Block 1

Question 1

What is the process for Human Digestion?

6 points

Answer 1

o Mechanical homogenization and mixing of solids with fluids secreted by GI tract glands
o Secretion of digestive enzymes- Hydrolyses macromolecules to oligomers, dimers, or monomers
o Secretion of electrolytes, acid, base to provide the appropriate environment- For optimal enzyme digestion
o Secretion of bile to enable lipid absorption
o Hydrolytic digestion of oligomers and dimers on the intestinal surface
o Import of nutrient molecules and electrolytes from the gut lumen into gut epithelial cells

Question 2

Why must Polymers be broken down into monomeric components?

2 points

Answer 2

To allow absorption.

Transport from the lumen of the gut into the blood.

Question 3

What bulk of ingested nutrients consist of?

1 point

Answer 3

Polymers

Question 4

What components ensure efficient digestion of food and how does it help?
(4 points)

Answer 4

o Peptides
o Amino Acids
o Fatty Acids

They stimulate the coordinated release of pancreatic juice & bile into the lumen of the small intestine.

Question 5

What is the function of Salivary glands in Digestion and Absorption?
(1 point)

Answer 5

Elaboration of fluid and digestive enzymes

Question 6

What is the function of the Stomach in Digestion and Absorption?
(1 point)

Answer 6

Elaboration of HCL and digestive enzymes

Question 7

What is the function of the Pancreas in Digestion and Absorption?
(1 point)

Answer 7

Elaboration of NaHCO3 and enzymes for intraluminal digestion

Question 8

What is the function of the Liver in Digestion and Absorption?
(1 point)

Answer 8

Elaboration of bile acids

Question 9

What is the function of the Gallbladder in Digestion and Absorption?
(1 point)

Answer 9

Storage and concentration of bile

Question 10

What is the function of the Small-Intestine in Digestion and Absorption?
(2 points)

Answer 10

Terminal digestion of food. Absorption of nutrients and electrolytes

Question 11

What is the function of the Large-Intestine in Digestion and Absorption?
(1 point)

Answer 11

Absorption of electrolytes

Question 12

Where are the Digestive enzymes secreted from?

3 points

Answer 12

o Salivary Glands
o Stomach
o Pancreas

Question 13

Where are the pancreatic enzymes and bile secreted together?

1 point

Answer 13

Duodenum

The pancreatic duct joins the common bile duct, where both flow into the duodenum

Question 14

what are the pancreatic enzymes?

3 points

Answer 14

o Amylase
o Protease
o Lipase

Question 15

After digestion, what do carbohydrates and peptides remain as?
(1 point)

Answer 15

Dimers and Oligomers

Question 16

Where are the hydrolytic enzymes located?

1 point

Answer 16

The outer surface of epithelial cells lining- forming the ‘brush border’

Question 17

What is covered on the outer surface of the brush border membrane?
(3 points)

Answer 17

o di- and oligosaccharides
o amino- and dipeptidases
o esterase

Question 18

Why do Surface enzymes not get digested by Soluble proteases?
(2 points)

Answer 18

o Surface enzymes have heavy glycosylation that prevents access of proteases to relevant peptide bonds

Question 19

What do carbohydrates break down into during digestion?

1 point

Answer 19

Monosaccharides for absorption

Question 20

What are the two barriers in the transcellular pathway?

2 points

Answer 20

o Luminal plasma membrane

o Contra luminal plasma membrane

Question 21

The small intestinal epithelial cells provide examples of the differentiation and specialisation of the two different membranes. In what way do two membranes differ?
(3 points)

Answer 21

o Morphological appearances
o Chemical compositions
o Different enzymes and transporters

Question 22

What is the main function of the intestinal epithelial cells?
(2 points)

Answer 22

It is the active absorption of…
o Nutrients
o Electrolytes
o Vitamins

Question 23

Define Chyme.

1 point

Answer 23

The semifluid mass of partially digested food

Question 24

What is the luminal membrane specialised for?

2 points

Answer 24

o For terminal digestion of nutrients through hydrolytic enzymes on its external surface and 
o For nutrient absorption through transporter or channels for 
	monosaccharides, 
	amino acids, 
	peptides, 
	fatty acids, 
	cholesterol and 
	electrolytes.

Question 25

What is the contra-luminal plasma membrane in contact with?

2 points

Answer 25

The intracellular fluid and hence indirectly with capillaries and lymph vessels.

Question 26

What is the role of nutrient transporters in the contra-luminal membrane?
(2 points)

Answer 26

o They serve to release nutrients into blood or lymph after a meal.
o As well as providing nutrients to enterocytes in between meals.

Question 27

The nutrients transporter in the contra-luminal membrane are…
(1 point)

Answer 27

…Bidirectional

Question 28

Describe the morphological appearance of Luminal plasma membranes?
(1 point)

Answer 28

Microvilli arranged as brush border

Question 29

What enzymes are present in the luminal plasma membrane?

6 points

Answer 29

o Di- and oligosaccharides
o Aminopeptidase
o Dipeptidases
o γ-Glutamyltransferase
o Alkaline Phosphates
o Guanylate Cyclase C

Question 30

Describe the morphological appearance of Contra-Luminal plasma membranes?
(1 point)

Answer 30

Few microvilli

Question 31

What enzymes are present in the contra-luminal plasma membrane?
(2 points)

Answer 31

o Na+/K+ ATPase

o Adenylate cyclase