First Chapter

Question 1

Is oxygen electronegative or electropositive

Answer 1

Electronegative

Question 2

Is hydrogen electronegative or positive

Answer 2

ElectroPositive

Question 3

Water is a polar molecule. What does this mean

Answer 3

It can form hydrogen bonds with other water molecules

Question 4

What is cohesion

Answer 4

It is an important part of transpiration
Water molecules stay close together when in liquid form
Enables of column of water to move through a plant

Question 5

What is the word for the attraction of water molecules to other substances

Answer 5

Adhesion

Question 6

Is water more or less dense in its solid form

Answer 6

Less dense (solid water floats!)

Question 7

Why is the fact that water is less dense in its solid form important

Answer 7

When water freezes in a river life can continue under it - even in an ice age

Question 8

What is a universal solvent

Answer 8

Due to the polarity of water molecules, liquid water can dissolve a wide range of polar solutes

Question 9

——- is a component of metabolic reactions

Answer 9

Water

Question 10

Reactions that produce water as a byproduct are called

Answer 10

Condensation reactions

Question 11

Reactions that take in water as a reactant are called

Answer 11

Hydrolysis reactions

Question 12

What is specific heat capacity

Answer 12

It takes 4.2J to heat up 1g of water by 1degree

Question 13

Why is it important that water has a high specific heat capacity

Answer 13

The water effectively buffers the temperature changes so organisms living in the water have a more stable environment in which they can operate
Over the whole planet water absorbs energy from the sun keeping the global temperature relatively constant

Question 14

How does the latent heat of vaporisation help in removing excess heat form the body

Answer 14

Water can absorb a lot of energy before turning from a liquid into a gas. Therefore when someone is sweating the evaporation removes some heat without requiring an excessive quantity of water

Question 15

What is hydrolysis

Answer 15

The chemical process by which water is used to break a bond in a molecule

Question 16

What type of bonding takes place between molecules in liquid water

Answer 16

Hydrogen bonding

Question 17

What is a glycosidic bond

Answer 17

A bond in a polysaccharide

Question 18

What elements are present in a carbohydrate

Answer 18

C, H and O

Question 19

What property of carbon enables it to form chains

Answer 19

It can form up to four covalent bonds with other atoms

Question 20

What sugars comprise the disaccharide sucrose

Answer 20

Alpha glucose and fructose

Question 21

What are the two structure types of starch

Answer 21

Amylopectin and amylose

Question 22

How does the structure of cellulose make it useful as a structural polysaccharide

Answer 22

It is an unbranched, straight, molecule with hydrogen bonding between the cellulose molecules. This makes it very strong

Question 23

What is the name of the bond between a fatty acid and glycerol

Answer 23

Ester bond

Question 24

What state will a fat and an oil be at 20 degrees C

Answer 24

Fats are solid whilst oils are liquid

Question 25

Why are lipids insoluable in water

Answer 25

They are hydrophobic

Question 26

How can a triglyceride be broken down into its constituent fatty acids and glycerol

Answer 26

Hydrolysis

Question 27

What is a saturated fat

Answer 27

A saturated fat has no double or triple bonds between carbon atoms in the fatty acid chains

Question 28

What is an unsaturated fat

Answer 28

An unsaturated fat has at least one double or triple bond between carbon atoms in the fatty acid chains

Question 29

Why is an unsaturated fat more likely to be an oil

Answer 29

The double or triple bonds in an unsaturated fat cause a “kink” to appear in the fatty acid chain. This makes unsaturated fats less able to form solids

Question 30

Give three reasons why triglycerides are useful to an organism

Answer 30

Temperature insulation electrical insulation around neurones support around organs energy store

Question 31

What is the name of the bond between two amino acids in a polypeptide

Answer 31

Peptide bond

Question 32

What groups are present in an amino acid

Answer 32

An amine group, NH2 A carboxylic acid group COOH An R group

Question 33

How many naturally occurring amino acids are there

Answer 33

20

Question 34

Where do animals obtain the essential amino acids

Answer 34

Animals have to eat other animals and plants

Question 35

What is meant by the primary structure of a polypeptide

Answer 35

The primary structure is the order of amino acids in the polypeptide

Question 36

Give four ways the three dimensional shape is maintained in the tertiary structure of a protein

Answer 36

Disulphides bridges Hydrogen bonding Ionic bonds Hydrophobic and hydrophilic interaction

Question 37

How does the quaternary structure of a protein differ from the tertiary structure

Answer 37

The quaternary structure includes more than one subunit

Question 38

Name the two types of protein and state if they are insoluble or soluble

Answer 38

Fibrous (insoluble) and globular (soluble)

Question 39

What is an enzyme

Answer 39

Enzymes are globular proteins that catalyse metabolic reactions

Question 40

Describe how a competitive inhibitor works

Answer 40

It attaches to the active site of an enzyme so that the actual substrate can not fit

Question 41

Describe how a non competitive inhibitor works

Answer 41

A non competitive inhibitor alters the shape of the active site from a distance

Question 42

Why is an enzyme denatured at high temperatures

Answer 42

High temperatures cause the disulphides bridges and hydrogen bonds to permanently break, causing the shape of the enzyme to be irreversibly altered

Question 43

How does pH affect the active site

Answer 43

Ph affects the active site by altering its shape. Unlike with temperature the change is not permanent

Question 44

How do enzymes affect activation energy

Answer 44

They reduce it

Question 45

Give an example of a coenzyme

Answer 45

Vitamin C (ascorbic acid)