Biology

Paper 1
Chapter 1: Cell structure
May/June 03

1 An actively growing cell is supplied with radioactive amino acids. Which cell component would first show an increase in radioactivity?
A Golgi body
B mitochondrion
C nucleus
D rough endoplasmic reticulum

2 Which pair of organelles has internal membranes?
A chloroplasts and mitochondria
B chloroplasts and nuclei
C mitochondria and ribosomes
D nuclei and ribosomes

3 Which combination is found in a prokaryotic cell?

Endoplasmic reticulum
DNA
RNA
Nucleus

A
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B
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C
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D
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key
✓ present
✗ absent

May/June 04

1 What is the order of size of cell components? largest smallest

A mitochondria ribosomes starch grains nuclei B nuclei chloroplasts mitochondria ribosomes C ribosomes mitochondria chloroplasts starch grains

D starch grains mitochondria chloroplasts ribosomes 2 The diagram shows the structure of a typical plant cell. Which cell component is also present in prokaryotes?

3 What is responsible for the high resolution of the electron microscope?

A high magnification
B short wavelength of the electron beam
C use of heavy metal stains
D very thin sections

4 A piece of mammalian tissue was homogenised and subjected to differential centrifugation to yield four subcellular fractions. The activity within each fraction, of four different types of enzyme, A, B, C and D, was investigated. Which bar chart shows the results of investigating hydrolytic enzyme activity?

5 Radioactively-labelled amino acids are introduced into a cell. In which cell structure will the radioactivity first become concentrated?

6 What is the function of nucleoli?

A the formation and breakdown of the nuclear envelope
B the formation of centromeres
C the formation of ribosomes
D the organisation of the spindle during nuclear division

May/June 05

1 What identifies a cell as a prokaryote?

A The DNA is associated with protein.
B The DNA is in a circular form.
C The DNA is in the form of a double spiral.
D The DNA is surrounded by a membrane system.

2 A lysosome measures 0.4µm in diameter. What is the diameter in nm?

A 4nm B 40nm C 400nm D 4000nm

3 What describes resolution in microscopy?

A the ability to distinguish between two objects that are very close together
B the clarity of the image formed by the microscope
C the number of times the image has been magnified by the objective lens
D the power of the microscope to focus on very small objects

4 What is a function of the smooth endoplasmic reticulum?

A aerobic respiration
B intracellular digestion
C synthesis of steroids
D transport of proteins

5 When mitochondria are extracted from cells for biochemical study, they are usually kept in a 0.25moldm–3 sucrose solution. Why is the sucrose solution used?

A to act as a solvent
B to enable the rate of respiration of the mitochondria to be determined
C to prevent the mitochondria from changing in structure
D to provide a source of energy

6 For which process is the large surface area of the cristae in the mitochondria important?

A energy radiation
B enzyme reaction
C gaseous exchange
D protein synthesis

Chapter 2: Biological Molecules
May/June 03

9 What is the general formula for a monosaccharide?

A C(H2O)n
B (CH2O)n
C C2(H2O)n
D Cn(H2O)

12 The diagram shows a molecule which is an important component of living organisms.

A forensic sample is tested for the presence of a polymer of this molecule.Which polymer is tested for?

A DNA
B lipid
C protein
D starch

26 Which condition is caused by a deficiency of vitamin A?

A anaemia
B anorexia nervosa
C night blindness
D rickets

27 What is a role of essential fatty acids in the body?

A as part of glycoproteins in cell membranes
B as part of phospholipids in cell membranes
C to use for enzyme formation
D to use for RNA formation

May/June 04

7 What is the theoretical number of chemically different dipeptides that may be assembled from 12 different types of amino acids?

A 24 B 72 C 144 D 400

8 What are the features of triglycerides?

polar less dense than water higher energy value than carbohydrates lower proportion of hydrogen than in carbohydrates

A
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B
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✓

C
✗
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D
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✓

9 Which polysaccharides are branched and which are unbranched?

branched

unbranched
A
amylose glycogen B amylopectin cellulose
C
cellulose amylose D glycogen amylopectin
10 The diagram shows a molecule. Which arrow labels a peptide bond?

11 Which bonds are the last to break when an enzyme is heated?

A disulphide
B hydrogen
C hydrophobic interactions
D ionic

12 How many haem groups are there in one molecule of human haemoglobin?

A 1
B 2
C 3
D 4

13 Which substance contains carbon, hydrogen, oxygen and nitrogen?

A collagen
B glycogen
C amylopectin
D triglyceride

May/June 2005

Chapter 3: Enzymes
May/June 03
14 An enzyme is completely denatured at 50 °C. A fixed concentration of this enzyme is added to a fixed concentration of its substrate. The time taken for completion of the reaction is measured at different temperatures. Which graph shows the results?

15 Which properties are characteristic of a non-competitive inhibitor of an enzyme?

binding

effect of adding more substrate
A
at active site reduces inhibition

B at active site does not reduce inhibition

C not at active site reduces inhibition

D not at active site does not reduce inhibition

May/June 04

14 During the development of the AIDS virus, a long polypeptide is hydrolysed by a protease enzyme, producing several smaller peptides. This viral enzyme is the target of new anti-AIDS drugs. Which feature is essential for the success of these drugs?

A a complex structure that inhibits many types of viral enzyme
B a molecule containing a heavy metal atom that is a non-competitive inhibitor of enzymes
C a protein that can act as a competitive inhibitor of protease enzymes
D a specific structure that inhibits only viral protease

15 A metabolic pathway is

Reactant enzyme 1substance X enzyme 2substance Y enzyme 3end product

What would be the effect of adding a small amount of a non-competitive inhibitor of enzyme 2?

A Enzyme 2 would be partially denatured.
B Substance X would increase in concentration.
C Substance Y would no longer be formed.
D The initial reactant would no longer be metabolised.

May/June 05

Chapter 4: Cell membrane and transport
May/June 03

Which concentration of sucrose solution, in mol dm–3, has the same water potential as the cell sap before immersion?
A 0.1 B 0.25 C 0.45 D 0.8

6 Many fresh water animals possess vacuoles which contract regularly, expelling excess water.
Why do plants living in fresh water not require such vacuoles?

A Plant cell sap has a much lower concentration of dissolved solutes than animal cytoplasm.
B Plant cell walls are impermeable to water.
C The water potential is the same inside and outside the plant cells.
D Water movement into plants is controlled by their roots.

13 How many fatty acid residues are normally present in a phospholipid molecule?

A 1
B 2
C 3
D 4

25 The diagram shows the water potential (ψ) in some plant cells and in their environment.

Which statement describes the movement of water between these cells and between them and their environment?

A All three cells are turgid, so no water moves.
B Water moves from cell 1, cell 3 and the environment into cell 2.
C Water moves from cell 3 to the environment, and from the environment to cell 1.
D Water moves from the environment into cells 1, 2 and 3.

May/June 04

16 Which process is the movement of molecules that are too large to diffuse in through a cell surface membrane?

A active transport
B endocytosis
C facilitated diffusion
D osmosis

17 A plant cell is placed in a solution with a less negative (higher) water potential than the cell contents. Which change occurs in the cell and what causes the change?

change cause A cell becomes more flaccid solution diffuses out of the cell
B
cell becomes more flaccid water diffuses out of the cell
C
cell becomes more turgid solution diffuses into cell
D
cell becomes more turgid water diffuses into cell
18 The diagram shows part of the cell surface membrane.

Which components help to maintain the fluidity of the membrane?

A 1 and 3
B 1 and 4
C 2 and 4
D 3 and 5

May/June 05

17 Which molecule prevents the cell surface membrane from becoming too fluid or too rigid?

A cholesterol
B glycolipid
C glycoprotein
D phospholipid

Chapter 5: Cell and nuclear division
May/June 03

16 What occurs in mitosis?

homologous chromosome pair

chromosomes number remains the same

A
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B
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C
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D
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17 The diagram shows chromosomes in a nucleus.

What are Y and Z?

Y
Z

A centromere centriole

B centromere chromatid

C chromatid centriole

D chromatid centromere

May/June 04

May/June 05

19 During which process does mitosis occur?

A the production of antibodies from B-lymphocyte memory cells
B the production of cancerous tissue in alveoli
C the production of mucus from goblet cells
D the production of plaques in atherosclerosis

20 What happens to chromosomes in prophase of mitosis?
A They are formed by replication of DNA.
B They attach to the spindle fibres.
C They divide to form chromatids.
D They shorten and become visible.

Chapter 6: Genetic control
May/June 03

18 A peptide consists of ten amino acids of four different kinds. What is the theoretical minimum number of tRNA molecules required to translate the mRNA forthis peptide?

A 4
B 10
C 12
D 30

19 Bacteria were cultured in a medium containing heavy nitrogen (15N) until all the DNA was labelled. These bacteria were then grown in a medium containing only normal nitrogen (14N) for five generations. The percentage of cells containing 15N in each generation was estimated. Which curve provides evidence that DNA replication is semi-conservative?

20 RNA is extracted from β cells in the pancreas. It is used to make DNA coding for human insulin. Which enzyme is used to make the DNA?

A DNA ligase
B restriction enzyme
C reverse transcriptase
D RNA polymerase

21 Which type of molecule is the end product of translation?

A amino acid
B DNA
C mRNA
D polypeptide

May/June 04

22 Which statement about the strands of a newly replicated DNA molecule is correct?

A Both strands are made up of newly assembled nucleotides.
B Both strands contain some nucleotides from the original molecule.
C One strand is new and the other is part of the original molecule.
D The sugar-phosphate chains are conserved and new bases are inserted between them.

May/June 05

22 The table shows the percentages of bases in DNA from various types of cell.

source of DNA: adenine guanine thymine cytosine calf thymus 28.2 21.5 27.8 22.5 bull spleen 27.9 22.7 27.3 22.1 bull sperm 28.7 22.2 27.2 22.0 rat bone marrow 28.6 21.4 28.4 21.5 yeast 31.3 18.7 32.9 17.1

What is a valid deduction from these data?

A DNA occurs in about the same amounts in all cells from the same species.
B Minute differences in DNA from different cells have large effects.
C The four bases show complementary base pairing.
D The structure of DNA is similar in both yeast and animal cells.

23 Which statement correctly describes the transcription of DNA?

A It is a semi-conservative process.
B It occurs at the surface of the ribosome.
C It produces messenger RNA.
D It produces polypeptides.

24 One of the codons for the amino acid phenylalanine is UUC. Which diagram shows how the tRNA carrying phenylalanine pairs with the corresponding section of mRNA?

A tRNA AAG mRNA UUC
B tRNA TTG mRNA UUC
C tRNA UUC mRNA AAG
D tRNA UUC mRNA TTG
Chapter 7: Transport in multicellular plants
May/June 03

24 The movement of water through xylem vessels is affected by external factors. A decrease in which external factor would result in an increase in water movement?

A atmospheric humidity
B external temperature
C light intensity
D wind velocity

May/June 04

27 Why is the mass flow of sap through sieve elements described as an active process?

A Phloem sap is able to flow in sieve elements against the pull of gravity.
B Sucrose is loaded into a sieve element against a concentration gradient.
C Sucrose passes out of the phloem into regions where cells are dividing.
D Water follows sucrose into a sieve element down a water potential gradient.
May/June 05
29 What is the main function of a companion cell in mature phloem tissue?
A providing cytoplasmic contact with the sieve tube for loading
B providing structural support for the sieve tube element
C providing the nucleus for cell division in the phloem
D providing the source of assimilates for storage

Chapter 8: The mammalian transport system
May/June 03

22 The graph shows the human haemoglobin dissociation curve.

Which range of partial pressures of oxygen would be found in pulmonary arteries?

A between 0 and 2 kPa
B between 2 and 6 kPa
C between 6 and 8 kPa
D between 8 and 12 kPa

30 What is the main limiting factor on the amount of work that muscles can perform during aerobic exercise?

A the percentage saturation of haemoglobin with oxygen in the lungs
B the speed of dissociation of oxygen from haemoglobin in the muscles
C the volume of blood flow through the lungs
D the volume of blood flow through the muscles

31 Why is aerobic respiration of a molecule of glucose considered more efficient than anaerobic respiration?

A More ATP is produced.
B More carbon dioxide is produced.
C More water is produced.
D More oxygen is used.

May/June 04

29 What is systolic blood pressure?

A the maximum blood pressure in the arteries
B the blood pressure in the left ventricle at the end of a contraction
C the maximum blood pressure in the right ventricle
D the blood pressure in the arteries when the heart is relaxing

May/June 05

25 Which type of tissue is present in the walls of all blood vessels?
A elastic
B endothelial
C fibrous
D smooth muscle
28 Normal venous pressure in the feet is 3.3 kPa. When a person stands very still venous blood pressure in the feet rises to 5.0kPa. What causes the high pressure?
A Muscles in the walls of the veins contract, reducing the diameter of the veins.
B Skeletal muscles in the legs are not squeezing blood upward in the veins.
C Systolic blood pressure increases.
D The semilunar valves in the veins of the leg cease to function.
Chapter 9: The mammalian heart
May/June 03

23 The graph shows changes in blood pressure during one cardiac cycle.

May/June 04

26 Fish oils are thought to have beneficial effects on the conduction of electrical excitation through the ventricles of the heart. What could the fish oils influence?

A atrioventricular node
B Purkyne tisssue
C sinoatrial node
D vagus nerve

32 An oxygen molecule diffuses directly from the air in an alveolus to haemoglobin in a red blood cell. What is the minimum number of cell surface membranes through which this molecule must pass?

A 2
B 3
C 4
D 5

May/June 05

Chapter 10: Gas exchange
May/June 03

28 Which tissues are present in the walls of a trachea and an alveolus?
32 What is an effect of inhaling tobacco smoke?
A decreased mucus production by goblet cells
B increased movement of cilia in bronchial epithelium
C reduced oxygen transport by blood
D thinning of bronchial epithelium
May/June 05
Chapter 11: Smoking
May/June 03

32 Which component of tobacco smoke affects blood pressure?

A carbon dioxide
B carbon monoxide
C nicotine
D tar

May/June 04

34 How does nicotine in cigarette smoke increase the risk of cardiac disease?

A by binding with haemoglobin
B by constricting blood vessels
C by inhibiting nerve transmission
D by stimulating the pacemaker
May/June 05

32 What is an effect of inhaling tobacco smoke?
A decreased mucus production by goblet cells
B increased movement of cilia in bronchial epithelium
C reduced oxygen transport by blood
D thinning of bronchial epithelium
May/June 05

Chapter 12: Infectious diseases
May/June 03

34 In parts of London, there was an increase in the number of cases of TB in the 1990s.
Which factor is most likely to have contributed to this?

A global warming increasing mean temperature
B increase in air pollution
C increased pathogen mutation rate
D overcrowded accommodation

35 What are the causative agent and method of transmission of cholera?

causative agent method of transmission
A bacterium airborne droplets
B bacterium water-borne
C virus airborne droplets
D virus water-borne

May/June 04

35 What are the causative agents of cholera, malaria and TB? cholera malaria TB
A bacterium insect virus
B bacterium protozoan bacterium
C virus insect virus
D virus protozoan bacterium
May/June 05
34 A village has improved its supply of clean water, sewage treatment, insect control and milk pasteurisation.
Which disease, present in the village, will not be reduced by these measures?
A cholera
B HIV/AIDS
C malaria
D tuberculosis (TB)
Chapter 13: Immunity
May/June 03

36 The graph shows the amount of antibody produced in response to an antigen.

From the graph, which statement is correct?
A It takes 25 days to achieve active immunity.
B Memory cells for this antigen are present in the body within 20 days.
C A second exposure to the antigen occurred on day 20.
D T helper cells are activated on day 12.

37 For a period after its birth, a human baby is immune to most of the diseases to which its mother is immune.
Which form of immunity does this represent?
A artificial active
B artificial passive
C natural active
D natural passive

May/June 04

36 A person’s blood group is determined by antigens present on the red blood cells. People have antibodies in their plasma even if they have never received a blood transfusion. It is these antibodies in the plasma of the person who receives the blood that make some blood transfusions unsafe.
The table shows the antigens and antibodies in the blood of people with different blood groups. blood group antigens on red blood cells antibodies in plasma A A antibodies to B B B antibodies to A
AB A and B neither
O neither antibodies to A and B

People with which blood groups can safely receive a transfusion of group A blood?

A A and B
B A and AB
C A, B and AB
D A and O

37 What is the immune system’s first line of defence against invading microorganisms?

A ingestion of the microorganisms by B-lymphocytes
B ingestion of the microorganisms by phagocytes
C production of antibodies
D production of antigens
May/June 05
35 Some antibiotics are used in animal feed to reduce disease.
What explains why these antibiotics should not be used in the treatment of human diseases?
A Humans may be allergic to these antibiotics.
B Human cells may stop responding to these antibiotics.
C Pathogenic bacteria may develop resistance to these antibiotics.
D Useful gut bacteria may be killed by these antibiotics.

Chapter 14: Ecology
May/June 03

39 What name is given to all the organisms in an area and their interactions with their environment?
A community
B ecosystem
C niche
D population

40 Which statement explains why two species cannot permanently occupy the same ecological niche?
A The two species could not interbreed.
B The two species may be part of separate food webs.
C The two species would compete for the same resources.
D The two species would have different nutritional requirements.

May/June 04

38 Which group could be a single population?

A all the animals and plants on an isolated island
B all the birds counted in one day in a garden
C all the bacteria in a colony of Bacillus subtilis
D all the insects occupying three hectares of farmland

39 What is the role of decomposers in the nitrogen cycle?

A They convert proteins to ammonium compounds.
B They fix atmospheric nitrogen.
C They oxidise ammonium compounds to nitrites.
D They oxidise nitrites to nitrates.

40 Within an ecosystem, the top consumers in a food chain are few in number.
Which statement explains this?

A Energy losses occur at each trophic level.
B Energy losses occur within the consumers’ digestive systems.
C Top consumers have a low reproductive rate.
D Top consumers are large in size.

May/June 05
38 Which agricultural practice will not provide an alternative to the use of ammonium nitrate as a fertiliser to increase the productivity of wheat?

A growing wheat and another cereal crop in the same field in alternate years
B growing wheat and beans in the same field in alternate years
C ploughing animal waste such as dung into the soil
D using synthetic urea as a fertiliser

39 Which stage in the nitrogen cycle is linked to its bacteria? stage bacteria
A ammonium ions → nitrate ions nitrogen-fixing
B ammonium ions → nitrite ions nitrifying
C nitrate ions → atmospheric nitrogen nitrogen-fixing
D atmospheric nitrogen → ammonium ions nitrifying

40 What is the ecological definition of the term community?

A all the food webs in an ecosystem
B all the individuals of one species in an area
C all the organisms in an area
D the living organisms and their non-living environment