LIFE SCIENCES
PAPER 1
GRADE 12 
NSC PAST PAPERS AND MEMOS
FEBRUARY/MARCH 2017

INSTRUCTIONS AND INFORMATION 
Read the following instructions carefully before answering the questions. 

1. Answer ALL the questions.
2. Write ALL the answers in the ANSWER BOOK. 
3. Start the answers to EACH question at the top of a NEW page. 
4. Number the answers correctly according to the numbering system used in this  question paper.
5. Present your answers according to the instructions of each question.
6. Do ALL drawings in pencil and label them in blue or black ink.
7. Draw diagrams, tables or flow charts only when asked to do so.
8. The diagrams in this question paper are NOT necessarily drawn to scale.
9. Do NOT use graph paper.
10. You must use a non-programmable calculator, protractor and a compass,  where necessary. 
11. Write neatly and legibly.

QUESTIONS

SECTION A 
QUESTION 1 
1.1 Various options are provided as possible answers to the following questions.  Write down the question number (1.1.1–1.1.10), choose the answer and make  a cross (X) over the letter (A–D) of your choice in the ANSWER BOOK. 
EXAMPLE: 
1.1.11 
1.1.1 After sperm cells have been produced in humans, they are stored  in the … until maturation. 

1. penis
2. urethra
3. epididymis
4. seminal vesicles 

1.1.2 Which ONE of the following parts in the diagram of a sperm cell  contains a haploid number of chromosomes? 

1. 1
2. 2
3. 3
4. 4 

1.1.3 Which ONE of the following plant hormones is responsible for the  germination of seeds? 

1. Growth hormone
2. Abscisic acid
3. Gibberellin
4. Auxin 

1.1.4 The phase in meiosis in which individual centromeres split is  called … 

1. anaphase I.
2. anaphase II.
3. metaphase I.
4. metaphase II.  

1.1.5 When Jane plays in the snow, her body maintains a constant core  temperature by … 

1. vasodilation and sweating. 
2. vasoconstriction and shivering.
3. sweating and shivering. 
4. vasoconstriction and vasodilation. 

1.1.6 Which ONE of the following hormones prepares the human body to  react to emergency situations? 

1. Insulin
2. Aldosterone
3. Adrenalin
4. Growth hormone 

QUESTIONS 1.1.7 AND 1.1.8 REFER TO THE INVESTIGATION BELOW. 

1.1.7 Which ONE of the following is the dependent variable in the  investigation? 

1. Fitness levels of the males
2. Age groups of the males
3. Number of active sperm cells
4. Amount of semen 

1.1.8 Which ONE of the following variables was kept constant during this  investigation? 

1. Number of participants in each age group
2. Fertility levels of males in each age group
3. Number of active sperm cells
4. Age groups of the males 

QUESTIONS 1.1.9 AND 1.1.10 REFER TO THE GRAPH BELOW.  THE GRAPH SHOWS THE CHANGES IN THE CONCENTRATION OF  FEMALE HORMONES (LH AND FSH) IN TWO FEMALES DURING THE  FIRST TWO WEEKS OF THE MENSTRUAL CYCLE. 

1.1.9 Which female will NOT ovulate on day 14? 

1. Female A, because the FSH levels are high 
2. Female A, because the LH levels are too high on day 13
3. Female B, because LH inhibits the development of a follicle
4. Female B, because a follicle did not develop in the ovary 

1.1.10 Which ONE of the following statements is CORRECT regarding  female A? 

1. FSH increases on day 14 because the Graafian follicle is  secreting progesterone.
2. FSH increases after day 9 as the pituitary gland/hypophysis is  secreting progesterone.
3. FSH decreases after day 4 to ensure that implantation occurs.
4. FSH increases in the first two days to stimulate the  development of a follicle.

(10 x 2) (20) 

1.2 Give the correct biological term for each of the following descriptions.  Write only the term next to the question number (1.2.1 to 1.2.8) in the  ANSWER BOOK. 

1.2.1 The diploid cell formed by the process of fertilisation 
1.2.2 A fluid that protects the human embryo against injuries and  large-scale temperature changes 
1.2.3 A disorder of the nervous system that is characterised by the breakdown of the myelin sheath of neurons 
1.2.4 A hormone produced by the pituitary gland/hypophysis that  stimulates milk production in human females 
1.2.5 Having access to enough food on a daily basis to ensure healthy  living 
1.2.6 A blood vessel in the umbilical cord that transports nutrients to the  foetus 
1.2.7 A part of the neuron that conducts impulses towards the cell body 
1.2.8 A disease that results from the body's inability to produce insulin

(8 x 1) (8) 

1.3 Indicate whether each of the statements in COLUMN I applies to A ONLY,  B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write A only,  B only, both A and B, or none next to the question number (1.3.1 to 1.3.3) in  the ANSWER BOOK. 

(3 x 2) (6)
1.4 The diagram below shows a phase of meiosis in an animal cell. 

1.4.1 Identify: 

1. 1. A (1) 
   2. B (1) 
   3. C  (1)

1.4.2 Which phase of meiosis is illustrated in the diagram above? (1) 
1.4.3 Name the phase that follows the one represented in the diagram above.  (1) 
1.4.4 How many chromosomes were there in the cell above before the  process of meiosis began? (1) 
1.4.5 What is the specific name given to meiosis when it takes place in a  human female? (1) 

(7)

1.5 The diagram below represents a section through a human eye. 

1.5.1 Identify: 

1. 1. A (1)
   2. B (1)
   3. C  (1)

1.5.2 Give the LETTER and NAME of the part that: 

1. Regulates the amount of light entering the eye (2)
2. Contains a dark pigment that absorbs excess light in the eye (2)
3. Contains receptors sensitive to light (2) 

(9) 
TOTAL SECTION A: 50 

SECTION B 
QUESTION 2 
2.1 The diagram below represents the human female reproductive system. A 

2.1.1 Identify part C. (1)
2.1.2 State ONE function of part D. (1) 
2.1.3 Name the hormone secreted by part B during the first week of the  menstrual cycle. (1) 
2.1.4 State how the hormone named in QUESTION 2.1.3 influences  part D. (1) 
2.1.5 During tubal ligation, part A is surgically cut or tied. 
Explain how this procedure prevents pregnancy. (3) (7) 
2.2 An investigation was carried out to determine the effects of smoking during  pregnancy on the baby's birth weight. Babies born weighing 2 499 g or less  have a low birth weight.  
The table below compares the percentage of babies with a low birth weight  born to mothers who smoked with mothers who did not smoke in a certain city in 2009. 

 [Adapted from www.ainw.gov.au] 
2.2.1 Draw a histogram to represent the percentage of births in each  weight group born to mothers who smoked.  (6) 
2.2.2 Why were babies that weighed more than 2 500 g at birth not  included in the investigation?  (1) 
2.2.3 State a general conclusion for the investigation based on the data in the table.  (2) 
2.2.4 Describe how chemicals from cigarette smoke are able to reach the baby's blood from the mother's blood.  (2)  (11)
2.3 Read the extract below. 

The graph below shows the percentage of survivors in a sea turtle population  over a period of time. 

[Adapted from https://bioweb.uwlax.edu] 

2.3.1 Write down whether the type of reproduction in sea turtles is  oviparous, viviparous or ovoviviparous. (1) 
2.3.2 Give a reason for your answer to QUESTION 2.3.1. (1) 
2.3.3 The shape of the graph would differ if there were parental care.  

1. 1. Describe how the shape of the graph would differ if there  were parental care. (1)
   2. Explain your answer to QUESTION 2.3.3(a).  (2) (5) 

2.4 The diagram below represents parts of the human ear. 

2.4.1 Identify parts: 

1. B (1) 
2. C (1) 
3. D  (1) 

2.4.2 Explain how parts A and D together are adapted to amplify sound.  (3) 
2.4.3 State ONE advantage of the middle ear being filled with air. (1) (7) 
2.5 Read the extract below. 

2.5.1 The part of the brain affected by CTE is the cerebrum.  State TWO possible symptoms of this disorder.  (2) 
2.5.2 State ONE way in which the brain is protected.  (1) 
2.5.3 Explain why CTE does not usually affect essential life processes  such as breathing or heart rate.  (2) (5) 

2.6 TSH and thyroxin are both secretions of endocrine glands, namely the  pituitary gland/hypophysis and the thyroid gland respectively.  

2.6.1 Where will you look for evidence to detect the levels of TSH and  thyroxin in the human body?  (1) 
2.6.2 A high level of TSH is detected in the human body. Explain TWO possible causes of high levels of TSH in the body.  (4)  (5) 

[40]

QUESTION 3 
3.1 An investigation was carried out to determine the effect of auxins on the  growth of coleoptiles. 
The procedure was as follows: 

• The tip of one coleoptile (young shoot) was removed and placed on a  block of agar jelly, as shown in diagram A. 
• After two hours the agar jelly was placed on the cut surface of the original  coleoptile, as shown in diagram B. 
• The coleoptile was covered with a black box and allowed to grow for two  days, as shown in diagram C. 

 [Adapted from www.plantphys.info.com] 

3.1.1 Explain why the tip of the coleoptile was placed on the agar jelly for  two hours at the start of the investigation. (2) 
3.1.2 Describe what occurred in diagram C to cause the coleoptile to  bend even though no light was present. (4) 
3.1.3 Describe a control for this investigation. (2)  (8) 

3.2 The diagram below represents a typical Snellen chart that is used to estimate  visual acuity (ability to see clearly). The extract explains how a Snellen chart  is used. 
 

3.2.1 A person is only able to read accurately to the end of line 5 on the  Snellen chart.  What is his/her visual acuity ratio? (1) 
3.2.2 Explain ONE reason why the special equipment, which can present  different patterns, arrangements and sizes of letters, is used when  testing eyesight for a driver's licence. (2) 
3.2.3 Some clinics have half-size charts that must be read at a distance  of 3 m instead of 6 m. Describe the process that occurs in the eye to ensure that the  letters of the chart are in focus at 3 m. (4) (7) 

3.3 Read the extract below. 

 
3.3.1 State TWO factors, according to the extract, that lead to the largest  amount of food being wasted.  (2) 
3.3.2 Suggest TWO ways in which shopkeepers can reduce the amount  of food going to waste.  (2) 
3.3.3 What percentage does seafood contribute to the total food wastage  cost in South Africa? Show ALL your calculations.  (2) 
3.3.4 Explain TWO ways in which the drought is expected to increase  the number of food-insecure South Africans.  (4) (10)

3.4 The graph below shows the changes in the human population and the  population of parrots (a type of bird) in a certain country over a period of  500 years. 

[Adapted from www.people.eku.edu] 

3.4.1 When was the human population at 3 million? (1) 
3.4.2 Describe the difference in the trends between the human  population and the parrot population since 1800.  (2) 
3.4.3 Suggest TWO reasons for the trend described in QUESTION 3.4.2. (4) 
3.4.4 If the current rate of decrease in the parrot population continues,  explain how the organisms that feed mainly on the parrot population would be affected. (2) (9)

3.5 Describe how the excessive use of fertilisers by farmers impacts on the  quality of water. (6)

[40] 
TOTAL SECTION B: 80 

SECTION C 
QUESTION 4 
Nontobeko had been walking in the desert, without water, for two days, when she  suddenly heard a sound behind her. She turned her head and saw a snake coming  towards her. She became scared and turned around to run away. As she was running,  she tripped and fell.  
Describe how her body regulated water content during the two days and describe how  her balance would have been restored after she fell down. 

Content: (17) 
Synthesis: (3) 
(20) 

NOTE: NO marks will be awarded for answers in the form of flow charts, tables or  diagrams. 

TOTAL SECTION C: 20 
GRAND TOTAL: 150