digestion - carbohydrates

Question 1

list monosaccarides

Answer 1

• glucose = blood sugar
• fuctose = fruit sugar
• galactose = part of milk sugar
• lactose = milk sugar (disaccaride of glucose and galactose)

Question 2

what is a starch

Answer 2

• polysaccharide
• storage form of glucose for plants

Question 3

what is glycogen

Answer 3

• polysaccaride
• storage form of glucose for animals

Question 4

describe the difference between amylose and amylopectin

Answer 4

• amylose = unbranched starch
• amylopectin = branched

Question 5

What is the composition of starch?

Answer 5

made up of 2 polysaccharides:
- amylose (Straight chain)
- amylopectin (branched chain)
- Insoluble in water

Question 6

Describe the composition of glycogen

Answer 6

• single, highly branched polysaccharide
• soluble in water as it is branched

Question 7

How are disaccharides and monosaccharides formed?

Answer 7

Sucrose = glucose + fructose
Lactose = glucose + galactose
Maltose = glucose + glucose
Formed in condensation reactions between 2 monosaccharides
Monosaccharides formed by hydrolysis of disaccharides

Question 8

Describe carbohydrate digestion

Answer 8

Salivary a-amylase begins starch digestion to maltose, some glucose and dextrins
Pancreatic amylase continues starch breakdown into maltose in SI
glucosidae enzymes in brush border of intestines breakdown disaccharides into monosaccharides to be transported into intestinal mucosa

Question 9

how are carbohydrates absorbed

Answer 9

• SGLT1 = actively transports glucose and galactose along with sodium ions into the lumen of enterocytes
• GLUT2 = facilitates diffusion of glucose from enterocytes into the bloodstream

Question 10

how does alpha amylase work to break down carbohydrates

Answer 10

• hyrdolyzes alpha 1-4 glycosidic bonds in starch and glycogen
• produces maltose, etc