PREPARATORY EXAMINATION GRADE 12 · PDF fileLife Sciences P1 5 FS/September 2016 ... 2.2.5...

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PREPARATORY EXAMINATION

GRADE 12

LIFE SCIENCES P1

SEPTEMBER 2016

MARKS: 150

TIME: 2½ HOURS

This question paper consists of 16pages.

Life Sciences P1 2 FS/September 2016 Grade 12 Prep. Exam.


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. 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. The diagrams in this question paper are NOT necessarily drawn to scale. Do NOT use graph paper. You may use a non-programmable calculator, protractor and a compass where necessary. Write neatly and legibly.



SECTION A QUESTION 1 1.1 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 number (1.1.1 to 1.1.10) in the ANSWER BOOK, for example 1.1.11 D.

1.1.1 The type of development in birds where the young birds can move

soon after hatching is … A Precocial development

B Altricial development C Ovipary D Ovovivipary 1.1.2 Which ONE of the following is controlled by a negative feedback

mechanism in the human body? A Changes in the speed and direction of the body B Colour vision

C Water content

D The activities of the right side of the body being controlled by the left hemisphere

1.1.3 Below is the list of events that occur during a human reproductive cycle.

(i) Birth (ii) Ovulation

(iii) Implantation (iv) Fertilisation Which ONE of the following represents the correct sequence of

events?

A (i), (ii), (iii), (iv)

B (ii), (i), (iv), (iii) C (ii), (iv), (iii), (i)

D (iv), (iii), (i), (ii) 1.1.4 Older people are seen to hold books at arm's length when they are

reading, because the … A refractive power of the lens has decreased with age.

B refractive power of the lens has increased with age. C lens has become less transparent with age.

D eyeball has become larger with age.



1.1.5 The list below refers to changes that occur in the human body.

(i) Interpretation of a bad smell

(ii) Decreasing the size of the pupil (iii) Control co-ordination of muscles when walking

(iv) Decreasing the heart-beat Which of the above can be considered as functions of the

autonomic nervous system in the human body? A (i), (iii) and (iv)

B (ii) only C (ii) and (iv)

D (i), (ii), (iii) and (iv) 1.1.6 Eutrophication is a process in which …

A contaminated water is recycled.

B algae grows uncontrollably in the river. C water is stored and later used for irrigation.

D indigenous forests are replaced by commercial tree plantations.

1.1.7 Sensory information that is sent to the cerebellum is used to …

A initiate voluntarily movement.

B co-ordinate motor movement. C provide conscious information of muscular movement.

D control reflexes of the gut and the blood system. 1.1.8 Which ONE of the following occurs during meiosis?

A A haploid cell gives rise to two haploid cells

B A diploid cell gives rise to two haploid cells C A haploid cell gives rise to four haploid cells

D A diploid cell gives rise to four haploid cells 1.1.9 The homeostatic function of the kidney can be affected by damage

to the hypothalamus because the … A blood flow to the kidney increases.

B levels of glucose drop drastically. C cellular metabolism increases.

D hypophysis/pituitary gland would not be able to secrete ADH.



1.1.10 Vivipary and ovovivipary are similar in that …

A internal fertilisation occurs.

B external fertilisation occurs. C the egg is protected by a shell.

D the egg has no covering. (10 x 2) (20) 1.2 Givethe correct biological term for each of the following descriptions. Write

only the term next to the question number (1.2.1 to 1.2.7) in the ANSWER BOOK.

1.2.1

A disorder of the eye in which the cornea is unevenly curved and prevents the proper focusing of light on the retina

1.2.2

The transparent membrane protecting the cornea

1.2.3

Specialised cells which transmit nerve impulses

1.2.4

The part of the ear which traps and directs sound waves to the auditory canal

1.2.5

Species that no longer exist on Earth

1.2.6

The structure in the amniotic egg used for gaseous exchange and the storage of waste products

1.2.7

The fatty layer that insulates the axon of a neuron (7 x 1) (7)

1.3 Indicate whether each of the statements in COLUMN I applies to A ONLY, B

ONLY, BOTH A AND BorNONE of the items in COLUMN II. Write A only, B only, both A and B,ornone next to the question number (1.3.1 to 1.3.4) in the ANSWER BOOK.

COLUMN I COLUMN II

1.3.1 Causes a decrease in the pH of the blood

A: Excess carbon dioxide B: Excess glucose

1.3.2 A disorder of the human nervous system that causes memory loss

A: Alzheimer's disease B: Multiple sclerosis

1.3.3 A part of the ear where sound stimuli are converted to nerve impulses

A: Semi-circular canals B: Oval window

1.3.4 Planting the same crop type every year on the same piece of land.

A: Crop rotation B: Monoculture

(4x2) (8)



1.4 The diagram below represents an animal cell in a phase of meiosis.

1.4.1 Identify part:

(a) A (b) B

(1)

(1) 1.4.2 State whether the phase of meiosis shown above is a part of

Meiosis I or Meiosis II.

(1) 1.4.3 Name the process visible in the diagram that took place that

contributes to genetic variation. (1)

1.4.4 How many: (a)

(b) (c)

Chromosomes are present in the cell above? Chromosomes will be present in each cell at the end of meiosis? Daughter cells will be present at the end of meiosis?

(1)

(1)

(1) 1.4.5 Name the: (a)

(b)

PROCESS that makes the chromosomes double stranded. MOLECULES involved that makes the chromosomes double stranded.

(1)

(1) (9)



1.5 The diagram below represents a part of the central nervous system.

1.5.1 Name the part of the neuron marked A. (1) 1.5.2 Name: (a)

The microscopic gap encircled marked as B.

(1)

A

B



(b) (c)

The importance of B. TWO types of neurons involved at B.

(1)

(2)

1.5.3 Name the root through which the impulse will leave the

central nervous system to reach the effector.

(1) (6)

TOTAL SECTION A: 50



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

2.1.1 Identify parts: (a)

(b)

A E

(1)

(1) 2.1.2 Give the LETTER and the NAME of the part: (a)

(b)

Where mature spermatozoa are temporarily stored. Where the male hormone is produced.

(2)

(2) 2.1.3 Explain the consequences to reproduction if part B is

surgically cut and the ends are sealed.

(3) (9)



2.2 The diagram below illustrates an oat seedling and a graph which shows the distribution of the plant growth hormone auxin, characterised mainly by its ability to stimulate cell elongation, in an oat seedling (Avenasativa).

Oat Seedling Relative Auxin Concentration

[Adapted fromThe Plant Hormones: Biochemistry and Metabolism]

2.2.1 Give TWO specific areas in a plant where cell elongation

occur.

(2) 2.2.2 Suggest a reason why there is a marked difference in the

relative auxin concentration between A and the growing root.

(1)

2.2.3 Describe the trend of the auxin concentration in A. (3)

A

Germinating Seed

0 0.5 1.0

Growing Root



The germinating seed is positioned horizontally as illustrated.

2.2.4 What will happen to the growing root? (1)

2.2.5 Explain your answer in QUESTION 2.2.4. (4) (11) 2.3 Thyroid disorders are caused by the abnormal secretion of thyroxin. 2.3.1 What is the abnormality referred to when the secretion of

thyroxin goes beyond the normal levels?

(1)

2.3.2 Explain what influence it will have on the body mass of a person if too much thyroxin is secreted.

(2)

2.3.3 Which hormone controls the level of thyroxin secretion in the

human body?

(1) 2.3.4 Describe the interaction between thyroxin and the hormone

mentioned in QUESTION 2.3.3 if the concentration of thyroxin goes higher than the normal level.

(4) (8) 2.4 Explain the role of the adrenal glands in bringing about changes to the

blood vessels in the human skin.

(3)

A Growing Root



2.5 Read the extract below.

DIABETES – TREATMENT AND MANAGEMENT Two forms of diabetes are found in humans namely type I and type II.

With type 1 diabetes, the body's immune system mistakenly sees the insulin-producing cells in the pancreas as foreign, and destroys them. People with type II diabetes are able to produce some of their own insulin. Often, it's not enough. Overeating, especially of foods rich in sugar, causes repeated stimulation of the pancreas, which responds by secreting large amounts of insulin. The excess insulin decreases the target cells' ability to respond to insulin. Treatment focuses on diet and exercise.

[Source: www.diabetesresearch.org]

2.5.1 Explain the consequence for TYPE I diabetics, when their

immune system destroys their insulin-producing cells.

(2) 2.5.2 Give TWO target cells in the human body whose ability to

respond to insulin can decrease.

(2) 2.5.3 Name ONE body fluid that can be used to test for the

presence of excess glucose in the body.

(1) (5) 2.6 Describe how the body is able to increase heat loss during a hot day. (4) [40]



QUESTION 3 3.1 In the run-up to the hosting of the World Cup Soccer in 2010, hosting cities

were confronted with a large increase in waste such as construction waste and domestic waste.

The pie chart below shows data on 183 tons of waste collected in Johannesburg.

[Source: www.environment.gov.za]

The list below gives an indication of the time it takes for some types of waste

(garbage) to decompose in the environment. TYPES OF WASTE TIME TO DECOMPOSE (YEARS)

Glass 1 million years

Plastic – beverage bottles 450 years

Plastic bags 10–20 years

Cans 80–200 years

Paper 6 weeks

[Source: www.blm.gov/education/lnt/background/packing.htm]

3.1.1 Which component of the waste in Johannesburg is

decomposed in the shortest time?

(1) 3.1.2 Give a possible reason for your answer in QUESTION 3.1.1. (1)

35% Plastic

32% Glass

13% Cans

20% Paper

PIE CHART SHOWING % OF WASTE COLLECTED AT WORLD CUP VENUES IN 2010 IN JOHANNESBURG



3.1.3 Calculate how many tons of glass was recovered in the city of Johannesburg. Show ALL working.

(3)

3.1.4 Suggest TWO possible reasons why you think the city of

Johannesburg should have banned the use of glass at their venues during the World Cup Soccer Tournament.

(2) 3.1.5 Explain ONE reason why open dump sites (landfills) near

residential areas pose a risk to humans.

(2) 3.1.6 Explain TWO reasons why recycling is important. (4) (13) 3.2 Deforestation is the permanent removal of trees in large numbers. 3.2.1 Suggest TWO reasons for deforestation. (2) 3.2.2 Explain TWO consequences of deforestation for the

ecosystem.

(4) (6) 3.3 An investigation was done to determine the change in the size of the pupil at

various distances from a light bulb. The procedure was as follow:

A lady sat in a dark room with her left eye covered.

A bright electric light bulb was switched on for a period of 20 seconds.

Afterwards the diameter of the pupil of the lady's right eye was measured.

The same procedure was repeated every time at a different distance from

the light bulb, at one-minute intervals between each measurement.

3.3.1 In this investigation, identify the:

(a) (b)

Dependent variable Independent variable

(1)

(1)



The results obtained are shown in the graph below.

3.3.2 Between which TWO adjacent distances did the largest

decrease in the size of the pupil take place?

(1) 3.3.3 At what distance was the electric bulb the furthest from the

lady?

(1) 3.3.4 Explain your answer in QUESTION 3.3.3. (3) 3.3.5 Describe why the investigator allowed one-minute intervals

between each measurement.

(2) 3.3.6 How can the reliability of the investigation be improved? (1) (10)

0

1

2

3

4

5

6

7

1 2 3 4 5 6 7 8

Dia

me

ter

of

pu

pil

(m

m)

Distances (arbitary units)

CHANGE IN PUPIL SIZE AT VARIOUS DISTANCES FROM A LIGHT BULB



3.4 The diagram below represents a part of a human ear.

3.4.1 Label part C. (1) 3.4.2 Name the receptors that are found in part B. (1) 3.4.3 To which part of the central nervous system will the impulses

formed in part C go?

(1) 3.4.4 Explain the result if the structures marked A are fused. (3) (6) 3.5 Describe the structure and function of the peripheral nervous system. (5) [40]

TOTAL SECTION B: 80



SECTION C QUESTION 4 Describe the development of the Graafian follicle until it becomes a corpus luteum during the menstrual cycle, describe oogenesis and also explain how another Graafian follicle is prevented from forming in the case of pregnancy. Content:

Synthesis: (17) (3)

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

diagrams.

TOTAL SECTION C:

GRAND TOTAL: 20

150

PREPARATORY EXAMINATION GRADE 12 · PDF fileLife Sciences P1 5 FS/September 2016 ... 2.2.5...

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