Life Sciences Grade 12 Question Paper

GN 0 is ‘* KwaZulu-Natal Department of Basic Education SS REPUBLIC OF SOUTH AFRICA a ee ee ee ee ee ee ee eee . a a LIFE SCIENCES q f WINTER CLASSES " i POST-TEST i 2017 1 NATIONAL SENIOR CERTIFICATE MARKS: 40 Downloaded from KZN Grade 12 Exam Papers app _ ‘ORLORE ON Google Play 8 ippcaliery oh education gore KZN Grade 12 Exam Papers on Play Store

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https://ultradeep.co.za Various possible options are provided as answers to the following questions. Choose the correct answer and write only the letter (A-D) next to the question number (1-20) in the answer book. For example: 21. D

1 Study the following list of molecules: (i) Sugar (ii) Phosphate (iii) Nitrogenous base (iv) Amino acid Which ONE of the following combinations represents components of a nucleotide? A (i), (ii) and (iv) only B (i), (ii) and (iii) only C (i), (ii), (iii) and (iv) D (ii), (iii) and (iv) only

2 RNA differs from DNA in that it
A has thymine and a phosphate group. B has a deoxyribose sugar and cytosine. C is a double stranded molecule. D has uracil and a ribose sugar.

3 In a DNA template, if the sequence of bases on the strand is AGG, the corresponding bases on the mRNA strand are
A TCC. B TAA. C CTT. D UCC.










4 If an analysis of DNA from cells in a human body showed that thymine made up 15% of the nucleotide bases, then the percentage composition of guanine making up the DNA would be
A 15% B 70% C 35% D 85%


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https://ultradeep.co.za 5 Crossing-over and random arrangement of chromosomes occur respectively in
A prophase II and metaphase II. B prophase I and metaphase I. C prophase II and anaphase II. D prophase I and anaphase I. 6 The diagrams below represent different phases of meiosis. !
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The correct order of the phases is ... A 1, 2 and 3. B 2, 3 and 1. C 3, 1 and 2. D 2, 1 and 3.

7 In gamete formation in human females, each diploid cell forms
A four diploid gametes. B one diploid gamete. C one haploid gamete. D two haploid gametes. https://tvetpapers.co.za

https://ultradeep.co.za 8 The table below shows the results of the F1 generation after an investigation into the inheritance of eye colour in fruit flies was carried out. EYE COLOUR NUMBER OF FLIES Red 182 White 61 The genotypes of the parents were
A RR x Rr. B Rr x rr. C Rr x Rr. D RR x rr. 9 In a monohybrid cross the two parental genotypes are AA and aa. The genotype of all the F1 plants is Aa. If the F1 plants are crossed, what percentage of the F2 generation will have the dominant phenotype? A 25 B 50 C 75 D 100 https://tvetpapers.co.za

https://ultradeep.co.za 10 QUESTIONS 10 and 11 are based on the pedigree diagram below. The pedigree diagram shows the inheritance of blood groups in a family. The blood groups of the individuals are represented by the letters.




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Which ONE of the following represents the genotype and phenotype of individual number 1 above? A ii and blood group O B IAi and blood group A C IAi and blood group O D IBi and blood group B https://tvetpapers.co.za

https://ultradeep.co.za 11 The diagram below represents the effect of a particular hormone on the growth of plant when exposed to unilateral light. Which hormone is responsible for the above effect? A gibberilins B abcisic acid C auxins D all of the above 12 Reproduction strategy involving the hatching of eggs in the female reproductive system, is called
A viviparous or oviparous B oviparous or ovoviviparous C viviparous only D ovoviviparous only 13 Which ONE of the following is used to produce genetically identical individuals? A Stem cell research B Genetic modification C Cloning D DNA profiling https://tvetpapers.co.za

https://ultradeep.co.za 14 The amniotic fluid
A attaches the embryo to the mother. B allows for the diffusion of nutrients and oxygen from the mother to the foetus. C secretes a hormone to maintain pregnancy. D acts as a shock absorber to protect the foetus against mechanical injury. 15 The diagram below represents the female reproductive system in humans. !
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Which ONE of the following correctly represents the events that take place at the parts labelled 1, 2 and 3? 1 2 3 A Fertilisation implantation ovulation B Ovulation implantation fertilisation C Implantation ovulation fertilisation D Fertilisation ovulation implantation https://tvetpapers.co.za

https://ultradeep.co.za 16 Menstruation starts when the production of
A oestrogen and progesterone decreases. B progesterone is at its maximum. C oestrogen is at its maximum. D luteinising hormone is at its maximum. 17 The part of the brain that interprets impulses from the retina of the eye is the ... A cerebrum. B cerebellum. C medulla oblongata. D corpus callosum. 18 The part of the brain that regulates breathing is the ... A medulla oblongata. B cerebrum. C corpus callosum. D cerebellum. 19 The auditory nerve transmits impulses to the ... A cerebrum and medulla oblongata. B cerebrum and cerebellum. C cerebellum and medulla oblongata. D cerebrum and corpus callosum. 20 After the publication of a scientist's results, other scientists repeated his investigation. What is the correct scientific reason for repeating the investigation? Other scientists ... A want to improve accuracy. B want to increase reliability of the results. C did not believe the original results. D did not understand the results. 20 X 2 = [40] https://tvetpapers.co.za

https://ultradeep.co.za GRADE 12 POST TEST – WINTER CLASSES ANSWER SHEET SURNAME AND NAME ___________________SCHOOL NAME:____________________ Select ONE answer from the alternatives given in the question and write down the LETTER of your choice next to the question number. QUESTION CORRECT NUMBER LETTER 1. 40 2. 3. 4. TOTAL MARKS 5. MARK: _________% 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. https://tvetpapers.co.za