Nutrient digestion and absorption 1

Question 1

List the 6 main dietary constituents

Answer 1

Carbohydrate, fat, protein, vitamins, minerals and water

Question 2

Name some minerals

Answer 2

Zinc, manganese and salt

Question 3

Name the 3 monosaccharides

Answer 3

glucose, galactose, fructose

Question 4

What are disaccharides?

Answer 4

2 monosaccharides linked by a glycosidic bond

Question 5

How are disaccharides broken down?

Answer 5

By enzymes in the brush border

Question 6

What are the 3 disaccharides?

Answer 6

Maltose, sucrose and lactose

Question 7

What are each of the disaccharides made from and what enzyme breaks each down

Answer 7

Maltose = 2 glucose (maltase)
sucrose = glucose and fructose (sucrose)
lactose = glucose and galactose (lactose)

Question 8

Can alpha amylase work only on alpha or beta 1,4 glycosidic bonds?

Answer 8

alpha

Question 9

What are the 2 forms of starch?

Answer 9

alpha amylose and amylopectin

Question 10

Where are the 2 sites of amylase production?

Answer 10

Pancreas and saliva

Question 11

What can break down cellulose?

Answer 11

Bacteria only as human do not possess the enzyme cellulase

Question 12

What 2 of the 3 polysaccharides can be broken down by alpha amylase?

Answer 12

starch and glycogen

Question 13

What are villi?

Answer 13

Small finger like projections found in the small intestine to increase surface area

Question 14

What type of epithelium are villi covered in?

Answer 14

Columnar

Question 15

What is on top of villi which is also known as the brush border?

Answer 15

Microvilli

Question 16

What are the 2 membranes of the microvilli known as?

Answer 16

Apical and basolateral

Question 17

What separates each microvilli membrane?

Answer 17

Tight junction complex and attachment proteins

Question 18

Name the 3 transport mechanisms for the microvilli

Answer 18

Transcellular, paracellular and transport mediated

Question 19

What is glucose coupled to for absorption?

Answer 19

sodium

Question 20

What transporter do glucose and sodium enter the microvilli by?

Answer 20

SGLT1

Question 21

What happens to glucose once it enters the cell?

Answer 21

Accumulates until normal blood glucose level (5mmol/l) and is then delivered to the gut by GLUT2

Question 22

What pathway does the water that follows take?

Answer 22

Paracellular

Question 23

What other monosaccharide follows the same process as glucose?

Answer 23

Galcatose

Question 24

What is the difference for fructose?

Answer 24

Uses GLUT5 instead of SGLT1 and is not coupled to sodium

Question 25

What is a protein?

Answer 25

Amino acids linked by peptide bonds to form polymers

Question 26

What number of amino acids form a peptide?

Answer 26

3-10

Question 27

What is the name of the enzymes generally which act to hydrolyse peptide bonds?

Answer 27

proteases/peptidases

Question 28

What is an endopeptidase?

Answer 28

Enzyme which hydrolyses the protein in the middle part of the chain

Question 29

What is an exopeptidase?

Answer 29

Enzyme which hydrolyses the protein at one of the terminal ends - carboxyl and amino

Question 30

Are amino acids coupled to sodium for transport?

Answer 30

Yes

Question 31

What transporter do amino acids use?

Answer 31

SAAT1

Question 32

How do amino acids exit the cell after absorption?

Answer 32

Depends on the class of amino acid

Question 33

What transporter is used for di/tri peptides?

Answer 33

pepT1

Question 34

What are the transport of di/tri peptides linked to?

Answer 34

Hydrogen ions

Question 35

How do di/tripeptides exit the cell?

Answer 35

As peptides or amino acids

Question 36

What is the hydrogen coupled to in order to leave the cell after the peptide has exited?

Answer 36

sodium via NHE3 transporter

Question 37

What is the acid microclimate due to?

Answer 37

mucus