Aqa gce question paper june 2005

General Certificate of EducationJune 2005Advanced Level Examination BIOLOGY (SPECIFICATION B)
Unit 8 Section A Behaviour and Populations
In addition to this paper you will require:
Section B provided as an insert (enclosed); a ruler with millimetre measurements.
Time allowed: The total time for Section A and Section B of this Instructions
• Use blue or black ink or ball-point pen.
• Fill in the boxes at the top of this page.
• Answer all the questions in Section A in the spaces provided. All
• Section A and Section B will be marked by different examiners. You
must ensure that any supplementary sheets are fastened to theappropriate question paper answer book.
• Do all rough work in this book. Cross through any work you do not Information
• The maximum mark for Section A is 50.
• Mark allocations are shown in brackets.
• You are reminded of the need for clear presentation in your answers. All answers should be in good English and should use accurate scientific • You are advised to spend 1 hour on Section A.
• You are reminded that Section A requires you to use your knowledge of
different parts of the specification as well as Module 8 in answering
synoptic questions. These questions are indicated by the letter S.
SECTION A
Answer all questions in the spaces provided.
Thyroxine is a hormone involved in the control of metabolism and growth.
Describe the effect of thyroxine on glucose metabolism.
Explain how the effect of thyroxine on glucose metabolism can influence rate ofgrowth during childhood.
The diagram shows how the secretion of thyroxine is regulated.
A woman starts to take a daily dose of thyroxine. This increases the amount of energyshe requires each day but her dietary energy input remains the same.
Explain why the woman initially loses body mass.
Use the diagram to explain why, after a short time, her mass remains constant.
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Ducklings move out of the nest soon after hatching. They imprint on the first moving objectthey see, usually a parent.
when selecting a mate as an adult bird.
An investigation was carried out into the effect of age on imprinting in mallard ducklings.
Eggs were incubated and, after they hatched, each duckling was reared in isolation. Atdifferent ages, separate groups were exposed to a model of a moving duck. Later, theducklings were tested for the strength of imprinting. This was measured by recording thepercentage of ducklings moving towards the model. The results are shown in the graph.
Percentage of ducklings moving towards model Explain the importance of rearing the ducklings in isolation after they hatched.
Using evidence from the graph, what is the optimum age for the ducklings to leavethe nest? Explain the evidence from the graph which supports your answer.
Suggest two advantages to the ducklings in being able to leave the nest at an early
age.
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An increased concentration of cholesterol in the blood is one factor increasing the risk ofmyocardial infarction (heart attack). The graph shows the relationship between death frommyocardial infarction and blood cholesterol concentration.
Concentration of cholesterol in blood plasma / mg 100 cm–3 Describe how high concentrations of cholesterol in the blood can lead to diseaseof the blood vessels supplying the heart.
Explain how disease of these blood vessels may lead to death from myocardialinfarction.
The number of deaths from myocardial infarction decreased at concentrations ofcholesterol above 250 mg 100 cm–3 blood whereas the risk of myocardial infarctioncontinued to rise. Suggest an explanation for this difference.
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Courtship and mating in fruitflies can occur equally well in the light or dark.
Fruitflies which mate in the dark are much more likely to produce offspring thanthose which mate in the light. Suggest an explanation for this.
Pheromones play a part in courtship of fruitflies. What is a pheromone? The diagrams show the courtship sequence of males from two closely related species of fruitfly
(species A and species B). The numbers show the probability of one courtship element
following from another.
Species A
Species B
Once a male of species A has orientated to the female, what is the probability that he
will perform each courtship element once only and then attempt to mate?
Show your working.
Suggest how the courtship sequences provide evidence to support the claim that the twospecies are During courtship, vibration of the wings creates a sound. The sound is different in thetwo species of fruitfly. Explain how this prevents mating between members of differentspecies.
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The flow chart shows the main sequence of events of in vitro fertilisation (IVF).
The events occurring during days 1 to 8 in the ovary in a normal menstrual cycle
differ from those described during days 1 to 8 in the flow chart. Give one way in
which they differ.
The drug clomiphene is used to stimulate production of ova.
concentration of oestrogen in the blood.
concentration of oestrogen in the blood, clomiphene stimulates ova to develop.
A woman comes from a family with a history of the sex-linked condition haemophilia.
A test was carried out to discover the sex of one of the embryos produced by IVF.
Explain how observation of the chromosomes from an embryo cell could enablethe sex to be determined.
The mother is known to carry the haemophilia allele. The father does not havehaemophilia. What is the probability of their first child having haemophilia?Explain your answer.
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The bar chart shows the results of an investigation into the relationship between the birth massof human babies and concentrations of lead and zinc in the placenta. Concentrations areshown as means, with a standard deviation bar given for each mean.
Concentrationin placenta /arbitrary units 2.00 – 2.49 2.50 – 2.99 3.00 – 3.49 3.50 – 3.99 4.00 – 4.49 4.50 – 4.99 Explain what is meant by standard deviation.
Describe the relationship between the birth mass of the baby and theconcentration of zinc in the placenta.
Zinc is an enzyme activator and an essential mineral ion.
presence of zinc ions will affect the growth of a fetus.
Suggest how the placenta may be adapted to allow zinc ions to pass to the fetus ata greater rate than some other types of ion.
Lead is a non-competitive enzyme inhibitor. Describe and explain how the presence oflead ions could influence the activity of enzymes in the fetus.
END OF SECTION A
SECTION B IS PROVIDED AS AN INSERT
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THERE ARE NO QUESTIONS PRINTED ON THIS PAGE
THERE ARE NO QUESTIONS PRINTED ON THIS PAGE
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Source: http://www.livingscience.co.uk/Year13Materials/Module8/june05.pdf