LIFE SCIENCES
PAPER 2
GRADE 12 
NSC PAST PAPERS AND MEMOS
FEBRUARY/MARCH 2018

INSTRUCTIONS AND INFORMATION 
Read the following instructions carefully before answering the questions. 

1. Answer ALL the questions. 
2. Write ALL the answers in the ANSWER BOOK. 
3. Start the answers to EACH question at the top of a NEW page. 
4. Number the answers correctly according to the numbering system used in this  question paper. 
5. Present your answers according to the instructions of each question. 
6. Do ALL drawings in pencil and label them in blue or black ink. 
7. Draw diagrams, tables or flow charts only when asked to do so. 
8. The diagrams in this question paper are NOT necessarily drawn to scale. 
9. Do NOT use graph paper. 
10. You must use a non-programmable calculator, protractor and a compass,  where necessary.
11. Write neatly and legibly.

QUESTIONS 

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 1.1.9) in the ANSWER BOOK, for example 1.1.10 D. 
1.1.1 A molecule of RNA is copied from DNA by the process of … 

1. transcription.
2. mitosis.
3. mutation.
4. translation. 

1.1.2 Evidence supporting the evolution theory is obtained by studying  the structure of vertebrate forelimbs. 
This type of evidence for evolution is best described as … 

1. biogeography.
2. modification by descent.
3. DNA evidence.
4. genetic evidence. 

1.1.3 What is the percentage chance of a woman having a female child? 

1. 25%
2. 100%
3. 50%
4. 75% 

1.1.4 A small section of mRNA has the following sequence of bases that  codes for different amino acids: 

G C U        C G U          U A A 

Which ONE of the following is the CORRECT representation of the  anticodons and number of amino acids coded for by this section?  

1.1.5 If a recessive allele on the X-chromosome is passed on to the  offspring it is an example of … 

1. sex-linked inheritance.
2. incomplete dominance.
3. multiple alleles.
4. co-dominance. 

1.1.6 The diagram below shows the DNA profiles of a child, her mother and four males. There is uncertainty about who the biological father  is. To establish paternity, DNA profiling was conducted.  

Which male is the biological father of this child? 

1. Male 1
2. Male 2
3. Male 3
4. Male 4 

1.1.7 Which ONE of the following is the correct genus and scientist for  the discovery of the 'Taung Child' fossil? 

1. Ardipithecus; Raymond Dart
2. Ardipithecus; Tim White 
3. Australopithecus; Raymond Dart  
4. Australopithecus; Tim White D 

1.1.8 Different frogs, which all belong to the genus Lithobates, are found  in the same forest. The graph below shows their mating activity. 

Based on the information, what kind of isolating mechanism is most  likely keeping the bullfrogs and wood frogs as separate species? 

1. Geographic isolation through the presence of geographic  barriers 
2. Reproductive isolation through species-specific courtship  behaviour 
3. Reproductive isolation through breeding at different times of  the year 
4. Reproductive isolation through the production of infertile  offspring 

1.1.9 Which ONE of the following statements is CORRECT for the 'Out  of Africa' hypothesis? 

1. All modern humans originated in Africa and migrated to other  parts of the world. 
2. All modern humans evolved from African apes and then  migrated to other parts of the world. 
3. The most developed artefacts (tools; cutlery; art) were found in  Africa. 
4. An analysis of mutations on the mitochondrial DNA shows that  the oldest male ancestors were located in Africa. (9 x 2) (18) 

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 1.2.8) in the  ANSWER BOOK. 
1.2.1 The type of RNA containing anticodons 
1.2.2 The process during which genetically identical organisms are  formed using biotechnology  
1.2.3 Undifferentiated animal cells that can form any type of tissue 
1.2.4 Type of inheritance where none of the two alleles is dominant over  the other and an intermediate phenotype is produced 
1.2.5 The breeding of organisms by humans to achieve a desirable  phenotype 
1.2.6 The point of crossing over between two adjacent chromosomes 
1.2.7 The organelle in a cell where translation occurs 
1.2.8 The variety of living organisms on Earth (8 x 1) (8) 
1.3 Indicate whether each of the statements 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 1.3.3) in  the ANSWER BOOK.   (3 x 2) (6) 

1.4 The diagram represents a portion of a nucleic acid. 

1.4.1 Name the nucleic acid. (1) 
1.4.2 Name TWO places in animal cells where this nucleic acid may be  found. (2) 
1.4.3 Identify: 

1. Portion V (1) 
2. Nitrogenous base W (1) 
3. Molecule Y (1) 
4. Bond Z  (1) 

1.4.4 What is the natural shape of this molecule? (1) 
1.4.5 Name the process during which this molecule makes a copy of  itself. (1) (9) 
1.5 The diagram below shows possible evolutionary relationships among some  hominids. 

1.5.1 What is this type of diagram called? (1) 
1.5.2 How many of EACH of the following are represented in the  diagram: 

1. Genera  (1) 
2. Homo species (1)

1.5.3 Name the species that have Paranthropus aethiopicus as a  common ancestor. (2) 
1.5.4 When did: 

1. Ardipithecus ramidus become extinct (1) 
2. Homo erectus first appear (1) 

1.5.5 Name the:  

1. Hominid species that existed at the same time as Homo  sapiens (1)
2. First Homo species to use tools (1)  (9) 

TOTAL SECTION A: 50 

SECTION B 
QUESTION 2 
2.1 The karyotype below shows the chromosomes of a person with Down  syndrome. 

2.1.1 Give the label for A.  (1) 
2.1.2 How many autosomes are there in a nucleus of this cell?  (1) 
2.1.3 Name the type of chromosomes at position 23. (1) 
2.1.4 What evidence suggests that this is a karyotype of a male?  (1) 
2.1.5 Name the type of mutation represented in the diagram. (1) 
2.1.6 Describe the events that led to Down syndrome. (6)  (11) 
2.2 The diagram below shows the pattern of inheritance of deafness in a family.  The letter H represents the allele for hearing and h represents the allele for  deafness.  

2.2.1 How many of EACH of the following are represented in this  diagram? 

1. Males (1) 
2. Generations (1) 

2.2.2 Give the: 

1. Phenotype of Jon (1) 
2. Genotype of Paul (1) 

2.2.3 Both Lyall's parents can hear, yet he is deaf.  Explain how he inherited deafness. (2) 
2.2.4 Lyall marries a woman who is homozygous dominant for hearing.  Use a genetic cross to show the percentage chance of them having  a deaf child. (7) (13) 
2.3 The extract below is about human evolution. 

2.3.1 Name the TWO lines of evidence for human evolution that is  referred to in the extract above. (2) 
2.3.2 How long did Homo floresiensis exist on Earth? (1) 
2.3.3 Name ONE Homo ancestor mentioned in the extract. (1) 
2.3.4 State THREE features of the jaw of H. floresiensis that might have led scientists to believe that it resembled that of Australopithecus, rather than of a Homo species. (3) 
2.3.5 Describe ONE feature of the skull that can be used as evidence for  bipedalism. (2) 
2.3.6 State TWO similarities between the hands of African apes and  modern humans. (2) 
2.3.7 Draw a table to show the brain volumes of the different Homo species, using information from the extract. (5) (16) [40]

QUESTION 3 
3.1 The table below shows the percentage of the populations with different blood  groups for two countries.  

3.1.1 Which blood group shows the greatest percentage difference  between the two countries? (1) 
3.1.2 The population size of country Q is 5 million people. Calculate the number of people who have blood group O. Show  ALL your working. (3) 
3.1.3 Explain how the inheritance of blood group AB is an example of  co-dominance. (2) 
3.1.4 Explain why blood groups are considered an example of  discontinuous variation. (2) 
3.1.5 In the inheritance of blood groups, give the: 

1. Recessive allele (1) 
2. Phenotype of an individual who is homozygous recessive (1) (10)

3.2 Read the extract below.  

3.2.1 Define punctuated equilibrium.  (3) 
3.2.2 What characteristic of the toad species protects it from predation?  (1) 
3.2.3 Explain how the change in jaw size helped the snakes to survive.  (3) 
3.2.4 How would Lamarck have explained the development of a small  jaw size in the snakes? (4) (11) 
3.3 In a plant species two characteristics, flower colour and plant height, were  studied. Each of these characteristics has two variations: flowers may be red or white in colour and the plants may be tall or short.  
Plants that are heterozygous for flower colour have red flowers and plants  that are homozygous recessive for plant height are short.  
The alleles for each characteristic are shown in the table below. 

3.3.1 What is the term given for a genetic cross involving two  characteristics? (1) 
3.3.2 Give the: 

1. Dominant phenotype for flower colour (1)
2. Recessive phenotype for plant height  (1)
3. Phenotype of a plant that is heterozygous for flower colour and  homozygous dominant for plant height (2)
4. Genotype of a white flowering, short plant (2) 

3.3.3 State Mendel's Law of Dominance. (3) (10)
3.4 Study the extract and the information provided. 

Scientists hypothesised that insect populations that had previously been  exposed to the insecticide had a higher survival rate when the grain was treated again.  
In an investigation to test this hypothesis, they: 

• Identified storage bins that had previously been treated with the insecticide  and bins that had never been treated with the insecticide
• Collected a sample of 300 insects from each bin 
• Kept each sample in a separate container of equal size and the same  conditions
• Sprayed the same concentration and volume of insecticide over both  containers
• Allowed 24 hours for the insecticide to take effect
• Counted the number of insects that survived in each container 

The results are given in the table below: 

3.4.1 Give the: 

1. Independent variable (1) 
2. Dependent variable  (1) 

3.4.2 State THREE factors that were kept constant in this investigation. (3) 
3.4.3  Give TWO reasons why the scientists' results may not be reliable.  (2) 
3.4.4 State a conclusion for this investigation. (2) (9) [40] 

TOTAL SECTION B: 80

SECTION C 
QUESTION 4
Describe how a gene mutation may influence the structure of a protein. Also use ONE  example to describe the role of mutations in evolution in present times. 

Content: (17) 
Synthesis: (3) 

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

TOTAL SECTION C: 20 
GRAND TOTAL: 150