3.1.2 carbohydrates

Question 1

what are the three main functions of carbohydrates

Answer 1

1. short term energy storage (convert to ATP to be used )
2. long term energy storage
3. a structural component

Question 2

what does carbohydrates mean

Answer 2

Hydrated carbon atoms + hydroxyde groups

Question 3

what 3 letters does carbohydrates tend to end in

Answer 3

• ose

Question 4

what is sucrose know as

Answer 4

store bought suger

Question 5

where are lactose and maltose found

Answer 5

lactose : milk
maltose : beer

Question 6

what polysaccharides can we digest

Answer 6

glycogen

Question 7

what is the glycemic index and what does it mean to have a high / low glycemic index

Answer 7

The glycemic index measures how blood glucose levels change following the ingestion of carbohydrate.

a high glycemic index means that suger is relesed really fast over a short period and therefore is unhealthy

vise versa for a low glycemic index

Question 8

what two disaccharides make:
maltose

Answer 8

2 x glucose

Question 9

what two disaccharides make:
lactose

Answer 9

galactose and glucose

Question 10

3 carbon suger is called ?
and function

Answer 10

triose
metabolic reactions

Question 11

what two disaccharides make:
sucrose

Answer 11

glucose and fructose

Question 12

5 carbon suger is called ?
and function

Answer 12

pentose
formation of nucliac acids

Question 13

6 carbon suger is called ?
and function

Answer 13

hexose
main source of energy

Question 14

draw an A-glycose

Answer 14

compare with web should have hydroxy pointing down

Question 15

draw an b-glycose

Answer 15

compare with web should have hydroxy pointing up

Question 16

draw a fructose molecule

Answer 16

compare with web

Question 17

draw a galactose molecule

Answer 17

compare with web

Question 18

what are the two isomers of glycose

Answer 18

alpha and beta glycose

Question 19

what type of reaction joins carbohydrates together

Answer 19

glycosidic bond
condensation reaction

Question 20

what is hydrolysis

Answer 20

the break down of a chemical bond through water

Question 21

where does hydrolasis take place

Answer 21

during digestion

Question 22

how do you test for reducing sugers

what is the order of percipitates

Answer 22

1.add an equal quantaty of benedics reagent to approximatly 2cm3 of test solution

2. shake and heat for a few min at 95 celceus in a water bath

3.a precipitate indicates a reducing suger

none ——> large amounts

blue , green / yellow , orange , brick red

Question 23

between which carbons does glycosidic bonds form

Answer 23

1-4

Question 24

what is a way of testing for the concentration of sugers

Answer 24

potassium permanginate , when sugers reduce potassium permanginate it goes colour less , by comparing it with know concentrations we can see how long it takes to decolour and there for the concentration of the solution.

Question 25

what are the main reducing sugers

Answer 25

all monosaccharides , maltose , lactose sucrose is not a reducing suger

Question 26

what is the role of starch in plants

Answer 26

insoluble store of glucose in plants

Question 27

what are the two types of polysaccharides

Answer 27

1. storage - starch and glycose 2. structural - cellulose

Question 28

is glycogen soluable

Answer 28

no it is insoluable

Question 29

what isotope of glycose is amylose made of

Answer 29

Alpha - glycose with1-4 glycosidic bonds

Question 30

describe the structure of amylose

Answer 30

amylose is a polymer made up of alpha - glycose . it is linear molecule with no branches

Question 31

describe the structure of amylopectin

Answer 31

the amylose molecule coils into a helix this is due to the hydrogen bonds , it is also branched (1-6 ) it branches around every 25 alpha glucose s

Question 32

relate the structure of alylopectin to its dunction

Answer 32

Compact shape takes up little space, but large and insoluble and so does not diffuse out of cells. Insoluble – therefore does not affect water potential, so water is not drawn into the cells by osmosis. Easily hydrolysed to glucose for respiration (by amylase)

Question 33

how whould you test for starch

Answer 33

using iodine solution , it would turn from a yellow solution to a more opaque blue/dark blue solution

Question 34

what is glycogen made of

Answer 34

alpha glucose

Question 35

relate the dunction of glycogen to function

Answer 35

Compact shape takes up little space Insoluble - therefore osmotically inert and does not diffuse outside of cells Easily hydrolysed to glucose for respiration (by amylase) because more branches than starch and so more of the ends can be worked on simultaneously by enzymes. Speed of hydrolysis important because animals have a higher metabolic rate than plants.

Question 36

describe the structure of glycogen

Answer 36

very simular to amylopectin however has more frequent branches

Question 37

describe the role of glycogen

Answer 37

Role: an insoluble, compact store of glucose in animals, found mainly in muscle and liver

Question 38

what is the role of cellulose in plants

Answer 38

Role: Structural polysaccharide in plants

Question 39

what is cellulose made out of

Answer 39

Beta glucose which human bodys cannot digest as we do not have the propper enzymes to do so

Question 40

describe the structure of cellulose

Answer 40

long parallel chains , unbranched , with hydrogen bonds linking adjacent chains

Question 41

why do hydrogen bonds form between beta glucose and not alpha glucose

Answer 41

beta glucose cannot react without one flipping over as the -OH on the 1-4 are not next to each other , this is not need for alpha glucose This difference leads to parallel, straight chains that bundle together because of the formation of H bonds between hydroxyl groups in adjacent chains. These bonds cannot form between alpha glucose units because they are not rotated

Question 42

describe the structure of a cellulose FIBER

Answer 42

60 -70 cellulose molecules become tightly cross linked to form bundles called Microfibrils. These join together with other microfibrils to form a macrofibril which bundle together to form cellulose fibres. The cell wall has multiple layers of fibres running in different directions to increase strength. Microfibrils are very strong and rigid and give huge structural stability to the plant