lec 2

Question 1

defect in the intestinal A.A transport system are seen in inborn errors of metabolism

Answer 1

1. HARTNUP DS

2. Cystinuria + slide 25

Question 2

Peptide Absorption

Answer 2

More rapid than absorption of free A.A
• Active transport
Metabolized into free A.A in enterocyte
• Only free A.A absorbed into blood

Question 3

Free Amino Acid Absorption

Answer 3

active transport
Carrier systems
• Neutral AA
• Basic AA
• Acidic AA
• Imino acids

Question 4

Absorption of Intact Proteins Newborns

Answer 4

– First 24 hours after birth
– Immunoglobulins
• Passive immunity

Question 5

Absorption of Intact Proteins Adults

Answer 5

– Paracellular routes
• Tight junctions between cells 
– Intracellular routes
• Endocytosis
• Pinocytosis

Question 6

Enterokinase or enteropeptidase)

Answer 6

• Trypsinogen  trypsin

* Trypsin then activates all the other enzymes

Question 7

Dipeptidases

Answer 7

Cleave dipeptides into Aas

Question 8

Aminopeptidases

Answer 8

Cleave at N-terminal AA

Question 9

In the Enterocytes

Answer 9

• First cells that can use the amino acids 
–Transport into portal blood
–Protein synthesis
•Digestive enzymes
• Structure and growth
–Energy

Question 10

Abnormalities in the protein digestion

and amino acid absorption

Answer 10

Defect in the pancreatic secreation.

Defective carrier system

Question 11

Defect in the pancreatic secreation

Answer 11

Cystic fibrosis,

Question 12

Cystic fibrosis,

Answer 12

,incomplete digestion of fat and protein,results in abnormal appearance of lipids (steatorrhea) and proteins in fece

Question 13

Glycerol absorption short and medium chain fatty acids

Answer 13

directly absorbed from the intestinal lumen → portal vein → liver for further utilization

Question 14

free cholesterol and βacyl glycerol absorption

Long chain fatty acids,

Answer 14

bile salts form mixed micelles.

Question 15

Mixed micelles are

Answer 15

soluble in the aqueous environment of the intestinal lumen

Question 16

monoglycerides and fatty acid

Answer 16

diffuse across the plasma membrane of the enterocyte.

NOT the micelles

Question 17

Lysophospholipids are recycled to form

Answer 17

phospholipids

Question 18

Cholesterol is re acylated to form

Answer 18

Cholesteryl esters

Question 19

Long chain fatty acids are used for

Answer 19

esterification to form

TGs, phospholipids and cholesteyl esters.

Question 20

Short and medium chain fatty acid are released in to

Answer 20

the portal circulation and are carried by serum albumin to liver.

Question 21

1-monoacyglycerols are hydrolyzed to

Answer 21

fatty acids and glycerol

Question 22

2-

monoacylglycerols are re-acylated

Answer 22

triacylglycerols via the monoacylglycerol pathway.

Question 23

Lipid malabsorption results in

Answer 23

increased lipids
including fat soluble vitamins A,D E and K in the
feces.

Question 24

Lipid Malabsorption(Steatorrhea) Cause

Answer 24

pancreatic insufficiency, including
cystic fibrosis , chronic diseases of pancreas or
surgical removal of pancreas
 Shortened bowel, Celiac diseases, sprue or
crohn’s disease
May be bile duct obstruction due to gall stones,
tumor of head of pancreas, enlarged lymph nodes
etc.
Milk and coconut oil are used therapeutically
since they contain medium chain fatty acids

Question 25

Secretion of lipids from enterocytes

Answer 25

40

Question 26

Physiologically important lipases

Answer 26

43

Question 27

fructose شو نوع الtransporter

Answer 27

GLUT 5,

Question 28

fructose (type of transportation )

Answer 28

down the gradient

Question 29

GLUT 2 transporter transports

Answer 29

glucose into blood.

Question 30

Pentoses type of transportation

Answer 30

passive diffusion

Question 31

Cancer cells express high level of

Answer 31

GLUT-1 and 3