Reproduction Exam Pack	

	Name:	
________________________	

Class:	
________________________	

Date:	
________________________	

 	
Time:	138 minutes	
Marks:	137 marks	
Comments:		

Q1.
When humans reproduce, chromosomes and genes are passed on to the next generation.
In each of the following questions, draw a ring around the correct answer to complete the sentence.
 
	 	 	cellulose.	
 
	(a)	A gene is a small section of	DNA.	
 
	 	 	protein.	
(1)
 
	 	 	X  and  X.	
 
	(b)	The sex chromosomes in the human male are	X  and  Y.	
 
	 	 	Y  and  Y.	
(1)
 
	 	 	23 chromosomes.	
 
	(c)     (i)	Most human body cells contain	46 chromosomes.	
 
	 	 	92 chromosomes.	
(1)
(ii)     The number of chromosomes in a human gamete (sex cell)

	 	the same number as	 	
 
	is	half the number	in body cells.	
 
	 	twice the number	 	
(1)
 
	 	 	fertilisation.	
 
	(d)	Gametes are produced by	meiosis.	
 
	 	 	mitosis.	
(1)
(Total 5 marks)
Q2.
Our understanding of genetics and inheritance has improved due to the work of many scientists.
(a)     Draw one line from each scientist to the description of their significant work.
 
Scientist	 	Description of significant work	
 	 	Carried out breeding experiments
on pea plants.	
Charles Darwin	 	 	
 	 	Wrote 'On the origin of species'.	
Alfred Russel Wallance	 	 	
 	 	Worked on plant defence systems.	
Gregor Mendel	 	 	
 	 	Worked on warning colouration in animals.	
(3)
(b)     In the mid-20th century the structure of DNA was discovered.
What is a section of DNA which codes for one specific protein called?
___________________________________________________________________
(1)
(c)     Figure 1 shows one strand of DNA.
The strand has a sequence of bases (A, C, G and T).
Figure 1
 
How many amino acids does the strand of DNA in Figure 1 code for?
 
Tick one box.	 	
2		
3		
4		
6		
(1)
(d)     Mutations of DNA cause some inherited disorders.
One inherited disorder is cystic fibrosis (CF).
A recessive allele causes CF.
Complete the genetic diagram in Figure 2.
•        Identify any children with CF.
•        Give the probability of any children having CF.
Each parent does not have CF.
The following symbols have been used:
D = dominant allele for not having CF
d = recessive allele for having CF
Figure 2
 
Probability of a child with CF = _____________________
(3)
(e)     What is the genotype of the mother shown in Figure 2?
 
Tick one box.	 	
Heterozygous		
Homozygous dominant		
Homozygous recessive		
(1)
(Total 9 marks)
Q3.
Figure 1 shows a human body cell.
Figure 1
 
(a)     Which part in Figure 1 contains chromosomes?
Tick one box.
 
A		 	B		 	C		
(1)
(b)     Humans have pairs of chromosomes in their body cells.
Draw one line from each type of cell to the number of chromosomes it contains.
 
Type of cell	 	Number of Chromosomes	
 
 	 	10	
 	 	 	
Human body cell	 	23	
 	 	 	
 	 	46	
 	 	 	
Sperm cell	 	60	
 	 	 	
 	 	92	
(2)
(c)     Humans have two different sex chromosomes, X and Y.
Figure 2 shows the inheritance of sex in humans.
Figure 2
 
Circle a part of Figure 2 that shows an egg cell.
(1)
(d)     Give the genotype of male offspring.
___________________________________________________________________
(1)
(e)     A man and a woman have two sons. The woman is pregnant with a third child.
What is the chance that this child will also be a boy?
 
Tick one box.	 	
    0%		
  25%		
  50%		
100%		
(1)
(Total 6 marks)
Q4.
In sexual reproduction, an egg fuses with a sperm.
(a)     (i)      Draw a ring around the correct answer to complete the sentence.
 
An egg and a sperm fuse together in the process of	cloning.
fertilisation.
mitosis.	
(1)
(ii)     Egg cells and sperm cells each contain the structures given in the box.
 
chromosome	gene	nucleus	
List these three structures in size order, starting with the smallest.
1 ____________________________________________________ (smallest)
2. ____________________________________________________________
3 _____________________________________________________ (largest)
(2)
(iii)     The egg and the sperm contain genetic material.
Draw a ring around the correct answer to complete the sentence.
 
The genetic material is made of	carbohydrate.
DNA.
protein.	
(1)
(b)     The diagram below shows the inheritance of X and Y chromosomes.
 
(i)      Draw a tick () on the part of the diagram that shows a sperm cell.
(1)
(ii)     What is the chance of having a female child?
Give the reason for your answer.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(Total 7 marks)
Q5.
In humans, hair colour is an inherited characteristic.
Red hair is caused by a recessive allele.
(a)     When does a recessive allele control the development of a characteristic?
 
Tick (✔) one box.	 	
When the allele is present on only one of the chromosomes.		
When the dominant allele is not present.		
When the allele is inherited from the female parent.		
(1)
(b)     Figure 1 shows the inheritance of hair colour in one family.
 
(i)      Brown hair is caused by a dominant allele, B.
Red hair is caused by the recessive allele, b.
What combination of alleles does person 1 have?
 
Tick (✔) one box.	 	
BB		
Bb		
bb		
(1)
(ii)     Person 3 married a woman with brown hair.
Figure 2 shows how hair colour could be inherited by their children.
Figure 2
 
Complete Figure 2 to show the combination of alleles that the children would inherit.
One has been done for you.
(2)
(iii)     What is the probability that one of the children would have red hair?
 
Tick (✔) one box.	 	
1 in 2		
1 in 3		
1 in 4		
(1)
(Total 5 marks)
Q6.
(a)     Which organ of the human body produces egg cells?
Draw a ring around the correct answer.
liver                      ovary                      testis
(1)
(b)     An egg joins with a sperm and develops into an embryo.
How many chromosomes are there in each cell of a human embryo?
Draw a ring around the correct answer.
23                      46                      48
(1)
(c)     Some women find it difficult to have a baby. A doctor may suggest that these women should use In Vitro Fertilisation (IVF) to help them have a baby.
Table 1 shows how successful IVF was for women of different ages at one clinic.
Table 1
 
Age of women in years	Percentage of women who had a baby	
   <35	35	
   35–37	31	
   38–39	25	
   40–42	32	
   43–44	  7	
   >44	  0	
(i)     A student thought that the result for women aged 40–42 was anomalous.
Suggest why the student thought this result was anomalous.
______________________________________________________________
______________________________________________________________
(1)
(ii)     Describe the general trend in the results in Table 1.
You should ignore the anomalous result.
______________________________________________________________
______________________________________________________________
(1)
(d)     Some babies are born with a faulty chromosome.
Scientists investigated whether the chance of having a baby with a faulty chromosome is also related to the age of the woman.
Table 2 shows the scientists’ results.
Table 2
 
Age of women in years	Number of women per 1000 who had a baby with a faulty chromosome	
   25	  2.0	
   30	  2.6	
   35	  6.1	
   40	19.6	
   45	66.0	
(i)      A 45-year-old woman is more likely than a 25-year-old woman to have a baby with a faulty chromosome.
How many times more likely?
______________________________________________________________
______________________________________________________________
Answer = _____________________ times
(2)
(ii)     Suggest two reasons why many fertility clinics will not accept women over 40 years of age for IVF treatment.
Use information from Table 1 and Table 2 in your answer.
1. ____________________________________________________________
______________________________________________________________
2. ____________________________________________________________
______________________________________________________________
(2)
(Total 8 marks)
Q7.
Genetic disorder E is a condition caused by a change in the chromosomes.
(a)     Figure 1 shows the chromosomes from one cell of a person with genetic disorder E.
 
(i)      How do you know this person is female?
Use information from Figure 1.
______________________________________________________________
______________________________________________________________
(1)
(ii)     Describe how the chromosomes shown in Figure 1 are different from the chromosomes from a person who does not have genetic disorder E.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(b)     As a woman gets older, the chance of her having a baby with genetic disorder E increases.
Figure 2 shows this.
 
(i)      The chance of a 35-year-old woman having a baby with genetic disorder E is 2 per 1000 births.
What is the chance of a 40-year-old woman having a baby with genetic disorder E?
_____________ per 1000 births
(1)
(ii)     A 40-year-old woman is more likely than a 35-year-old woman to have a baby with genetic disorder E.
How many times more likely?
_____________________ times
(1)
(c)     A 41-year-old woman wants to have a baby. A 41-year-old woman has an increased chance of having a baby with genetic disorder E.
Doctors can screen embryos for genetic disorder E.
The table gives some information about two methods of embryo screening.
 
Method 1	Method 2	
1. The woman is given hormones to
    cause the release of a few eggs.
    The eggs are taken from her body
    in a minor operation.
    The eggs are fertilised in a glass
    dish.	1. The woman gets pregnant in the
    normal way.	
2. One cell is taken from each embryo
    when the embryo is 3 days old.	2. Cells are taken when the embryo is
    10 weeks old.	
3. Cells are screened for genetic
    disorder E.	3. Cells are screened for genetic
    disorder E.	
4. An unaffected embryo is placed in
    the woman’s uterus.
    Embryos that are not used are
    destroyed or used in medical
    research.	4. An unaffected fetus is allowed to
    develop.
    If the fetus has genetic disorder
    E, the woman can choose to have
    an abortion.	
5. This method costs about £6000.	5. This method costs about £600.	
Use information from the table to give two advantages and one disadvantage of Method 1 compared with Method 2 for detecting genetic disorder E.
Advantages of Method 1:
1. _________________________________________________________________
___________________________________________________________________
2. _________________________________________________________________
___________________________________________________________________
Disadvantage of Method 1:
___________________________________________________________________
___________________________________________________________________
(3)
(Total 8 marks)
Q8.
DNA is the genetic material of human cells.
Figure 1 shows the structure of part of a DNA molecule.
 
(a)     (i)      Describe where DNA is found in a human cell.
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(ii)     When a cell divides by mitosis the new cells are genetically identical.
What causes the cells to be genetically identical?
______________________________________________________________
______________________________________________________________
(1)
(b)     Many genes have different forms called alleles.
(i)      A person has polydactyly (extra fingers or toes). Polydactyly is caused by a dominant allele.
What is the smallest number of copies of the dominant allele for polydactyly that could be found in a body cell of this person?
______________
(1)
(ii)     Another person has cystic fibrosis. Cystic fibrosis (CF) is caused by a recessive allele.
How many copies of the recessive CF allele are there in a body cell of this person?
______________
(1)
(c)     A burglar broke into a house. The burglar cut his hand on some broken glass. Scientists extracted DNA from the blood on the broken glass.
The scientists analysed the DNA from the glass and DNA from three suspects, A, B and C. The scientists used a method called DNA fingerprinting.
Figure 2 shows the scientists’ results.
 
Which suspect, A, B or C, is most likely to have been the burglar?
Tick () one box.
 
A		
B		
C		
(1)
(Total 6 marks)
Q9.
CRAM is an inherited condition which causes muscle breakdown.
The breakdown products enter the urine, making it dark-coloured.
The diagram below shows the inheritance of CRAM in one family.
 
CRAM is caused by a recessive allele, n.
The allele for normal health is N.
(a)     (i)      What is an allele?
______________________________________________________________
______________________________________________________________
(1)
(ii)     What does recessive mean?
______________________________________________________________
______________________________________________________________
(1)
(iii)    Give evidence from the diagram that CRAM is caused by a recessive allele.
______________________________________________________________
______________________________________________________________
(1)
(b)     (i)      Person 2 is homozygous for CRAM.
What does homozygous mean?
______________________________________________________________
______________________________________________________________
(1)
(ii)     None of person 2’s children have CRAM.
Explain why.
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(c)     Persons 7 and 8 want to have another child.
(i)      What is the probability that this child will have CRAM?
Draw a genetic diagram to explain your answer.
Probability = _____________________________
(4)
(ii)     To avoid having another child with CRAM, persons 7 and 8 may decide to use embryo screening.
Two ways of doing this are:
•        PGD (pre-implantation genetic diagnosis)
•        CVS (chorionic villus sampling).
PGD involves IVF (in vitro fertilisation) of a few eggs, then taking a cell from each embryo when it is 3 days old.
The image below shows how the cell is removed.
 
                    © Rtimages/iStock/Thinkstock
The DNA in the cell can then be tested. An unaffected embryo can be implanted in the woman’s uterus. The possibility of a false positive result is around 1 in 6. The procedure costs about £6000. Affected embryos would be discarded. Extra unaffected embryos might be frozen and kept for later implantation. Alternatively, the extra embryos might be used in scientific research.
CVS involves taking a sample of blood from the placenta a few weeks into pregnancy. DNA from white blood cells can then be tested.
If an affected embryo is detected, the parents then have to decide whether to terminate the pregnancy or allow it to continue.
CVS has a 1 percent chance of giving an incorrect result and a 0.9 percent chance of causing a miscarriage. CVS costs about £600.
Evaluate the benefits of these two methods of embryo screening.
You should include a conclusion to your evaluation.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(5)
(Total 15 marks)