Proteins and Carbohydrates

Question 1

Protein digestion in stomach

Answer 1

HCl denatures proteins

Pepsinogen -> Pepsin (via gastric juices)

Question 2

Protein digestion in duodenum

Answer 2

Pancreatic proteases are secreted

• endopeptidases: cleaves peptide bonds in centre of peptide chain
• exopeptidases - cleaves pepide bonds at the ends of the peptide chain

Question 3

Brush border peptidases are ____ numerous than cytoplasmic peptidases

Answer 3

More

Question 4

Composition of starch

Answer 4

Amylose + Amylopectin

Found in plants

Question 5

Amylose

Answer 5

Straight chain

a-1,4 linkages

Question 6

Amylopectin

Answer 6

Branched chain
a-1,4 linkages
a-1,6 linkages every 30th monomer (approx)

Question 7

Glycogen

Answer 7

Found in animals
Highly branched chain
a-1,4 linkages
a-1,6 linkages

Question 8

Cellulose

Answer 8

Not digestible my humans

b-1,4 linkages

Question 9

Oligosaccharides

Answer 9

“a few” monosaccharides

eg: sucrose (glucose+fructose), lactose (glucose+galactose)

Question 10

Absorption of carbohydrates

Answer 10

Must be converted to monosaccharides for absorption

Mainly occurs in the SI (duodenum and jejunum)

Question 11

a-amylase

Answer 11

b/d internal a-1,4 linkages
doesn’t b/d terminal a-1,4 linkages (ie: can’t produce glucose)
can’t b/d a-1,4 linkages adjacent to branch points

Products: linear glucose oligomers

Question 12

OligosaccharidASES

Answer 12

Cleave terminal a-1,4 linkages to yield glucose (monosaccharide)