1 3 marks

QUESTION

Enzymes are proteins.

Describe how

ribosomes and

mitochondria help a

cell to make enzymes. Command word ‘describe’:

To give an ordered account.

Connectives:

First, next, then, lastly,

finally,….

KEYWORDS

Energy, amino acids

B2.1

(B2.1 - 1)

MARKING POINTS (B2.1 - 1)

1

1

1

Ribosomes make proteins

using amino acids.

The energy required for the process is

provided by the mitochondria.

1a 6 marks

QUESTION

Describe the structure of a

leaf and functions of the

tissues in the leaf.

You should include the

names of the tissues in your

answer.

Command word ‘describe’:

to give an ordered account

of a process,

method or event.

Connectives:

Firstly, next, then, finally,

lastly,….

KEYWORDS

Epidermis, palisade, mesophyll,

photosynthesis, phloem, xylem,

transport, water, chloroplasts, dissolved

B2.1

MARKING POINTS

0 marks

No relevant

comment made

1-2 marks

Brief description of at least

1 tissue or at least 1

function of an indicated

part of the leaf. Poor SPAG.

3-4 marks

There is a clear description of

at least 1 tissue and at least one

function of an indicated part

of the leaf

Some SPAG errors.

5-6 marks

There is a detailed description

of most of the structures and

their functions. Almost

faultless SPAG.

The whole plant is covered in a

layer of epidermis. This layer,

which does not contain any

chlorophyll to allow sun light

to penetrate, protects the

underlying cells. Most of the

cells in a leaf are mesophyll

cells. Photosynthesis takes

place inside these cells which

is why they are packed with

chloroplasts. Xylem tubes

transport water through the

plant, phloem tube transport

dissolved sugars.

1a

2 6 marks

QUESTION

Describe how you would

use a 1/2-metre x 1/2-

metre quadrat frame and a

30-metre tape measure to

obtain data on plant

distribution along a transect

line. You should include

details of how you would

make sure that you would

obtain valid results. Command word ‘describe’:

to give an ordered account

of a process,

method or event.

Connectives:

Firstly, next, then, finally,

lastly,….

KEYWORDS

Random, place, count, regular, repeat,

interval, distribution, quadrat, across,

along, mean, sample size, quantitative,

habitat

B2.2

MARKING POINTS

0 marks

No relevant

comment made

1-2 marks

There is a basic description

of how a quadrat or a

meter tape could be used

to collect data. Poor SPAG.

3-4 marks

There is a clear description of

how a quadrat and a metre tape

could be used to collect

data along a line. Some SPAG

Errors.

5-6 marks

There is a clear, logical

and detailed description

of a method that will

produce valid, repeatable

results at intervals along

the chosen sample area.

Almost faultless SPAG.

Use a tape measure to

produce a transect along

the sample area, i.e a

stream.

Place the quadrat at

regular intervals along the

tape and count each plant

species inside the

quadrat. Repeat the

transect several times at

random or regular

intervals along the stream.

2

2a 5 marks

QUESTION The rate of

photosynthesis

depends on several

factors such as light

intensity and the

availability of water.

Describe and explain

the effect of two other

factors that affect the

rate of photosynthesis.

Command word ‘explain’:

to link all points logically.

Connectives:

Due to, therefore,

consequently, so, as a result,….

KEYWORDS

Carbon dioxide, concentration,

photosynthesis, limiting factor,

temperature, rate, enzyme,

denature

B2.2

Command word ‘describe’: to

give an ordered account of a

process,

method or event.

Connectives:

Firstly, next, then, finally,

lastly,….

MARKING POINTS As the concentration of carbon

dioxide (1) increases so does the rate

of photosynthesis as carbon dioxide

is a raw material in photosynthesis

(1). However, the rate eventually

levels off as another factor is now

limiting the rate of photosynthesis.

This second factor is temperature (1).

As the temperature increases, so

does the rate as the particles

involved in the reaction gain kinetic

energy (1). However, the rate will

eventually decrease because

enzymes are denatured (1).

B2.3

2a

3 6 marks

QUESTION

Control systems are used to

keep the human body

temperature at around

37oC. Explain why it is

dangerous for our body

temperature to go much

higher. Refer to enzymes in

your answer.

KEYWORDS

Active site, denature, lock and key,

substrate, inhibit, bind, surface, amino

acid chain, catalyst, protein structure

B2.3

Command word ‘explain’:

to link all points logically.

Connectives:

Due to, therefore,

consequently, so, as a

result,….

MARKING POINTS

0 marks

No relevant

comment made

1-2 marks

Incomplete description,

stating that enzymes do

not work over 37oC.

Limited use of keywords.

Poor SPAG

3-4 marks

Limited description that includes

a statement that above 37oC the

shape of the enzyme is changed

and enzyme function is inhibited.

Some SPAG errors.

5-6 marks

Detailed description of how

prolonged exposure to

temperatures above 37oC

results in denaturation. Answer

includes detail about the

importance of the shape of

the enzyme and why enzymes

are vital for life. Almost

faultless SPAG.

Enzymes are vital for life

processes such as digestion,

growth and repair. At about

40oC the protein structure of

an enzyme is affected. This

means that the long amino

acid chains unravel and as a

result the shape of the active

site is altered. The substrate

can no longer bind to the

enzyme surface and therefore

the enzyme can no longer

catalyse important biological

reactions.

3

3a 6 marks

QUESTION

Describe how different

parts of the human

digestive system help to

break down molecules of

fat so that they can be

absorbed into the body.

Make references to any

enzymes involved, the

products of digestion and

any other chemicals

involved in the process.

KEYWORDS

Mechanical, mouth, stomach, acid, fatty

acid, glycerol, lipase, pancreas, small

intestines, bile, liver, neutralisation, alkali,

surface area, emulsifier, absorption,

bloodstream

B2.3

Command word ‘describe’:

to give an ordered account

of a process,

method or event.

Connectives:

Firstly, next, then, finally,

lastly,….

MARKING POINTS

0 marks

No relevant

comment made

1-2 marks

Incomplete description;

Reference to at least one o

process (mechanical digestion,

lipase, bile, product of enzyme

action, site of digestion). Poor

SPAG

3-4 marks

There is a description of at

least one process linking ideas.

Some SPAG errors.

5-6 marks

Clear description of the

process including reference to

the majority of mechanical

digestion, lipase, bile, products

of digestion and site of

digestion/absorption. Almost

faultless SPAG.

Food is broken down

mechanically inside the mouth

and stomach to increase the

surface area. Lipase, produced in

the pancreas and small intestines,

catalyses the breakdown of fats

into fatty acids and glycerol

inside the small intestines. Bile,

which is produced by the liver, is

added for two reasons. Firstly, it

is an alkaline substances and

neutralises the stomach acid.

Secondly, it emulsifies the fat to

increase the rate of digestion.

The fatty acids and glycerol pass

through the walls of the small

intestines into the bloodstream.

3a

4 3 marks

QUESTION

State three differences

between aerobic and

anaerobic respiration.

Command word ‘state’:

To list facts.

Connectives:

N/A

KEYWORDS

Oxygen, energy, lactic acid,

carbon dioxide, water

B2.4

(B2.4 - 4)

MARKING POINTS (B2.4 - 4)

1

1

1

Oxygen is used in aerobic respiration

Aerobic respiration produces more energy

Aerobic respiration produces CO2 and H2O,

anaerobic respiration produces lactic acid

4a 4 marks

QUESTION

Explain the advantage

to athletes of the

change in heart rate

during exercise.

Command word ‘explain’:

to link all points logically.

Connectives:

Due to, therefore,

consequently, so, as a

result,….

KEYWORDS

Heart rate, oxygen, muscles,

glucose, respiration, carbon

dioxide, lactic acid

B2.4

4a

MARKING POINTS

During exercise the heart

rate increases and as a

result more oxygen (1) and

glucose are delivered to the

muscles (1) .

This also means that

carbon dioxide (1) and

lactic acid are removed

faster (1).

B2.5

5 3 marks

QUESTION

Parkinson’s disease is

caused by the death of

brain cells. Explain how

stem cells could be

used to treat this

condition.

KEYWORDS

Adult, embryo, bone marrow,

differentiate

B2.5

(B2.5 - 5)

Command word ‘explain’:

to link all points logically.

Connectives:

Due to, therefore,

consequently, so, as a

result,….

MARKING POINTS (B2.5 - 5)

1

1

1

Embryonic stem cells or adult stem cells

from adult bone marrow could be

placed next to brain cells inside a Petri dish

so that they differentiate and form new

brain cells which are transplanted into the

patient’s brain.

5a 6 marks

QUESTION

Embryos can be screened

for genetic disorders. Many

people would favour the

use of embryo screening for

cystic fibrosis but not for

polydactyly. Compare the

issues involved in the use of

embryo screening for cystic

fibrosis and for polydactyly. Command word ‘compare’:

to describe the similarities

and differences/advantages

and disadvantages of two

methods, processes, objects

commenting on both.

Connectives:

Unlike, similar to, however,

compared to, like,……

KEYWORDS

Abort, population, health care costs,

religion, unethical, moral, life

threatening, disfigurement, operable

B2.5

MARKING POINTS

0 marks

No relevant

comment made

1-2 marks

There is a brief description

of the issues involved in

screening for at least one

condition. Poor SPAG.

3-4 marks There is some description of the issues

involved in screening

for both conditions but there is

a lack of both pros and cons

for the two conditions.

Some SPAG errors.

5-6 marks

There is a clear, balanced and

detailed description of the

issues involved in screening

for both conditions, giving

pros and cons for each

condition. Almost faultless

SPAG.

Screening for cystic fibrosis is

useful as parents might decide

to abort the foetus and

therefore reduce the number

of people with CF in the

population which would

reduce health care costs.

Unfortunately, screening could

damage the embryo or

mother and for religious

reasons abortion might not be

considered unethical.

Unlike CF, polydactyly is not

life threatening and there are

ways to cure the

disfigurement, so screening is

really not justified.

5a

6 3 marks

QUESTION

How do fossils provide

evidence that species

alive today have

evolved from simpler

organisms?

KEYWORDS

Remains, millions, simple,

complex, features

B2.6

(B2.6- 6)

Command word ‘explain’:

to link all points logically.

Connectives:

Due to, therefore,

consequently, so, as a

result,….

MARKING POINTS (B2.6 - 6)

1

1

1

Fossils are the remains of organisms that lived millions of

years ago.

These fossils show similar features to present-day species

but older fossils are simpler compared to today’s complex

species.

6a 4 marks

QUESTION

Four different species of

terrestrial salamanders are

found on a small island

although originally, there

was only one species in the

country. Suggest an

explanation for the

development of the four

different species of

salamander.

Command word ‘explain’:

to link all points logically.

Connectives:

Due to, therefore,

consequently, so, as a

result,….

KEYWORDS

Population, isolation, gene

mutation, variation, natural

selection, interbreeding, species

B2.6

6a

MARKING POINTS

The original population of

salamanders became geologically (1)

separated (1).

Due to gene mutation a variety of

salamanders with different

characteristics was present within the

two isolated populations (1). Natural

selection meant that only some of

the salamanders survived and were

able to breed and pass on their

genes (1).

Eventually, the two isolated

populations were genetically so

different that interbreeding was no

longer possible (1). New species had

formed.

B2