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PRETORIA HIGH SCHOOL FOR GIRLS
LIFE SCIENCES: PAPER 1
PRELIMINARY EXAMINATION JUNE 2008
TIME: 2 HOURS 30 MINUTES
EXAMINER: E. RUSSELL
TOTAL: 150
INSTRUCTIONS AND INFORMATION:
1. Answer ALL the questions.
2. Write ALL the answers of each question as follows:
i. SECTION A: answer on the answer sheet provided.
ii. SECTION B: answer each question (2, 3 and 4) on a separate folio.
iii. SECTION C: answer questions 5.1 and 5.2 on one folio and then
question 5.3 on a separate folio.
3. Make sure that you write your own name and the name of your Life Sciences
teacher on each of the folios.
4. Number the answers correctly according to the numbering system used in this question paper.
5. If answers are NOT presented according to the instructions of each question, candidates will
lose marks.
6. ALL drawings should be done in pencil and labeled in blue or black ink.
7. Draw diagrams and flow charts ONLY when requested to do so.
8. The diagrams in this question paper may NOT necessarily be drawn to scale.
9. The use of graph paper is NOT permitted.
10. Non-programmable calculators, protractors and compasses may be used.
11. Write neatly and legibly.
12. This paper consists of 15 pages.
13. Note: The rubric at the end of the paper should guide you when answering your essay. Please
detach it from the question paper and hand it in with your essay.
1
SECTION A
QUESTION 1.1
Various possible options are provided as answers to the following questions. Choose the correct
answer and write only the corresponding letter next to the question number on the answer sheet.
Questions 1.1.1 and 1.1.2 are based on the following information:
Fruit flies are often used for genetic experiments because they have a short life cycle and results
for a cross can be obtained in two or three weeks. They are easy to keep and produce large
numbers of offspring.
The pictures above show the phenotypes of fruit flies in general but do not directly apply to the
questions.
Some fruit flies have normal wings and some have vestigial wings, which are short and misshapen
and do not allow flight. The wing phenotype is determined by one gene. Use the symbols N for
dominant normal wing and n for recessive vestigial wing. The body colour phenotype is determined
by one gene as well. Use G for dominant grey body and g for recessive black body.
1.1.1
What would the genotype of a parent generation be, if the offspring generation
produced this result: 9:3:3:1?
A NnGg X NnGg
B nngg X NNGG
C NnGg X Nngg
D NNGG X nngg
1.1.2
What would the genotype of a parent generation be, if the offspring generation
produced this result: 1:1:1:1?
A NnGg X NnGg
B nngg X NNGG
C NnGg X nngg
D NNgg x nnGG
2
Questions 1.1.3 – 1.1.5 refer to the following information:
Below are two karyograms that show two sets of human chromosomes.
Below is a picture of a 24 year-old Down’s syndrome woman and next to it is a picture that shows
a type of procedure that a pregnant woman can undergo to confirm that her baby is a Down’s
syndrome baby.
3
1.1.3
Which of the following statements is true for A and B?
A Karyogram A belongs to a normal person and B to a Down’s syndrome person
B Karyogram B belongs to a normal person and A to a Down’s syndrome person
C Karyogram A shows an organism with 23 pairs of chromosomes
D Karyogram B belongs to a person with Klinefelter’s syndrome.
1.1.4
Which karyogram, A or B, could possibly belong to the person C?
A A
B B
C It could be A or B
D Neither A nor B
1.1.5
What is the procedure in diagram D called?
A chorionic villus sampling
B spina bifidensis
C pregnancy test
D amniocentesis.
[5 x 2 = 10]
QUESTION 1.2
Give one word or term for each of the following:
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
The process used to sterilize a man by cutting the vas deferens.
The cells in the seminiferous tubule that provide nutrition for the developing sperms.
The monk who is regarded as being the father of present day genetics.
A blood-clotting disorder, occurring mainly in males, that is linked to a recessive gene on the
X chromosome.
The type of tissue that lines the fallopian tubes.
[5]
QUESTION 1.3
The graphs below represent the increases in mass and height of boys and girls over a period of
eighteen years.
4
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
Which line (solid or dotted) in each figure represents girls?
Give reasons as read from the graph for your answer.
State three changes that take place in the male body between the ages
of 13 and 18 years.
Name the hormone that is responsible for these changes.
State three changes that take place in the female body between the ages
of 11 and 17 years.
[10]
(1)
(2)
(3)
(1)
(3)
QUESTION 1.4
The owners of a flat saw a girl breaking in. They described her to the police.
They said:
 She was a young, dark girl
 She had long dark hair, brown or even black
 She was wearing a striped top
 She may have been wearing jeans or blue pants.
The police thought they knew who the burglar was. Her name is Gail. The owners of the flat picked
out Gail in an identity parade. The police said that they needed other evidence to prove that she
was the right girl. They returned to the scene of the crime and found the following:
5
The pictures below show the girls that were used in the identity parade.
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
Which girl is the most likely girl that they chose?
(1)
Why is this evidence not enough to confirm the case against Gail?
(2)
Which finger print is like Gail’s, A or B?
(1)
Can we positively say that it belongs to Gail? Give a reason for your answer. (2)
Can this evidence alone be used against Gail in a Court of Law? Give a reason
for your answer.
(2)
The bar graph below shows the frequency of human blood groups in South
Africa:
Gail’s parents are blood group A and B. The blood on the window is group O.
1.4.6.1 Is it possible that this could be Gail’s blood?
1.4.6.2 Explain, by doing a crossing using a Punnett diagram, why you gave your
answer to 1.4.6.1 above.
1.4.6.3 Does this prove that the blood is Gail’s?
(1)
(5)
(1)
6
1.4.6.4 Explain your answer by referring to the bar graph and your knowledge of
genetics.
(2)
1.4.7
The Police Chief told the investigators that despite the fact that they felt
that the evidence was overwhelming, they would have to be 100% certain of
their facts before they went into court. Gail had a brilliant lawyer who
would easily have the evidence discounted. He told them that they had to
get further evidence. Suggest a further test that can be done to prove
that Gail is the burglar. Give reasons why this will be a positive test.
(3)
1.4.8
Crime in South Africa is at an all time high. It has been suggested that we
start a database storing certain information of every individual in the
country. Explain how this database will work. Present 1 argument for and 1
against this idea. Use sound scientific logic – you will be penalized if you
become emotional.
(5)
[25]
SUBTOTAL: 50
7
SECTION B
QUESTION 2
Study the two processes indicated by A and B below:
2.1
Make a fully labeled diagram of the portion of the DNA molecule shown in
the block marked C. Your diagram should provide detailed information,
clearly showing the component molecules that make up this section of DNA.
All the molecules should be arranged spatially correctly to show how they
attach to each other. (Use particular shapes to represent the different
molecules that make up this portion of DNA.)
(6)
2.2
Identify the processes A and B.
(2)
2.3
When does process A occur in the cell?
(1)
8
2.4
Explain the significance of this process to living organisms.
(2)
2.5
When does process B take place?
(1)
2.6
Explain the significance of this process to living organisms.
(3)
2.7
Sometimes errors occur during process B.
errors that can occur.
(2)
2.8
Name any two types of
Of what importance could these errors be in the life cycle of a human?
(3)
{20}
9
QUESTION 3
3.1
3.1.1
The diagram below represents a phase of meiosis. Study the diagram and answer the
questions that follow:
What are the paired chromosomes labeled A called?
(1)
3.1.2 Which phase of meiosis is represented here?
(1)
3.1.3 How many chromosomes are shown in the diagram?
(1)
3.1.4 How many chromosomes would there be in each daughter cell at the end of
meiosis?
(1)
3.1.5 Explain what happened to the chromosomes of this cell in the 2 phases prior
(before) to this phase.
(3)
3.1.6 Of what importance are these two phases mentioned in 3.1.5 for natural
selection?
[10]
3.2
(3)
Red-green colour blindness is a sex-linked trait. The allele for red-green colour
blindness (Xb) is recessive to the normal allele (XB ).
The pedigree shown on the next page represents the inheritance of this characteristic.
10
3.2.1 With respect to vision, what are the phenotypes of A, B and G?
(3)
3.2.2 With respect to sex chromosomes, what are the genotypes of A, B and G?
(3)
3.2.3 Is it possible for C and D ever to have an affected daughter? Explain your
answer by making use of a Punnett diagram.
(4)
[10]
{20}
11
QUESTION 4
4.1
4.1.1
The questions refer to the diagram below:
Identify structure W.
(1)
4.1.2 Explain how structure W changes to allow sexual intercourse to take place.
(1)
4.1.3 Identify the 3 parts by letter and name that play a role in semen production.
Say what each part produces and the importance of it in reproduction.
(9)
[11]
12
4.2.1
Identify the female contraceptive shown below.
(1)
4.2.2
Make a simple sketch showing the exact position of this contraceptive in the
female reproductive system. Label the appropriate parts.
(3)
4.2.3
Certain religions are against the use of this method of contraception.
Imagine that you belong to such a religion. Explain to your daughter
how this method of contraception works and why it is that you believe that
she should not use it.
(5)
[9]
{20}
SUBTOTAL: 60
13
SECTION C
QUESTION 5
Mrs A van Niekerk was overheard saying the following in the staffroom:
`The development of biotechnological methods has greatly improved the quality of life – for both
young and old – by leaps and bounds. Biotechnological methods revolve around any manipulation of
medication or of biological organisms.’
This section deals specifically with different biotechnological techniques involving plants and
humans.
5.1
A group of grade 12 learners carried out a survey about genetically modified foods (GM).
They used the following two questions in their survey:
1. Are GM foods better than normal foods?
2. Are you aware of any dangers in using GM foods?
The results of the survey are shown in the table below. Study the table and then answer
the questions that follow:
Question
1
2
Yes
5
10
No
35
30
5.1.1
Explain what GM foods are.
(2)
5.1.2
State one advantage of genetic modification for food production in South
Africa.
(1)
5.1.3
Draw a bar graph that represents the information in the table.
(7)
5.1.4
Suggest one way in which the learners can make sure that the results of
their survey are reliable.
(2)
5.1.5
State one conclusion that can be made from this survey.
(1)
5.1.6
Name two crops that are genetically modified in South Africa.
(2)
5.1.7
Name two disadvantages of GM crops in South Africa.
(2)
[17]
5.2
The article on the next page appeared in the Pretoria News (Wednesday April 30
2008)
under the heading: FRESH HOPE IN SIGHT FOR RETINAL DISEASE PATIENTS.(SAPA-AFP)
14
5.2
Biotechnology involving gene therapy is a fairly new technique and obviously
there is a lot of concern from the man in the street about its place in a
healthy society.
Briefly give your opinion, backing it up with sound scientific argument, as to
the benefits to society of gene therapy.
[5]
5.3
Human reproduction has been a matter of much debate for many years. Discuss the effect
that biotechnology has had on human reproduction and lifestyle in the last few decades.
Your essay must include mention of the following:
 Contraceptive pill
 Morning after pill
 Fertility clinics
 Sperm banks
Your essay must mention advantages of these techniques, whilst, at the same time,
pointing out areas of concern regarding social norms e.g. nuclear families with a mom
and a dad, is this a thing of the past, does it matter? All of these ideas should be
taken
into consideration in your essay.
[15]
Synthesis
[3]
SUBTOTAL: 40
Please detach, put your name on it and hand it in with your essay.
REMINDER: DETACH THIS RUBRIC AND HAND IN WITH YOUR ESSAY!!
15
Name:…………………………………………………………
Teacher:………………………………………………………………….
Criteria
Introduction and
conclusion
Paragraphs
0
Not done/incorrect
1
Introduction /
conclusion
Clear & correct
Contraceptive pill
Not done/incorrect /
muddled
Incorrect / not done
Contraceptive pill
Incorrect / not done
Morning after pill
Incorrect / not done /
explains how used /
effect on society
Incorrect / not done
Mentions how it is
used and effect on
society
Mentions advantages
or disadvantages
Incorrect / not done /
explains how used /
effect on society
Incorrect / not done
Mentions how it is
used and effect on
society
Mentions advantages
or disadvantages
Incorrect / not done /
explains how used /
effect on society
Incorrect / not done
Mentions how it is
used and effect on
society
Mentions advantages
or disadvantages
Vague / no understanding
Clear reasoning &
insight
Clear flow of ideas
Morning after pill
Fertility clinics
Fertility clinics
Sperm banks
Sperm banks
Views on situation in
SA / society
Sequence of ideas
TOTAL
Muddled
Mentions how it is
used / effect on
society
Mentions advantages
or disadvantages
2
Both correct
Mentions both
advantages and
disadvantages
Mentions both
advantages and
disadvantages
Mentions both
advantages and
disadvantages
Mentions both
advantages and
disadvantages
Excellent insight and
linking of ideas
18
16
MEMORANDUM:
SECTION A
QUESTION 1.1
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
A
C
B
D
D
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
vasectomy
Sertoli
Mendel
haemophilia
ciliated (columnar) epithelium
[5 x 2 = 10]
QUESTION 1.2
[5]
QUESTION 1.3
1.3.1 dotted
(1)
1.3.2 girls overtake boys in both graphs for mass and height at about the age of 10/11.
By the age of 13/14, however, the boys have overtaken the girls.
OR as girls mature sooner than boys, they reach maximum growth earlier
(GIVE one mark only if they haven’t read from the graph)
(2)
1.3.3 pubic hair, hair underarms, on chest, beard, deepening voice, testes and penis
enlarge, testosterone produced
(any 3)
1.3.4 testosterone
(1)
1.3.5 breasts, growth of hair on pubis and under arms, menstruation, more fat stored /
rounded shape, widening hips / pelvix, oestrogen and progesterone produced (any 3)
[10]
QUESTION 1.4
1.4.1 F (accept E too)
(1)
1.4.2 many similar looking girls fit the description,
clothes can be changed
(2)
1.4.3 B
(1)
1.4.4 yes. Finger prints are individual
(2)
BUT part is missing
1.4.5 yes. It positively places her at the scene of the crime
NO - fingerprints could have been placed there / she could have been there at
another time (2)
1.4.6.1
yes
(1)
1.4.6.2
if her parents are AO and BO
17
gametes
B
O
A
AB
AO
O
BO
OO
OR
USING NEW METHOD:
A = IAIA OR IAIO
B = IBIB OR IBIO
AB = IAIB
O = IOIO
(5)
1.4.6.3
NO
(1)
1.4.6.4
44% of the population has O blood type / most common blood type
This blood could belong to any of them
(2)
1.4.7 DNA fingerprinting – each person has their own individual DNA / unique (3)
1.4.8 DNA data base
All individuals data kept in a national data base
Advantage – police can solve crimes much faster
Disadvantage – has to be kept in a secure place so that public does not have access to
the information – this could lead to problems
(any 4 facts + one for good argument)
(5)
[25]
SECTION B
QUESTION 2
2.1.1
(6)
2.1.2 A – DNA REPLICATION
B – TRANSCRIPTION (2)
2.1.3 during interphase / just before cell division starts (1)
2.1.4 all daughter cells in one organism
Have identical DNA
2.1.5 during protein synthesis
(2)
(1)
2.1.6 proteins are building blocks / enzymes / some hormones etc (3)
2.1.7 point mutations, frameshift mutations, chromosomal mutations (any 2)
2.1.8 e.g. sickle cell anaemia is a point mutation
Could be lethal or lead to diseases
Or perhaps it will have no effect at all / neutral mutation
And a fixed mutation gives an advantage to the offspring and form new species (3)
[20]
18
QUESTION 3
3.1.1 homologous chromosomes
3.1.2 metaphase I
3.1.3 4
(1)
3.1.4 2
(1)
(1)
(1)
3.1.5 crossing over at chiasmata
Of sister chromatids
Exchanging of genetic material
Was formed from chromatin network
Paired up with homologous partner (any 3)
3.1.6 very important how chromosomes align at equator as this is random and
Affects which genetic material is passed to the gametes
Increases variation which is important for the survival of the species
(3)
[10]
3.2.1 A – carrier of colour blindness but has normal sight
B – normal i.e. not colour blind
G – is colour blind
(3)
3.2.2 A - XBXb
B - XB Y
G – XbY
(3)
3.2.3 never
Gametes
XB
XB
Xb
XB Xb
XB Xb
Y
XB Y
XB Y
All daughters will be carriers but can never be colour blind (4)
[10]
[20]
QUESTION 4
4.1.1 W – penis
(1)
4.1.2 blood fills the spaces and penis becomes erect
(1)
4.1.3 A – prostate gland – secretes white, alkaline fluid – neutralizes acids in urethra /
vagina and imporoves motility of sperm
B – testes – sperm – fertilizes the ova
C – seminal vesicle – produces thick yellowish fluid with fructose – nourishes
sperms
/ supplies energy for movement
(9)
19
[11]
4.2.1 IUD / intra-uterine device
(1)
4.2.2
(3)
4.2.3 fertilization takes place
The IUD prevents implantation
It is like a mini-abortion / causes embryo to be lost from the body
Conception has taken place so a little soul is lost etc. or whatever good argument
against this method
(3 + 2 for argument)
(5)
[9]
[20]
SECTION C
QUESTION 5
5.1.1 GM foods have been genetically engineered to take on new / better
characteristics
(2)
5.1.2 better and more food production / crops withstand pests or insecticides or
drought / more nutritious grains or fruit produced / last longer (longer shelf(1)
life)
5.1.3
Heading
X – question
Y – total number of people
Scale
Spaces
Bars
Accurate
(7)
5.1.4 take many surveys over a larger section of the community (2)
5.1.5 people do not know about GM foods / we need to inform people about pros and cons of
using GM foods (any 1)
5.1.6 soya, maize, alfalfa, cotton
(2)
5.1.7 not enough is known / offspring do not reproduce as well / pollination could see that
genes from the GM plants get into the wild / natural population , long
term influence on
health
(any 2)
20
5.2
Excellent benefits when it can help a person who is ill
Example quoted in the article suggests that people who suffer from this eye disease
can be cured of the symptoms if they are injected with the genes
That have been cloned in a laboratory
This method is clean and holds no toxins etc for the patient
Cost could be reduced as can be mass produced by bacteria / viruses in a lab under
clean conditions
No rejection of donor tissue / looking for donors
(The argument is important)
(5)
5.3
Must have something about the history of reproduction
e.g. if parents could not have children then they had to accept their lot in life
or they had to adopt
may have been judged by their community as failures
women / couples did not have much control over their reproductive output
Nowadays:
contraceptive pill – means that woman are free to have sexual partners without having
to be married OR married couples can
control when they want children i.e. when they have saved enough money to buy a
house / are more settled / can afford children
they can also decide how many children they want – so reducing the strain of
overpopulation on a society where food shortages scream from the headlines
everyday
and their own finances and general situation
moral values in a society are slowly deteriorating / could lead to promiscuity and no
responsibility for offspring
if people are controlling the number of children they have, then possibly it could lead
to an imbalance of boys and girls
morning after pill – if a girl has had unprotected sex then she can obtain this from the
clinic or pharmacy – to prevent unwanted pregnancy
however, girls are using it as a method of contraception i.e. mini abortion and doing
nothing about their promiscuous life style
fertility clinics – woman are placed on hormone treatments to stimulate egg
production – this ensures that women can fall pregnant – in the past she would just
have to give up the thought of having a family.
Usually this results in multiple births – financial strain on family
Many cases of infertility due to e.g. mature mother or father being infertile / variety
of reasons
Very expensive and unpredictable results – may not conceive the first time,
artificial methods used for something that should be natural
Sperm banks – men donate sperm which is housed in a central point
Gay or infertile couples can obtain sperm from here to be artificially inseminated –
giving them the opportunity of raising their own children
Disadvantage is that many children could possible be marrying half brothers or sisters
as no personal details of the donor are supplied the couples
21
Also, single mothers who choose to be single, could become pregnant – again, this
impacts on nuclear family etc
Disrupted in any way e.g. parents work and grandparents look after kids
AIDS – orphans looking after siblings
Second marriages; living together with children from previous relationships
(3 x 4 = 12) – + 1 for how 4 + 1 for + 1 against
+ 3 for excellent insight
+ 3 for paragraphs, introduction etc
[18]
22
Please detach, put your name on it and hand it in with your essay.
Name:…………………………………………………………
Criteria
Introduction and
conclusion
Paragraphs
0
Not done/incorrect
1
Introduction /
conclusion
Clear & correct
Contraceptive pill
Not done/incorrect /
muddled
Incorrect / not done
Contraceptive pill
Incorrect / not done
Morning after pill
Incorrect / not done /
explains how used /
effect on society
Incorrect / not done
Mentions how it is
used and effect on
society
Mentions advantages
or disadvantages
Incorrect / not done /
explains how used /
effect on society
Incorrect / not done
Mentions how it is
used and effect on
society
Mentions advantages
or disadvantages
Incorrect / not done /
explains how used /
effect on society
Incorrect / not done
Mentions how it is
used and effect on
society
Mentions advantages
or disadvantages
Vague / no understanding
Clear reasoning &
insight
Clear flow of ideas
Morning after pill
Fertility clinics
Fertility clinics
Sperm banks
Sperm banks
Views on situation in
SA / society
Sequence of ideas
TOTAL
Muddled
Mentions how it is
used / effect on
society
Mentions advantages
or disadvantages
2
Both correct
Mentions both
advantages and
disadvantages
Mentions both
advantages and
disadvantages
Mentions both
advantages and
disadvantages
Mentions both
advantages and
disadvantages
Excellent insight and
linking of ideas
18
23
ANSWER SHEET: GRADE 12 LIFE SCIENCES PAPER ONE
PRELIMINARY EXAMINATION
NAME:
TEACHER:
QUESTION 1.1
QUESTION 1.2
1.1.1
…………………
1.2.1
…………………………………………………………………………………….
1.1.2
…………………
1.2.2
……………………………………………………………………………………..
1.1.3
………………….
1.2.3
……………………………………………………………………………………….
1.1.4
…………………
1.2.4
……………………………………………………………………………………….
1.1.5
………………….
1.2.5
………………………………………………………………………………….[5]
[2 X 5 = 10]
QUESTION 1.3
1.3.1
……………………………………………………………. (1)
1.3.2
…………………………………………………….……………………………………………………………………………………………………………….
…………………………………………………….……………………………………………………………………………………………………………….
…………………………………………………..…………………………………………………………………………………………………………. (2)
1.3.3
………………………………………………………………………………………………………….………………………………………………………….
………………………………………………………………………………………………………………………………………………………………. (3)
1.3.4
…………………………………………………………….. (1)
1.3.5
……………………………………………………………………………………………………………….…………………………………………………….
………………………………………………………………………………………………………………………………………………………………. (3)
[10]
QUESTION 1.4
1.4.1
…………………….. (1)
1.4.2
……………………………………………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………………………………………. (2)
24
1.4.3
…………………….. (1)
1.4.4
…………………………………………………………………………………………………………………………………………………………….……….
……….………………………………………………………………………………………………………………………………………………………(2)
1.4.5
…………………………………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………………………... (2)
1.4.6.1 ………………………..
(1)
1.4.6.2
(5)
1.4.6.3 ……………………
(1)
1.4.6.4 ……………………………………………………………………………………………………………………………………………………………………..
…………………………………………………..………………………………………………………………………………………………………….. (2)
1.4.7
………………………………………………………………………………………………………….………………………………………………………….
……………………………………………………………………………………………………………………………………………………………….…….
……………………………………………………………………………………………………………………………………………………………..…(3)
1.4.8
……………………………………………………………………………………………………………………………………………………………………..
……………………………………………………………………………………………………….…………………………………………………………….
…………………………………………………………………………………………………………………………………………………………….……….
……………………………………………………………………………………………………………………………………………………………………..
……………………………………………………………………………………………………………………………………………………………………..
……………………………………………………………………………………………………………………………………………………………..…(5)
[25]
25
SUBTOTAL: 50
BLOCK C
A
B
A
B
C
D
E
F
W
Z
U
V
Y
X
Scrotum
sperm duct
G
vas deferens
26