Carbohydrates

Question 1

What is the general formula for carbohydrates?

Answer 1

(CH2O)n

Question 2

(C6H12O6)
Name the 3 carbohydrates that have this same general formula and what type of ‘saccharide’ they are.

Answer 2

glucose
galactose
fructose

These are monosaccharides

Question 3

Identify similarities between starch and glycogen

Answer 3

Both have 1,6 glycosidic links.
Starch’s component amylopectin is highly branched and glycogen is highly branched.
Both are insoluble in water (no effect on osmosis) Both polymers of a-glucose

Question 4

Identify differences between cellulose and starch

Answer 4

Starch has 1,6 glycosidic links along with 1,4 links whereas cellulose only has 1,4.
Cellulose’s structure is comprised of straight long chains that run parallel to each other
Cellulose.s function is strength and support whereas starch is used as an energy store in plants
Cellulose has microfibrils formed between its hydrogen links

Question 5

Describe the test for reducing sugars

Answer 5

Add Benedict’s
Heat
Red precipitate

Question 6

Describe the test for non reducing sugars

Answer 6

Add dilute HCL
neutralise with NAOH
add Benedict’s
heat

Question 7

Draw the structure of alpha glucose

Answer 7

. |__________O
H / \ H (C6H12O6)
\/ \/
/ \ / \
/ \___________/ \
OH OH