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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