Nutrient Absorption

Question 1

What are the 2 forms of carbs?

Answer 1

Simple

• Monosaccharides (glucose, galactose, fructose)
• Disaccharides (Sucrose, lactose, maltose

Complex

• Starch (plant storage of glucose)
• Glycogen (animal storage of glucose)

Question 2

Out of simple and complex carbs, which ones are readily absorbed?

Answer 2

Only monosaccharides

-disaccharides, starch and glycogen all need chemical digestion before they can be absorbed

Question 3

Are carbs digested in the mouth?

Answer 3

Yes, if carbs contain starch salivary amylase will start to turn it into maltose

Question 4

Are carbs digested in the stomach?

Answer 4

no, salivary amylase is inactivated because of the stomach acid

Question 5

Are carbs digested in the small intestine?

Answer 5

Yes, but the brush border enzymes

Question 6

What are the brush border enzymes?

Answer 6

Lactase- lactose into glucose and glycogen
Sucrase- sucrose into glucose and fructose
Maltase-maltose into glucose and glucose

Question 7

How are starch and glycogen digested into monosaccharides?

Answer 7

Amylase breaks them down to disaccharides and then brush border enzymes break them down into monosaccharides

Question 8

How are glucose and galactose absorbed through the luminal side?

Answer 8

Trough Glucose/ galactose and Na symporter with Na concentration gradient
-because they have the same carbon configuration

Question 9

How is fructose absorbed on the luminal side?

Answer 9

Fructose uniporter because it is a different carbon configuration and normally low levels in the body

Question 10

How are sugars moved from the basolateral side to the interstitial fluid and then blood?

Answer 10

Moves through a monosaccharide (sugar) uniporter. Once in interstitial space, sugars diffuse into the capillaries

Question 11

How do we maintain Na concentrations in the epithelial cells of small intestines?

Answer 11

Through Na/KATPase pump

Question 12

What are sources of protein?

Answer 12

Plant
Animal
-different and same aminos for each group

Question 13

What are essential amino acids?

Answer 13

Those that we require from food that our body can not make

Question 14

Is there digestion of protein in the mouth?

Answer 14

No chemical because there are no enzymes but there is mechanical digestion due to chewing

Question 15

Is there protein digestion in the stomach?

Answer 15

Yes, pepsin in the stomach breaks down polypeptides into smaller peptide strands

Question 16

Is there protein digestion in the small intestine?

Answer 16

Yes

• Aminopeptidase and dipeptidase
• Pancreas secretion of trypsin, chymotrypsin, carboxypeptidase (all activated in small intestine)

Question 17

What are exopeptidase?

Answer 17

Enzymes that cut one amino acid off either end of a polypeptide
-aminopeptidase and carboxypeptidase

Question 18

What are endopeptidases?

Answer 18

Enzymes that cut polypeptides in the middle to form smaller peptides

Question 19

How are di and tripeptides absorbed?

Answer 19

Enter through the luminal membrane via H/di and tripeptide symporter
-they either remain as di and tripeptides and exit via Na/di and tripeptide exchanger or they are broken down into single amino acids

Question 20

How are single amino acids absorbed?

Answer 20

Enter through the luminal membrane via Na/AA symporter and exit through Na/AA exchanger

Question 21

How are peptides absorbed?

Answer 21

Common in infants but through endo and exocytosis

Question 22

What is a triglyceride?

Answer 22

glycerol backbone with 3 fatty acid chains

-chains do not have to be the same, can have different amount of carbon and can be saturated and unsaturated

Question 23

Is there fat digestion in the mouth?

Answer 23

Yes, lingual lipase is present but does not work in the mouth

Question 24

Is there fat digestion in the stomach?

Answer 24

Yes, this is where lingual lipase is activated due to the acidic environment.
-Gastric lipase is also there and ready

Question 25

Is there fat digestion in the small intestine?

Answer 25

Yes, pancreatic lipase does the best job at digesting fat (with the help of collapse)
-liver secretes bile which also helps

Question 26

What are chylomicrons?

Answer 26

Repacking of lipids within cells into carriers to allow for transport in the body

Question 27

What are the functions of the lipases?

Answer 27

Within the fat droplet ball after mixing, they break down the triglyceride into di,mono and free fatty acids

Question 28

What is the role of colipase?

Answer 28

Is able to move bile salts aside on the fat droplet in order to let lipase in and start breaking down the triglycerides

Question 29

How are lipids absorbed?

Answer 29

When large lipid droplets are broken down via SI into smaller drops, the bile salts attach sound the outside. Colipase separates bile salts to allow pancreatic lipase to enter and break down triglycerides in the droplet. Once broken down into monoglycerides and fatty acid chains and if the micelles are close enough to the cell membranes, the fatty acids and monoglycerides diffuse into the cell, and are repacked by the smooth ER into chylomicrons in which those are leased into the lymphatic vessels

Question 30

What are chylomicrons?

Answer 30

Reformed balls of fatty acids and monoglycerides in the cell by smooth ER.
-transportation form of the lipids to other cells and throughout the body

Question 31

What makes a chylomicron different from a micelle?

Answer 31

Chylomicrons are protected with a protein shell

Micelles have bile salts surrounding the outside

Question 32

How to chylomicrons exit the cell and enter the lymph?

Answer 32

Exit via exocytosis

Enter via pores

Question 33

What are the fat soluble vitamins?

Answer 33

ADEK

Question 34

What are the water soluble vitamins?

Answer 34

CB(except b12)

Question 35

How to water soluble vitamins enter the cell?

Answer 35

Through transporters on the cell membrane in order to bring them in

Question 36

What does intrinsic factor help with?

Answer 36

With transport of water soluble vitamins into the cell