2015 E.C. Biology EUEE past paper

Q1 · Circulatory system / heart

1. A. The noise of heartbeat one hears through a stethoscope is the sound of valves.
2. B. As the heart beats blood travels through the arteries with a uniform pressure.
3. C. Diastole is when the heart muscles contract and force the blood out.
4. D. Systole is when the heart muscles relax and it fills with blood.

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Q2 · Microbiology / culturing

1. A. tilting the lid of the Petri dish during inoculation.
2. B. adding distilled water to a sterilized agar
3. C. sterilizing the inoculating loops.
4. D. transferring target micro-organisms into an agar medium.

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Q3 · Microbial diseases

1. A. Cholera
2. B. Gastroenteritis
3. C. Typhoid
4. D. Tuberculosis

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Q4 · STIs / disease causes

1. A. Syphilis is caused by Neisseria gonorrhoeae.
2. B. Gonorrhoea has a burning sensation symptom while urinating.
3. C. Gonorrhoea is caused by Treponema pallidum.
4. D. Syphilis has sore ulceration on the genitals as a symptom.

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Q5 · Taxonomy / nomenclature

1. A. The two lowest units of classification
2. B. The two middle units of classification
3. C. The highest and the lowest unit of classification
4. D. The two highest units of classification

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Q6 · Genetics / dihybrid cross

1. A. 300
2. B. 450
3. C. 150
4. D. 225

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Q8 · Meiosis / crossing over

1. A. In meiosis I, there is splitting up of pairs of homologous chromosomes and line up.
2. B. In meiosis I, there is exchange of a section of DNA between chromatids.
3. C. In meiosis II, homologous chromosomes align themselves independent of other pairs.
4. D. In meiosis II, chromatids from each chromosome are separated at random.

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Q10 · Molecular biology / tRNA

1. A. Carrying genetic information from DNA in the nucleus to ribosomes
2. B. Recognizing the codon of mRNA and bring the correct amino acid to the ribosomes
3. C. Acting as a template for converting a genetic code into amino acid sequence
4. D. Assembling the amino acid into a polypeptide chain

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Q11 · Biotechnology

1. A. insulin using transgenic bacteria
2. B. dairy products at household level
3. C. myco-proteins under a laboratory
4. D. vinegar using industrial fermenter

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Q12 · Ecology / energy pyramid

This item uses a figure in the original paper (not redrawn here).

1. A. The organisms of each trophic level use large proportion of the energy to build their body.
2. B. The organisms of the first trophic level convert light energy into chemical energy.
3. C. The energy lost as heat to the surrounding in each trophic level is insignificant.
4. D. The amount of energy transferred through the trophic levels drops with each step up of the pyramid.

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Q13 · Cell division / mitosis

1. A. is the division of sex cells resulting in identical daughter cells.
2. B. produces four different daughter cells from a single cell.
3. C. is the division of somatic cells to make identical daughter cells.
4. D. produces half number of chromosomes from the original cell.

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Q14 · Genetics / monohybrid probability

1. A. Rr is 25%.
2. B. Rr is 75%.
3. C. RR is 50%.
4. D. rr is 25%.

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Q15 · Nucleic acids / DNA

1. A. smaller molecule and coding for only protein.
2. B. made of phosphate, sugar and bases.
3. C. a single stranded molecule.
4. D. less stable and degrades quickly.

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Q16 · Animal classification / phyla

1. A. Phylum Mollusca
2. B. Phylum Chordata
3. C. Phylum Arthropoda
4. D. Phylum Annelida

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Q17 · Animal classification / phyla

1. A. Starfish-Phylum Echinodermata
2. B. Fish- Phylum Arthropoda
3. C. Snail - Phylum Annelida
4. D. Earthworm - Phylum Mollusca

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Q21 · Plant adaptation

1. A. Spreading its seeds in wider areas
2. B. Increasing number of stomata in its leaves
3. C. Having broad leaves
4. D. Storing water in its tissue

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Q22 · Skin structure

1. A. acts as protection against heat loss.
2. B. protects the entry of pathogens into the body.
3. C. forms a waterproof around the body tissue.
4. D. contains blood vessels and sweat glands.

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Q23 · Sensory system / balance

1. A. The otoliths round in the same direction with the head.
2. B. The optic nerves reports that the children are still moving.
3. C. The fluid in their semicircular canals keeps on moving after they stop.
4. D. The sensory hairs vibrate highly in response to movement of their body.

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Q24 · Reproduction / menstrual cycle

1. A. the fertilized ovum reaches the uterus and attaches into the thick, spongy lining.
2. B. the FSH stimulates the development of a follicle in the ovary and the egg ripens.
3. C. pregnancy occurs and the embryo obtains nourishment and oxygen.
4. D. thick spongy lining of the uterus detaches in the absence of pregnancy.

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Q25 · Excretion / kidney

1. A. Bowman's capsule - acts as a filter to produce urine
2. B. Cortex - monitors the osmotic pressure of the blood
3. C. Glomerulus - concentrates urine and conserves water
4. D. Loop of Henle' - involved in ultrafiltration

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Q26 · Thermoregulation / behaviour

1. A. Sweating when the temperature increases
2. B. Constriction of capillaries when the temperature falls
3. C. Shivering as a result of drop in temperature
4. D. Seeking shade when the temperature rises

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Q27 · Biotechnology / medicine

1. A. restoring blood supply to area of heart muscle.
2. B. detecting toxic metabolites in the blood.
3. C. easy diagnosis of diabetes by examining a urine sample.
4. D. reducing the viscosity of mucus.

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Q28 · Enzymes / EC classification

1. A. 11 - gives a sub-subclass to which the enzyme belongs.
2. B. 1 - a reference of Enzyme Commission.
3. C. 4 - shows to which main class the enzyme belongs.
4. D. 3 - indicates a subclass to which the enzyme belongs.

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Q29 · Enzymes / lock-and-key

1. A. attached substrate- the enzyme complex enters into a transition state.
2. B. model explains enzyme inhibition in a complete manner.
3. C. shapes of the substrate is complementary to the active site.
4. D. attachment of substrate to an enzyme produces a conformational change.

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Q30 · Enzymes / apoenzymes

1. A. cofactors that give an enzyme its catalytic activity.
2. B. proteins that combine with cofactors to form active enzymes.
3. C. organic molecules and many are derived from vitamins.
4. D. inorganic molecules that bind loosely with the cofactors.

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Q31 · Enzymes / inhibition

1. A. denaturing the active site of the enzyme.
2. B. producing conformational change of the enzyme
3. C. binding to the allosteric site of the enzyme
4. D. blocking the active site of the enzyme

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Q32 · Plant tissues / leaf

1. A. Palisade mesophyll - the main photosynthetic tissue of the leaf
2. B. Waxy cuticle - controls the entry of carbon dioxide into the leaf
3. C. Guard cells - have lots of air space and gas exchange area of the leaf
4. D. Spongy mesophyll - helps to prevent water loss from the leaf

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Q33 · Plant transport

1. A. Passive transport can takes place in the phloem.
2. B. The transport of organic materials is due to transpiration.
3. C. Water is transported in dead tissue.
4. D. Active transport can take place in the xylem.

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Q34 · Plant hormones / gibberellins

1. A. leaves will fall.
2. B. stem will grow.
3. C. roots will elongate.
4. D. side shoots will grow fast.

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Q35 · Seed germination

1. A. Both SA and SB are of monocots.
2. B. SA is of a monocot, while SB is of a dicot.
3. C. Both SA and SB are of dicots.
4. D. SA is of a dicot, while SB is of a monocot.

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Q36 · Biochemistry / properties of water

1. A. contracts when it freezes and ice acts as an insulator.
2. B. takes low energy to change into vapor.
3. C. allows all light wavelengths to pass through its various depths.
4. D. requires high amount of energy to heat up.

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Q37 · Biochemistry / chromosome structure

1. A. amino acid.
2. B. glycogen.
3. C. amylose.
4. D. triglyceride.

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Q38 · Carbohydrates / glycogen

1. A. microfibrils in its side chain.
2. B. α-1,6-glycosidic bonds.
3. C. β-1,4-glycosidic bonds.
4. D. enzymes that hydrolyze it easily.

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Q42 · Scientific method

1. A. making her hypothesis.
2. B. reporting her result.
3. C. drawing her conclusion.
4. D. analyzing her data.

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Q43 · Ethiopian biodiversity / endemic animals

1. A. Nechsar National Park.
2. B. Omo National Park.
3. C. Bale Mountain National Park.
4. D. Simien Mountain National Park.

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Q44 · Pollution

1. A. deforestation increases the amount of CO2 absorbed from the atmosphere.
2. B. decomposition of dead bodies increases the amount of CO2 in the atmosphere.
3. C. burning fossil fuels increases pollution due to the release of hydrocarbons.
4. D. burning of wood increases pollution by causing global dimming which blocks sunlight.

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Q45 · Biochemistry / organic vs inorganic

1. A. 2
2. B. 3
3. C. 4
4. D. 1

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Q46 · Digestion / enzymes

1. A. Pepsin - protein
2. B. Maltase - lipids
3. C. Amylase - fats
4. D. Trypsin - starch

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Q47 · First aid / resuscitation

1. A. Remove any obstacle from the mouth that might block the airway
2. B. Open the airway by removing any obstacles from the mouth
3. C. Make sure the airway is open and the head is tilted back
4. D. Give mouth-to-mouth resuscitation if he is conscious

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Q48 · Respiration / breathing model

This item uses a figure in the original paper (not redrawn here).

1. A. Air enters when the bell-jar thorax contracts.
2. B. Air enters when the rubber sheet is pushed up.
3. C. Air exits when Y-piece is rotated both clock wise and counter-clockwise.
4. D. Air exits when the balloon lungs have higher pressure than the external environment.

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Q49 · Circulatory system / heart

1. A. Right atrium - contracts and forces deoxygenated blood into the lungs
2. B. Left ventricle - contracts and forces oxygenated blood around the body
3. C. Right ventricle - contracts and forces blood into the left ventricles
4. D. Left atrium - contracts and forces blood into the right ventricles

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Q50 · Cellular respiration

1. A. Krebs cycle takes place in the cytoplasm.
2. B. glycolysis takes place in the mitochondria.
3. C. electron transport chain takes place in the cytoplasm.
4. D. pyruvate enters into the mitochondria for further stages.

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Q52 · Cell membrane / proteins

1. A. Peripheral proteins - anchor integral proteins to the cytoskeleton
2. B. Glycoproteins - reduces the fluidity of the membrane
3. C. Channel proteins - larger molecules can pass through them
4. D. Carrier proteins - specific ions can pass along them

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Q53 · Osmosis

1. A. From the cell to the beaker
2. B. From the beaker to the cell
3. C. Both into and out of the cell
4. D. Both into and out of the beaker

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Q54 · Animal behaviour / learning

1. A. Nest-building
2. B. Knee-jerk reflex
3. C. Weaving a web
4. D. Classical conditioning

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Q55 · Membrane transport

1. A. Simple diffusion - large particles transported through channel proteins
2. B. Facilitated diffusion - particles move from high water potential to lower one
3. C. Passive transport - particles require energy in the form of ATP to derive the transport
4. D. Active transport - particles move from low to higher concentration using carrier proteins

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Q56 · Cellular respiration / Krebs cycle

1. A. Hydrogen atoms carried by reduced NAD and FAD are released and split into protons and electrons.
2. B. Two molecules of ATP are used to phosphorylate each molecules of glucose.
3. C. Two carbon group from acetyl coenzyme A reacts with a 4-carbon compound to form citrate.
4. D. Fructose 1, 6-bisphosphate is split into two molecules of the three-carbon sugar GP.

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Q58 · Animal behaviour / innate

1. A. training killer whales at marine parks.
2. B. increasing breathing rate during exercise.
3. C. producing tears when dust gets into the eyes.
4. D. a fly moving its maggot into more humid environment.

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Q59 · Animal behaviour / insight learning

1. A. Salivation of a dog when a bell was rung in the absence of food, which was paired with the conditioned stimulus.
2. B. Use of boxes, after several trials, by a chimpanzee placed in an enclosed area to obtain bananas placed on the top of an enclosure.
3. C. Exhibition of modifications of natural behaviors of guide dogs, horses or zoo animals to desired behaviors.
4. D. Lack of response from a lady, which sat in a shop in which a strong deodorant was continuously released from a can.

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Q60 · Animal behaviour / territorial

1. A. A male robin threatening an intruder
2. B. Fixed action of zebra fish to find a mate
3. C. Penguins huddling to reduce heat loss
4. D. Honeybees nesting in a tree

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Q61 · Ethiopian biologists

1. A. Professor Sebsebe Demissew
2. B. Professor Yalemtshay Mekonnen
3. C. Professor Beyene Petros
4. D. Professor Tilahun Yilma

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Q62 · Microscopy

1. A. Adjust the iris diaphragm until the maximum brightness is coming.
2. B. Set up the microscope with the lowest power objective in place.
3. C. Using coarse focusing knob to rotate the nosepiece for a higher magnification lens.
4. D. Looking through the eyepiece lens to move the objectives down.

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Q63 · Cell biology / plant cells

1. A. Vacuole which controls all activities of the cell.
2. B. Lysosomes which contain hydrolytic enzymes.
3. C. chloroplast which is filled with sap, liquids and minerals.
4. D. cell wall which gives support and strengthen to the cell.

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Q64 · Osmosis / plant cells

1. A. turgid.
2. B. flaccid.
3. C. plasmolysed.
4. D. burst.

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Q65 · Digestion

1. A. The stomach physically breaks down the ingested food.
2. B. Mouth use protease enzyme to breakdown proteins.
3. C. Large intestine is the site of lipid hydrolysis.
4. D. The small intestine is site of absorption of digested molecules.

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Q66 · Mutation

1. A. Addition
2. B. Substitution
3. C. Inversion
4. D. Deletion

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Q67 · Origin of life / Miller experiment

1. A. NH3
2. B. CH4
3. C. H2
4. D. CO2

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Q68 · Evolution / Darwin

1. A. Environment changes, creating a need for organism to change.
2. B. There is a natural variation in features that are heritable.
3. C. New features acquired in lifetime are passed to the offspring.
4. D. There is development of new feature in order to survive.

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Q69 · Evidence of evolution

1. A. looks at structural similarities of organisms.
2. B. has remains of animals and plants from the remote past.
3. C. has an impression of animal even if the actual parts are missing.
4. D. studies the development of the embryos of vertibrates.

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Q70 · Speciation / isolation

1. A. Seasonal isolation
2. B. Geographical isolation
3. C. Behavioural isolation
4. D. Temporal isolation

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Q71 · Enzymes / end-product inhibition

1. A. last product of the pathway inhibits the last enzymatic reaction.
2. B. first product of the pathway inhibits the last enzymatic reaction.
3. C. first product of the pathway inhibits the third enzyme of the reaction.
4. D. last product of the pathway inhibits the first enzymatic reaction.

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Q73 · Cell theory

1. A. Schleiden and Schwann stated that all cells come from pre-existing cells.
2. B. Virchow stated that cell is the unit of structure, physiology and organization of living things.
3. C. Modern cell theory states that cells contain hereditary information that passes from cell to cell.
4. D. Spontaneous generation theory states that all cells have basically different chemical composition.

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Q74 · Microscopy / calculation

1. A. 250μm
2. B. 200μm
3. C. 150μm
4. D. 300μm

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Q75 · Prokaryotic cells

1. A. Division of labor within the cell
2. B. Continuous loop of DNA
3. C. 10 -100 μm long
4. D. Higher level of complexity

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Q77 · Virology / HIV life cycle

1. A. 4, 5, 6, 1, 2, 3.
2. B. 4, 2, 5, 6, 1, 3.
3. C. 4, 6, 5, 2, 1, 3.
4. D. 4, 1, 2, 5, 6, 3.

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Q78 · Nitrogen cycle / bacteria

1. A. Klebsiella
2. B. Azotobacter
3. C. Pseudomonas
4. D. Rhizobium

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Q81 · Ecology / biomes

1. A. poor and thin soil.
2. B. sparse - succulent plants.
3. C. frozen and rocky soil.
4. D. migrating animals.

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Q82 · Ecology / freshwater biomes

1. A. corals, crabs and planktons.
2. B. algae, planktons and fish.
3. C. corals, kelps and angler fish.
4. D. angler fish, algae and crabs.

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Q84 · Meiosis II

1. A. Prophase II - pairs of homologous chromosomes split up
2. B. Anaphase II - chromatids from each chromosome separate
3. C. Metaphase II - chromosomes pair and exchange segments
4. D. Telophase II - two haploid cells are produced

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Q85 · Genetics / sex-influenced traits

1. A. Pattern baldness
2. B. Lactation
3. C. Ritinitis pigmentosa
4. D. Undescended testicles

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Q87 · Photosynthesis / photosystem

1. A. Chlorophyll a - a reaction center molecule
2. B. Antenna complex -light dependent reaction begins
3. C. Carotenoid - provides the hydrogen ions
4. D. Thylakoid - absorbs blue and red pigments

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Q88 · Respiration / electron transport

1. A. four-carbon compound undergoes molecular transformation to generate oxaloacetate.
2. B. hydrogen atoms carried by FADH and NADH are released and split into protons and electrons.
3. C. citrate loses a carbon atom to form a five-carbon atom compound and CO2.
4. D. five carbon compound is further decarboxylated to form a four-carbon compound.

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Q89 · Photosynthesis / Calvin cycle

1. A. synthesis of reduced NADP that provides hydrogen ion.
2. B. six turns of the Calvin cycle to make one molecule of glucose.
3. C. release of hydrogen ions at the electron transport chain.
4. D. transmission of electrons to the inside of the thylakoid.

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Q90 · Photosynthesis / limiting factors

1. A. CO2 concentration - limits the reactions by influencing rate of initial reaction with RuBP
2. B. Low temperature - limits the rate of reactions by reducing the number of electrons in the chlorophyll
3. C. Low Rubisco - limits the number of reactions in the light dependent reaction
4. D. Light intensity - limits the rate of ATP synthase enzyme action in light dependent reactions

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Q92 · Conservation

1. A. Using local practices for conservation
2. B. Replanting of land with endemic species
3. C. Replanting indigenous tree species
4. D. Large scale introduction of exotic plants

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Q93 · Nervous system / synapse

1. A. chemical that transmits nerve impulses across the nervous system.
2. B. part of the skull that encloses brain for the purpose of protection.
3. C. junction between two neurons or a neuron and a muscle.
4. D. short term change in the electrical potential on the surface of cells.

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Q95 · Sensory system / eye

1. A. Pupil - serves as the eye's protective outer layer.
2. B. Iris - controls the amount of light entering the eye.
3. C. Cornea - provides nutrition to the retina.
4. D. Choroid - bends the light into the eye.

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Q96 · Photosynthesis / CAM pathway

1. A. malate is stored in the mesophyll cells during the day.
2. B. glucose is synthesized in the bundle sheath cell during night.
3. C. ATP and NADPH are produced during the night.
4. D. the C4 stage and the Calvin cycle are separated in time.

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Q97 · Microbiology / Gram staining

1. A. Gram positive.
2. B. Gram negative.
3. C. Gram intermediate.
4. D. Gram variable.

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Q99 · Genetic engineering

1. A. isolate genes from donor DNA.
2. B. open up a plasmid.
3. C. cut genes from donor DNA.
4. D. contain a recombinant plasmid.

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Q100 · Virology

1. A. has differentiated organelles.
2. B. is saprophytic.
3. C. is acellular.
4. D. undergoes respiration.

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