NAMIBIA SENIOR SECONDARY CERTIFICATE BIOLOGY HIGHER …1).pdf · NAMIBIA SENIOR SECONDARY...
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Centre Number Candidate Number Candidate Name NAMIBIA SENIOR SECONDARY CERTIFICATE BIOLOGY HIGHER LEVEL 8321/2 PAPER 2 2 hours 15 minutes Marks 100 2013 No Additional Materials are required. INSTRUCTIONS AND INFORMATION TO CANDIDATES Candidates answer on the Question Paper in the spaces provided. • Write your Centre Number, Candidate Number and Name in the spaces at the top of this page. • Write in dark blue or black pen. • You may use a soft pencil for any rough work, diagrams or graphs. • Do not use correction fluid. • You may use a non-programmable calculator. • Do not write in the margin • For Examiner’s Use. Section A Answer • all questions. You are advised to spend no longer than 1 hour on Section A. • Section B Answer • two questions. Write your answers on the answer sheets provided at the back of • the booklet. The number of marks is given in brackets [ ] at the end of each • question or part question. This document consists of 19 printed pages and 1 blank page. Republic of Namibia MINISTRY OF EDUCATION [Turn over © MoE/DNEA 8321/2/13 Marker Checker For Examiner’s Use Section A Section B Question............. Question............. Total HIGHER LEVEL 110215 723124
Transcript of NAMIBIA SENIOR SECONDARY CERTIFICATE BIOLOGY HIGHER …1).pdf · NAMIBIA SENIOR SECONDARY...
Centre Number Candidate Number Candidate Name
NAMIBIA SENIOR SECONDARY CERTIFICATE
BIOLOGY HIGHER LEVEL 8321/2PAPER 2 2 hours 15 minutes
Marks 100 2013
No Additional Materials are required.
INSTRUCTIONS AND INFORMATION TO CANDIDATES
Candidates answer on the Question Paper in the spaces provided.•Write your Centre Number, Candidate Number and Name in the spaces at the top of this page. •Write in dark blue or black pen.•You may use a soft pencil for any rough work, diagrams or graphs.•Donotusecorrectionfluid.•You may use a non-programmable calculator.•Do not write in the margin • For Examiner’s Use.
Section AAnswer • all questions.You are advised to spend no longer than 1 hour on Section A.•
Section BAnswer• two questions.Write your answers on the answer sheets provided at the back of •the booklet.
The number of marks is given in brackets [ ] at the end of each •question or part question.
This document consists of 19 printed pages and 1 blank page.
Republic of NamibiaMINISTRY OF EDUCATION
[Turn over© MoE/DNEA 8321/2/13
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Section A
Section B
Question.............
Question.............
TotalHIGHER LEVEL
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SECTION A
Answer all the questions from this section in the spaces provided.
Fig. 1.1 is a drawing made from an electron micrograph of a longitudinal section 1 of a capillary in muscle tissue.
A B
Fig. 1.1
Cell (a) A ingests and digests pathogens.
State the name of this cell.(i)
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With reference to Fig.1.1, suggest how cell (ii) A is able to leave the capillary andfightinfectionsinthemuscletissue.
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Describe how this cell ingests and digests the pathogens.(iii)
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Cell (b) B is a red blood cell.
Explain how the shape of this cell helps it to absorb a large amount of oxygen.
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Explain how oxygen and glucose move from the blood inside the capillary to (c) thetissuefluidinthemuscle.
oxygen ......................................................................................................
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Fig. 2.12 shows Amoeba proteus, which is a unicellular organism that lives in fresh water. It has a contractile vacuole which pumps out excess water which has entered from the environment. The contraction rate of the vacuole depends on the salt concentration of the water in which it lives.
contractile vacuolenucleus
Fig. 2.1
Name the process by which water enters(a) (i) A. proteus.
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The diffusion of water in and out of cells depends on the water potential (ii) gradient between the cell and its environment.
Explain why water moves into A. proteus.
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Suggest why the contraction of the vacuole stops when there is no (iii) oxygen in the water.
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Astudentsetupanexperimenttofindouthowthecontractionrateofthe(b) vacuole varied with the salt concentration of the water surrounding A. proteus.
Fig. 2.2 is a graph showing the results of the experiment.
0 1 2 3 4 5 60
5
10
15
20
25
30
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number of contractions/min
percentage concentration of salt solution
X
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Fig. 2.2With reference to Fig. 2.2, describe the effect of salt concentration on (i) the number of contractions.
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Suggest and explain what would happen if the concentration of the (ii) solution increased to more than 5% .
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Valonia(c) is a unicellular organism which lives in sea water. It has a cell wall and a vacuole like a plant cell. The ion concentrations in the vacuole of Valonia were analysed and compared to the ion concentrations of the surrounding sea water in Table 2.1.
Table 2.1
ion concentration (mol/cm3)
sea water
vacuole of Valonia
potassium 0.012 0.60
sodium 0.498 0.09
calcium 0.012 0.0017
chloride 0.580 0.597
Calculate the ratio of the potassium ion concentration in sea water to (i) the potassium ion concentration in Valonia. Show your working.
Ratio……………………………….. [2]
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With reference to your answer to (ii) (i), state the process by which potassium enters Valonia and explain your choice.
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Describe the process named in (iii) (ii).
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Suggest what would happen to (iv) Valonia if it were placed into fresh water.
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Fig. 3.1 shows how the ovary and the uterus are changed by various hormones 3 during the menstrual cycle.
Z
lining of uterus
oestrogen
pituitary
ovary
A
W
X
B
Fig. 3.1Name structures (a) (i) A and B.
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Name hormone (ii) W and describe its function.
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All the undeveloped ova in the ovary of a woman are diploid primary (iii) oocytes.
At which stage of development is the ovum in structure A?
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Name hormone (b) (i) X and explain its functions with reference to Fig. 3.1.
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With reference to Fig. 3.1, name hormone (ii) Z and outline how it helps to control the menstrual cycle.
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The element nitrogen is very important for the formation of many biological 4 molecules, such as amino acids and proteins.
Fig. 4.1 shows part of the nitrogen cycle.
urea in urine
proteins in plants
urea
amino acids in animals
proteins in animal
ammonium ions in the soil
nitrite ions in the soil
nitrogen (N) in the atmosphere
nitrate ions in the soil
amino acids in plants
A
B
C
E
F
D
G Fig. 4.1
Name (a) one other biological molecule which contains nitrogen.
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Name the process taking place at (b) (i) B.
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Name the type of bacteria responsible for the process at (ii) C.
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Amino acids are changed to proteins in plants and animals.(c) (i)
Name the part of the cell where this process occurs.
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Name and describe the biological process taking place at (ii) A.
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Process (d) (i) E takes place inside animals. Name this process.
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State where the process named in(ii) (i) takes place and describe the process.
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Describe (e) three ways in which farmers can maintain soil fertility without using artificiallyproducedfertilizers.
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SECTION B
Answer any two questions from this section.Write your answer on the answer sheets provided at the back of the booklet.Use labelled or annotated diagrams if it will make your answer more clearly understood.
5 (a) Comparewind-andinsect-pollinatedflowersreferringtotheimportance of each feature. [7]
(b) Explain how abscisic acid and giberellins affect the germination of seeds in dry areas, such as Namibia. [7]
(c) Explain why water, oxygen and a suitable temperature are necessary for germination of seeds. [6]
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6 (a) Describe and explain how the body of a human responds when it moves from a warm room into the open on a very cold day. [12]
(b) Explain with named examples, how different surface areas and body coveringsinfluencetherateofcoolingofawarmbody. [8]
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7 (a) Draw and label a simple diagram to show the structure of how DNA is constructed from sugars, phosphates and bases. [8]
(b) Compare the following terms:
genotype and phenotype.(i)
homozygousandheterozygous.[4](ii)
(c) IA, IB, and IO are the alleles of the gene which controls human blood groups.
Draw a genetic diagram to show the possible blood groups amongst theoffspringofafather,whoisheterozygousforbloodgroupA,and amother,whoisheterozygousforbloodgroupB.
Identify the offspring with the blood group that is the result of codominance,anddefinecodominance. [8]
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8 (a) Explain the role of photosynthesis and cellular respiration in food chains. [10]
(b) Compare anaerobic and aerobic respiration in plants and animals. [5]
(c) Outline the different ways in which the rate of photosynthesis could be measured. [5]
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