IEB Assessment Matters National Senior Certificate Examination Life Sciences 2016

NATIONAL SENIOR CERTIFICATE EXAMINATION
NOVEMBER 2016



LIFE SCIENCES: PAPER I

Time: 3 hours 200 marks


PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY

1. This question paper consists of 11 pages and a yellow Answer Booklet of 11 pages (i–xi).
Please check that your question paper is complete. Detach the yellow Answer Booklet from
the middle of the question paper. Remember to write your examination number in the
blocks provided.

2. This question paper consists of four questions.

3. Question 1 must be answered in the yellow Answer Booklet provided. Questions 2, 3 and 4
must be answered in your Answer Book.

4. Read the questions carefully.

5. Number the answers exactly as the questions are numbered.

6. Use the total marks that can be awarded for each of Questions 1, 2, 3 and 4 as an indication
of the detail required.

7. It is in your own interest to write legibly and to present your work neatly.




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,NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I Page 2 of 11

QUESTION 2

2.1 Study the diagram below and answer the questions that follow:




[Adapted from: <http://image.slidesharecdn.com>]

2.1.1 Name the overall process occurring in the diagram above. (1)

2.1.2 Give the letter that represents:

(a) transcription (1)

(b) a polypeptide chain (1)

(c) codon–anticodon linkage (1)

2.1.3 Using the letters A–E in the diagram above, place the letters in the correct
sequence from start to finish. (2)

2.1.4 If a particular DNA nucleotide base coding sequence was AGC-CTA-ATG,
write the sequence on the corresponding mRNA molecule. (There is no
need to draw the nucleotides. Just list the bases in the correct sequence.) (3)




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,NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I Page 3 of 11

2.2 A Grade 12 Life Sciences teacher sets a task for her students to build a model of a
section of double-stranded, helix-shaped DNA. The DNA strand that they must
build should only code for the two amino acids: histidine and tyrosine.

They were to use:

• Liquorice Allsorts to represent the sugars.
• Wine Gums to represent the phosphates.
• Pink Jelly Tots to represent thymine.
• Green Jelly Tots to represent cytosine.
• Yellow Jelly Tots to represent adenine.
• Red Jelly Tots to represent guanine.

She gave them a table of mRNA codons with their respective amino acids:

mRNA Codons and Amino Acids
mRNA Codon Amino Acid
UAC Tyrosine
AGU Serine
GAC Aspartic acid
GAG Glutamine
CAU Histidine
CUA Leucine

2.2.1 How many of each of the following sweets are needed to build this portion
of DNA?

(a) Liquorice Allsorts (1)

(b) Wine Gums (1)

(c) Pink Jelly Tots (1)

(d) Green Jelly Tots (1)

(e) Yellow Jelly Tots (1)

(f) Red Jelly Tots (1)

2.2.2 The Human Genome Project was launched in 1990 and finally completed
and published in 2003.

(a) What was the main aim of the Human Genome Project? (2)

(b) Discuss TWO ways in which the information gained from the
Human Genome Project has been useful to society. (4)




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, NATIONAL SENIOR CERTIFICATE: LIFE SCIENCES: PAPER I Page 4 of 11

2.3 A gene mutation is a permanent alteration in the DNA sequence that makes up a
gene. Study the diagrams below that show three types of mutations, and answer the
questions that follow:




[Adapted from: <http://image.slidesharecdn.com>]

2.3.1 Name the three specific types of mutation illustrated in the diagrams above.
Be sure to link the names to the diagrams, e.g. Type 1 is a ... mutation. (3)

2.3.2 What possible effect would a Type 3 mutation have on the protein coded for
if this type of mutation occurred in a coding region of DNA? (1)

2.3.3 The effect of any of these mutations might be neutral, harmful or beneficial.
Which ONE of these effects could possibly contribute to speciation?
Explain your answer. (4)




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