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

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 learner's  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.
19. Changes to the memorandum
    No changes must be made to the memoranda. The provincial internal moderator  must be consulted, 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.

MEMORANDUM 

SECTION A
QUESTION 1 
1.1

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

1.2

1.2.1 Zygote✔
1.2.2 Amniotic✔fluid 
1.2.3 Multiple sclerosis✔
1.2.4 Prolactin✔
1.2.5 Food security✔
1.2.6 Umbilical vein✔/Vein 
1.2.7 Dendrite✔  
1.2.8 Diabetes✔ (8 x 1) (8) 

1.3

1.3.1 None✔✔(2) 
1.3.2  Both A and B✔✔(2) 
1.3.3  B only✔✔(2) (3 x 2)  (6) 

1.4

1.4.1 

1. 1.  Centriole✔
   2. Chromosome✔(do not accept homologous chromosome/  chromatid) 
   3. Centromere✔ (3) 

1.4.2 Anaphase I✔(1) 
1.4.3 Telophase I✔(1) 
1.4.4 4✔ (1)
1.4.5 Oogenesis✔ (1) (7) 

1.5

1.5.1

1. 1. Sclera✔ (1) 
   2. Cornea✔ (1) 
   3. Pupil✔ (1) 

1.5.2 

1. 1. D✔ – Iris✔ (2) 
   2. G✔ – Choroid✔ (2) 
   3. E✔ – Retina✔ (2) (9) 

TOTAL SECTION A: 50

SECTION B
QUESTION 2
2.1

2.1.1 Vagina✔/vaginal canal (birth canal not accepted since it is not  always a birth canal) (1) 
2.1.2 

• • Protects the developing foetus✔
  • Contracts to push the baby out during labour✔
  • Allows for implantation of embryo✔
  • Contracts to push out blood/lining during menstruation✔  
    (MARK FIRST ONE ONLY) Any (1) 

2.1.3 Oestrogen✔ (1) 
2.1.4 It causes the initial thickening of the endometrium/endometrium  become more vascular and glandular (1) 
2.1.5 

• • Sperm✔
  • cannot reach the ovum✔
  • therefore fertilisation cannot take place✔
    OR
  • Ovum✔ cannot move into A/the Fallopian tube/oviduct
  • cannot be reached by the sperm✔
  • therefore fertilisation cannot take place✔ (3) (7)

2.2

2.2.1 

Mark allocation of the graph 

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 
If learners draw both graphs on the same system of axes: 

• Learners will lose the mark for the title 
• If 8 bars are drawn, mark the first 4 bars only 

If learners draw two graphs mark the first graph (6)

2.2.2 Babies that weigh 2 500 g or more are considered to be of a  normal/healthy birth weight✔ (1)
2.2.3 The total percentage of low birth weight babies born to mothers  who smoked was higher than those born to mothers who did not  smoke✔✔
OR 
The total percentage of low birth weight babies born to mothers  who did not smoke was lower than those born to mothers who  smoked✔✔(2)
2.2.4 

• • Chemicals dissolved in the mothers blood✔
  • are able to move across the placenta✔/and through the  umbilical cord into the babies blood
  • by diffusion✔ Any  (2)

2.3

2.3.1 Oviparous✔ (1)
2.3.2 Eggs are laid✔ in the nest  (1)
2.3.3 

1. 1. The graph will decrease more slowly✔at the beginning /not  decrease as quickly at the beginning/more convex (1)
   2. The offspring are protected✔ by the parents for a longer  period of time
      Therefore more of them will survive✔ to become adults (2)  (5)

2.4

2.4.1

1. 1. Semi-circular canals✔ (1)
   2. Eustachian tube✔ (1)
   3. Oval window✔/fenestra ovalis (1)

2.4.2 

• • A/the tympanic membrane is larger✔/larger surface area
  • than D/the oval window✔/smaller surface area
  • Therefore the incoming sound waves are concentrated on to a  smaller area✔ thus amplifying the sound (3)

2.4.3 Allows ossicles/tympanum to vibrate freely✔ (1)  (7)

2.5

2.5.1

• Loss of higher thought processes✔/memory/judgement/ problem solving/any example 
• Loss of one or more of the senses✔/loss of smell/hearing/ any example 
• Loss of voluntary actions✔/paralysis could occur 
  (MARK FIRST TWO ONLY) Any  (2)

2.5.2 

• • The skull✔/cranium 
  • The meninges✔/name of ALL three i.e. pia mater,  arachnoid and dura mater 
  •  The cerebrospinal fluid✔  
    (MARK FIRST ONE ONLY) Any (1)

2.5.3

• • CTE mainly affects the cerebrum✔
  • Therefore the medulla oblongata✔ which controls breathing and heart rate 
  • is generally not damaged✔ Any (2) (5) 

2.6

2.6.1 Blood✔ (1)
2.6.2

• • The pituitary gland/hypophysis is malfunctioning✔and  secretes large amount of TSH✔
  • Thyroid gland secretes less thyroxin✔and  this will not have a negative feedback effect on  the pituitary gland to secrete less TSH✔  
    (MARK FIRST TWO ONLY) (2 x 2) 

QUESTION 3
3.1

3.1.1

• • To allow time for the auxins from the tip✔ 
  • to diffuse into the agar jelly✔ (2)

3.1.2

• • Auxins from the agar jelly✔
  • diffused into the shoot/coleoptile on one side/the left side only✔
  • The cells on this side were stimulated to grow✔/elongate
  • The cells on the other side/right side did not receive auxins✔
  • and grew more slowly✔
  • This uneven growth✔ caused the stem to bend to the right  
    Any (4)

3.1.3

• • Remove the agar jelly completely✔/use agar jelly/substance  that does not contain auxins 
  • and place a black box✔ around the tip of the coleoptile  (2)   (8)

3.2

3.2.1 6/12✔/6:12  (1)
3.2.2

• • People cannot learn the pattern✔/arrangement/sizes  and therefore cheat on the test✔ (2)

3.2.3

• • The ciliary muscles contract✔
  • and tension on the suspensory ligaments is released✔/ suspensory ligaments slacken 
  • The lens becomes more convex✔/bulges 
  • and its refractive power increases✔
  • so that a clear image is formed on the retina✔
    Any  (4)   (7)

3.3

3.3.1

• • The transport of food over long distances✔
  • - The packaging and processing of food✔
    (MARK FIRST TWO ONLY)  (2)

3.3.2

• • Reduce prices✔
  • Sell locally grown products✔
  • Donate unsold food to charities✔
  • Only buy quantities that they can sell✔
  • Use large refrigerators✔/ storages 
    (MARK FIRST TWO ONLY) Any (2)

3.3.3 8/60 x 100✔ = 13,3✔/13,33/13 %  (2)
3.3.4 

• • Crops will fail✔/farmers cannot plant crops therefore less food  will be produced✔
  • Decrease in supply of food✔/more food will have to be  imported and this food will be more expensive✔ to purchase 
    (MARK FIRST TWO ONLY) (2 x 2)  (4)

3.4

3.4.1 1650✔ (1) 
3.4.2 There was an increase in the human population✔and a decrease in the parrot population✔ (2)
3.4.3

• • Humans cut down the trees✔which are the parrots habita✔
  • Humans probably killed the parrots✔ for food✔/sport/ as pests
  • Humans introduces diseases✔that kill the parrots✔
  • Humans introduce other species✔ which use resources that the  parrots would normally use✔
    (MARK FIRST TWO ONLY) Any (2 x 2)  (4)

3.4.4

• • The organisms that feed on the parrots would probably  migrat✔/die   as they would no longer have any food✔
  • They will have to find an alternative food source✔  and that will affect other food chains✔
    Any (1 x 2)  (2)  (9)

3.5

• Fertilisers are washed into water bodies when it rains✔/excessive  irrigation 
• and cause eutrophication✔
• The excess nutrients✔ in the fertilisers 
• cause an algal bloom✔ 
• The algae block out the sunlight✔
• and the water plants cannot photosynthesise✔
• Less oxygen is released into the water✔
• plants die and bacteria cause decay✔
• This removes more oxygen from the water✔
• other organisms then also die✔
• due to the reduced water quality✔
  Any (6)

[40]

SECTION C  
QUESTION 4 
Regulating water 

• The water levels in her body are low✔/she is dehydrated 
• Osmoreceptors✔
• in the hypothalamus✔ are stimulated by the low water levels and send impulses
• to the pituitary gland✔/hypophysis 
• which is stimulated to secrete more ADH✔
• ADH increases the permeabilit✔ 
• of the tubules✔/collecting ducts and distal convoluted tubules 
• in the kidneys✔
• More water is reabsorbed✔
• and passed to the surrounding blood vessels✔
• Less urine is produced✔
• and the urine is more concentrated✔ 
• in order to conserve water✔
• Aldosterone✔ is secreted by the adrenal glands 
• to ensure more Na+ions✔ are reabsorbed by the distal convoluted tubules
• The increase in Na+ions in the blood✔ 
• causes more water to be reabsorbed✔ into the blood capillaries
  Max 12 

Balance is achieved in the following way: 

• The maculae✔
• in the utriculus and sacculus✔ and 
• the cristae✔
• in the semi-circular canals✔ are stimulated 
• They generate impulses✔ 
• which is transmitted through the auditory nerve✔
• to the cerebellum✔where they are interpreted  
• Impulses are transmitted via the motor neuron✔
• to skeletal muscles✔
  Max 5

Content: (17) 
Synthesis: (3)
(20) 

ASSESSING THE PRESENTATION OF THE ESSAY 

TOTAL SECTION C: 20 
 GRAND TOTAL: 150