Digestion of Carbohydrates and Proteins

Question 1

What are the principle dietary nutrients?

Answer 1

• Carbohydrate
• Protein
• Fat
• Vitamins
• Minerals
• Water

Question 2

What are the 3 monosaccharides?

Answer 2

• Glucose
• Galactose
• Fructose

Question 3

What are hexose sugars?

Answer 3

Breakdown products of complex CHOs which are absorbed by small intestine

Question 4

What are disaccharides?

Answer 4

2 monosaccharide linked together by glycosidic bond

Question 5

How are disaccharides broken down?

Answer 5

Broken down to constituent monomers by brush border enzymes in small intestine

Question 6

What is lactose composed of?

Answer 6

Glucose and galactose

Question 7

What is sucrose composed of?

Answer 7

Glucose and fructose

Question 8

What is maltose composed of?

Answer 8

Glucose and glucose

Question 9

What enzyme breaks down lactose?

Answer 9

Lactase

Question 10

What enzyme breaks down sucrose?

Answer 10

Sucrase

Question 11

What enzyme breaks down maltose?

Answer 11

Maltase

Question 12

Name 3 polysaccharides.

Answer 12

• Starch
• Cellulose
• Glycogen

Question 13

What is starch?

Answer 13

Plant storage form of glucose

Question 14

What is cellulose?

Answer 14

Constituent of plant cell walls

Question 15

What is glycogen?

Answer 15

Animal storage form of glucose

Question 16

What is the structure of a-amylase?

Answer 16

Glucose linked in straight chains

Question 17

What is the structure of amylopectin?

Answer 17

Glucose chains highly branched

Question 18

What is the structure of starch?

Answer 18

Glucose monomers linked by a-1,4 glycosidic bonds

Question 19

What breaks down starch?

Answer 19

Amylases

Question 20

Where are amylases found?

Answer 20

• Saliva

- Pancreas

Question 21

What is the structure of cellulose?

Answer 21

Unbranched, linear chaind of glucose monomers linked by B-1,4 glycosidic bonds

Question 22

Why is cellulose known as dietary fibre?

Answer 22

There is no enzymatic digestion in vertebrates

Question 23

What is the structure of glycogen?

Answer 23

Glucose monomers linked by a-1,4 glycosidic bonds

Question 24

Where are the disaccharide ‘ases’ expressed?

Answer 24

Brush border

Question 25

Where is the apical membrane found?

Answer 25

Microvilli

Question 26

Where is the basolateral membrane found?

Answer 26

Membrane furthest from the lumen

Question 27

How are the cells in the small intestine joined?

Answer 27

Tight junctions

Question 28

How can molecules pass form the gut tube into the body?

Answer 28

- Transcellular - Paracellular - Vectorial transport

Question 29

What is the name of the transporter that transports glucose into the cell?

Answer 29

SGLT1

Question 30

What is the name of the transporter that transports glucose out of the cell?

Answer 30

GLUT-2

Question 31

Other than glucose what does SGLT1 also recognise?

Answer 31

Galactose

Question 32

What is the name of the transporter that transports fructose into the cell?

Answer 32

GLUT-5

Question 33

What is the name of the transporter that transports fructose out of the cell?

Answer 33

GLUT-2

Question 34

What are proteins?

Answer 34

Polymers of amino acids linked together by peptide bonds

Question 35

How do proteins differ?

Answer 35

Amino acids used and chain length

Question 36

What do proteins often undergo?

Answer 36

Post-translational modification

Question 37

What are small proteins with chains 3-10 amino acids long known as?

Answer 37

Peptides

Question 38

What are proteases/peptidases?

Answer 38

They are enzymes which hydrolyse peptide bonds and reduce proteins or peptides to amino acids

Question 39

What does endopeptidase do?

Answer 39

They act on the internal part of a protein to produce 2 smaller peptides

Question 40

What does exopeptidase do?

Answer 40

They act on the terminal amino acid of a protein to remove 1 amino acid at a time

Question 41

Where do aminopeptidases act?

Answer 41

At the amine end of a protein

Question 42

Where do carboxypeptidases act?

Answer 42

At the carboxylic end of a protein

Question 43

What is the generic amino acid transporter?

Answer 43

SAAT1

Question 44

What enters the cell along with amino acids?

Answer 44

Sodium

Question 45

What is the name of the transporter that transports dipeptides?

Answer 45

PepT1

Question 46

What is transported along side dipeptides?

Answer 46

Hydrogen

Question 47

What is the name of the transporter that removes hydrogen from the cell?

Answer 47

NHE3

Question 48

What enters the cell using the NHE3 transporter?

Answer 48

Sodium

Question 49

What happens to dipeptides once they are in the cell?

Answer 49

They can pass through into the blood