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SENIOR CERTIFICATE EXAMINATION

MARKS: 150

TIME: 2½ hours

This question paper consists of 14 pages.

LIFE SCIENCES P2

2015

Life Sciences/P2 2 DBE/2015

SCE


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. ALL drawings must be done in pencil and labelled 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 must use a non-programmable calculator, protractor and a compass where necessary. Write neatly and legibly.


SCE


SECTION A QUESTION 1 1.1 Various options are given 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 1.1.8) in the ANSWER BOOK, for example 1.1.9 D.

1.1.1 Humans have 46 chromosomes in each somatic cell. Each gamete produced will have …

A

B C D

22 autosomes and 1 gonosome. 21 autosomes and 2 gonosomes. 23 autosomes. 23 gonosomes.

1.1.2 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 B C D

RR x Rr. Rr x rr. Rr x Rr. RR x rr.

1.1.3 Which ONE of the following is TRUE about genes?

Genes are …

A B C D

codes for a particular characteristic. made up of amino acids. made up of RNA. found in a ribosome.

A

B C D

Stem cell research Genetic modification Cloning DNA profiling

1.1.4 Which ONE of the following is used to produce genetically identical individuals?


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QUESTIONS 1.1.5 and 1.1.6 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.

1.1.5 Which ONE of the following represents the genotype and

phenotype of individual number 1 above?

A B C D

ii and blood group O IAi and blood group A IAi and blood group O IBi and blood group B

1.1.6 If individual 2 has a child with blood group AB, then her partner

could only have blood group …

A

B C D

AB. A. O. B.

2

O O

KEY

Female

Male

A PEDIGREE DIAGRAM

A

AB

B O

B

1


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1.1.7 Which ONE of the following is CORRECT with regard to the

structure of DNA and RNA?

A B C D

RNA is double-stranded and DNA is single-stranded. RNA contains uracil and DNA contains thymine. RNA is a very long molecule while DNA is a short molecule. RNA forms a double helix while DNA does not.

1.1.8 Which ONE of the following represents molecules that make up a

single nucleotide?

A B C D

Phosphate, sugar and a nitrogenous base Sugar, protein and phosphate Nitrogenous base, phospholipid and sugar Adenine, sugar and a nitrogenous base (8 x 2)

(16)

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 1.2.9) in the ANSWER BOOK.

1.2.1

1.2.2 1.2.3 1.2.4 1.2.5 1.2.6 1.2.7 1.2.8 1.2.9

The type of inheritance involving two alleles of a gene that are not dominant over one other Characteristics controlled by genes which are located on the sex chromosomes Chromosomes that are similar in structure and code for the same characteristics The monomers/building blocks of proteins The type of inheritance involving alleles that equally determine the phenotype of heterozygous offspring Undifferentiated cells which are able to develop into any other types of cells Intermediate fossils showing features of both more primitive and more advanced organisms An allele that is expressed phenotypically only in the homozygous condition A genetic cross involving one characteristic only

(9)


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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 1.3.4) in the ANSWER BOOK.

COLUMN I COLUMN II

1.3.1

Discovered the fossil of Australopithecus sediba

A: B:

Raymond Dart Ron Clark

1.3.2

Example of continuous variation A: B:

Height Blood groups

1.3.3

Pronounced brow ridges A: B:

African apes Homo sapiens

1.3.4

Discovered the structure of DNA

A: B:

Watson Crick

(4 x 2) (8) 1.4 In tomato plants the allele for red fruit (R) is dominant over the allele for

yellow fruit (r). The allele for tallness (T) is dominant over the allele for shortness (t). Plant A, which is heterozygous for red fruit and homozygous tall, was crossed with Plant B, which has yellow fruit and is short.

1.4.1

1.4.2 1.4.3 1.4.4

Write down the genotype of: (a) Plant A (b) Plant B Write down ALL the possible genotypes of the gametes of plant A. Name the phenotype of an offspring having the genotype: (a) Rrtt (b) RrTt Plant B was then crossed with another plant (Plant C) and all the offspring had red fruit and were tall. Use this information to write down the genotype of Plant C.

(1) (1) (2) (1) (1) (2) (8)


SCE


1.5 The diagram below shows cells of an organism in one of the phases of

meiosis.

1.5.1

1.5.2 1.5.3

Which phase of meiosis is represented in the diagram? Give the LETTER and NAME of the part that: (a) Is responsible for the formation of the spindle fibres (b) Carries the genetic information (c) Holds the chromatids together State the number of chromosomes that would be present in each of the cells of this organism: (a) At the beginning of meiosis (b) In a gamete of this organism

(1) (2) (2) (2) (1) (1) (9)

TOTAL SECTION A: 50

A B C

E D

A PHASE OF MEIOSIS


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SECTION B QUESTION 2

2.1 Diagram 1 shows variation in a species of fish living in a lake. There was a

rocky island that extended across the whole length of the lake, but it was under water due to the high water level. The fish were therefore able to move freely throughout the lake. Diagram 2 shows the same lake many years later. A drought had caused the level of the water in the lake to drop so that the rocky island in the centre separated the lake into two smaller lakes, A and B, for a long period of time.

2.1.1

2.1.2 2.1.3

Define population. State FOUR possible causes of the variation in the fish population in Diagram 1. Eventually, as shown in Diagram 2, lake A and lake B contained two different species of fish.

(2) (4)

(a) (b)

Name the process that resulted in the fish population becoming two different species. Explain how the new species was formed.

(1) (6) (13)

2.2 A grey (G) male rabbit was mated with an albino (g) female rabbit. The entire

F1 generation was grey.

Use a genetic cross to show the phenotypic ratio of their offspring if one of the males of the F1 generation was mated with an albino female.

(7)

Diagram 1

Diagram 2

Rocky island

FISH POPULATION IN A LAKE

Lake A Lake B


SCE


2.3 The diagram below shows the process of protein synthesis. 2.3.1 Identify the following molecules:

(a) (b)

W Y

(1) (1)

2.3.2

2.3.3

Name the part of protein synthesis indicated by process A. Describe how a mutation on molecule W will affect the structure of the protein formed by process B.

(1) (4)

2.3.4

The following sequence represents a part of the nitrogenous base sequence on molecule X.

AGA AUG GGA triplet 1 triplet 2 triplet 3

(a) (b)

Write down the base sequence of the anticodon of triplet 1 shown above. The table below shows the amino acids that correspond with different DNA codes.

AMINO ACID DNA CODE Arginine TCT Glycine CCT

Methionine TAC Write down the correct sequence of amino acids for triplets 1 to 3.

(1) (3) (11)

Process B X

Y

W

PROTEIN SYNTHESIS

Z

Process A


SCE


[Adapted from http://www.mindfully.org] 2.4.1

2.4.2 2.4.3 2.4.4

Formulate a hypothesis for this investigation. State the dependent variable in this investigation. How many more successful convictions per 1 000 arrests were made in 2003 with the use of DNA evidence? Show ALL calculations. A DNA database is a collection of the DNA profiles of all the citizens of a country. Explain how you would use the information in the graph to convince the government to create a DNA database.

(2) (1) (2) (4) (9) [40]

2.4 The graph below represents the results of an investigation which compares the conviction (number of people found guilty) of criminals with the use of DNA evidence and without the use of DNA evidence from 1989 to 2003.

COMPARISON OF THE CONVICTIONS WITH THE USE OF DNA EVIDENCE AND WITHOUT THE USE OF DNA EVIDENCE, FROM 1989 TO 2003

Year 1989 1991 1993 1995 1997 1999 2001 2003

Num

ber o

f peo

ple

foun

d gu

ilty

(per

1 0

00 a

rres

ts)

0

10

20

30

40

50

Convictions without DNA evidence

Convictions with DNA evidence


SCE


QUESTION 3 3.1

The photographs of two butterflies are provided below. Both butterflies live in the same habitat and are preyed on by predators. Although these butterflies are very similar in appearance they are two separate biological species. Amauris ochlea has an unpleasant taste while Hypolimnas deceptor does not have an unpleasant taste.

[From http://www.biodiversityexplorer.org.]

3.1.1

3.1.2 3.1.3

Explain why most predators are less likely to feed on Hypolimnas

deceptor. Use Darwin's theory of evolution through natural selection to explain the evolution of the Hypolimnas deceptor butterfly. State ONE way in which natural selection differs from artificial selection.

(3) (6) (2) (11)

Amauris ochlea Hypolimnas deceptor

TWO SPECIES OF BUTTERFLY

http://www.biodiversityexplorer.org/insects/insect_mimicry/index.htm


SCE


3.2

The diagram below shows possible relationships between members of the family Hominidae.

[Adapted from http://www.ideacentre.org]

3.2.1

3.2.2

What is the name given to the type of diagram above? How many of each of the following are represented in the diagram?

(1)

(a)

(b)

Genera Species

(1) (1)

3.2.3

3.2.4 3.2.5 3.2.6

Explain why A. robustus and A. boisei are more closely related than A. boisei and A. afarensis.

Which of the hominids in the diagram above is considered to have been the first to use tools? Name TWO Australopithecus fossils found in South Africa. Explain how the location and the age of Homo fossils are used as evidence for the 'Out of Africa' hypothesis.

(2) (1) (2) (3) (11)

POSSIBLE RELATIONSHIPS BETWEEN HOMINIDS

Australopithecus boisei

Australopithecus robustus

Australopithecus afarensis

Homo habilis

Tim

e (m

illio

n ye

ars

ago)

Australopithecus

africanus

Present

Homo sapiens

Homo erectus

http://www.ideacentre.org/contentngr/showdetails/.php/id/1146


SCE


3.3

The diagrams below represent parts of the skeletons of an African ape and a human. Diagrams A and B are drawn to scale.

TOTAL SECTION B:

[40] 80

3.3.1 3.3.2 3.3.3 3.3.4 3.3.5

Write down the LETTERS only of the diagrams (A–D) that represent bipedal organisms. Explain how the shape of the pelvis contributes to bipedalism. Explain the significance of the position of the foramen magnum in the skulls in diagram A and in diagram B. Tabulate THREE visible differences between the jaws/teeth of the skulls labelled A and B that indicate trends in human evolution. State THREE physical characteristics of the forelimb/upper limb that humans share with African apes.

(2) (2) (4) (7) (3) (18)

DIAGRAM A DIAGRAM B

DIAGRAM C DIAGRAM D

SKELETON PARTS OF AFRICAN APE AND HUMAN


SCE

Copyright reserved

SECTION C QUESTION 4

Describe TWO types of mutations and how they lead to altered characteristics in FOUR genetic disorders you have studied.

Content: Synthesis:

(17) (3)

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

diagrams.

TOTAL SECTION C:

GRAND TOTAL: 20

150


SENIOR CERTIFICATE EXAMINATION

MARKS: 150

This memorandum consists of 11 pages.

LIFE SCIENCES P2

2015

MEMORANDUM


SCE – Memorandum


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.


SCE – Memorandum


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 learners' 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 without consulting the provincial internal moderator 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.


SCE – Memorandum


SECTION A QUESTION 1 1.1 1.1.1

1.1.2 1.1.3 1.1.4 1.1.5 1.1.6 1.1.7 1.1.8

A33 C33 A33 C33 B33 A33/B B33 A33 (8 x 2)

(16)

1.2 1.2.1 Incomplete dominance 3/(co dominance) 1.2.2 Sex-linked3 1.2.3 Homologous 3 chromosome 1.2.4 Amino acids3 1.2.5 Co dominance3 1.2.6

1.2.7 1.2.8 1.2.9

Stem cells3/(meristematic) Transitional 3 Recessive3 Monohybrid3 (9 x 1)

(9)

1.3 1.3.1

1.3.2 1.3.3 1.3.4

None33 A only33 A only 33 Both A and B33 (4 x 2)

(8)

1.4 1.4.1

1.4.2 1.4.3 1.4.4

(a) RrTT3

(b) rrtt9

RT9 rT3 (a) Red fruit, short3 (b) Red fruit, tall3 RRTT33

(1) (1) (2) (1) (1) (2) (8)

1.5 1.5.1

1.5.2 1.5.3

Prophase II3/Telophase I

(a) D3- centriole3/(centrosome) (b) B3- chromosome3 (c) E3- centromere3 (a) 43 (b) 23

TOTAL SECTION A:

(1) (2) (2) (2) (1) (1) (9) 50


SCE – Memorandum


SECTION B QUESTION 2 2.1 2.1.1

2.1.2 2.1.3

A group of organisms of the same species3 that can interbreed to produce fertile offspring3 - Crossing over9 - Random arrangement9of chromosomes - Independent assortment 9/random segregation /

random assortment - Mutations3 - Chance fertilization3/Random fertilization - Random mating3 (Mark first FOUR only) (Any 4) (a) Speciation3 (b) - The rocky island3* /geographic barrier - separated the fish into two populations3 - with different environmental conditions3 on each side - Each group underwent natural selection independently3 - and developed differently3 - Each group became genotypically3 - and phenotypically3 different - which prevented them from interbreeding3 leading to the

formation of a new species *1 compulsory + any 5

(2) (4) (1) (6) (13)

Meiosis3


SCE – Memorandum


2.2 P2 Phenotype Grey male x Albino female3

Genotype Gg x gg3 Meiosis G/gametes G, g x g, g3

Fertilisation

F2 Genotype Gg; Gg; gg; gg 3 Phenotype 2 grey rabbits : 2 albino rabbits 3

Phenotypic ratio of offspring is *1 : 13 P2 and F23

Meiosis and fertilisation3 *1 compulsory + any 6

OR

P2 Phenotype Grey male x Albino female3 Genotype Gg x gg3 Meiosis

Gametes G g g Gg gg g Gg gg

1 mark for correct gametes 1 mark for correct genotypes

Fertilisation

F2 Phenotype 2 grey rabbits : 2 albino rabbits 3

Phenotypic ratio of offspring is *1 : 13 P2 and F23

Meiosis and fertilisation3 *1 compulsory + any 6

(7)

2.3 2.3.1

2.3.2 2.3.3 2.3.4

(a) DNA3 molecule (b) Amino acid3 Transcription3 - The sequence of nitrogen bases on molecule W/DNA will

change3 - This would cause a corresponding change on the molecule

X9/mRNA - The amino acid brought in by tRNA will be different9 - A different protein will form9 (a) UCU3 (b) Arginine3 ; Methionine3 ; Glycine3

(1) (1) (1) (4) (1)


SCE – Memorandum


(Must be in the correct order) (3) (11)

2.4 2.4.1

2.4.2 2.4.3 2.4.4

Using/not using DNA evidence increases/decreases the number of people found guilty of crimes99

OR Using/not using DNA evidence has no effect in finding people guilty of crimes99 Number of people9 found guilty/convicted 44 – 259 = 199 - More criminals are found guilty when DNA evidence is

included9in the investigation - DNA found at a crime scene9 - can be compared to the DNA database9 - making it easier9/faster - to identify suspects in the crime9 any 4

(2) (1) (2) (4) (9) [40]


SCE – Memorandum


3.1 3.1.1

3.1.2 3.1.3

- Predators may mistake it9 - for A. ochlea9 - which has an unpleasant taste9 - There was variation 9amongst the H. deceptor butterflies - Some butterflies did not appear similar9 to A. ochlea

- Those that did not appear similar to A. ochlea were preyed upon9/died

- Some were similar in appearance9to the A. ochlea butterfly - Fewer of these butterflies were preyed upon9 - and more of them survived9 - They passed this gene to their offspring9 - More butterflies in the next generation were similar in

appearance to the A. ochlea9 Any 6 - In natural selection the environment/nature is the

driving/selective force9 while in artificial selection humans represent the selective force9

- Natural selection occurs in response to suitability to the environment9 while artificial selection is in response to satisfying human needs9

- Natural selection occurs within a species9 while artificial selection may involve one or more species9

(Mark first ONE only) (Any 1 x 2)

(3) (6) (2) (11)

3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6

Phylogenetic tree9 (a) 29 (b) 79

- A. boisei and A. robustus share a more recent9 - common ancestor3 Homo habilis9

Taung child9 Mrs Ples9 Karabo9/A. sediba Little foot9 /A. prometheus (Mark first TWO only) Any 2

- The oldest fossils of Homo9/Homo habilis /Homo erectus - are found only in Africa 9 - The younger fossils of Homo9/Homo erectus - were found in Africa and other parts of the world9 - This implies that earliest Homo sp. evolved in Africa9/Homo

erectus migrated out of Africa Any 3

(1) (1) (1) (2) (1) (2) (3) (11)

QUESTION 3

A. africanus9


SCE – Memorandum


3.3

3.3.1 3.3.2 3.3.3 3.3.4 3.3.5

A9 and D9 (Mark first TWO only) - The pelvis is wide9/cup-shaped - to support the weight9 of an organism walking upright Diagram A - The foramen magnum is located centrally9/more forward

position below the skull - so that the vertebral column arises from beneath the skull9 - for bipedalism9 any 2 Diagram B - The foramen magnum is located towards the back9 of the skull - so that the vertebral column arises from the back of the skull9 - for quadrupedal locomotion9 any 2

Diagram A Diagram B Gently curved9/C-shaped jaw Rectangular9/U-shaped jaw Small jaws9 Large jaws9 Smaller canines9 /(teeth) Larger canines9/(teeth) No diastema/Fewer spaces between the teeth9

Diastema present/Larger spaces between the teeth9

Table format 1 (Mark first THREE only) Any 3 x 2 6 Freely rotating arm9 Rotation around elbow joints9 Rotation around the wrist9 Bare fingertips/nails instead of claws9 Long upper arms9 Opposable thumbs9 Five fingers9 (Mark first THREE only) Any 3

TOTAL SECTION B:

(2) (2) (4) (7) (3) (18) [40] 80


SCE – Memorandum


SECTION C QUESTION 4 Mutations • Mutations refer to sudden changes9 • in the genetic composition of an individual9

• Gene mutations9 • result in a change in the structure of the DNA in a single gene9 • Chromosomal aberrations9 • are changes in the normal structure/number of chromosomes9

• Harmful/lethal mutations9 • result in genetic disorders9/characteristics that decrease the survival of an

organism Any 5 Genetic disorders • Haemophilia9 • Blood does not clot9 • because the protein for blood clotting is not produced9 • Colour blindness9 • The person cannot differentiate between different colours9 • due to the absence of the necessary protein for photoreception9

• Albinism9 • The lack of pigment in the skin9 • due to the absence of the protein that forms melanin9 • Down syndrome9 • The person has an extra copy of chromosome 219 • due to non-disjunction9 during meiosis. (4 x 3)

Content: Synthesis:

(5)

(12) (17) (3) (20)


SCE – Memorandum

Copyright reserved

ASSESSING THE PRESENTATION OF THE ESSAY

Criterion Relevance (R) Logical sequence (L) Comprehensive (C) Generally All information

provided is relevant to the topic

Ideas are arranged in a logical/cause-effect sequence

All aspects required by the essay have been sufficiently addressed

In this essay Only information regarding mutations and the related to genetic disorders is given. (no irrelevant information).

Information regarding mutations and related genetic disorders are each explained in a logical order.

At least two types of mutation; and two disorders fully described.

Mark 1 1 1

TOTAL SECTION C: 20 GRAND TOTAL: 150

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