topic 1 - carbohydrates

Question 1

what are polymers

Answer 1

large, complex molecules composed of long chains of monomers joined together

Question 2

what are monomers

Answer 2

small basic molecular units

Question 3

what are 3 examples of monomers

Answer 3

monosaccharides, amino acids and nucleotides

Question 4

what elements do all carbohydrates contain

Answer 4

C,H, O

Question 5

examples of monomers made from monosaccharides

Answer 5

glucose, fructose, galactose

Question 6

what is glucose

Answer 6

a hexose sugar - a monosaccharide with six carbon atoms in each molecule

Question 7

what are the two types of glucose

Answer 7

alpha α, beta β

Question 8

what are isomers

Answer 8

molecules with the same molecular formula as each other but with the atoms connected in a different way

Question 9

what is a condensation reaction

Answer 9

when two molecules join together with the formation of a new chemical bond and a water molecule is released when the bond is formed

Question 10

what are monosaccharides joined together by

Answer 10

condensation reactions

Question 11

how is a glycosidic bond formed

Answer 11

by a condensation reaction between an alcohol or amine of one molecule and the anomeric carbon of the sugar

Question 12

how is a disaccharide formed

Answer 12

when two monosaccharides join together

Question 13

what is sucrose

Answer 13

a disaccharide formed from a condensation reaction between a glucose molecule and a fructose molecule

Question 14

what is lactose

Answer 14

a disaccharide formed from a glucose molecule and a galactose molecule

Question 15

how can polymers be broken down into monomers

Answer 15

by hydrolysis reactions

Question 16

what do hydrolysis reactions break

Answer 16

chemical bonds between monomers using a water molecule - basically the opposite of a condensation reaction

Question 17

what is an example of a hydrolysis reaction

Answer 17

carbohydrates being broken down into their constituent monosaccharide by hydrolysis reactions

Question 18

what is sugar a general term for

Answer 18

monosaccharides and disaccharides

Question 19

how can all sugars be classified as

Answer 19

reducing or non reducing

Question 20

what does the benedict’s test test for

Answer 20

sugars

Question 21

how does the benedict’s test differ depending on

Answer 21

the type of sugar you are testing for

Question 22

what do reducing sugars include

Answer 22

all monosaccharides and some disaccharides

Question 23

how is a polysaccharide formed

Answer 23

when more than two monosaccharides are joined together by condensation reactions

Question 24

what is the main energy storage material in plants

Answer 24

starch

Question 25

how do plants store excess glucose

Answer 25

as starch

Question 26

what do plants do when it needs more glucose for energy

Answer 26

it breaks down starch to release the glucose

Question 27

what is starch a mixture of

Answer 27

two polysaccharides of alpha glucose (amylose and amylopectin)

Question 28

what are the two polysaccharides of alpha glucose that form starch

Answer 28

amylose and amylopectin

Question 29

what is amylose

Answer 29

the crystallizable form of starch, consisting of long, unbranched chains of α-glucose

Question 30

what’s the structure of amylose, why and what characteristic does this give

Answer 30

coiled structure (almost like a cylinder) - due to the angles of the glycosidic bonds
this makes it compact, therefore really good for storage as you can fit more into a small space

Question 31

what is amylopectin

Answer 31

a non-crystallizable form of starch, consisting of long, branched chains of α - glucose

Question 32

what do the side branches of amylopectin allow it to do

Answer 32

its side branches allow the enzymes that break down the molecule to get to the glycosidic bonds easily - meaning that the glucose can be released quickly

Question 33

is starch soluble or insoluble in water, why

Answer 33

insoluble in water and doesn’t affect water potential, therefore doesn’t cause water to enter cells by osmosis which would make them swell - making it good for storage

Question 34

what test do you use for starch

Answer 34

iodine test

Question 35

how is the iodine test carried out

Answer 35

add iodine dissolved in potassium iodide solution to the test sample - if there’s starch present the sample changes from brown orange to a dark blue black

Question 36

what is the main energy storage material in animals

Answer 36

glycogen

Question 37

where do animals also get energy, how is it stored

Answer 37

glucose - animals store excess glucose as glycogen

Question 38

what is glycogen a polysaccharide of

Answer 38

α - glucose

Question 39

what is glycogen’s structure similar to

Answer 39

amylopectin - except that it has loads more side branches, so stored glucose can be released quickly

Question 40

why is glycogen good for storage

Answer 40

it is a compact molecule

Question 41

what is cellulose a major component of

Answer 41

cell walls in plants

Question 42

what is cellulose made of

Answer 42

long, unbranched chains of beta-glucose

Question 43

how are cellulose chains formed

Answer 43

when beta-glucose molecules bond

Question 44

what are microfibres

Answer 44

cellulose chains linked together by hydrogen bonds forming strong fibres (microfibres)

Question 45

why are microfibres important to cellulose

Answer 45

strong fibres mean cellulose provides structural support for cells

Question 46

what is a monosaccharide

Answer 46

the monomers from which larger carbohydrates are made

Question 47

what are four examples of reducing sugars that are monosaccharides

Answer 47

glucose, galactose, fructose, lactose

Question 48

what is one example of a reducing sugar that is a disaccharide

Answer 48

maltose