4XDOLÛFDWLRQV - SQA

AHNationalQuali cations2019X707/77/02BiologySection 1 — QuestionsTUESDAY, 30 APRIL1:00 PM – 3:30 PMInstructions for the completion of Section 1 are given on page 02 of your question and answerbooklet X707/77/01.Record your answers on the answer grid on page 03 of your question and answer booklet.Before leaving the examination room you must give your question and answer booklet to theInvigilator; if you do not, you may lose all the marks for this paper. *X7077702*A/SA

SECTION 1 — 25 marksAttempt ALL questions1.2.3.Primary cell lines haveAa limited number of cell divisions and are sourced from tumoursBa limited number of cell divisions and are sourced directly from normal animal tissueCan indefinite number of cell divisions and are sourced from tumoursDan indefinite number of cell divisions and are sourced directly from normal animaltissue.The proteome is larger than the number of genes in the genome of an organism becauseAnot all genes are expressed as proteins in a particular cellBpost translational modifications generate multiple RNAs from a single geneCalternative splicing generates multiple RNAs from a single geneDeach mRNA molecule is translated by many ribosomes.A neuron in a squid, running from the brain to the tentacles, is 0·9 m long. A 25 mm lengthof neuron is depolarised every 0·001 s.The time taken for an impulse to travel the length of this neuron isA0·000028 sB0·000036 sC0·028 sD0·036 spage 02

4.The list shows some events that occur in the cell membrane of a neuron during nervetransmission.1.Binding of neurotransmitter to neuron2.Closure of voltage-gated ion channels3.Opening of ligand-gated ion channels4.Opening of voltage-gated ion channelsWhich events contribute to the depolarisation of the resting potential of a neuron?5.6.A1 and 2 onlyB2 and 3 onlyC1, 2 and 3 onlyD1, 3 and 4 onlyWhich row in the table describes the expected effects of inhibition of the Na/KATPase?Intracellular Na ionconcentrationIntracellular K ionconcentrationMembrane decreaseA decrease in the activity of glucose symport proteins in the cells lining the small intestinecould be caused by an increase in theAglucose concentration inside the small intestineBsodium ion concentration in the cellsCATP concentration in the cellsDpotassium ion concentration in the cells.[Turn overpage 03

7.The surface area to volume ratio of a cell is an important factor affecting transport intocells.The surface area to volume ratio of an E. coli cell is 4·5. A eukaryotic cell has a surface areaof 1809 μm2 and a volume of 7235 μm3.Compared to E. coli, the surface area to volume ratio of the eukaryotic cell is approximately8.9.A1·1 times largerB1·1 times smallerC18 times largerD18 times smaller.Alpha helices in proteins are stabilised byAhydrogen bondsBionic bondsCdisulphide bridgesDhydrophobic interactions.Which row in the table describes the effects of an increase in temperature on haemoglobinand oxygen delivery to cells?Affinity of haemoglobinfor oxygenOxygen delivery to ncreaseDdecreasedecreasepage 04

The lipid bilayers of cell membranes contain a number of different phospholipids, which arepresent in different proportions and distributed unevenly across the extracellular andintracellular faces of the bilayer.Figures 1 and 2 show the proportions and distribution of four phospholipids in the cellmembrane of human red blood cells.Figure 1 Proportions of four phospholipids in the cell membranePE – phosphatidyl ethanolamineSPPCPS – phosphatidyl serineSP – sphingomyelinPSPC – phosphatidyl cholinePEFigure 2 Distribution of the phospholipids in the two faces of the membrane100percentage of total10.SPPCextracellular face50PE0PS50intracellular face100The key can be used to identify each of the phospholipids.1more than 25 % of total lipidless than 25 % of total lipidgo to 2go to 32found mainly on the extracellular facefound mainly on the intracellular faceAB3found mainly on the extracellular facefound mainly on the intracellular faceCDWhich letter represents sphingomyelin?[Turn overpage 05

Questions 11 and 12 refer to the following information.Short-term variations in the time interval between heart beats is termed heart rate variability(HRV). HRV is one measure that can be used to assess health. The box plots give information fromone study about the influence of age and gender on HRV.heart rate variability (units)100Keymalesfemales80maximum value60upper quartile40median20lower quartile025–34 35–44 45–54 55–64 65–74minimum valueage (years)11.12.From the data shown, which of the statements about HRV is correct?AThere is a trend towards lower HRV in femalesBThe greatest error in measurements is for ages 25–34CThe mean HRV for females aged 35–44 is lower than 40 unitsDGender-related differences in median values are greater than age-related differencesWhich row in the table describes features of this study?Design of experimentType of data rialrankedDmultifactorialcontinuouspage 06

13.There are approximately 40 species of birds of paradise in New Guinea, on islands nearby,and in areas of mainland Australia. They are thought to have evolved from a crow-likecommon ancestor that lived 20 million years ago.The list describes processes that are likely to have contributed to the evolution of thedifferent species.XThe food availability on a certain part of one island favoured the survival of male andfemale individuals with slender curved bills.YOn one island with abundant food choices, females choose mates whose head feathershave elongated plumes.ZSome males and females of a species of crow-like mainland bird were blown by a freakstorm to some of the islands.Which row in the table matches processes of evolution with descriptions from the list?Processes of evolutionGenetic h row in the table indicates factors that can all lead to a high rate of e n[Turn overpage 07

15.16.Which of the following adaptations can be explained using the Red Queen hypothesis?1.Acceleration of cheetahs is related to the speed of the antelope they prey on2.Migration of insectivorous birds is influenced by the availability of insects3.Resistance of insect larvae to parasitic wasp infection is a response to these wasps4.Ornamental head plumes of some male birds are attractive to femalesA1 and 2 onlyB1 and 3 onlyC2 and 3 onlyD3 and 4 onlyA student used a colorimetric assay to measure the activity of an enzyme in bananas. Anextract was prepared from one banana and used five times to measure the enzyme activity.Three absorbance readings were taken for each of the five assays.The data collected are shown in the table.Absorbance reading at 540 �570·5740·620·630·6250·580·580·59The student evaluated the data to be reliable and accurate.The student’s evaluation of the data isAcorrect because the data are reliable and accurateBincorrect because the data are accurate but not reliableCincorrect because the data are reliable but not necessarily accurateDincorrect because the data are not reliable and not necessarily accurate.page 08

17.Biological fieldwork can sometimes be more dangerous than laboratory work.Which of the following would not generally be involved in a risk assessment for carrying outfieldwork safely?18.AIdentify hazardsBSpecify control measuresCAssess safety training records of participantsDConsider hazard severity and likelihood of occurringSome populations of a species may evolve to become more r-selected or K-selecteddepending on the nature of the habitat they occupy.Which row in the table shows changes in the factors likely to be associated with a populationbecoming more K-selected?Environmental stabilityNumber of seincreaseDdecreasedecrease[Turn overpage 09

19.The population of the snail Vertigo antivertigo was investigated at a small site in Wales.Equal numbers of quadrat samples were taken in three areas with different dominantvegetation and the number of individual snails in each was recorded.The results are shown in the chart.Keyabsent8–39 individuals1–7 individuals40 or more individuals60quadrats (%)50403020100iris andrusheslonggrassshortgrassdominant vegetation in areaThe information in the chart indicates that this species of snail prefers20.Ashort grass to long grassBirises and rushes to long grassClong grass to irises and rushesDshort grass to irises and rushes.Biological fieldwork often requires the estimation of population size for a prey species. Onemethod used is mark and recapture. If the method of marking reduced the camouflagecoloration of this species, what effect would this be likely to have on the population estimateobtained?ARecapture numbers would be increased and population size would be overestimatedBRecapture numbers would be increased and population size would be underestimatedCRecapture numbers would be decreased and population size would be overestimatedDRecapture numbers would be decreased and population size would be underestimatedpage 10

21.In three-spined stickleback fish, males have a distinctive red underside in the breedingseason, which is not present in females. Territorial males were presented with model fish,some of which had their undersides painted red and some of which were left unpainted.Males showed an automatic attack response to only the red-painted models.This attack response behaviour is triggered by22.Asexual dimorphismBsexual selectionCan honest signalDa sign stimulus.The list shows three events in meiosis I.QIndependent assortmentRRecombination of alleles of linked genesSPairing of homologous chromosomesThe order in which these events occur isAS–R–QBS–Q–RCQ–R–SDQ – S – R.[Turn overpage 11

23.The graph shows species richness of mollusc populations in areas of fenland. The number ofspecies of mollusc was recorded in several areas as well as the calcium concentration in thefenland water. At each site the concentration of iron was also measured.Key40number of specieslow iron concentrationhigh iron concentration30201000100300200400calcium (mg/l)Which of the following generalisations can be drawn from the graph?24.AAn increase in calcium from 100 to 400 mg/l increases the species richnessBHigh iron concentration leads to the highest species richnessCWhen both calcium and iron concentrations are high the species richness is highestDAn increase in calcium up to 150 mg/l increases species richnessNew patterns of resistance in Plasmodium have increased the challenge experienced in thetreatment of malaria.Which of the following strategies is least likely to reduce the challenges in the treatmentand control of malaria?AImproved sanitationBDevelopment of new culture methods for PlasmodiumCCoordinated vector controlDBuilding of new low-density housing in malarial areaspage 12

25.Which diagram shows the sequence of events in the scientific cycle?Aform a hypothesisform a new hypothesisdraw conclusionsBdraw conclusionsform a new hypothesisgather and analyse dataform a hypothesisform a new hypothesisgather and analyse dataDgather and analyse datadesign experimentform a hypothesisCdesign experimentdesign experimentdraw conclusionsdesign experimentform a new hypothesisdraw conclusionsgather and analyse dataform a hypothesis[END OF SECTION 1. NOW ATTEMPT THE QUESTIONS IN SECTION 2 OFYOUR QUESTION AND ANSWER BOOKLET.]page 13

[BLANK PAGE]DO NOT WRITE ON THIS PAGEpage 14

[BLANK PAGE]DO NOT WRITE ON THIS PAGEpage 15

[BLANK PAGE]DO NOT WRITE ON THIS PAGEpage 16