# Life Sciences Grade 12 Paper 1 Limpopo Prelim 2024 Memo

> Grade 12 Life Sciences Paper 1 memorandum from the Limpopo Prelim Exam 2024, 24 pages. Read online or download the free PDF.

- Page: https://www.hlayiso.com/library/lp-life-sciences-grade-12-september-2024-p1-and-memo/695a95e8-1e36-4836-982f-67a2712419b2
- Updated: 2026-09-27
- Subject: Life Sciences
- Grade: Grade 12
- Document type: Memorandum
- Year: 2024
- Exam period: Limpopo Prelim Exam
- Paper: 1
- Curriculum: CAPS
- Pages: 24

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## About this document

Life Sciences · Grade 12 · Limpopo Prelim Exam · 2024. Memorandum, 24 pages. Read online or download the PDF.

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T,TL RA POS PO

PROVINCIAL GOVERNMENT
REPUBLIC OF SOUTH AFRICA

DEPARTMENT OF

EDUCATION

NATIONAL SENIOR
CERTIFICATE

[ GRADE 12

MARKS: 150
DURATION: 2%2 HOURS

This question paper consists of 13 pages

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INSTRUCTIONS AND INFORMATION

Read the following instructions carefully before answering the questions.
1. Answer ALL the questions.

Write ALL the answers in the ANSWER BOOK.

Start the answers to each question at the top of a NEW page.

PON

Number the answers correctly according to the numbering system used in this question
paper.

Present your answers according to the instructions of each question.

Do ALL drawings in pencil and label them in blue or black ink.

Draw diagrams, flow charts or tables only when asked to do so.

PN oo

The diagrams in this question paper are NOT necessarily drawn to scale.
9. Do NOT use graph paper.

10. You may use a non-programmable calculator, protractor and compass, where necessary.
11.Write neatly and legibly.

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NSC
SECTION A

1.1

QUESTION 1

Various options are provided as possible answers to the following questions.
Choose the answer and write only the letter (A to D) next to the question numbers
(1.1.1 to 1.1.9) in the ANSWER BOOK, e.g. 1.1.10D.

Which ONE of the following occurs when an apical bud from a rose bush is regularly
removed? The rose bush will...

. regulate appeti le.
B. inhibit voluntary movements.
C. control higher thought processes.
D. control muscle tone and balance.

Which of the following parts of the brain co-ordinates voluntary movements?

A. Cerebellum
B. Spinal cord
C. Cell body
D. Meninges

The tough, non-elastic tissue that covers the outer part of the eyeball is the...

A. sclera.

B. conjunctiva.
C. choroid.

D. retina.

The amniotic fluid that surrounds the developing embryo of a human helps to...

A. transport oxygen to the developing embryo.

B. transport carbon dioxide to the developing embryo.

C. protect the embryo against mechanical injury.

D. transport nitrogenous waste substances to the developing embryo.

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QUESTIONS 1.1.6 AND 1.1.7 REFER TO THE INVESTIGATION
BELOW.

Ascientist did an investigation to determine the effect of drinking
water on urine production.

A healthy athlete was requested not to drink water or eat food for five
hours before the investigation started. The investigation was
conducted over a period of three days.

The following procedure was followed.

- Day 1, the athlete was given 500ml of water to drink.

- Day 2, the athlete was given 700m! of water to drink.

- Day 3, the athlete was given 900ml of water to drink.

- Oneach day of the investigation, the amount of urine produced
by the athlete was measured and recorded over a four hour
period after drinking the water.

- The average was calculated.

1.1.6 Which ONE of the following CORRECTLY indicates the dependent
and independent variable?

Independent variable Dependent variable

A The amount of urine produ Time in hours

B The amount of The amount of urine
consumed produced

Cc The amount The amount of water

consumed
D The person pa ting Time in hours
1.1.7 The list below PA, s before and after the
investigation.

(i) Permission was obtained from the athlete.

(ii) The measuring tool was decided upon.

(iii) | The amount of water was measured.

(iv) | The duration of the investigation was decided upon.

Which of the planning steps above are correct?

A. (i), (ii) and (iii)
B. (i), (iii) and (iv)
C. (ii), (iii) and (iv)
D. (i), (ii) and (iv)

121-8 Which ONE of the following is a function of gibberellins?
A. Slows down the germination of seeds.
B. Stimulate the germination of seeds.

C. Promotes the ageing of leaves.
D. Brings about tropism.

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149 Which ONE of the following is a characteristic of external fertilisation?

A. The embryo is protected inside the body of the female.
B. Copulation takes place.

C. Alarge number of ova are produced.

D. Sperm is introduced into the body of the female.

(9x2) (18)
12 Give the correct biological term for each of the following descriptions.

Write only the term next to the question numbers (1.2.1.to 1.2.10) in
the ANSWER BOOK.

12.1 A process where an embryo attaches itself into the endometrium.

122 The division of the nervous system that is made up of the cranial and
spinal nerves.

172.3 A hormone that stimulates the mammary s to luce milk.

1.2.4 The outer membrane that encloses i us of a
human. i 5

1:2.5. The structure that connects the left and tighthemi SI of the
cerebrum. :

12:6 The blood vessel in the umbilical cord that transports nutrients to the
foetus.

12-7 A disorder of the nervous system caused by the breakdown of the
myelin sheath of neurons.

128 The open passage through which sound waves travel to the middle
ear.

12.9 The external physical structures used by plants that prevents

herbivores from feeding on them.
1.2.10 A behavioural pattern of animals feeding their young and protecting

them from predators.
(10x 1) (10)

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1.3 Indicate whether each of the descriptions in COLUMN | apply 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.

COLUMN | COLUMN II
1.3.1. A hormone that stimulates the secretion | A: Testosterone
of the hormone of the thyroid gland B: Abscisic acid
1.3.2.-A part of the ear that absorbs sound A: Round window
waves from the inner ear B: Pinna
1.3.3. A gland that has ducts to transport its A: Endocrine gland
secretions to where they are needed B: Exocrine gland
(3x2) (6)
1.4 The diagram below represents a part of the human central nervous
system.
1.4.1. Identify part:
(a)A (1)
(b)D (1)
(c) Microscopic gap at E (1)
1.4.2 Give the LETTER and NAME of the part which is probably damaged if a
person...
(a) can walk, but cannot detect any stimulus. (2)
(b) can feel the stimulus, but cannot respond. (2)

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1.4.3 Write down in the correct order the LETTERS ONLY of the path taken

by a nerve impulse until a response takes place. (2)
1.4.4 Give the name of the process which enables a person to quickly and
involuntarily respond to a stimulus. (1)
(10)
1:5. The diagram below represents the human endocrine system.

1.5.1 Identify gland:
(a) C (1)
(b) D (1)

1.5.2 Give the name of the hormone that...

(a) Is involved in the reabsorption of salts in the renal tubules of the (1)
kidneys.
(b) Controls the growth of long bones. (1)

1.5.3 Name the disease that results when gland C is unable to produce the
hormone insulin. (1)

1.5.4 Name the type of interaction that occurs between the hormones
secreted by glands A and B. (1)

(6)

TOTAL QUESTION 1: 50
TOTAL SECTION A: [50]

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SECTION B

QUESTION 2

24 The diagram below represents the human ear.

2.1.1 Identify part:

(a)c (1)

(b)D (1)

(c)E (1)
2.1.2 State ONE function of part F. (1)
2.1.3. Middle ear infection is a common cause for loss of hearing.

Name ONE way in which middle ear infection can be treated. (1)
2.1.4 Describe how part A, B and E assists in amplifying sound. (4)
2.1.5 Describe how the semi-circular canals play a role in maintaining balance

when the body changes speed and direction. (5)

(14)

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2.2
22:1
2.2.2
2.2.3

2.3

2.4
2.4.1
2.4.2
2.4.3

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The diagram below represents the female reproductive system.

Give the LETTER and NAME of the part where:
(a) Fertilisation takes place.
(b) The embryo develops.

State TWO functions of part D.

Name and describe the type of gametogenesis that takes place in part A.

Draw a labelled diagram to show the structure of a haploid cell that will
fuse with a haploid cell produced in part A.

The table below indicates the growth of a human foetus six months after
fertilisation has taken place.

Months after fertilisation 1 4 3 4 5 6

Length of foetus (cm) 0,5 4 iS 15 25 30

Between which two consecutive months did foetal growth double?

What is the percentage increase in foetus length between the 3 and 6"
month after fertilization? Show ALL working.

Draw a line graph to represent the data in the table.

LIMPOPO DoE/ Sep 2024

(2)
(2)
(2)
(5)
(11)

(5)

(1)
(3)

(6)
(10)

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2.5 The graph below represents a menstrual cycle and the influence of the
different hormones on it.

@

Ovula

si anal |
Progesterone

Pituitary
hormone levels

Ovarian events

\

Ovarian
hormone levels

‘G Uterine events

9
Ss

2.5.1 On which day does ovulation take place? (1)
2.5.2 Between which days does menstruation take place? (1)
2.5.3 State ONE function of LH other than ovulation. (1)
2.5.4 Describe the functional relationship between progesterone and FSH. (2)
2.5.5 Account for the change in the thickness of the endometrial lining between

day 14 and day 21. (2)
2.5.6 Did fertilisation take place in the 28-day cycle illustrated in the graph? (1)
2.5.7 Explain your ANSWER to question 2.5.6. cn

TOTAL QUESTION 2: 50

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The table below shows a comparison of the composition of the amniotic
egg in different bird species.

COMPOSITION BIRD SPECIES
1 2 3
Yolk (%) 30 38 18
Water content in yolk (%) 79 59 57
Energy (kcal/g) 1,16 1,46 1,03
Define ovovivipary (2)
Which ONE of the bird species (1, 2 or 3) shows altricial development as a
reproductive strategy? (1)
Explain your answer to QUESTION 3.1.2. (2)
(5)

QUESTION 3
3.1
3.1.1
3.1.2
3.1.3
3.2

Dale did an investigation to determine the effect of auxins on the growth of
three plant shoots (A, B and C). The plant shoots were treated as follows:

e Shoot A — Tip of the shoot was not removed
e Shoot B — Tip removed and an agar plate with auxins placed on top
e Shoot C-— Tip removed and agar plate without auxins placed on top

(Agar is a jelly-like substance that allows auxins to diffuse through it)
All shoots were exposed to the same light conditions.

The diagram below indicates the set-up at the beginning of the
investigation.

Agar plate Agar plate
with auxins without

auxins

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3.2.1 Explain the results as observed in:

(a) Shoot B after a few days (2)
(b) Shoot C after a few days (2)
3.2.2 State TWO factors that must be kept constant in this investigation. (2)
3.2.3 State TWO ways in which Dale could have improved the reliability of her
investigation. (2)
(8)
3.3 The diagrams below show parts of the human eye

Diagram 1 Diagram 2

3.3.1. Give the LETTER and NAME of the part that regulates the amount of light

that enters the eye. (2)
3.3.2 Name and describe the process that the part named in QUESTION 3.3.1

will undergo when exposed to bright light. (5)
3.3.3 Explain how part A is structurally suited to perform its function. (2)
3.3.4 State TWO functions of the liquid in part E. (2)
3.3.5. Which diagram (1 or 2) is adapted to distant vision? (1)
3.3.6 Give a reason for your answer to question 3.3.5. (1)

3.3.7 Describe how the changes in the lens from diagram 1 to diagram 2 are
brought about. (5)
(18)

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3.4 The diagram below represents a homeostatic response that occurs when a
person is dehydrated.
The decrease in blood volume, as a result of the excessive loss of water, is
detected by the brain

3.4.1. Define the term homeostasis. (2)
3.4.2 Identify:
(a) Hormone X. (1)
(b) Target organ Y. (1)
(4)
3.5 Describe what happens when the Carbon dioxide level in the blood
increases above normal. (5)
3.6 Read the passage below

Sphiwe was walking alone in the bush. She suddenly saw a big snake
and she was very frightened. She screamed asking for help, turned
around and ran away. During that time, she was breathing heavily and
her eyes were wide open.

3.6.1 Name the hormone that prepared the body to evade the danger. (1)
3.6.2 State the role of the liver during an emergency. (1)

3.6.3 Explain the effects of the hormone mentioned in question 3.6.1 on the

blood vessels of skeletal muscles. (4)
(6)

3.7 Explain how the thyroid gland is functionally related to body temperature
on a cold day. (4)

TOTAL QUESTION 3: 50
TOTAL SECTION B: 100
GRAND TOTAL: 150

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LIMPOPO

PROVINCIAL GOVERNMENT
REPUBLIC OF SOUTH AFRICA

DEPARTMENT OF

EDUCATION

NATIONAL SENIOR CERTIFICATE

MARKS: 150

This MARKING GUIDELINES consists of 10 pages

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PRINCIPLES RELATED TO MARKING LIFE SCIENCES

1. If more information than marks allocated is given
Stop marking when maximum marks is reached and put a wavy line and 'max'
in the right hand margin.

2) If, for example, three reasons are required and five are given
Mark the first three irrespective of whether all or some are correct/incorrect.

3. If whole process is given when only part of it is required
Read all and credit relevant part.

4. If comparisons are asked for and descriptions are given
Accept if differences/similarities are clear.

5. If tabulation is required but paragraphs are given
Candidates will lose marks for not tabulating.

6. If diagrams are given with annotations when descriptions are required
Candidates will lose marks.

te If flow charts are given instead of descriptions
Candidates will lose marks.

8. If sequence is muddled and links do not make sense
Where sequence and links are correct, credit. Where sequence and links are
incorrect, do not credit. If sequence and links becomes correct again, resume
credit.

9. Non-recognized abbreviations
Accept if first defined in answer. If not defined, do not credit the unrecognised
abbreviation but credit the rest of answer if correct.

10. Wrong numbering
If answer fits into the correct sequence of questions but the wrong
number is given, it is acceptable.

11. If language used changes the intended meaning
Do not accept.

12, Spelling errors
If recognizable, accept, provided it does not mean something else in Life
Sciences or if it is out of context.

13: If common names given in terminology
Accept, provided it was accepted at the National memo discussion meeting.

14. If only letter is asked for and only name is given (and vice versa)
No credit.

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15.

16.

f=

18.

If units are not given in measurements
Memorandum will allocate marks for units separately, except where it is
already given in the question.

Be sensitive to the sense of an answer, which may be stated in a different
way.

Caption
Credit will be given for captions to all illustrations (diagrams, graphs, tables,
etc.) except where it is already given in the question.

Code-switching of official languages (terms and concepts)

A single word or two that appears in any official language other than the
learners' assessment language used to the greatest extent in his/her answers
should be credited, if it is correct. A marker that is proficient in the relevant
official language should be consulted. This is applicable to all official
languages.

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SECTION A

QUESTION 1
1.1

(9x2) (18)

1:2
1.2.1 Implantation’
1.2.2 PeripheralVnervous system
1.2.3. Prolactinv
1.2.4 Chorionv
1.2.5 Corpus callosumv .
1.2.6 Umbilical veinv
1.2.7. Multiple sclerosisW
1.2.8 auditory canalv
1.2.9 Thorns”
1.2.10 Parental carev (10 x1) (10)
41:3
1.3.1. Nonevv
1.3.2 Aonlyvv
1.3.3. Bonlyvv (3x2) (6)
1.4
1.4.1 (a) EffectorY/muscle (1)
(b) Interneuron” /connector/relay (1)
(c) SynapseY (1)
1.4.2 (a) CY — Sensory neuronY (2)
(b) BY - Motor neuron’ (2)
1.4.3 C,D,B vv /CDBA (In the correct order) (2)
1.4.4 Reflex action’ (1)
(10)
15
1.5.1 (a) PancreasY (1)
(b) Adrenal Y gland (1)
1.5.2 (a) Aldosteronev (1)
(b) Growth hormonev / GH / STH (1)
1.5.3 Diabetes Y mellitus (1)
1.5.4 Negative feedback mechanismv (1)
(6)

TOTAL SECTION A: 50

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SECTION B
QUESTION 2
2.1
2.1.1. (a) Auditory nervev / cochlear nerve (1)
(b) Cochlea¥ (1)
(c) Oval window V / fenestra ovalis (1)
2.1.2 | Equalises pressure on both sides of the eardrumv tympanum /
tympanic membrane (Mark FIRST ONE only) (1)
2.1.3 - use of grommetsY
- antibiotics v
(Mark FIRST ONE only) (1)
2.1.4 - the sound vibrations are transmitted from the large tympanic
membranev /A
- to the smaller oval window”
- through the ossiclesvY / B
- which are arranged from largest to smallestv
- this concentrates the vibrationsv thus amplifying them
Any (4)
21,5 ion of movement
d into an impulseY
d to the cerebellumy
vey / vestibular nerve
=) com Wa to the skeletal muscles v
to restore balance
(5)
(14)
22
2.2.1 (a) BY — Fallopian tube / oviduct (2)
(b) CY — UterusY (2)
2.2.2 -it receives the penis during copulation’
- place where semen is released during ejaculation’
- itis a birth canalv
(Mark FIRST TWO only) (2)
2.2.3 -Oogenesis*v

- Diploid cellsY / germinal epithelial cells
- in the ovary undergo mitosis“
- to form numerous follicles”
- under the influence of FSHY
- one cell inside the follicle enlarges and undergoes meiosis
- to form a haploid ovumv
(1*Compulsory mark+ Any4) (5)
(11)

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2.3
Sperm cell Middle-Piece Nucleus
Acrosome
Caption (C) 1 mark
Correct diagram (D) 1 mark
3 correct Labels (L) 3 marks (5)
2.4
2.4.1 3and4v
(Mark FIRST ONE only) (1)
2.4.2 30-7,5
v v
75 x 100
= 300%Y

(3)

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24.3

2.5
25:41

2.5.2
2.5.3

2.5.4

2.5.5

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'> O .0)
Length of foetus in cm after six months

nn)

Criteria for marking graph

Criteria Mark allocation
Line graph is drawn (T) 1

Caption of graph _ include both
variables(C) 1
Correct labels for X and Y axis(L) 1
Correct scale for X and Y axis (S) 4

Plotting (P)
1-4 Co-ordinates plotted 1
All co-ordinates correct 2

(10)
Day 14v/15 (accept 15) (1)
Day 1-4~ (1)
- Stimulates the formation of the corpus luteumv (1)

- an increase in the level of progesterone*v
- inhibits the secretion of FSHY
- no follicle will developy

OR
- a decrease in the level progesterone*v
- stimulates the secretion of FSHY
- new follicle will develop”

(1* Compulsory mark + Any1) (2)

- the corpus luteum starts to secrete progesteronev / highest

levels of progesterone
- that continues to thicken the endometrium” (2)

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2.5.6 Nov (1)

2.5.7 - corpus luteum degeneratedv
- progesterone levels decreasedvY
- FSH levels start to increasev
- LH levels decreaseY
- endometrium breaks downY Any (2)
(10)
TOTAL QUESTION 2: 50

QUESTION 3
31
3.1.1. Eggs are retained/hatch inside the female body and the young
are born livev v (2)
3.1.2 3v (Mark FIRST ONE only) (1)
3.1.3. - the egg has the lowest/least yolkv /energy content
- this will not allow maximum development before hatchingY (2)
(5)

3.2
3.2.1 (a) — shoot will grow straight upwardsY
— auxins in the agar gel diffused evenly downwardsv
— causing equal growth on both sides of the shootv/cell
elongation
— no lateral branches will developY Any (2)

(b) — No upward growthy
— since there is no auxinsY
— lateral branches developY Any (2)

3.2.2 — same type of plantv
— same age of plantw
— measure length at the same timev
— same environmental conditions” / (any example)
— tip removed at the same timev
— tip removed at the same lengthy
— same concentration/ amount of auxinsv
— same type of agarv
Any

(2)

3.2.3 — Repeat the investigationy
— use more than one plant shoot” /increase the sample size
(Mark FIRST TWO only) (2)

(8)

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3.3
3.3.1 Cv -Irisv (2)

3.3.2 *Pupillary mechanismv
- circular muscles contractY
- the radial muscles relax”
- the pupil constrictsv’
- less light enters the eyev
(1* Compulsory mark + Any 4) (5)

3.3.3. Transparentv - to permit light to pass throughy
OR
it is convexY - for the minor refraction of light raysY (2)

3.3.4 -maintains the shape of the cornea Vv
- supplies the lens and cornea with food and oxygenv
- plays a minor role in their fraction of lightY
(Mark FIRST TWO only) (2)
33.5 1” (1)

3.3.6 The lens is less convex” (1)

3.3.7 - the ciliary mi
- the ciliary bo
- suspensory ligame
- and tension on thi

ie lens¥
sion decreases

- the elastic lens b (5)
(18)
ra
3.4
3.4.1. Maintenance of a constant internal environment within the
bodyv ¥ (2)
3.4.2
(a) ADHY (1)
(b) KidneyY (1)
(4)

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3.5 - receptor cells in the carotid arteryY in the neck are stimulated
- to send nerve impulses to the medulla oblongatav
- medulla oblongata stimulates breathing musclesY
and heartY
- breathing muscles contract more activelyY
- increasing the depth and rate of breathingy
- the heart beats fastery
- more carbon dioxide is exhaledv
- the Carbon dioxide level returns back to normal’

keeee Any (5)
3.6
3.6.1. Adrenaliny (1)
3.6.2 It converts glycogen into glucosev (1)
3.6.3. - adrenalin causes the blood vessels to dilatev since
— the muscles require more bloodv
— with more oxygen and glucoseY
— for increased cellular respiration’ / increase breakdown of
glucose
- to supply additional energy” Any (4)
(6)
3.7 -the thyroid gland becomes more active”
- more thyroxin is secretedv’
- which increases metabolismv /cellular respiration
- more heat is generated on a cold dayY (4)
TOTAL QUESTION 3: 50
TOTAL SECTION B: 100
GRAND TOTAL: 150

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