2018 Biology Higher Finalised Marking Instructions

NationalQualifications20182018 BiologyHigherFinalised Marking Instructions Scottish Qualifications Authority 2018The information in this publication may be reproduced to support SQA qualifications only on a noncommercial basis. If it is reproduced, SQA should be clearly acknowledged as the source. If it is to beused for any other purpose, written permission must be obtained from permissions@sqa.org.uk.Where the publication includes materials from sources other than SQA (secondary copyright), thismaterial should only be reproduced for the purposes of examination or assessment. If it needs to bereproduced for any other purpose it is the centre’s responsibility to obtain the necessary copyrightclearance. SQA’s NQ Assessment team may be able to direct you to the secondary sources.These marking instructions have been prepared by examination teams for use by SQA appointedmarkers when marking external course assessments. This publication must not be reproduced forcommercial or trade purposes.

General marking principles for Higher BiologyThis information is provided to help you understand the general principles you must apply when markingcandidate responses to questions in this paper. These principles must be read in conjunction with thedetailed marking instructions, which identify the key features required in candidate responses.(a)Marks for each candidate response must always be assigned in line with these general markingprinciples and the detailed marking instructions for this assessment.(b)Marking should always be positive. Marks should be awarded for what is correct and not deducted forerrors or omissions.(c)If a specific candidate response does not seem to be covered by either the principles or detailedmarking instructions, and you are uncertain how to assess it, you should seek guidance from yourteam leader.(d)There are no half marks awarded.(e)Where a candidate makes an error in the first part of a question, credit should normally be given forsubsequent answers that are correct with regard to this original error. Candidates should not bepenalised more than once for the same error.(f)Unless a numerical question specifically requires evidence of working to be shown, full marks shouldbe awarded for a correct final answer (including units, if appropriate) on its own.(g)Bulleted lists should not be used for extended response questions. Candidates must respond to the“command” word as appropriate and write extended answers in order to communicate fully theirknowledge and understanding. Candidate responses in the form of bulleted lists may not be able toaccess the full range of available marks.(h)In the detailed marking instructions, if a word is underlined then it is essential; if a word is(bracketed) then it is not essential.(i)In the detailed marking instructions, words separated by / are alternatives.(j)A correct answer can be negated if: an extra, incorrect, response is given additional information that contradicts the correct response is included.(k)Where the candidate is instructed to choose one question to answer but instead answers bothquestions, both responses should be marked and the better mark awarded.(l)Unless otherwise required by the question, use of abbreviations (eg DNA, ATP) or chemical formulae(eg CO2, H20) are acceptable alternatives to naming.(m) If a numerical answer is required and units are not given in the stem of the question or in the answerspace, candidates must supply the units to gain the mark. If units are required on more than oneoccasion, candidates should not be penalised repeatedly.(n)Incorrect spelling is given. Sound out the word(s). If the correct word is recognisable then give the mark. If the word can easily be confused with another biological term then do not give the mark egglucagon and glycogen.page 02

(o)Presentation of data: If a candidate provides two graphs, in response to one question, mark both and give the higherscore. If a question asks for a particular type of graph/chart and the wrong type is given, then fullmarks cannot be awarded. Candidates cannot achieve the plot mark but may be able to achievethe mark for scale and label. If the x and y data are transposed, then do not give the scale andlabel mark. If the graph uses less than 50% of the axes then do not give the scale and label mark. If 0 is plotted when no data for this is given, then do not give the plot mark (ie candidatesshould only plot the data given).(p)Marks are awarded only for a valid response to the question asked. For example, in response toquestions that ask candidate to: identify, name, give or state, they need only answer or present in brief form; describe, they must provide a statement as opposed to simply one word; explain, they must provide a reason for the information given; compare, they must demonstrate knowledge and understanding of the similarities and/ordifferences between topics being examined; calculate, they must determine a number from given facts, figures or information; predict, they must indicate what may happen based on available information; suggest, they must apply their knowledge and understanding to a new situation.page 03

Marking instructions for each questionSection 19.A120.D1page 04

Section 2Question1.(a)Expected responseMaxmarkAdditional guidance(i)Negative feedback (control)/homeostasis.1Not – Negative control.(ii)Hypothalamus.1Accept hypothalmus.NOT – Hypothalus.(iii) rough nerves.(b)(i)Blood vessels/arterioles1NOT - Central nervous systemAdditional incorrect answers negateseg Hormones/nerve receptorsnarrow.OR1Additional physiological responsesnegate;eg Hairs standing on end/shivering.Vasoconstriction/blood vesselsconstrict.ORMuscles contract.(ii)Less blood flow to the skin so lessheat lost.NOT - “Less heat lost (by radiation)”alone.NOT - Stops/prevents heat loss.NOT - Stops/prevents blood flow tothe skin.page 05

Question1.(c)Expected responseSo enzymes work fastest/faster.MaxmarkAdditional guidance1ORSo enzymes are at their optimum(temperature).OREnzymes work too slowly whentemperature is too low.NOT - “So enzymes do notdenature”.OROptimal/fasterNOT - “Enzymes have an optimumtemperature” alone.diffusion rates.page 06

Question2.MaxmarkExpected response(a)2 21(b)As temperature increased heart rateincreased.1Additional guidanceNOT - The heart rate is dependentupon the temperature of the water.Direction must be indicated.NOT – As heart rate increasestemperature increases.(c)Increased/optimum enzymeactivity/oxygen delivery.2(1)Leading toincreased respiration/ATPproduction.(1)ORIncreased diffusion(1)Leading toincreased supply ioural (response).1page 07NOT – Examples alone.

Question3.(a)Expected responseMaxmarkAdditional nts/competition.1NOT – “Kills otherorganisms” alone.1NOT – “Use/getplant” alone.bacteria/micro-ORAllows it to out-compete otherbacteria/micro-organisms.ORKills other bacteria/microorganisms which might damage theplant thereby affecting/reducingStreptomyces food supply.(b)(i)The microorganisms can use/thecarbohydrates nts from theORThey can feed on the carbohydrates.(ii)The plant/it is protected frompathogens/diseases/bacteria/microorganisms.NOT – Eat carbohydrates1NOT - “Kills other bacteria/microorganisms” alone.ORKills otherorganismsplant/it.(c)bacteria/microthat might harm the(i)Fusidic acid/gentamycin.1(ii)Streptomycin is less effective thanfusidic acid/gentamycin/others ofthe same concentration.1Streptomycin must be mentioned togain the mark.Survival of bacteria is not equivalentto effectiveness of antibiotic.Conclusion must relate to aim.page 08

4.MaxmarkQuestionExpected response(a)Advantage - to avoid adverseconditions/metabolic adversity/lackof food.2ORMore food available.(1)Disadvantage –/usesenergy/metabolic cost.(1)(b)Each generation dies after layingeggs.1OROnly one/4thmigrates.(c)generation(Daily) torpor.1page 09Additional guidanceNOT – “Harsh/coldweather/temperature” alonewithout a link to metabolism.

5.MaxmarkQuestionExpected response(a)Restriction endonuclease – EcoR1.(1)(i)Additional guidance2Reason –Complementary/same/matchingsticky ends.NOT – So that it can be inserted intothe plasmid.ORComplementary bases/basepairs/DNA sequence.(ii)(1)(DNA) ligase.1(iii) 50(b)1Origin of replication/replicationorigin/ORI.page 101NOT – Replication site (does notnegate correct response).

6.QuestionExpected response(a)(The number of breeding pairs)rises/increases from 0 2 (breedingpairs)/km2 in March 2011 to 1 6 inJune 2011.(1)(i)Maxmark2Additional guidanceCannot access any marks unlessJune 2011 and 1.6 are mentioned.Accept 11 or 12 as equivalent to2011 and 2012.(The number of breeding pairs) thendrops to 0 4 in March 2012.(1)km2 not equivalent to /km2Do not penalise for additionalmonths between March 2011 andMarch 2012, if figures are correct.If grey described correctly and redsquirrel data also used 1 mark.Correct values with no units 1mark.(ii)(b)331(iii) 1:41(i)1The same animal may have beencounted more than once.ORNot every animal passes a camera.ORToo few cameras/ cameras onlyrecord animals in some parts of thearea.OREquipment failure or description.page 11NOT – Triggered by other animals

Question6.(b)(ii)Expected response1. When the pine marten/predatornumber is high/more/45 ORin wooded area 1.Maxmark2ANDThere are more red (squirrels)than grey (squirrels).(1)2. When pine marten/predatornumbers are low/less/12 ORin wooded area 2.ANDThere are more grey (squirrels)than red (squirrels).(1)(c)Invasive (species).1page 12Additional guidance

7.MaxmarkQuestionExpected response(a)(i)Treated (plants) have higher/greaterabsorption (of light) between 450600 (nm) or converse.1Do not negate for stays the same350-450 and 600-700 (nm).(ii)Treated plants have a highercarotenoid content/more carotenoidpigments.1NOT – Accessory pigments.(iii) Generate/converted toATP.NOT – Greater number(s) ofcarotenoids.1ORProduces hydrogen/H.ORUsed for photolysis/to split water.ORExcite electrons/increase energylevels of electrons.OREnergy used to pump hydrogen ionsacross membrane.(b)More photosynthesis.(1)More energy/glucose for growth/oil (production)/seed (production).(1)page 13Additional guidance2NOT – To make chemicalenergy/glucose.

Question8.(a)(b)Expected responseMaxmark(i)2001(ii)5000000/5 million1(i)Food security1(ii)Less energy lost/more energy inanchovies as there are fewer/lesstrophic levels.1Additional guidanceNOT – Less energy lost between/introphic levels.A comparison is required to accessthe mark.ORLess energy in salmon as they are ata higher trophic level.page 14

Question9.(a)MaxmarkExpected responseCrossbreeds/F1/offspring/lambsmay have improvedcharacteristics/traits/genes.1Additional guidanceNOT – Answer suggesting twodifferent species.NOT – To get the best of both breeds(as no mention of characteristics/trait).ORTo get the bestcharacteristics/traits/genesboth (breeds).fromORTo introduce oduce hybrid vigour.(b)Greater/increased (genetic)variation/variety (in F2/offspring).1ORNot all offspring will show desiredcharacteristics.(c)(d)(i)Test (cross)1NOT – Back cross(ii)All/ higher chance ristic/allele/dominantgene.1NOT – “So desired trait is ensured”alone (as offspring is not indicated).(Inbreeding) results in the buildup/accumulation of (recessive/deleterious) homozygous alleles1NOT – “There is a buildup/accumulation of recessivedeleterious alleles” alone (as nomention of homozygous)ORresults in inbreeding depressionpage 15