carbohydrates

Question 1

examples of monosaccharides (monomers)

Answer 1

glucose
fructose
ribose

Question 2

examples of disaccharides? (dimers)

Answer 2

sucrose
maltose
lactose

Question 3

examples of polysaccharides (polymers)

Answer 3

starch
cellulose
glycogen

Question 4

what two forms does glucose come in?

Answer 4

alpha and beta

Question 5

is glucose a monomer or a polymer?

Answer 5

monomer

Question 6

what is an isomer?

Answer 6

molecules with the same molecular formula but atoms are connected in a different way

Question 7

what is the disaccharide formed when two glucose molecules are joined together?

Answer 7

maltose

Question 8

what is the disaccharide formed when a glucose and a galactose molecule are joined together?

Answer 8

lactose

Question 9

what is the disaccharide formed when a glucose and a fructose molecule are joined together?

Answer 9

sucrose

Question 10

what type of bond joins these monomers together?

Answer 10

glycosidic bond

Question 11

what two forms does starch come in?

Answer 11

amylose and amylopectin

Question 12

what is the structure of amylose like?

Answer 12

long, unbranched, chain of ALPHA glucose, tightly coiled

Question 13

why is it good that amylose is coiled?

Answer 13

coiled tightly so it is compact for storage

– stores excess glucose in plants

Question 14

what is the structure of amylopectin like?

Answer 14

branched - allows enzymes to quickly break it down

Question 15

why is it good that starch molecules are insoluble and big?

Answer 15

insoluble - won’t affect water potential
large - can’t leave the cell

Question 16

what is glycogen made from?

Answer 16

ALPHA glucose

Question 17

what is glycogen used for in the body?

Answer 17

to store excess glucose

Question 18

what is the structure of glycogen like?

Answer 18

increadibly highly branched

Question 19

why are the side brances in glycogen good?

Answer 19

so stored glucose can be released quickly

Question 20

what is cellulose made of?

Answer 20

BETA glucose

Question 21

what holds the seperate chains of beta glucose together?

Answer 21

hydrogen bonds

Question 22

steps for reducing sugars test?

Answer 22

1. add 2cm3 of solutions to test tube
2. add 2cm3 of benedicts solution
3. put test tubes in a 70c water bath for 2-3 mins

positive = brick red, orange, yellow, green
negatie = blue

Question 23

steps for non reducing sugars test

Answer 23

1. add 2cm3 of fresh sample of solutions that did not give +ve result to reducing test
2. add 2cm3 dilute hcl
3. heat in 70c water bath for 5 mins
4. add sodiumhydrogencarbonate and test with litmus paper to make sure it is neutral
5. add 2cm3 of benedicts
6. heat in 70c water bath for 2-3 min

positive = brick red, orange, yellow, green
negative = blue

Question 24

why might a solution test positive in non-reducing but negative in reducing?

Answer 24

the reducing sugars were produced from the hydrolysis of the non-reducing sugars

Question 25

test for starch

Answer 25

1. add 2cm3 of sample 2. add 2 drops of potassium iodide solution positive = blue/black negative = orange/brown