NATIONAL SENIOR CERTIFICATE EXAMINATION
NOVEMBER 2019
LIFE SCIENCES: PAPER I
Time: 3 hours 200 marks
PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY
1. This question paper consists of 14 pages and a yellow Answer Booklet of 15 pages
(i–xv). Please check that your question paper is complete. Detach the yellow
Answer Booklet from the middle of the question paper. Remember to write your
examination number in the blocks provided.
2. This question paper consists of four questions.
3. Read the questions carefully.
4. Question 1 appears in the Answer Booklet and must be answered in this Booklet.
5. Questions 2, 3 and 4 must be answered in your Answer Book.
6. Start each question on a new page.
7. Number the answers exactly as the questions are numbered.
8. Use the total marks that can be awarded for each question as an indication of the
detail required.
9. It is in your own interest to write legibly and to present your work neatly.
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QUESTION 2
2.1 Read the article below. Use the information in the source and your own
knowledge to answer the questions that follow:
A study was conducted on a group of healthy women between the ages of 20 and 30
years. The women had no history of diseases of the reproductive system and had regular
menstrual cycles. The women had not taken oral contraceptives in the last six months.
The thickness of the endometrium was measured at various intervals during one
menstrual cycle. The data collected during the study is represented in the graph below.
Graph showing the average thickness of the
endometrium of women aged between 20 and 30 years
over one menstrual cycle
0.7
thickness of endometrium (mm)
0.6
0.5
0.4
0.3
0.2
0.1
0
day 2 of menstrual
day 2 phase before
phase ovulation phase after
period
menstrual ovulation
before ovulation and
period ovulation before
menstruation
phase of menstrual cycle
[Adapted: <https://posterng.netkey>]
2.1.1 Where in the body is the endometrium located? (1)
2.1.2 What is the purpose of the endometrium? (1)
2.1.3 What happens to the endometrium during menstruation? (2)
2.1.4 Describe the trend shown by the graph. (2)
2.1.5 Name TWO hormones released from the ovary during the menstrual
cycle that stimulate the thickening of the endometrium. (2)
2.1.6 The thickness of the endometrium was measured on day two of the
menstrual period. Suggest why a specific day was not indicated
when measuring the endometrium thickness at ovulation. (2)
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,NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I Page 3 of 14
2.1.7 Suggest why the researchers used women in the study who had not
used oral contraceptives in the six months before the study. (1)
2.1.8 List TWO ethical guidelines that should be followed when conducting
this type of research. (2)
2.1.9 Why is it important that ethical guidelines should be followed in this
study? (2)
2.1.10 If one of the women in the study fell pregnant, predict what would
happen to the endometrium thickness. (1)
2.2 Read the following extract and answer the questions that follow:
Scientists are developing a hormonal birth-control pill for men that would be
taken on a daily basis. Hormonal contraception works for men much as it does
for women — by changing levels of certain hormones so that the body stops
making its own.
In men, synthetic testosterone suppresses the pituitary gland's release of LH and
FSH. This reduction in LH and FSH stops the testes from making natural
testosterone as well as sperm cells. Once men stop taking the birth control pill,
the body goes back to producing reproductive hormones and sperm production
returns.
[Adapted: <https://www.sciencenews.org>]
2.2.1 Name the hormone that the male contraceptive pill would contain. (1)
2.2.2 Suggest TWO reasons why a birth-control pill for men is a good idea. (2)
2.2.3 The male birth-control pill is currently being developed by scientists.
Suggest TWO considerations that would need to be taken into
account before this pill is made available for use by the public. (2)
2.2.4 Use a flow diagram to explain the negative feedback mechanism
involved in sperm production in a male not taking the birth-control
pill. Start in the following manner:
Testosterone levels low (6)
2.2.5 Name and briefly discuss ONE other form of contraception that can
currently be used by men. (3)
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2.3 Study the graph below that shows the relationship between testis volume
and the length of seminiferous tubules in a human male.
Graph showing the relationship between testis volume and
length of seminiferous tubules in a human male at different ages
Length of seminiferous
tubules in testis (m)
Testis volume (cm3)
Key
Testis volume
Length of
seminiferous tubules
[Adapted: <https://oncohemakey.com>]
2.3.1 What is the function of the seminiferous tubules? (1)
2.3.2 What can be concluded from the data shown in the graph? (3)
2.3.3 From the graph, determine the length of seminiferous tubules at the
age of 16. (2)
2.3.4 Does the graph suggest that puberty starts at age 13? Provide an
explanation for your answer. (2)
2.3.5 Briefly describe TWO other physical changes not shown in the graph
that occur in males during puberty. (2)
[40]
IEB Copyright © 2019
NOVEMBER 2019
LIFE SCIENCES: PAPER I
Time: 3 hours 200 marks
PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY
1. This question paper consists of 14 pages and a yellow Answer Booklet of 15 pages
(i–xv). Please check that your question paper is complete. Detach the yellow
Answer Booklet from the middle of the question paper. Remember to write your
examination number in the blocks provided.
2. This question paper consists of four questions.
3. Read the questions carefully.
4. Question 1 appears in the Answer Booklet and must be answered in this Booklet.
5. Questions 2, 3 and 4 must be answered in your Answer Book.
6. Start each question on a new page.
7. Number the answers exactly as the questions are numbered.
8. Use the total marks that can be awarded for each question as an indication of the
detail required.
9. It is in your own interest to write legibly and to present your work neatly.
IEB Copyright © 2019 PLEASE TURN OVER
,NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I Page 2 of 14
QUESTION 2
2.1 Read the article below. Use the information in the source and your own
knowledge to answer the questions that follow:
A study was conducted on a group of healthy women between the ages of 20 and 30
years. The women had no history of diseases of the reproductive system and had regular
menstrual cycles. The women had not taken oral contraceptives in the last six months.
The thickness of the endometrium was measured at various intervals during one
menstrual cycle. The data collected during the study is represented in the graph below.
Graph showing the average thickness of the
endometrium of women aged between 20 and 30 years
over one menstrual cycle
0.7
thickness of endometrium (mm)
0.6
0.5
0.4
0.3
0.2
0.1
0
day 2 of menstrual
day 2 phase before
phase ovulation phase after
period
menstrual ovulation
before ovulation and
period ovulation before
menstruation
phase of menstrual cycle
[Adapted: <https://posterng.netkey>]
2.1.1 Where in the body is the endometrium located? (1)
2.1.2 What is the purpose of the endometrium? (1)
2.1.3 What happens to the endometrium during menstruation? (2)
2.1.4 Describe the trend shown by the graph. (2)
2.1.5 Name TWO hormones released from the ovary during the menstrual
cycle that stimulate the thickening of the endometrium. (2)
2.1.6 The thickness of the endometrium was measured on day two of the
menstrual period. Suggest why a specific day was not indicated
when measuring the endometrium thickness at ovulation. (2)
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,NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I Page 3 of 14
2.1.7 Suggest why the researchers used women in the study who had not
used oral contraceptives in the six months before the study. (1)
2.1.8 List TWO ethical guidelines that should be followed when conducting
this type of research. (2)
2.1.9 Why is it important that ethical guidelines should be followed in this
study? (2)
2.1.10 If one of the women in the study fell pregnant, predict what would
happen to the endometrium thickness. (1)
2.2 Read the following extract and answer the questions that follow:
Scientists are developing a hormonal birth-control pill for men that would be
taken on a daily basis. Hormonal contraception works for men much as it does
for women — by changing levels of certain hormones so that the body stops
making its own.
In men, synthetic testosterone suppresses the pituitary gland's release of LH and
FSH. This reduction in LH and FSH stops the testes from making natural
testosterone as well as sperm cells. Once men stop taking the birth control pill,
the body goes back to producing reproductive hormones and sperm production
returns.
[Adapted: <https://www.sciencenews.org>]
2.2.1 Name the hormone that the male contraceptive pill would contain. (1)
2.2.2 Suggest TWO reasons why a birth-control pill for men is a good idea. (2)
2.2.3 The male birth-control pill is currently being developed by scientists.
Suggest TWO considerations that would need to be taken into
account before this pill is made available for use by the public. (2)
2.2.4 Use a flow diagram to explain the negative feedback mechanism
involved in sperm production in a male not taking the birth-control
pill. Start in the following manner:
Testosterone levels low (6)
2.2.5 Name and briefly discuss ONE other form of contraception that can
currently be used by men. (3)
IEB Copyright © 2019 PLEASE TURN OVER
, NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I Page 4 of 14
2.3 Study the graph below that shows the relationship between testis volume
and the length of seminiferous tubules in a human male.
Graph showing the relationship between testis volume and
length of seminiferous tubules in a human male at different ages
Length of seminiferous
tubules in testis (m)
Testis volume (cm3)
Key
Testis volume
Length of
seminiferous tubules
[Adapted: <https://oncohemakey.com>]
2.3.1 What is the function of the seminiferous tubules? (1)
2.3.2 What can be concluded from the data shown in the graph? (3)
2.3.3 From the graph, determine the length of seminiferous tubules at the
age of 16. (2)
2.3.4 Does the graph suggest that puberty starts at age 13? Provide an
explanation for your answer. (2)
2.3.5 Briefly describe TWO other physical changes not shown in the graph
that occur in males during puberty. (2)
[40]
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