What is role of VLDL?

Answer 31

Transport fat generated from CARBOHYDRATES

Question 32

Fatty acids and cholesterol taken up by the liver from [ ] can be repackaged with [ ] as very low density lipoprotein (VLDL).

What is the similarity between VLDL and chylomicrons?

Answer 32

Fatty acids and cholesterol taken up by the liver from chylomicron remnants can be repackaged with ApoB100 as very low density lipoprotein (VLDL).

VLDL serves a similar function as chylomicrons: To deliver fatty acid fuels to the tissues of the body.

Question 33

(T/F) Adipose can only store fatty acids as triacylglycerol in the fed state.

Answer 33

True. Adipose can only store fatty acids as triacylglycerol in the fed state, because the glycerol 3-phosphate backbone can only be produced by glycolysis in adipocytes.

Adipose tissue can take up fatty acids from chylomicrons or VLDL particles.

Question 34

Which has the highest % of cholesterol?

HDL, LDL, ILDL, VLDL, Chylomicron

Answer 34

LDL