Download Q1.Phenylketonuria (PKU) is an inherited condition. PKU makes

Q1.Phenylketonuria (PKU) is an inherited condition. PKU makes people ill.
(a)
PKU is caused by a recessive allele.
(i)
What is an allele?
...............................................................................................................
...............................................................................................................
(1)
(ii)
What is meant by recessive?
...............................................................................................................
...............................................................................................................
(1)
(b)
The diagram below shows the inheritance of PKU in one family.
(i)
Give one piece of evidence from the diagram that PKU is caused by a
recessive allele.
...............................................................................................................
...............................................................................................................
(1)
Page 1
(ii)
Persons 6 and 7 are planning to have another child.
Use a genetic diagram to find the probability that the new child will have PKU.
Use the following symbols in your answer:
N = the dominant allele for not having PKU
n = the recessive allele for PKU.
Probability = ..................................................
(4)
(c)
Persons 6 and 7 wish to avoid having another child with PKU.
A genetic counsellor advises that they could produce several embryos by IVF
treatment.
(i)
During IVF treatment, each fertilised egg cell forms an embryo by cell division.
Name this type of cell division.
...............................................................................................................
(1)
(ii)
An embryo screening technique could be used to find the genotype of each
embryo.
An unaffected embryo could then be placed in person 7’s uterus.
The screening technique is carried out on a cell from an embryo after just
three cell divisions of the fertilised egg.
How many cells will there be in an embryo after the fertilised egg has
divided three times?
(1)
(iii)
During embryo screening, a technician tests the genetic material of the
embryo to find out which alleles are present.
The genetic material is made up of large molecules of a chemical substance.
Name this chemical substance.
...............................................................................................................
(1)
Page 2
(Total 10 marks)
Q2.The drawings show two different species of butterfly.
Amauris
Hypolimnas
•
Both species can be eaten by most birds.
•
Amauris has an unpleasant taste which birds do not like, so birds have learnednot
to prey on it.
•
Hypolimnas does not have an unpleasant taste but most birds do not prey on it.
(a)
Suggest why most birds do not prey on Hypolimnas.
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........................................................................................................................
........................................................................................................................
........................................................................................................................
(2)
(b)
Suggest an explanation, in terms of natural selection, for the markings on the wings
of Hypolimnas.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
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(3)
(Total 5 marks)
Page 3
Q3.The photographs show two breeds of cow.
Friesian cowJersey cow
By Keith Weller/USDA (www.ars.usda.gov: Image
Number K5176-3) [Public domain], via Wikimedia Commons
By Jamain (Own work)
[CC-BY-SA-3.0-2.5-2.0-1.0], via Wikimedia Commons
In parts (a) and (b) draw a ring around the correct answer to complete each sentence.
asexual
reproduction.
(a)
Cows produce their young (calves)
by
cloning.
sexual reproduction.
(1)
(b)
Cows and their calves have many similar characteristics.
clones.
(i)
The information for characteristics is carried
by
embryos.
genes
(1)
Page 4
(ii)
The information for characteristics is passed to the next generation in cells
body
cells.
called
gametes.
neurones
.
(1)
(c)
Friesian and Jersey cows can both be used for meat or to produce milk.
The information shows features of Friesian and Jersey cows.
Friesian cows
Jersey cows
Body mass up to 600 kg
Body mass up to 400 kg
Milk contains 3.4% protein
Milk contains 3.8% protein
Can be milked for 325 days after
giving birth
Can be milked for 250 days after
giving birth
Produce no milk for 55 days before Produce no milk for 45 days before
having a calf
having a calf
Produce > 30 litres of milk per day
Produce < 30 litres of milk per day
Use only the information above to answer these questions.
In your answers you must make comparisons between the two breeds of cow.
(i)
Give two advantages of a farmer keeping Friesian cows and not Jersey
cows.
1.............................................................................................................
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2.............................................................................................................
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(2)
Page 5
(ii)
Give two advantages of a farmer keeping Jersey cows and not Friesian
cows.
1.............................................................................................................
...............................................................................................................
2.............................................................................................................
...............................................................................................................
(2)
(Total 7 marks)
Q4.
When scientists look at dividing cells under a microscope, they can see strands that
contain a chemical called DNA.
A photograph of these strands can be cut up and re-arranged.
The diagram shows an arrangement of the strands from a human cell.
(a)
What name is given to the strands containing DNA shown in the diagram?
Draw a ring around one answer.
alleles
chromosomes
genes
(1)
Page 6
(b)
Look carefully at the diagram.
(i)
The cell was taken from a man and not from a woman.
How can you tell?
...............................................................................................................
(1)
(ii)
What evidence is there that the strands are from a body cell, and not from a
gamete?
Tick (
) one box.
The strands are arranged in order of size.
The strands are in pairs.
Gametes are made in the testes and ovaries.
(1)
(iii)
When a human cell is not dividing the strands containing DNA are not clearly
visible.
Draw a ring around the correct answer to complete the sentence.
cell membrane.
In a human cell, the DNA is normally found in the
cytoplasm.
nucleus.
(1)
(Total 4 marks)
Page 7
Q5.
Diagram 1 shows the nucleus of a body cell as it begins to divide by mitosis.
Diagram 1
(a)
Use a word from the box to label Diagram 1.
alleles
chromosomes
gametes
(1)
(b)
Complete Diagram 2 to show what the nucleus of one of the cells produced by this
mitosis would look like.
Diagram 2
(1)
Page 8
(c)
Stem cells from a recently dead embryo can be grown in special solutions.
Some facts about stem cells are given below.
•
Stem cells from an embryo can grow into any type of tissue.
•
Stem cells may grow out of control, to form cancers.
•
Large numbers of stem cells can be grown in the laboratory.
•
Stem cells may be used in medical research or to treat some human diseases.
•
Patients treated with stem cells need to take drugs for the rest of their life to
prevent rejection.
•
Collecting and growing stem cells is expensive.
Use only the information above to answer these questions.
(i)
Give two advantages of using stem cells.
1 ........................................................................................................................
...........................................................................................................................
2 ........................................................................................................................
...........................................................................................................................
(2)
(ii)
Give two disadvantages of using stem cells.
1 ........................................................................................................................
...........................................................................................................................
2 ........................................................................................................................
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(2)
(Total 6 marks)
Page 9
Q6.
The diagram shows two patterns of cell division. Cell division type A is used in
gamete formation. Cell division type B is used in normal growth.
(a)
Name the two types of cell division, A and B, shown in the diagram.
Type A ........................................................................................................................
Type B ........................................................................................................................
(2)
(b)
Name the process in which an egg and sperm join together.
.............................................................................................................................
(1)
(c)
Cell 1 contains 46 chromosomes. How many chromosomes will there be in:
(i)
cell 10; ..............................................................................................................
(1)
(ii)
cell 14?
.............................................................................................................
(1)
(Total 5 marks)
Page 10
M1.(a)
(i)
one form of a / one gene
do not allow ‘a type of gene’
allow a mutation of a gene
1
(ii)
not expressed if dominant / other allele is present / if heterozygous
or
only expressed if dominant allele not present / or no other allele present
allow need two copies to be expressed / not expressed if
only one copy / only expressed if homozygous
1
(b)
(i)
two parents without PKU produce a child with PKU / 6 and 7 → 10
allow ‘it skips a generation’
1
(ii)
genetic diagram including:
accept alternative symbols if defined
Parental gametes:
6: N and n
and 7: N and n
1
derivation of offspring genotypes:
NN
Nn
Nn
nn
allow genotypes correctly derived from student’s parental
gametes
1
identification: NN and Nn as non-PKU
OR nn as PKU
allow correct identification of student’s offspring genotypes
1
correct probability only: 0.25 / ¼ / 1 in 4 / 25% / 1 : 3
do not allow 3 : 1 / 1 : 4
do not allow if extra incorrect probabilities given
1
Page 11
(c)
(i)
mitosis
correct spelling only
1
(ii)
8
1
(iii)
DNA
allow deoxyribonucleic acid
do not allow RNA / ribonucleic acid
1
[10]
M2.(a)
wing pattern similar to Amauris
allow looks similar to Amauris
1
birds assume it will have an unpleasant taste
1
(b)
mutation / variation produced wing pattern similar to Amauris
do not accept breeds with Amauris
do not accept idea of intentional adaptation
1
these butterflies not eaten (by birds)
1
these butterflies breed or their genes are passed to the next generation
1
[5]
Page 12
M3.(a)
sexual reproduction
1
(b)
(i)
genes
1
(ii)
gametes
1
(c)
(i)
any two from:
answers must be comparative
•
more meat (per cow)
ignore bigger unqualified
•
more milk each day
•
can be milked for more time after giving birth / greater proportion of
time
accept ‘(produce) more milk’, for 1 mark, if neither more milk
each day nor can be milked for more time after giving birth
are given
2
(ii)
(milk contains) more protein
answers must be comparative
1
less time before having a calf when no milk produced
1
[7]
Page 13
M4.
(a)
chromosomes
1
(b)
(i)
has XY / Y
allow female would be XX / has no Y
1
(ii)
The strands are in pairs
1
(iii)
nucleus
1
[4]
M5.
(a)
chromosomes
1
(b)
diagram showing four separate chromosomes two long and two short
(as in diagram 1)
allow each chromosome shown as two joined chromatids
do not allow if chromosomes touching each other
1
(c)
(i)
any two from:
•
can grow into any type of tissue / named tissue
•
used in medical research
•
used to treat human diseases
•
large numbers can be grown
2
Page 14
(ii)
any two from:
•
expensive
•
grow out of control / ref cancers
•
may be rejected
•
need for drugs (for rest of life)
2
[6]
M6.
(a)
A = meiosis
accept ‘mieosis’
do not accept ‘miosis’
1
B = mitosis
do not accept ‘meitosis’ etc
1
(b)
fertilisation allow conception
1
(c)
(i)
23
1
(ii)
46
1
[5]
Page 15