L10: Digestion And Absorption Of Carbohydrate And Protein

Question 1

What are the dietary carbohydrates

Answer 1

Monosaccharides
Oligosaccharides
Polysaccharides

Question 2

Which dietary carbohydrates can the small intestine only absorb

Answer 2

Monosaccharides only

Question 3

What do dietary fibres consist of

Answer 3

Insoluble and soluble fibres

Question 4

What are oligosacharrides

Answer 4

Short polymers

Question 5

What is the most common form of dietary carbohydrates

Answer 5

Starch (polysaccharides)

Question 6

What does starch consist of

Answer 6

Amylose and amylopectin

Question 7

What is the structure of amylose

Answer 7

Straight chain polymer with alpha-1,4 linkage

Question 8

What is the structure of amylopectin

Answer 8

Branched polymer with alpha-1,4 and alpha-1,6 linkage

Question 9

What is the structure of glycogen

Answer 9

Branched structure with alpha-1,4 and alpha-1,6 linkage.

More branched than amylopectin

Question 10

What is the second most common form of dietary carbohydrates

Answer 10

Disaccharides of sucrose and lactose

Question 11

What is the least common form of dietary carbohydrates

Answer 11

Monosaccharides of fructose and glucose

Question 12

If the small intestine can only absorbed monosaccharides what happens to polysaccharides and disaccharides

Answer 12

They are digested into monosaccharides for absorption

Question 13

What are the two step process of digestive process

Answer 13

1) intraluminal hydrolysis

2) membrane digestion

Question 14

What is intraluminal hydrolysis

Answer 14

Starch is digested to oligosaccharides by salivary and pancreatic amylase

Question 15

What is membrane digestion

Answer 15

Oligosaccharides are digested into monosaccharides by brush border disachharidases

Question 16

What are the enzymes involved in luminal digestion

Answer 16

Salivary Amylase and pancreatic amylase

Question 17

Where does salivary amylase take action

Answer 17

Mouth

Question 18

What is salivary amylase inactivated by

Answer 18

Gastric acid

Question 19

What triggers pancreatic amylase

Answer 19

CCK which is secreted by I-cells

Question 20

Which cell synthesises amylase

Answer 20

Salivary and pancreatic Acinar cells

Question 21

Is amylase and exo or endoenzyme

Answer 21

Endoenzyme

Question 22

What does endoenzyme mean

Answer 22

Cleaves within a chain (internal linkages not terminal linkages)

Question 23

What products does the digestion of starch by amylase give

Answer 23

Maltose
Maltotriose
Alpha-limit dextrins (branched points)

Question 24

What are disaccharides enzymes involved in membrane digestion

Answer 24

Lactase
Maltase
Sucrase
isomaltase

Question 25

What is the substrate of lactase

Answer 25

Lactose

Question 26

What products is lactose digested into by lactase

Answer 26

Glucose | Galactose

Question 27

What is the substrate of maltase

Answer 27

Maltose

Question 28

What are the products of maltose

Answer 28

Glucose

Question 29

What is the substrate of sucrose

Answer 29

Sucrose

Question 30

What are the products of sucrose

Answer 30

Glucose | Fructose

Question 31

What is the substrate of isomaltase

Answer 31

Alpha limit dextrins

Question 32

What linkages does isomaltase break that any other enzyme cannot

Answer 32

Alpha-1,6 linkages

Question 33

What linkage does lactase, maltase and sucrase digest

Answer 33

Alpha-1,4 linkage

Question 34

What are the monosaccharides that are absorbed by the small intestine

Answer 34

Glucose Galactose Fructose

Question 35

How are the monosaccharides absorbed by the small intestine

Answer 35

Two step process

Question 36

What does the two step process absorption by the small intestine involve

Answer 36

1) uptakes across apical membrane into epithelial cell | 2) exit across basolateral membrane

Question 37

What occurs at the apical membrane for glucose

Answer 37

Get brought into the epithelial cell by SGLT1

Question 38

What occurs at the apical membrane for galactose

Answer 38

Get brought into the cell by SGLT1

Question 39

What occurs at the apical membrane for fructose

Answer 39

Get brought into the cell by GLUT5

Question 40

Which glucose transporter effluxes glucose, galactose and fructose

Answer 40

GLUT2

Question 41

What type of transport does SGLT1 do

Answer 41

Secondary Active transport

Question 42

Why does active transport with SGLT2 occur

Answer 42

Glucose is influxed against its glucose concentration gradient

Question 43

How does secondary active transport of SLGT1 occur

Answer 43

Sodium ions is influxed with glucose via SGLT1 | Sodium ions are effluxed on the basolateral membrane by a sodium potassium pump

Question 44

What type of transport does GLUT5 do

Answer 44

Facilitated diffusion

Question 45

What are the transporters on the apical membrane of the small intestine

Answer 45

SGLT1 | GLUT5

Question 46

What are the transporters on the basolateral membrane

Answer 46

GLUT2

Question 47

What happens in lactase defiency

Answer 47

Body cannot break down lactose to glucose | Lactose is fermented by colonic bacteria to give increase in H2

Question 48

Where does protein come from

Answer 48

Dietary | Endogenous

Question 49

What are endogenous proteins

Answer 49

Enzymes Hormones Desquamated cells Etc

Question 50

What form of protein can be absorbed by the small intestine

Answer 50

Amino acids | Oligopeptides

Question 51

What are the enzymes that digest protein

Answer 51

Gastric peptidase | Pancreatic peptidase

Question 52

What are the products of the digestion of proteins

Answer 52

Oligopeptides | Amino acids

Question 53

What are the mechanism of absorption of oligopeptides and amino acids

Answer 53

1) amino acids are absorbed by amino acid transporters on the apical membrane and transported into the interstitial space 2) oligopeptides are Brocken down by peptidase on the apical membrane to give amino acids which are absorbed 3) oligopeptides are Brocken down by peptidases and oligopeptide is absorbed by PepT1. Oliogopeptide is Brocken down into amino acids inside the cell which are then taken transported into the interstitial space 4) oligopeptideis absorbed by PepT1 and makes it straight into the interstitial space

Question 54

How do you trigger protein digestion via the proteases in the stomach

Answer 54

Gastric chief cell is activated by ach to secrete pepsinogen (inactive) which is activated to pepsin by low ph

Question 55

How are gastric and pancreatic proteases secreted

Answer 55

As pro-enzymes

Question 56

What are the 5 pancreatic enzymes (inacitve)

Answer 56

``` Trypsinogen Chymotrypsinogen Proelastase Procarboxypepase A Procarbocypepase B ```

Question 57

What activates trypsinogen to trypsin

Answer 57

Enterokinase

Question 58

Where is enterokinase found

Answer 58

On the gut wall

Question 59

What does trypsin do

Answer 59

Activate the rest of the enzymes

Question 60

What is the action of endopeptidases

Answer 60

Enzymes that give off oligopeptides

Question 61

What are the endopeptidases

Answer 61

Trypsin Chymotrypsin Elastase

Question 62

What is the action of exopeptidase

Answer 62

Give off amino acids

Question 63

What are the exopeptidases

Answer 63

Carboxypeptidase A | Carboxypeptidase B

Question 64

What are the types of amino acid transporters on the apical membrane of epithelial cells

Answer 64

EAAT3 B0 B0+ IMINO

Question 65

Which amino acid transporter is sodium dependent

Answer 65

IMINO B0 EAAT3

Question 66

What is b0+ amino acid transporter dependent on

Answer 66

Efflux of neutral amino acids

Question 67

What happens when specific the amino acid transporters do no transport

Answer 67

You do not get the specific amino acid absorbed. | This results in disorder but no nutritional defiency

Question 68

Why do you not get nutritional deficiency when amino acid transporters dot no work

Answer 68

You can absorb amino acids in an oligopeptide form by PepT1 and be Brocken down within the cell by peptidase

Question 69

What are the 2 routes of absorbing intact protein

Answer 69

1) enterocyte phagocytosis | 2) M cells