LIFE SCIENCES P1
FEBRUARY/MARCH 2016
MEMORANDUM
NATIONAL SENIOR CERTIFICATE

SECTION A
QUESTION 1
1.1

1.1.1 C
1.1.2 D
1.1.3 C
1.1.4 B
1.1.5 B
1.1.6 C
1.1.7 A
1.1.8 D
1.1.9 B
1.1.1 A (10 x 2) (20)

1.2

1.2.1 Vivipary✓/Viviparous
1.2.2 Centrioles✓/Centrosome
1.2.3 Geotropism✓/Gravitropism
1.2.4 Carbon footprint✓
1.2.5 Puberty✓
1.2.6 Stimulus✓
1.2.7 Grommets✓
1.2.8 Pinna✓ (8 x 1) (8)

1.3

1.3.1 B only✓✓
1.3.2 Both A and B✓✓
1.3.3 B only✓✓
1.3.4 None✓✓(4 x 2) (8)

1.4

1.4.1

1. A✓- penis✓(2)
2. E✓ - testes✓(2)

1.4.2

1. D✓ and E✓ (2)
   (Mark first TWO only)
2. B✓ and C✓ (2)
   (Mark first TWO only)   (8)

1.5
1.5.1 

1. E✓(1)
2. A✓(1)
3. C✓(1)

1.5.2 F✓ - motor neuron✓(2)
1.5.3 D to E✓(1) (6)

TOTAL SECTION A: 50

SECTION B
QUESTION 2
2.1

2.1.1

1. Round window✓(1)
2. Cochlea✓(1)

2.1.2Cristae✓(1)
2.1.3 (a)

• Impulses from the cochlea cannot be transmitted to the brain✓
• and therefore hearing will not occur✓(2)

2.1.4 (b)

• Part A will not be able to vibrate✓
• The round window will not absorb the sound waves✓ from the cochlea
• and hearing will be affected✓ (Any 2)(2)   (7)

2.2

• Mucus in the middle ear✓
• will lead to the blockage of the Eustachian tube✓
•  which will not be able to equalise the pressure✓ in the middle ear
• resulting in pressure on the tympanic membrane✓
• that may cause the tympanic membrane to burst✓
• leading to hearing loss✓ (Any 4) (4)

2.3
2.3.1

Mark allocation of the graph

NOTE:
If axes are transposed: marks will be lost only for labelling of X-axis and Y-axis (6)
2.3.2The older the women, the higher the chances of having miscarriages✓✓
OR
The younger the women, the lower the chances of having miscarriages✓✓
2.3.3 50% x 12✓ = 6✓(2)
OR
 50 x 12 ✓ = 6✓(2)  (10)
100
2.4.1 

2.4.1

• As a result of the blocked Fallopian tube✓
• the sperm cannot reach the ovum✓
• therefore fertilisation cannot take place✓(Any 2)

2.4.2

1. FSH✓/follicle stimulating hormone (1)
   (Mark first ONE only)
2. Oestrogen✓(1)
   (Mark first ONE only)

2.4.3 

• A zygote✓ is formed
• which divides by mitosis✓
• forming a ball of cells✓
• called the morula✓
• which further divides to form a hollow ball of cells✓ (Any 4)

2.4.4

• Progesterone levels would fall ✓
• The endometrium would no longer be maintained ✓
• A miscarriage would occur ✓ (3) (11)

2.5
2.5.1Metaphase I✓ (1)
2.5.2

• Crossing over has taken place✓ (2)
• and genetic material was exchanged ✓ (1)

2.5.3Anaphase II✓ (1)
2.5.4

• The spindle fibres contract✓
• The centromeres split✓
• and pull the daughter chromosomes✓/chromatids
• to the opposite poles of the cells✓
• Cytokinesis begins✓ (Any 3) (3)

2.5.5Testes✓/seminiferous tubules
(Mark first ONE only) (8)                                                                                                                                                                     [40]

QUESTION 3
3.1
3.1.1

1. ADH✓/antidiuretic hormone(1)
2. Hypothalamus✓Pituitary gland(1)
3. Kidneys✓(1)

3.1.2

1. An increase in ADH causes the walls of the kidney tubules✓
2. to become more permeable✓ to water
3. More water is reabsorbed✓
4. and the blood volume increases✓
5. Less urine is produced✓
6. and the urine is more concentrated✓ (Any 4)( 4)   (7)

3.2
3.2.1Pancreas✓ (1) 
3.2.2 

TABULATION IS NOT REQUIRED (Any 2 x 2) (4)
(Mark first TWO only)  (5)
3.3
3.3.1

1. Amount of thyroxin✓ (1)
2. Body weight✓(1)

3.3.2

1. Same number of rats in each group✓
2. All rats were of the same species✓
3. All groups were investigated for the same period of time✓
4. All rats were the same gender✓
5. All groups were weighed after the same interval✓ (Any 3) (3)
   (Mark first THREE only)

3.3.3Group A✓ (1)
3.3.4

1. Low thyroxin levels✓
2. will lead to low metabolic rate✓
3. Therefore the energy from the diet is used very slowly✓
4. and more organic compounds are stored✓ (Any 3) (3)

3.3.5Group B✓
3.3.6 

1. These rats have high levels of thyroxin in their blood✓
2. Therefore pituitary gland will not be stimulated✓to secrete TSH (2)                                                                                               (12)

3.4

3.4.1

1. Poor infrastructure✓
2. Climate change✓
3. Wastage✓
4. Pollution of water sources✓ (Any 2) (2)
   (Mark first TWO only)

3.4.2 The need of water for irrigation will be reduced✓(1)
3.4.3

1. Decreased production✓
2. will lead to loss of profit✓(2)

3.4.4

1. More revenue for fixing poor infrastructure✓/building dams
2. Less water wastage✓by individuals and companies(2)
   (Mark first TWO only) (7)

3.5
3.5.1 (a)

• Invasive alien plants reduce food security✓
• since they grow rapidly and invade land✓
• that could be used to grow crops✓ (3)
  
  (b)

• Invasive alien plants reduce water availability✓

• since they use more water ✓ (2)

3.5.2 (a)

• The new organism may become a pest itself✓/it may feed on indigenous plants instead of the targeted alien plant
• since no natural enemy for it was brought into the area✓ (2)
  
  (b)
• Some parts that are left behind✓
• can regrow✓/will cost more money to remove them again(2) (9)

                                                                                                                                                                                                                      [40]
TOTAL SECTION B: 80
SECTION C
QUESTION 4
Plant stems response to unilateral light

• Plant stems response to light is positively phototropic✓
• Auxins✓
• produced in the tip of the stem✓
• move away from unilateral light✓
• so that there is a high concentration of auxins on the darker side✓
• which stimulates growth✓/cell division/cell elongation
• The low concentration of auxins on the side exposed to light✓
• inhibits growth✓
• This uneven growth✓
• causes the stem to bend towards the light✓ (Max 7)

How humans receive and interpret light stimuli

• Light enters the eye ✓
• through the cornea✓
• which refracts the light✓
• It then passes through the aqueous humour✓
• and the pupil✓
• The size of the pupil is adjusted by the iris✓
• to regulate the amount of light that enters the eye✓
• The light then passes through the lens✓
• which also refracts the light✓
• It then passes through the vitreous humour✓
• and reaches the retina✓
• which has the photoreceptors✓/rods and cones which convert the light stimulus into a nerve impulse

Max: 10 (10)
Content:(17)
Synthesis:(3)
                                                                                                                                                                                                                     (20)

ASSESSING THE PRESENTATION OF THE ESSAY

TOTAL SECTION C: 20
GRAND TOTAL:150