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SENIOR CERTIFICATE EXAMINATION

MARKS: 150

TIME: 2½ hours

This question paper consists of 15 pages.

LIFE SCIENCES P1

2015

Life Sciences/P1 2 DBE/2015 SCE


INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

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. Number the answers correctly according to the numbering system used in this question paper. Present your answers according to the instructions of each question. ALL drawings must be done in pencil and labelled in blue or black ink. Draw diagrams, flow charts or tables only when asked to do so. The diagrams in this question paper are NOT necessarily drawn to scale. Do NOT use graph paper. You must use a non-programmable calculator, protractor and a compass, where necessary. Write neatly and legibly.



SECTION A QUESTION 1 1.1 Various options are given as possible answers to the following questions.

Choose the answer and write only the letter (A to D) next to the question number (1.1.1 to 1.1.10) in the ANSWER BOOK, for example 1.1.11 D.

1.1.1 Which ONE of the following factors will decrease food security? A

B C D

Planting more fruit trees Increase in biodiversity Increase in alien plants Controlled use of fertilisers

1.1.2 Which gas released from landfill sites can be used for domestic

purposes?

A

B C D

Carbon dioxide Oxygen Carbon monoxide Methane

1.1.3 The auditory nerve transmits impulses to the ... A

B C D

cerebrum and medulla oblongata. cerebrum and cerebellum. cerebellum and medulla oblongata. cerebrum and corpus callosum.

1.1.4 Which ONE of the following is a characteristic of external

fertilisation?

A

B C D

Copulation takes place. A large number of eggs are produced. The embryo is protected in the female body. Sperm is introduced into the body of the female.

1.1.5 During a 400 metre race, the autonomic nervous system of an

athlete will decrease the ...

A

B C D

heartbeat. flow of blood to the intestine. flow of blood to the muscles. breathing rate.



1.1.6 The correct sequence of the diagrams above is ... A

B C D

1, 2, 3, 4, 5. 3, 5, 1, 4, 2. 1, 3, 4, 2, 5. 3, 1, 5, 2, 4.

1.1.7 In which ONE of the phases above does random arrangement of

chromosomes at the equator take place?

A

B C D

3 1 5 4

1.1.8 An extract from a gland of an adult monkey was injected into the

bloodstream of a young monkey. It caused the young monkey to grow abnormally tall. From which gland was the extract obtained?

A

B C D

Hypothalamus Adrenal gland Hypophysis/Pituitary gland Pancreas

QUESTIONS 1.1.6 and 1.1.7 refer to the diagrams below which illustrate different phases of meiosis.



A

B C D

insulin and glucagon levels will decrease. adrenalin and thyroxin levels will increase. FSH and thyroxin levels will increase. adrenalin and insulin levels will decrease.

1.1.10 Which ONE of the following would be the result of a person

drinking a large volume of water?

A

B

C

D (10 x 2)

AMOUNT OF ADH SECRETED

REABSORPTION OF WATER FROM KIDNEY TUBULE

VOLUME OF URINE

PRODUCED Decreases Decreases Increases Decreases Increases Decreases Increases Decreases Increases Increases Increases Decreases

(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 1.2.9) in the ANSWER BOOK.

1.2.1

1.2.2 1.2.3 1.2.4 1.2.5 1.2.6 1.2.7 1.2.8 1.2.9

The variety of plant and animal species on Earth The membrane that transmits sound vibrations to the inner ear The reproductive strategy where the development of the young takes place in the uterus of the mother The male reproductive tube that connects the testis with the urethra The reproductive strategy involving the laying of eggs Splitting of the cytoplasm during cell division The access, by all people at all times, to adequate, safe and nutritious food The part of the ear that equalises the pressure on either side of the tympanic membrane A defective condition of the eye where a person can see nearby objects clearly while distant objects are blurred (9 x 1)

(9)

1.1.9 When a person is being chased by a fierce dog, ...



1.3 Indicate whether each of the descriptions 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 1.3.4) in the ANSWER BOOK.

COLUMN I COLUMN II

1.3.1 Stimulated by changes in the position of the head

A: Maculae B: Cristae

1.3.2 Occurs during accommodation for distant vision

A: Suspensory ligaments slacken B: Lens becomes less convex

1.3.3 Occurs in the iris under dim light conditions

A: Circular muscles relax B: Radial muscles contract

1.3.4 A young bird is helpless soon after hatching

A: Precocial development B: Altricial development

(4 x 2) (8) 1.4 Study the diagram of a longitudinal section through a human eye below.

1.4.1 Label parts A, B and E. (3) 1.4.2 Give the LETTER only of the part which: (a)

(b) (c) (d)

Protects the delicate internal structures Transmits impulses to the cerebrum Becomes cloudy or opaque as a person gets older, leading to decreased vision Contracts or relaxes when the distance of an object from the eye changes

(1) (1) (1) (1) (7)

F

D

B C

F

A

E



1.5.1 Identify: (a)

(b) (c) (d) (e)

Region A Part B Part C Phase of meiosis Process taking place in this phase of meiosis

(1) (1) (1) (1) (1)

1.5.2

Predict what would happen if the process identified in QUESTION 1.5.1(e) above did NOT occur.

(1) (6)

TOTAL SECTION A: 50

1.5 Study the diagram below showing a phase of meiosis.

A

B

C



SECTION B QUESTION 2

2.1 Study the diagram below of a section through a human spinal cord and the

neurons involved in a reflex arc.

2.1.1 Define a reflex action. (2)

2.1.2 Identify neurons A, B and C. (3)

2.1.3 Write down only the LETTER of the neuron (A or C) which is

probably damaged if a person:

(a)

(b)

Can feel the stimulus but cannot respond Is able to walk but cannot detect any stimulus

(1) (1)

2.1.4

State the significance of the reflex action in humans. (1)

(8)



2.2 Read the passage below and answer the questions that follow. EXERCISE AND SPERM COUNT

Research was conducted to determine the effect of lifestyle on the sperm count of young males. In this study, 189 young male students from a university in New York filled out questionnaires on their physical activity, diet, stress and other lifestyle factors. Each male student then provided a semen sample. The results showed that the male students who exercised for more than 15 hours a week had a sperm count 73 percent higher than those who exercised fewer than 5 hours a week. A second investigation showed that men who watched more than 20 hours of TV per week instead of exercising had a 44 percent lower sperm count than men who watched little or no TV. A person who exercises, secretes more antioxidant enzymes that can prevent a natural process called oxidative stress from damaging cell membranes in the body. This damage can disrupt the formation of new sperm. When watching TV or sitting, the scrotum gets pushed against their body, making the region of the testis hotter and possibly preventing new sperm from being produced. [Adapted from National Geographic News, February 2013]

2.2.1

2.2.2 2.2.3 2.2.4 2.2.5

Name the specific meiotic process responsible for the production of sperm cells. Explain why a high temperature in the region of the testis may prevent the production of new sperm. State a general conclusion that can be drawn from the results in the first investigation. State ONE way in which the reliability of this study can be increased. Draw a labelled diagram to show the structure of a sperm cell.

(1) (2) (2) (1) (4) (10)



2.3 Studies have shown that when the blood alcohol content exceeds

0,1 mg/100 ml, a person displays a slowing of motor coordination, as well as poor judgement and hearing. An investigation was done to determine the influence of blood alcohol content on reaction time. The reaction time was tested by measuring the braking response time of a motorcyclist. The results are shown in the table below.

BLOOD ALCOHOL CONTENT

(mg/100 ml) BRAKING RESPONSE TIME

(s) 0 0,572

0,15 0,585 0,25 0,610

[Adapted from www-nrd.nhtsa.dot.gov] 2.3.1

2.3.2 2.3.3 2.3.4

Calculate how much longer (in seconds) the braking response time of the motorcyclist was when there was 0,25 mg/100 ml of alcohol in his blood compared to when there was no alcohol in the blood. Describe the general relationship between the blood alcohol content and the braking response time. Explain why poor judgement of a motorist can lead to an accident. Identify the part of the brain affected by alcohol that leads to the following:

(2) (2) (2)

(a)

(b) (c)

Hearing being affected Loss of judgement Motor coordination being affected

(1) (1) (1)

2.3.5

Explain the purpose of measuring the braking response of the motorcyclist when the blood alcohol content was 0 mg/100 ml.

(2) (11)



2.4 Lerato conducted an investigation to determine the effect of exercise on skin

temperature. She asked 100 learners in her school to participate in the investigation. The sample consisted of 100 girls of the same age. The investigation was done as follows: • The learners were divided into two groups of 50 each (Groups A and B). • The skin temperature was measured for all the participants. • Group A was asked to run around the sportsfield for 10 minutes. • Group B was asked to remain seated on the benches next to the field

for 10 minutes.

After 10 minutes the skin temperature of all participants was measured and the average was calculated for each group (A and B).

2.4.1 In this investigation, identify the:

(a)

(b)

Independent variable Dependent variable

(1) (1)

2.4.2

2.4.3 2.4.4 2.4.5 2.4.6

State TWO steps that Lerato took into consideration during the planning stage of the investigation. What is the expected results for the participants in group A? State ONE factor that Lerato kept constant during the investigation. Which of the two groups (A or B) will release more sweat? Explain why sweat production will increase in the group identified in QUESTION 2.4.5.

(2) (1) (1) (1) (4) (11) [40]



QUESTION 3 3.1

The table below shows the concentration of abscisic acid and gibberellins in germinating seeds over 10 days.

TIME (DAYS)

HORMONE CONCENTRATION IN GERMINATING SEEDS (ARBITRARY UNITS)

ABSCISIC ACID GIBBERELLINS 0 20 0 2 8 1 4 4 4 6 3 7 8 2 10 10 1 12

[Adapted from Biology Cambridge, 2013] 3.1.1

3.1.2

Draw a line graph to show the changes in the concentration of abscisic acid over the period of the investigation. State what happened to the concentration of each of the following hormones over the period of the investigation:

(6)

(a)

(b)

Abscisic acid Gibberellins

(1) (1) (8)

3.2 Explain the growth response of a plant when the stem is exposed to light

coming from one side only.

(4)



3.3 Study the flow diagram below showing the response of an endocrine gland to

changes in the amount of glucose found in the blood.

3.3.2 Identify:

(a) (b)

Hormone 1 Hormone 2

(1) (1)

3.3.1 Define the term endocrine gland. (2)

3.3.3 3.3.4

Name the gland that releases hormone 1 and hormone 2. Explain the consequences for a person if the gland mentioned in QUESTION 3.3.3 fails to release hormone 1.

(1) (4) (9)

Glucose level

Detection by an endocrine gland

Too HIGH

Too LOW

Response

Hormone 2

Hormone 1

Response



3.4 Energy in South Africa is mainly generated from coal power stations.

The pie chart below shows the energy consumption in different sectors of a South African city in 2007.

[Adapted from Energy Scenarios for CT to – 2050, 2011] 3.4.1

3.4.2 3.4.3 3.4.4 3.4.5

Determine the value of X. Show ALL calculations. Which sector consumes the most energy in this city? The residential energy consumption in this city increased by 3% in 2009. Give TWO possible reasons for this increase. Explain the impact of the increased use of energy generated from coal power stations on climate change. South Africa, like many other countries, has signed a declaration to reduce its CO2 output over time. Explain TWO strategies that could be implemented by the South African government to achieve this reduction in CO2 output.

(2) (1) (2) (4) (4) (13)

Residential X%

Industrial 17%

Commercial 14%

Transport 45%

Other 6%

Energy consumption in different sectors of a city


Copyright reserved

3.5

Water hyacinth is an invasive alien species. It grows and floats in dams and lakes. It is a fast-growing species which can invade, cover and take over the whole dam or lake.

3.5.1

3.5.2

What is meant by invasive alien species? Explain TWO ways in which alien plants, like the water hyacinth, could upset the balance in ecosystems.

(2) (4) (6) [40]

TOTAL SECTION B: 80

SECTION C QUESTION 4

Describe the interaction and the influence of hormones on the events during the menstrual cycle.

Content: Synthesis:

(17) (3)

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

diagrams.

TOTAL SECTION C:

GRAND TOTAL: 20

150


SENIOR CERTIFICATE EXAMINATION

MARKS: 150

This memorandum consists of 11 pages.

LIFE SCIENCES P1

2015

MEMORANDUM

Life Sciences/P1 2 DBE/2015 SCE – Memorandum


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 a part of it is required

Read all and credit the relevant part. 4. If comparisons are asked for but descriptions are given

Accept if the 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. 7. 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 become correct again, resume credit.

9. Non-recognised abbreviations

Accept if first defined in answer. If not defined, do not credit the unrecognised abbreviation but credit the rest of the 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 recognisable, accept the answer, provided it does not mean something else in Life Sciences or if it is out of context.

13. If common names are given in terminology

Accept, provided it was accepted at the national memo discussion meeting. 14. If only the letter is asked for but only the name is given (and vice versa)

Do not credit.



15. If units are not given in measurements

Candidates will lose marks. Memorandum will allocate marks for units separately. 16. Be sensitive to the sense of an answer, which may be stated in a different way. 17. Caption

All illustrations (diagrams, graphs, tables, etc.) must have a caption. 18. Code-switching of official languages (terms and concepts)

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

19. Changes to the memorandum No changes must be made to the memoranda without consulting the provincial internal moderator who in turn will consult with the national internal moderator (and the Umalusi moderators where necessary).

20. Official memoranda

Only memoranda bearing the signatures of the national internal moderator and the Umalusi moderators and distributed by the National Department of Basic Education via the provinces must be used.



SECTION A QUESTION 1 1.1 1.1.1

1.1.2 1.1.3 1.1.4 1.1.5 1.1.6 1.1.7 1.1.8 1.1.9 1.1.10

C33 D33 B33 B33 B33 D33 B33 C33 B33 A33 (10 x 2)

(20)

1.2 1.2.1 Biodiversity3 1.2.2 Oval window3 1.2.3 Vivipary3 1.2.4 Vas deferens3/sperm duct 1.2.5 Ovipary3 1.2.6 Cytokinesis3 1.2.7 Food security3 1.2.8 Eustachian tube3 1.2.9 Short-sightedness3/Myopia /near-sightedness (9 x 1) (9) 1.3 1.3.1

1.3.2 1.3.3 1.3.4

A only33 B only33 Both A and B33 B only33 (4 x 2)

(8)

1.4 1.4.1 A – Ciliary3muscle/(body)

B – Iris3 E – Choroid3

(3) 1.4.2 (a) F3

(b) D3 (c) C3 (d) A3

(1) (1) (1) (1) (7)

1.5 1.5.1

1.5.2

(a) Chiasma3 (b) Chromatid3/chromosome (c) Cell membrane3/plasmalemma (d) Prophase I3 (e) Crossing-over3 There would be a decrease in genetic variation3

(1) (1) (1) (1) (1) (1) (6)

TOTAL SECTION A: 50



SECTION B QUESTION 2

2.1 2.1.1

2.1.2 2.1.3 2.1.4

Rapid3, automatic response3 to a stimulus A – Sensory neuron3/Afferent neuron B – Interneuron3/connector neuron/association neuron/relay neuron C – Motor neuron3/Efferent neuron (a) C3 (b) A3 Protects the human body against further damage3

(2) (3) (1) (1) (1) (8)

2.2 2.2.1

2.2.2 2.2.3 2.2.4 2.2.5

Spermatogenesis3 - Higher temperature will denature the enzymes3 - and damage cell membranes3 - An increase in exercise3 increases sperm count3 - Increase the number of participants3/sample size - Repeat the investigation3 (Any 1) (MARK FIRST ONE ONLY)

Sperm cell3

Mark allocation: Heading3 Any 2 correct labels 33 Correct drawing3 (Must have head, mid-piece and a tail in appropriate proportions)

(1) (2) (2) (1) (4) (10)

Mitochondrion

Acrosome

Nucleus Head

Mid-piece/Neck

Tail



2.3 2.3.1 0,03833s (2) 2.3.2 - As blood alcohol content increases3

- the braking response time increases3

OR - The braking response time increases3 - as the blood alcohol content increases3

(2)

2.3.3

- The motorist cannot judge the distance of an obstacle3 - and will therefore not be able to stop in time to avoid the accident3

OR - Cannot judge boundaries of a lane3 - and may therefore drive in the wrong lane3

(2)

2.3.4 (a)

(b) (c)

Cerebrum9 Cerebrum9 Cerebellum9

(1) (1) (1)

2.3.5

- Acts as a control3/baseline assessment - so that the results can be attributed to the alcohol content in the blood and not any other factor3

(2) (11)

2.4.1 2.4.1 (a) Exercise3/level of activity

(b) Skin temperature3

(1) (1)

2.4.2

2.4.3 2.4.4 2.4.5

- Ask permission3 from school/parents/learners - Deciding how many learners to include in the sample3 - Deciding which gender to choose3 - Deciding which age group to choose3 - Deciding on the venue3 - Deciding on the duration3 - Deciding on the groups3/experiment and control - Deciding on the measuring techniques3 - Deciding on the measuring apparatus3 - Deciding on recording method3 (Any 2) (MARK FIRST TWO ONLY) Skin temperature increased3 Gender3 Age3 Duration of the exercise3/10 minutes (Any 1) (MARK FIRST ONE ONLY) Group A3

(2) (1) (1) (1)



2.4.6

- Increased respiration3 - causes increased body temperature3 - Hypothalamus is stimulated3 - which leads to dilation of blood vessels3 - More blood flows to the skin3 - and the sweat glands3 - which become more active3/releasing more sweat - to lower the body temperature3 (Any 4)

(4) (11) [40]



3.1 3.1.1

Mark allocation of the graph

Criteria Mark Allocation Correct type of graph including the joining of points 1

Title of graph 1 Correct scale, label and unit for X-axis 1

Correct scale, label and unit for Y-axis 1

Drawing of the graph 0: No points plotted correctly 1: 1 to 5 points plotted correctly 2: All 6 points plotted correctly

NOTE: If the wrong type of graph is drawn: Marks will be lost for "correct type of graph". If axes are transposed: Marks will be lost only for labelling of X-axis and Y-axis. (6)

3.1.2 (a) Decreased9

(b) Increased9

(1) (1) (8)

20

8

4 3

2 1

02468

101214161820

0 2 4 6 8 10

Absc

isic

aci

d co

ncen

trat

ion

(arb

itrar

y un

its)

Time (days)

Changes in concentration of abscisic acid in germinating seeds over time3 3

T3

3

QUESTION 3

P33



3.2 - Auxins9

- are sensitive to light9 - Light stimulus from one side causes auxins to move to the shaded side9/destroyed on the illuminated side - Auxin concentration is higher on the shaded side3 - This promotes cell elongation9 on shaded side of plant - resulting in more growth9 on this side - Stem grows towards the light stimulus 9 - This is called phototropism9 (Any 4)

(4)

3.3 3.3.1

3.3.2 3.3.3 3.3.4

- Gland that secretes hormones3 - directly into the blood3/(rather than through ducts) (a) Insulin3 (b) Glucagon3 Pancreas3/Islets of Langerhans - There will be NO conversion of glucose into glycogen3 - in liver3/muscles - No absorption of glucose by cells3 - The blood glucose levels will stay high3 - and may lead to diabetes3/any example of symptoms (Any 4)

(2) (1) (1) (1) (4) (9)

3.4 3.4.1 3.4.2 3.4.3 3.4.4

100 – (17+14+45+6)3/82% = 183% Transport3 - Increased number of houses built3/increased population - More houses received electricity connectivity3 - More street lamps provided by municipality3 - A very cold winter3 (Any 2) (MARK FIRST TWO ONLY) - It creates more CO2 3which is released into the atmosphere - CO2 traps more heat within the atmosphere3 - causing the 'enhanced greenhouse effect' 3 - which causes a rise in the average global temperature3 - This is known as ‘global warming’3 (Any 4)

(2) (1) (2) (4)



3.4.5 - Invest in alternative forms of fuels 3/energy generation/solar/ wind/nuclear that will limit dependence on fossil fuels3

- Improve public transport system3 to reduce the number of cars on the roads3 - Invest in research and development of new technologies3/any example to decrease CO2 output3 - Introduce legislation3 to penalise offending industries3/to allow incentives to industries that adhere to legalisation to reduce CO2 emissions - Educating people3 on strategies to reduce CO2 output3 (Any 2 x 2) (MARK FIRST TWO ONLY)

(4) (13)

3.5 3.5.1 3.5.2

A species that does NOT occur naturally in a country3 outcompeting the natural species of the country3 - An excessive growth of water hyacinths on the surface of the water will block out the light3/deprive submerged plants of sunlight/limits photosynthesis - disrupting food chains/webs3 - Alien plants outcompete the indigenous species3 - this may lead to some of the indigenous species becoming eliminated thus disrupting food chains3/webs - Alien plants have a greater demand on natural resources 3 - resulting in a depletion of natural resources for the indigenous species3 (Any 2 x 2) (MARK FIRST TWO ONLY)

(2) (4) (6) [40]


Copyright reserved

SECTION C QUESTION 4 - FSH3/follicle stimulating hormone - is secreted by the pituitary gland3 - FSH stimulates the development of a primary follicle3 - into a Graafian follicle3 - As the follicle develops it secretes oestrogen3 - which causes the lining of the uterus3/endometrium - to become thicker3/more vascular - in preparation for a possible implantation of the embryo3/development of the foetus - The pituitary gland3 - secretes LH3 - which causes the Graafian follicle to rupture and release the ovum3 - This is called ovulation3 - The empty follicle changes and becomes a corpus luteum3 - which begins to secretes progesterone3 - which causes further thickening3 - of the endometrium3 - High levels of progesterone3 - inhibits the secretion of FSH3 - which prevents development of a new follicle in the ovary3 - If there is no fertilisation, the corpus luteum degenerates3 - which leads to a drop in progesterone3 - The endometrium disintegrates and is shed during menstruation3 - If fertilisation occurs, the corpus luteum remains intact3 - which leads to the levels of progesterone remaining high3 - to maintain pregnancy3 (Any 17)

Content: Synthesis:

(17) (3)

ASSESSING THE PRESENTATION OF THE ESSAY

Relevance Logical sequence Comprehensive All information provided is relevant

to the topic. Ideas arranged in a logical/cause-effect

sequence.

Answered all aspects required by the essay.

All information relevant to the events of the menstrual cycle only (no pregnancy) and the hormones

FSH, LH, oestrogen and progesterone.

All events of the menstrual cycle are in

sequence.

All FOUR correct hormones mentioned with their

functions.

1 mark 1 mark 1 mark

TOTAL SECTION C: 20 GRAND TOTAL: 150

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