NSS Mastering Biology Suggested Answer Book 1B (eng).doc

New Senior Secondary Mastering BiologyBook 1B Teaching notesp.14/14Suggested answers to Exercise and Reading to learn(Note: The overseas examination boards bear no responsibility for the suggested answers contained in this publication. Answers for HKCEE and HKALE questions are not available due to copyright restrictions.)Chapter 7Gas exchange in humansExerciseMultiple-choice questions (p. 7-26)1D2B3C4C5C6B7B8A9C10C11DShort questions (p. 7-28)12 The dust particles and bacteria from the air cannot be filtered by cilia or trapped by mucus.1mThey can go directly into our lungs.1mThe dust will block the air passage and the bacteria will cause respiratory infection. 1m13aAir sacs1mbNasal cavity1mTrachea1mBronchi1m Bronchioles (except the smallest ones)1mcIntercostal muscles1mRibs1mDiaphragm1m 14aIn sequence:upwards / outwards1mdownwards / flatten1mbiOn diagram:Oxygen arrow to blood from air and CO2 arrow to air from blood1mOxygen arrow to red blood cell1mCO2 arrow from plasma1miiDiffusion1miiiLarge surface area1m15HKCEE Biology 2005 I Q416InspirationExpirationIntercostal musclesContractRelaxMovement of rib cageUpwards and outwardsDownwards and inwardsDiaphragmFlattenReturn to dome shapeVolume of thoraxIncreaseDecreasePressure in thoraxDecreaseIncreaseDirection of movement of airInto the lungsOut of the lungs(1m for both correct on each row, 1m x 6)Structured questions (p.7-29)17aB and C2mMucus traps dust.1mCilia beat mucus up the trachea,preventing it from entering the lungs.1mbF, G and H3mcE, air sac1m x 2It is the site of gas exchange between air and blood.1m18aGeneral description of pressure changesDecreases to a minimum of 0.29 / 0.3 / 0.31 kPa1mat 0.80.9 s0.5mThen returns to zero at the end of inspiration1mat 1.621.7 s0.5mbChanges from 0.29 / 0.3 / 0.31 kPa to 0.29 / 0.3 / 0.31 kPa1mOverall change of 0.580.62 kPa1mciContraction of diaphragm and intercostal muscles1mIncreased volume in thorax / chest, decreased pressure1mPressure rises as air moves in1miiRelaxation of diaphragm and intercostal muscles0.5mReference to elasticity / elastic fibres0.5m Decreased volume in thorax / chest, increased pressure1mPressure decreases as air moves out1m19HKCEE Biology 2001 I Q4b20HKCEE Human Biology 1999 I Q1b21a1mbHydrogencarbonate indicator / lime water1mcA: Hydrogencarbonate indicator changes to yellow / lime water turns milky1mB: Hydrogencarbonate indicator remains orange / lime water remains clear1mdiCollect a jar of atmospheric air as inhaled air.1mCollect a jar of exhaled air by blowing slowly into a gas jar over water.1mLower a burning candle into the jar of inhaled air and the jar of exhaled air.1mRecord how long the candle can burn in each jar.1miiThe candle can burn longer in the jar of inhaled air.1mIt is because some oxygen of the inhaled air is absorbed in the lungs and the exhaled air contains less oxygen.1m22aiArrow at peak of curve1miiIntercostal muscles contract1mDiaphragm contracts / flattens / moves down1mRibs move upwards and outwards1miiiLine goes up1mbiBronchiole1miiMucus traps dust / microorganisms1mCilia sweep mucus away from air sacs1miiiAny two from:1m x 2Stimulates mucus-secreting cells / excess mucus producedInhibits ciliaLeads to cancerEssays (p. 7-31)23CartilageIn trachea / bronchi0.5mHolds airway open / prevents collapse0.5mLow resistance to air movement0.5mCiliated epithelium / ciliaSweep mucus0.5mRemove particles from lungs0.5mMucus-secreting cellsSecrete mucus0.5mTrap bacteria / dust / pollen / particles0.5mBlood vesselsSupply oxygen / nutrients to tissues of lung0.5mSurround air sacs / good blood supply to air sacs0.5mDeliver carbon dioxide / pick up oxygen0.5mReference to wall of capillary being thin0.5mEase of / rapid gaseous exchange OR short diffusion pathway0.5mSmooth muscleAdjust size of airways in exercise0.5mEpitheliumThin wall of air sacs0.5mEase of / rapid gaseous exchange OR short diffusion pathway0.5mReference to larger surface area of numerous air sacs0.5mQuality of written communication2m24Any three from:1m x 3Inhaled air contains more oxygen than exhaled airInhaled air contains less carbon dioxide than exhaled airInhaled air contains less water vapourRelative amount / percentage of nitrogen also changesExplanation:Respiration results in lower blood oxygen / higher blood carbon dioxide1mOxygen enters blood / carbon dioxide leaves blood in air sacs1mby diffusion1mWater vapour diffuses from moist surface1mBreadth of knowledge2m maxQuality of written communication1m maxReading to learn (p. 7-32)1During inhalation,diaphragm muscles and intercostal muscles contract.1mDiaphragm flattens and rib cage moves upwards and outwards.1mVolume of thoracic cavity increases and pressure decreases.0.5mAir rushes into the lungs.0.5mDuring exhalation,diaphragm muscles and intercostal muscles relax.1mDiaphragm returns to dome shape and rib cage moves downwards and inwards.1mVolume of thoracic cavity decreases and pressure increases.Air is forced out of the lungs.1m2The iron lung was connected with a pump which changed the pressure inside.1mWhen the pressure inside the iron lung is lower than that inside the lungs of the patient, airrushes into the lungs.1mWhen the pressure inside the iron lung is higher than that inside the lungs of the patient, airinside the lungs is forced out of it.1m3Advancement in the making of artificial joint1mReduces risk of allergy allows patients to move more flexibly1m(Accept other reasonable answers)Chapter 8Transport in humansExerciseMultiple-choice questions (p. 8-31)1C2D3B4A5B6B7A8B9C10B11B12BShort questions (p. 8-33)13aiHaemoglobin1miiCarries oxygen / forms oxyhaemoglobin1mfrom lungs to tissues1mbNo nucleus / biconcave disc1m14HKCEE Biology 2006 I Q115aBlood flows twice through heart1mper one full circulation1mORPulmonary circulation / to lungs1mSystemic circulation / to the body 1mbAny one from:1mMore oxygen reaches tissues / cells OR more efficient supply to tissues / cellsHelps sustain high blood pressureLess resistance to flowEasier to return blood to heartMore rapid circulationGreater activity possibleToo high a pressure does not damage lungs16HKCEE Biology 2001 I Q3bStructured questions (p. 8-34)17HKCEE Biology 2005 I Q8a18HKCEE Biology 2004 I Q3c19aAs the total cross-sectional area of vessels increases (due to branching of arteries intoarterioles) / large number of capillaries1mResistance to blood flow increases and blood pressure falls1mORFormation of tissue fluid at the arterial end of capillary beds1mDecreases blood volume and therefore decreases blood pressure within the capillarybeds1mORGreater distance from heart1mPressure gradually reduces with distance from heart / pressure is maintained by small lumen of the arteries1mORVeins have a larger lumen1mLarger volume equals decreased pressure1mbAny two from:1m x 2The arteries have a thick wall (particularly the tunica media) to resist pressureThe arteries contain numerous elastic fibresElastic fibres allow expansion under pressureSmall arterial lumen ensures high pressurecAny two from:1m x 2The veins have a large lumen to reduce the resistance of blood flowing into themVeins rely on the movement of surrounding muscle tissue to move blood alongThey possess valves to prevent backflowDescription of how valves workdiTissue fluid forms at the arterial end of capillary networks because of the highblood pressure.1miiReabsorption at the venule end is brought about osmotically because of thelower solute potential provided by the retained proteins.1m20aPulmonary artery1mbS D C P X Q B A R(2m for all correct answers or no marks)cR has a thicker wall than S.1mR has a smaller lumen than S.1mdBlood in R has more oxygen / less carbon dioxide / more glucose than in S. (any 2)1m x 2eThe semilunar valves are closed.1mThe cardiac muscle of A and C relaxes.1mThe pressure inside A and C is lower than the pressure in P and R.1mEssay (p. 8-35)21Any 10 from:1m x 10Highest pressure is in the aorta / arteries / closest to heart, where there is rhythmic rise andfall / pulse.Pressure drops progressively from arteries to arterioles.Pressure drops further through capillaries / progressive drop with increased distance fromheart.Pressure in veins is low.(Marks of the above points may be awarded on annotated graph)Rise and fall in aorta or arteries corresponds to contraction of ventricles.Friction with walls causes pressure drop.Arterioles have large total cross sectional area. Capillaries give even greater crosssectional area.Few vessels subdividing into many smaller vessels, causing substantial pressure drop fromarterial values / narrow lumen increases friction so pressure drops.Effect depends on whether arterioles are dilated or constricted / reference to elastic recoilin artery walls / maintains pressure.Pressure also drops in capillaries because of leakage of fluids into tissues.Pressure in veins / away from heart is non-rhythmic because influence of ventricles hasbeen dissipated.Pressure in veins can be increased by squeezing action of (skeletal) muscles.This works because of the presence of valves in veins.Reading to learn (p. 8-36)1 Blood is returned to the heart from different organs through blood vessels, instead of being used up as suggested by Galen.1mBlood cannot flow from one ventricle to the other through pores in the septum of the heart, because there is no pore in the septum. Blood flows from one ventricle to the other through blood vessels.1m2 Some of the deoxygenated blood in the right atrium and ventricle will bypass the lungs.1mBlood in the right atrium and ventricle directly goes to the left atrium and ventricle and pumped to different parts of the body.1mOrgans and tissues cannot get enough oxygen supply from the blood.1m3Harvey used careful calculations and repeated experiments to show blood was not used up, but flowed in a closed loop.1mHe dissected the septum of the heart to show it contained no pores.1m4Yes, scientists should be skeptical of other peoples findings.1mThough Galens idea remained unchallenged for over 1000 years, Harvey was skeptical of the idea and did experiments to prove that it was wrong. Because of his skeptics and hard work, he finally worked out the correct theory of blood flow1mChapter 9Nutrition and gas exchange in plantsExerciseMultiple-choice questions (p. 9-23)1C2B3C4D5D6C7C8D9A10AShort questions (p. 9-25)11aphotosynthesis, autotrophs0.5m x 2bMinerals, deficiency diseases0.5m x 2cphotosynthesis, respiration0.5m x 2dOxygen, carbon dioxide0.5m x 2ecompensation point, respiration0.5m x 212HKCEE Biology 2005 I Q8b13aAny one from: 1mLongThin cell wallLack of waterproof layer / cuticleLarge surface areaPresent in large numbersMembrane proteins / carriers / channelsMany mitochondriabActive transport / diffusion1mcThe water potential of soil water is usually higher than that of the root cells.0.5mWater moves down the water potential gradient into the root cells by osmosis0.5mthrough the channel proteins / differentially permeable cell membranes and 0.5mthe freely permeable cell walls.0.5m14aD (mesophyll cell), E (air space) and F (guard cell)0.5m x 3There are many air spaces to allow diffusion of gases on the moist surfaces of mesophyll cells.1mGuard cells control the opening of stomata, which allow diffusion of gases.0.5mbA (cuticle) and F (guard cell)0.5m x 2Cuticle is impermeable to water.0.5mGuard cells control the opening of stomata, which allow diffusion of water vapour.0.5m15aArea of the field of view = 0.1 mm (height) (5.7 cm / 3.4 cm 0.1 mm) (length) = 0.0168 mm21mStomatal density = 4 stomata / 0.0168 mm2 238 stomata per mm2 of the leaf surface1mbSorghum grows in dry conditions.1mIt loses water through the stomata rapidly.1mHaving few stomata can reduce water loss and hence conserve more water.1m16aTo carry out photosynthesis. 1mThe cells locate near the top of the leaf so that they can trap the maximum amount of light for photosynthesis.1mThe cells are densely packed and contain many chloroplasts.1mbBuoyancyStorage of oxygen / carbon dioxide / gasesAllows rapid diffusion of gases(any 2)1m x 2cTo enable exchange of gases.1mIt would let in water if stomata are in lower epidermis.1mStructured questions (p. 9-26)17HKALE Biology 1998 I Q9a 18HKCEE Biology 2004 I Q4c19HKCEE Biology 2005 I Q9Essay (p. 9-27)20Plants need to obtain oxygen and carbon dioxide from the atmosphere for respiration and photosynthesis respectively.They also need to obtain water and minerals from the soil for the production of different substances they need.1mCarbon dioxide and oxygen:Plants exchange gases with the environment by diffusion. In terrestrial plants, gas exchange takes place through leaves, stems and roots.In leaves, gases from the environment diffuse into the air space through the stomata. Gases dissolve in the moist surface of the mesophyll cells. They then diffuse to the neighbouring cells.1mGases diffuse from the leaves to the environment in the reverse way.In woody stems, gas exchange takes place through the lenticels.1mIn roots, gas exchange takes place all over their surfaces.1mWater and minerals:The water potential of the soil water is usually higher than that of the cytoplasm of the root hairs, water moves into the root hairs by osmosis.1mWater passes across the cortex from cell to cell by osmosis or moves along the cell walls.1mWater is drawn up the xylem vessels by transpiration pull.1mMost minerals are absorbed into the root cells by active transport. They are taken up against a concentration gradient using energy from respiration.1mSome dissolved minerals are absorbed along water.1mCommunicationmax 3mReading to learn (p. 9-28)1Certain plants can make use of toxic substances as their nutrients.1m2It is cost-effective.1m3The toxic substances absorbed by the plants may escape from the leaves and pollute the air.The plants containing the toxic substances may affect the environment if they are not properly disposed of.The clean-up process is slow because the plants take months to grow. (any 2)1m x 24When the plants decay, the toxic substances absorbed by the plants may return to the soil. Animals living in soil may be harmed by the toxic substances.1mChapter 10Transpiration, transport and support in plantsExerciseMultiple-choice questions (p. 10-23)1D2C3A4C5BShort questions (p. 10-24)6HKCEE Biology 1997 I Q17HKCEE Biology 2001 I Q38HKCEE Biology 2006 I Q99aXylem cells have thick cell walls which contain a hard substance called lignin as wellas cellulose. This makes the xylem strong enough to provide support to the plants.2mThe cortex cells have thin cell walls only. Support is provided by their turgidity. When the cells are turgid, they become rigid and press against each other.2mbDiagram: The stem bends greatly and the leaves drooped1mReason:The non-woody stem contains little xylem tissue.1mIts support is mainly by the turgidity of cells. The cells become flaccid when there isnot enough water.1mcThe buoyancy of water provides much support to the submerged plant.1m10aiWater flow is not restricted. / Transpiration stream is maintained.1miiProvides support / Waterproof to prevent water loss1mbiThe rate of water flow in xylem decreases as the total area of the stomatalopenings decreases.1miiIncreasing temperature leads to higher rate of evaporation / transpiration.1miiiLower plateau (start and finish at same point)1m11HKCEE Biology 2002 I Q3Structured question (p. 10-26)12aThe dye had travelled 9 cm up the stem in two hours.0.5mRate of water movement = 9/20.5m= 4.5 cm per hour1mbAny two of the following:1m x 2Increase the light intensity around the plant.Decrease the relative humidity around the plant.Use a fan to increase ventilation around the plant.cPrepare several Coleus plants with different numbers of leaves.1mPut them under the same condition and start the experiment at the same time.1mEstimate the total surface area of leaves in each plant by tracing all the leaves ongraph paper and counting the number of squares.1mThe rate of water movement is expected to increase with the surface area of leaves.1mThe relationship may not be a directly proportional one since the surface areas ofstems are not included but transpiration occurs through the cuticle of stems as well.2mEssay (p. 10-27)13Light intensity:The rate of transpiration increases with an in