BRITISH BIOLOGY OLYMPIAD 2004

PART A QUESTIONS Instructions: • There are two parts to the test, A and B. • Part A consists of 80 multiple choice questions. Fill in the circle of the

correct answer for each question on the answer sheet. • Part B consists of 23 short answer questions. For Part B, give your

answers in the space provided on the test paper. • Part A questions each score 1 mark, total 80.

The marks for Part B are indicated on the paper but the total will be halved.

• You have a total of 2 hours to complete both sets of questions. • Put your name and school / college on both the Part A answer sheet

and on the Part B test paper. • When you have completed and checked your tests return all the test

materials to the invigilator.

GOOD LUCK!

Cell Biology.

1. If an enzyme solution is saturated with substrate, the most effective way to obtain an even faster yield of products would be to:

A. add more of the enzyme

B. heat the solution to 900C C. add more substrate D. add an allosteric inhibitor

E. add a non-competitive inhibitor 2. What is the usual approximate temperature co-efficient (Q10) of an enzyme-

controlled reaction within the temperature range 0°C–30°C?

A. 50 B. 12 C. 10 D. 2

E. 1

3. In a photomicrograph, that had been magnified 3500 times, an organelle measured 12mm. What was the actual length?

A. 3.4 µm B. 34 µm C. 420 µm D. 0.42 µm E. 0.042 µm 4. Which of the biochemical processes listed below take place outside the

mitochondrion? A. TCA cycle/Krebs cycle B. fatty acid oxidation C. ATP synthesis associated with the electron transport chain D. glycolysis E. more than one of these 5. Which one of the following organelles is especia lly rich in hydrolytic enzymes? A. chloroplasts B. mitochondria C. ribosomes

D. peroxisomes E. lysosomes

6. Where in the mitochondrion do the reactions of the electron transport chain occur?

1. on the inner membrane 2. on the outer membrane 3. in the matrix of the mitochondrion

A. 1 only; B. 2 only; C. 3 only; D. 1 & 2 only; E. 1 & 3 only.

7. The structural level of a protein least affected by a disruption in hydrogen bonding is:

A. primary level B. secondary level C. tertiary level D. quaternary level E. all structural levels are equally affected

8. Which of the following statements about chromosomes in eukaryotes is/are true?

1. They are composed of DNA combined with protein 2. They are composed of DNA and RNA only 3. They are usually only visible under the light microscope during mitosis

and meiosis

A. 1 only; B. 2 only; C. 3 only; D. 1 & 2; E. 1 and 3.

9. Which of the following are involved in both aerobic respiration and photosynthesis?

1. ATP 2. NADP 3. enzymes 4. cytochromes

A. all of them; B. 1, 2, & 3; C. 1, 3 & 4; D. 1 & 3 only; E. 2, 3, & 4;

10. The hydrolysis of a triglyceride leads to which of the following:

1. products which are less soluble in water than are triglycerides 2. an increase in pH 3. a decrease in pH

A. 1 only; B. 2 only; C. 3 only; D. 1 & 2; E. 1 & 3;

11. Which of the following statements are true of both cellulose and protein?

1. They may be used as an energy source by certain organisms 2. They are polymers of large molecular mass 3. They act as structural materials in the cell membrane 4. They are synthesized by a series of condensation reactions

A. 1 & 2; B. 2 & 3; C. 3 & 4; D. 1, 2 & 3; E. 1, 2 & 4.

12. A flask of nutrient medium was inoculated with a suspension of yeast cells.

Every two hours a sample of the culture was taken in order to estimate the growth of the population. The sampling continued after the population had reached the carrying capacity of the environment.

Which graph best represents the rate of growth of the population?

13. Which one of the following statements about nucleic acids is true?

A. DNA and RNA are isomers because they have the same elemental composition.

B. Adenine and guanine are purines. C. Uracil and thymine are pyrimidines with each containing two hexagonal

rings. D. The sugar-phosphate backbone is held together with hydrogen bonds E. In any sample of DNA the total amount of adenine plus guanine is equal

to the total amount of cytosine plus uracil. 14. The water potential of three adjacent plant cells was measured as follows: Cell A (-300kPa); Cell B (-400kPa); Cell C (-500kPa). Which one of the

following statements is true?

A. Water will move up a water potential gradient from Cell A to Cell B to Cell C.

B. Water will move down a water potential gradient from Cell A to Cell B to Cell C.

C. Cell C will burst. D. Cell C will become plasmolysed.

E. Cell B receives water form both the other cells.

15. Which one of the following statements about the plasmalemma (cell surface membrane) is true?

A. It is totally impermeable to water due to the large number of

hydrophobic molecules it contains B. It is a bilayer, 7 – 10nm thick, containing two layers of intrinsic proteins

sandwiched between two layers of phospholipids C. It sometimes contains cholesterol which is thought to affect the fluidity

of the membrane D. Glycolipids and glycoproteins are biological markers which act as

antibodies to destroy foreign antigens E. It allows free and unlimited movement of essential molecules into and

out of the cytoplasm. 16. When radioactively labelled amino acids are introduced into the cells of the

salivary glands of a mammal, the precursors of the amylase which are subsequently synthesised by the cells are detected first in the

A. Golgi apparatus B. Messenger RNA C. Nucleolus D. Rough endoplasmic reticulum E. Zymogen granules

17. Select from the list the enzyme that catalyses the following reaction: pyruvate + reduced NAD lactate + oxidised NAD

A. decarboxylase B. dehydrogenase C. hydrolase D. phosphorylase E. transferase

18. Which of the following most accurately describes the net directional movement of

molecules when a red blood cell is placed in a hypotonic solution (one of high water potential)?

A. solute and solvent molecules into the cell B. solvent molecules into the cell C. solute molecules into the cell D. water molecules out of the cell E. water molecules and some solutes move out of the cell

19. The following graph shows the growth of a bacterial culture. Which of the following statements about this graph are true?

1. In phase 3 some bacteria may be dividing 2. Phase 2 is called the lag phase and Phase 1 is called the log phase 3. Phase 4 could be caused by the build-up of metabolic toxins 4. Growth in Phase 2 follows an arithmetical progression 5. The fastest rate of growth is seen at the plateau, Phase 3

A. 1 & 3; B. 2 & 5; C. 3 & 4; D. 1 & 4; E. 2 & 4.

20. Which of the following statements about viruses are true?

1. They can only be seen by the electron microscope 2. They possess DNA but not RNA 3. They have a simple structure based on nucleic acids, proteins and

polysaccharides 4. They are obligate parasites 5. Some possess an outer layer called a capsomere, made of individual

units called capsids.

A. 1 & 3; B. 2 & 5; C. 3 & 4; D. 1, 4 & 5; E. 2, 4 & 5.

Animal Anatomy & Physiology. 1. The rhythmic beating of cardiac muscle in the mammalian heart is initiated by the

A. atrio-ventricular node B. sympathetic nervous system C. parasympathetic nervous system D. Purkinje tissue E. sino-atrial node

2. The histogram represents the proportions of new-born mammals falling into

various birth weight categories. The line graph represents mortality.

From the information given, which of the following conclusions is correct?

A. Birth weight is undergoing continuous variation B. Birth weight is an example of discontinuous variation C. Birth weight is genetically linked to mortality D. Birth weight is dependent on mortality E. Birth weight and mortality are directly proportional

3. If the “threshold” value for glucose reabsorption by the human kidney is 350 mg per 100 cm3 blood plasma, which one of the graphs below correctly represents normal kidney function?

4. Injection of insulin into diabetics leads to a lowering of their blood sugar levels by

1. decreasing the permeability of cells to glucose 2. increasing the excretion of glucose 3. promoting the synthesis of fat and polysaccharide

A. 1 only; B. 2 only; C. 3 only; D. 1, & 2; E. 2 & 3.

5. Which of the following statements concerning bile is/are correct? 1. It increases the pH of the chyme 2. It degrades any alcohol not absorbed in the stomach 3. It stimulates peristalsis. 4. It emulsifies fats present in the food.

A. All of them; B. 1 & 4; C. 1 & 2; D. 2 & 4; E. 4 only.

6. The following are all associated with the transport of carbon dioxide by blood except:

A. carbaminohaemoglobin B. carboxyhaemoglobin C. carbonic anhydrase D. chloride shift E. hydrogencarbonate

glucose in blood plasma (mg per 100 cm3)

glucose in blood plasma (mg per 100 cm3)

glucose in blood plasma (mg per 100 cm3)

glucose in blood plasma (mg per 100 cm3)

mg glucose excreted per 100 cm3 of glomerular filtrate

mg glucose excreted per 100 cm3 of glomerular filtrate

mg glucose excreted per 100 cm3 of glomerular filtrate

mg glucose excreted per 100 cm3 of glomerular filtrate

7. All of the following are associated with inspiration in a mammal except:

A. contraction of external intercostal muscles B. lowering of diaphragm C. relaxation of internal intercostal muscles D. increase in lung volume E. increase in thoracic pressure

8. Which of the following tubes present in the human body is lined with ciliated

epithelium?

A. oviduct B. artery C. vein D. nephron E. intestine

9. Human blood passes from the inferior vena cava into the right atrium of the heart

during diastole as a result of:

A. the closure of venous valves B. pulsate nature of venous blood C. the beating of the sino-atrial node D. the closure of the atrio-ventricular valves E. a pressure difference between the atrium and the vena cava

10. Ovulation does not occur during pregnancy in the human female because

A. the follicles are not influenced by the level of progesterone in the blood B. the corpus luteum and later the placenta produce large amounts of

progesterone C. the corpus luteum degenerates as luteinising hormone is no longer

produced D. the embryo produces hormones which directly retard the production of

FSH E. menstruation does not occur during pregnancy

11. The force for the formation of glomerular filtrate in the kidney is provided by

A. the action of the sodium pump B. the action of the heart muscle C. the activity of mitochondria in the cells of the Bowman’s capsule

(renal capsule) D. the osmotic pressure of the blood E. more than one of these

12. During vigorous physical exercise by a mammal, the body temperature may be prevented from rising by

1. sweating 2. blood redirected nearer to the surface of the body due to closure of shunt

vessels 3. panting 4. reducing the thickness of the layer of fat

A. 1 & 2 only; B. 1,2 & 3; C. 1 & 3 only; D. 2 & 3 only; E. 3 & 4 only.

Plant Anatomy and Physiology.

1. Which plant cells are being described here?

“These cells are the major sites of photosynthesis in a leaf. The cells are packed vertically, each one having many chloroplasts which can move by cytoplasmic streaming to an optimum position for the absorption of light.”

A. Guard cells B. Cortical collenchyma cells C. Spongy mesophyll cells D. Palisade mesophyll cells E. Epidermal cells

2. The rate of photosynthesis of a freshwater plant is measured using five spectral

colours.

Which sequence of colours would give an increasing photosynthetic response? smallest largest response

A. blue green yellow orange red B. green yellow orange red blue C. red orange yellow green blue D. yellow green orange blue red E. red blue yellow orange green

3. In the graph below, the rate of CO2 production/uptake by a green plant is shown to vary with increasing light intensity.

Which of the following is true at point X?

A. The plant is photosynthesising B. Respiration equals photosynthesis C. CO2 is a limiting factor D. The plant is not respiring E. There is not enough light for photosynthesis to have commenced.

4. The most important process in raising water from the roots to the leaves of tall

trees in the xylem is:

A. osmosis B. root pressure C. loss of water vapour in transpiration D. mass flow E. evaporation of water from mesophyll cells

5. In plant tissue cultures, the cells are held together by

A. cellulose B. cutin C. lignin D. pectases E. suberin

6. One pollen mother cell may produce four germinating pollen grains, each with

two male nuclei and one tube nucleus. How many meiotic divisions are necessary to bring this about?

A. none B. one C. three D. four E. twelve

CO2 uptake

CO2 production

7. Trees may be damaged by animals which rub against them, wearing away a strip of bark right around the tree trunk and exposing the xylem. The tree will then

A. die quickly, because the leaves are deprived of food and water B. die quickly, because fungi enter the trunk through the wounds C. continue to grow, because bark always regrows to cover a wound D. die slowly, because the roots cannot replenish their food reserves E. die slowly, because the leaves will wilt when deprived of water and

cannot manufacture food. 8. Which of the following effects is brought about by gibberellins but not by auxins?

A. stimulation of cambial activity B. stimulation of fruit development C. inhibition of leaf abscission D. promotion of phototropic responses E. breaking of dormancy in leaf buds

9. Where in an active chloroplast would you find the highest levels of protons?

A. Stroma B. Reaction centre C. Middle lamella D. Thylakoid membranal space E. Stalked particles

10. Which of the following statements about photosynthesis are correct?

1. The first stable product of the light- independent reactions is glycerate 3-phosphate

2. Photolysis takes place in the light-dependent stage 3. Water supplies electrons for non-cyclic photophosphorylation 4. Products of the light-dependent stage include reduced NAD and ATP

A. 1 & 2 only; B. 2 & 3 only; C. 3 & 4 only; D. 1,2 & 3; E. 2,3 & 4.

11. Which of the following are required for the light- independent reaction (dark

reaction) of photosynthesis? 1. O2 2. CO2 3. Chlorophyll a 4. ATP

A. 1, 3 & 4; B. 2, 3 & 4; C. 2 & 4; D. 2 & 3; E. 3 & 4.

12. Three similar sized individuals of a small aquatic plant were collected and placed into each of three petri dishes, P, Q & R, containing different culture solutions. After six weeks the plant in dish P had the same number of leaves as it had previously and they were all small and yellowish. The plant in dish Q had more leaves and they were normal size and much darker green. The plant in dish R also had more leaves, of normal size but very pale. Which one of the following shows which elements were missing from the culture solutions?

P Q R A. magnesium nitrogen phosphorus B. magnesium phosphorus nitrogen C. nitrogen phosphorus magnesium D. phosphorus magnesium nitrogen E. phosphorus nitrogen magnesium

Ethology.

1. If an animal is subjected to repeated stimulation it may gradually cease to

respond. This is an example of:

A. taxis B. habituation C. sign stimulus D. instinct E. kinesis

2. Earthworms come to the surface of the soil at night, but if touched they will

retreat into their burrows. This is an example of:

A. a conditioned reflex B. learned behaviour C. a simple innate reflex D. kinesis E. territorial behaviour

3. The movement of a whole organism in response to a stimulus, where the direction

of movement is related to the direction of the stimulus is called a:

A. taxis B. tropism C. simple reflex D. learned reflex E. sign stimulus

4. Features of courtship behaviour include all the following except:

A. it ensures that both sexes are ready to mate B. it acts as a stimulus for gamete production C. it is largely learned behaviour D. it is species specific E. it allows recognition of the sexes

Genetics and Evolution.

1. Manx cats have no tail. Their phenotype is determined by a single gene with two

alleles, normal and Manx. Crosses between Manx cats yield ratios of 2 Manx : 1 normal. This ratio suggests that:

A. the Manx allele is recessive B. it is an example of co-dominance C. it is an example of a lethal gene D. it is a sex- linked gene E. Manx cats are homozygous for the Manx allele.

2. Which of the following do mitosis and the second division of meiosis have in

common?

1. Genetically identical material passes to each pole 2. A ‘resting phase’ (interphase) always occurs before the division

commences 3. Both chromosomes of an homologous pair lie at the equator during

metaphase 4. Chromatids separate during anaphase

A. 1 & 3; B. 2 & 4; C. 3& 4; D. 3 only; E. 4 only.

3. A somatic mutation is a change in the DNA that:

A. occurs in an ordinary body cell and is not transmitted to the next generation

B. occurs in a sex cell and is not transmitted to the next generation C. occurs in all body cells at the same time D. affects the genes associated with sleep E. occurs in any cell and is passed on to the next generation

4. What is the probability that the son of a female carrier of haemophilia and a normal male will be a haemophiliac?

A. zero B. 0.25 C. 0.50 D. 0.75 E. 1.00

5. Which one of the following operations with flowering plants would be most likely

to produce the greatest numbers of variations in the offspring?

A. self pollination B. cross pollination between a pure line and a hybrid C. cross pollination between two pure lines D. cross pollination with another species E. cross pollination between two hybrids

6. In humans, right-handedness is dominant to left-handedness and the gene is

autosomal. A right-handed man, whose father was left-handed, married a left-handed woman. Which one of the following statements is true?

A. the man was heterozygous, his father was homozygous B. the man was homozygous, his father was heterozygous C. the man was homozygous and his wife was heterozygous D. the man and his father were both homozygous E. the man and his wife were both heterozygous

7. A population’s gene pool was found to have remained unaltered for many

generations. Which of the following conditions must have existed in the population?

A. mating had always been random B. genetic drift had often occurred C. immigration and emigration were common D. inbreeding had been commonly practised E. certain alleles had enjoyed a selective advantage

8. Competition, isolation and selection are thought to be events that take place

during the origin of new species. In which order do these events take place in the process of speciation?

A. competition, selection, isolation B. selection, isolation, competition C. isolation, competition, selection D. competition, selection, isolation E. isolation, selection, competition

9. Which of the following is/are characteristic(s) of polyploid plants which may explain the fact that polyploidy has not been a major factor in evolutionary change?

1. decreased resistance to disease 2. reduced hardiness 3. lowered fertility

A. 1 only; B. 2 only; C. 3 only; D. 1 & 3; E. 2 & 3.

10. The feature of silky feathers in show fowl is caused by a recessive allele. A pure

breeding bird with normal feathers was crossed with a bird with silky feathers and all the offspring were normal. The offspring were then allowed to interbreed. Which of the following statements would be true about the F2 generation?

1. the expected ratio of normal to silky would be 3:1 2. half of the F2 birds would be heterozygous 3. all males would be silky 4. a quarter of the F2 birds would be homozygous 5. some of the normal birds would be pure breeding.

A. 1, 2 & 3; B. 2, 3 & 4; C. 3, 4 & 5; D. 1, 2 & 5; E. 2, 4 & 5.

11. In a disputed paternity case, the following blood groups were identified:

Mother Group AB Baby Group A Mr Happy Group O Mr Go-Lucky Group AB

Which combination of the following statements is correct?

1. The genotype of the baby could be IA IA or IAIo 2. Mr Happy could be the father. 3. Mr Go-Lucky cannot be the father. 4. Neither man could be the father. 5. Either man could be the father.

A. 1 & 2; B. 2 & 3; C. 3 & 4; D. 1, 2 & 5; E. 2, 3 & 4.

12. Continued self- fertilization in a population of plants heterozygous for a character would normally result in which of the following?

1. a decrease in the percentage of recessive homozygotes 2. an increase in the percentage of dominant homozygotes 3. a decrease in the numbers of recessive homozygotes 4. a reduction of heterozygotes by 50% in each generation

A. 1 & 2; B. 1 & 3; C. 2 only; D. 2 & 4; E. 4 only.

Ecology. 1. Which of the following statements about ecology are true?

1. The non- living parts of an ecosystem are called the abiotic factors. 2. Respiratory and excretory losses account for most of the energy lost in a

food chain. 3. Saprophytic bacteria and fungi are called detritivores. 4. Biological niche and microhabitat are terms with the same biological

meaning. 5. In succession, the term climax refers to woodlands which have become

extinct due to natural disasters.

A. 1 & 2; B. 2 & 3; C. 3 & 4; D. 1, 2 & 3; E. 2, 3 & 4.

2. Which one of the following defines an ecological niche?

A. the habitat in which an organism finds the most suitable climate B. the habitat in which an organism finds its food supply C. the method by which an organism obtains its food D. the total way in which an environment is exploited by an organism E. the relationship between an organism and other species

3. In complex natural communities, organisms whose food is obtained from plants

by the same number of steps are said to belong to the same trophic level. Which of the following statements is correct?

A. Only one species may occupy a trophic level. B. One species may occupy more than one trophic level. C. Carnivores are always at the second trophic level.

D. There are always four trophic levels in a food chain. E. The biomass of eash trophic level remains constant.

4. Which box in the diagram below, A, B, C, D or E contains only the constituents of an ecosystem which are classed as a community?

5. Two bird species feed on small invertebrates lodged in bark crevices on the same tree but they do not compete for the food resources because of different food preferences and differing locomotor patterns in foraging behaviour. Each of these bird species occupies:

A. the same niche in different habitats B. a different niche in the same habitat C. the same habitat in different ecosystems D. a different habitat in the same ecosystem E. the same niche in the same ecosystem 6. Which of the following are xerophytic adaptations?

1. Reduction in leaf area 2. Thick waxy cuticles 3. Hairy leaves 4. Stomata close at night and open in day 5. Rolled leaves

A. 1, 2 & 3; B. 2, 3 & 4; C. 1, 2, 3 & 4; D. 1, 2, 3 & 5; E. All of them.

7. The graph shows how the wet mass of three samples of different species of fucoid algae varies when allowed to come into contact with the air in a laboratory. Each species occupies a different level in the littoral (intertidal) zone.

Which one of the following shows the order in which the species are distributed

down the shore?

A. x, y, z B. y, z, x C. z, x, y D. y, x, z E. x, z, y

8. Which of the following statements about pyramids of biomass are correct? 1. They can sometimes be inverted 2. The length of each bar represents the standing crop 3. The length of each bar represents the energy available for the next stage

of the food chain 4. They are subject to seasonal variation

A. 1, 2 & 3; B. 2, 3 & 4; C. 1, 2, & 4; D. 1 & 2 only; E. 3 & 4 only.

9. Which of the following will reduce the denitrifying activity of denitrifying bacteria?

A. An increase in soil moisture content B. An increase in soil nitrate concentration C. A decrease in nitrogen concentration D. A decrease in oxygen concentration E. An increase in oxygen concentration

Wet

mas

s/g

time/h

10. Which of the following statements about eutrophication are TRUE? 1. It can be a naturally occurring process. 2. It is commonly found in standing rather than running water 3. It can lead to oxygen depletion 4. It is commonly associated with high levels of nitrates and sulphates 5. It is commonly associated with high levels of phosphates and nitrates.

A. all of them; B. 1, 2, 3 & 4 only; C. 2, 3, & 4 only; D. 1, 2, 4 & 5 only; E. 1, 2, 3, & 5 only.

11. Which of the following statements about primary productivity are correct?

1. It determines the total energy flow through an ecosystem 2. It is only carried out by green plants 3. It determines the amount of life which an ecosystem can support 4. Gross productivity minus respiration is equal to net productivity 5. it is only carried out by chemoautotrophs and photoautotrophs

A. 1, 2 & 3; B. 1, 2 & 4; C. 3, 4, & 5; D. 1, 3, 4 & 5; E. all of them.

12. 75g of a soil was heated at 80OC to a constant mass of 37g. It was then heated at a much higher temperature to a constant mass of 27g. Which of the following represents the percentage of humus in the original sample of soil?

A. 13.3% B. 15.2% C. 27.0% D. 36.0% E. 49.3%

Biosystematics. 1. Which of the following is a characteristic of all fungi?

A. symbiotic B. heterotrophic C. flagellated D. pathogenic E. saprobiontic

2. Two plants which belong to different families must also belong to different

A. classes B. genera C. orders D. phyla E. superfamilies

3. Which of the following statements about Amoeba are correct? It is:

1. classified in the Animalia 2. a protoctist 3. a protozoan 4. heterotrophic

A. 1, 2 & 3; B. 2, 3 & 4; C. 1, 3, & 4; D. 2 & 4 only; E. 2 & 3 only.

4. Mycorrhizae are: A. asexual reproductive structures formed by lichens B. the hyphae that grow directly into host tissues C. the mycelium that forms fairy rings D. compact, dikaryotic hyphae that form a basidiocarp E. mutualistic associa tions between plant roots and fungi. 5. Insects have all the following features except: A. body in three parts – head, thorax, abdomen B. three pairs of legs C. one pair of antennae D. one pair of compound eyes E. exoskeleton made of calcium

6. Which plant has the following features? The embryo has one cotyledon, its leaves are narrow with parallel venation, its flower parts are usually in threes.

A. daisy B. dandelion C. nettle D. wheat E. buttercup 7. The Kingdom Plantae includes all the following except: A. mosses B. club mosses C. horsetails D. conifers E. algae 8. Which of the following statements about pairs of taxonomic groups is/are true?

1. Annelids show true segmentation while platyhelminthes do not. 2. Both insects and molluscs possess a chitinous exo-skeleton. 3. Ferns do not possess true roots while bryophytes do. 4. Angoisperms and gymonosperms both produce seeds.

A. 1 & 4; B. 2 & 4; C. 1 & 3; D. 2 & 3; E. 1,3 & 4 only.