B1H Edexcel PiXL Mark Scheme November 2014
Question
1 (a)
1 (b)
1 (c)
1 (d) (i)
1 (d) (ii)
1 (e)
2 (a) (i)
2 (a) (ii)
2 (b)
2 (c)
Answer
B alleles (1)
Variation caused by genes (1) (inherited) from parents
(1)
23 (1)
T
t
t
Tt
tt
t
Tt
tt
3 (b)
3 (c)
1 mark for parents
1 mark for offspring
Parents can be either way
round
If more than one
50% or ½ or 1 in 2 or 2 in 4 or 2:2 or 1:1 (1)
probability is given and
any are incorrect, the
mark is negated
Accept correct alternative
Breathing difficulties (1) and weight loss (1)
and higher level
responses
(Total for Question 1 = 9 marks)
A chemical (1) that changes the way the body works (1)
C addicted (1)
Score 0 marks if more
than one box is crossed
Alcohol is a depressant (1) so slows down the activity of
neurones in the brain (1)
Short-term effects, any 2 from:
Maximum of 2 marks for
short-term effects
 Reduces negative feelings/makes you feel happier
Ignore references to
 Lower inhibitions/take greater risks
reaction time as this is
 Blurred vision
 Affect co-ordination/difficult to do simple mental or mentioned in the stem of
the question
physical tasks
 Vomiting
 Unconsciousness
(2)
Maximum of 2 marks for
Long-term effects, any 2 from:
long-term effects




3 (a)
Additional Guidance
Score 0 marks if more
than one box is crossed
Liver cirrhosis
Affecting learning/memory in the brain
Blood clot in the brain
Addictive
(2)
(Total for Question 2 = 9 marks)
Score 0 marks if more
A tears (1)
than one box is crossed
Chemical substances (1) that kill microorganisms outside
the body (1)
Antibiotics can only kill/stop the growth of bacteria (1)
3 (d)
Any 4 from:

Some bacteria are more resistant to antibiotics
than others

Susceptible bacteria are killed by the antibiotic

The more resistant bacteria are still there/continue
to cause infection if the patient stops taking the
antibiotics

These resistant bacteria reproduce and spread to
other patients

This causes an infection that cannot be treated
now with that specific antibiotic
(4)
3 (e)
4 (a) (i)
4 (a) (ii)
Wash hands/use alcohol gel (1)
(Total for Question 3 = 9 marks)
0.6 on its own = 2 marks
104
2.4 x
4 x 106
x 100 (1)
0.6 (1)
Any 2 from:




Accept correct alternative
or higher level responses
reflected
not absorbed or misses chloroplasts / chlorophyll
photosynthesis inefficient
some lost through respiration / as heat (from
respiration)
(2)
4 (a) (iii)
Any 2 from:





Ignore just ‘cell walls’
Cellulose cell walls
Multicellular
Autotrophic
Complex cell structure
Has a nucleus
(2)
4 (b)
Energy lost via faeces / not
digested / waste / excreted (of
insect-eating birds) (1)
Energy loss via respiration /
movement / muscle contraction /
heat (by insect-eating bird) (1)
Some of (insect eating) bird not
eaten but all / most / more of
insect is eaten (1)
(Total for Question 4 = 9 marks)
5 (a)
Any 2 from:



Chemical messengers
Released by (endocrine glands)
That travel in the blood
(2)
*5 (b)
Indicative content:
Mark the answer
according to the levels
below. Identify the level
first of all, then award the
top of the mark band if the
student’s literacy is
generally good or the
bottom if there are many
literacy errors.
Lowering blood glucose





Insulin is released
From the pancreas
Glucose is converted into glycogen
In the liver
Blood glucose levels fall
Accept higher level
answers and a well
annotated diagram
covering the level
description.
Rising blood glucose





Level
0
1
Glucagon is released
From the pancreas
Glycogen is converted into glucose
In the liver
Blood glucose levels rise
Level Description
No relevant answer.
A simple explanation of how hormones raise or lower
blood glucose levels
Marks
0
1-2
or
2
Mention that insulin decreases and glucagon increases
blood glucose levels.
A simple explanation of how hormones raise and lower
blood glucose levels
3-4
or
5 (c) (i)
A detailed explanation of how hormones raise or lower
blood glucose levels.
A detailed explanation of how hormones raise and lower
blood glucose levels. Correct scientific terminology is
used and the candidate’s answer flows well in a clear
logical order.
86.7 / (1.72) (1)
5 (c) (ii)
30 (1)
Any 1 from:
3




5-6
30 on its own = 2 marks
Accept correct alternative
wording, such as ‘eating
too much saturated fat’
Lack of exercise
High-fat diets
Ageing
Genetics
(1)
5 (d)
6 (a)
6 (b)
6 (c)
6 (d)
D homeostasis (1)
Score 0 marks if more
than one box is crossed
(Total for Question 5 = 12 marks)
Score 0 marks if more
B auxin (1)
than one box is crossed
Score 0 marks if more
D positive gravitotropism (1)
than one box is crossed
Auxins cause cell elongation (1). Auxins move to shaded
side of the shoot (1) when light is coming from one
direction (1). Cells on the shaded side elongate more (1).
Indicative content:
Mark the answer
according to the levels
Selective weedkillers
below. Identify the level
first of all, then award the
top of the mark band if the
 Use artificial auxin
student’s literacy is
 It only makes plants with broad leaves
generally good or the
 These grow out of control and die
bottom if there are many
 Farmers can kill all the weeds in a field of e.g.
literacy errors.
wheat without affecting their crop
Making seedless fruit



Accept higher level
answers.
Some seedless fruits are made using plant
hormones
The flowers are sprayed with plant hormones
causing fruits to develop only (not the seeds)
Naturally seedless fruits are sprayed with
gibberellins to make them bigger
Fruit ripening



Level
0
1
2
Plant hormones can be sprayed onto fruit trees to
increase their speed of ripening and make them
all ripe at the same time
Plant hormones can be sprayed onto fruit trees to
stop fruit falling off and allow them to increase in
size
Plant hormones can be sprayed onto unripe fruit
to make them ripe just in time for purchase
Level Description
No relevant answer.
A simple explanation of one of: selective weedkillers,
making seedless fruit and fruit ripening as plant hormone
uses.
A simple explanation of two of: selective weedkillers,
making seedless fruit and fruit ripening as plant hormone
uses.
or
A detailed explanation of one of: selective weedkillers,
making seedless fruit and fruit ripening as plant hormone
uses.
Marks
0
1-2
3-4
3
A detailed explanation of selective weedkillers, making
5-6
seedless fruit and fruit ripening as plant hormone uses.
Correct scientific terminology is used and the candidate’s
answer flows well in a clear logical order.
(Total for Question 6 = 12 marks)
TOTAL FOR PAPER = 60 MARKS