Mark Scheme Unit 5

7/21/2019 Mark Scheme Unit 5

1/6

Surname Other names

AHS Examinations

Semester 4BIOLOGYAdvanced LevelUnit 5: Exercise, energ and coordination!

April, 2015

"ime: # $o%r 45 min%tes

Write your name here

Paper Reference

&BI'5('#

)A*+ SHE)ETotal Marks

-'

Grade #.

Q.NO MARK SCHEME REMARKS

1 (a) (i) Decreases; A- Any word that means a

decrease, eg,

shorter/narrower/ smalleretc

(ii) Nothing / stay the same length / does not change ;

(b) (i) 1.3,Maim!m o"erla# / m!scle ($!lly) contracted / actin sites allocc!#ied /no $!rther cross bridge $ormation; 1

(ii) Actin and myosin, no o"erla# / com#letely se#arated;

No cross bridge $ormation ;

%he m!scle cannot contract; & ma

(iii) M!scle is contracting;

'eca!se binding sites a"ailable / interactions can occ!r;


& (a) yr!"ate / #yr!"ic acid;

(b) yto#lasm/cytosol;


2/6

(c) (i) A% #rod!ction inhibited / sto#s;

(ii) (ii) 1 No red!ced NAD (released);

& No #yr!"ate / lin* reaction / +rebs cycle inhibited;

3 Mo"ement o$ electrons / #rotons / hydrogens (down the

chain)

sto#s;

(Acce#t no electrochemical gradient)

No (release o$ $ree) energy (to #hos#horylate AD);

3 ma

(d) (i) Mitochondrion; (Reject cristae)(e) yr!"ate reacts with coenyme A;

%o #rod!ce acetyl coenyme A / acetyl coA;And carbon dioide #rod!ced;NAD is red!ced / red!ced NAD is $ormed;

Acetylcoenyme A combines with a molec!le (in the+rebs cycle) ;(Accept oxaloacetate)

3 ma


3 (a) (oygen/carbon dioide) detected by chemorece#tors /

(#ress!re) detected by barorece#tors ;

Med!lla/cardiac centre in"ol"ed;

More im#!lses to AN/along sym#athetic ner"e;

(b) (i) rod!ces electrical acti"ity / im#!lses / action #otentials thatinitiates each beat / #rod!ces electrical acti"ity that ca!sesatria to contract / stim!late AN;


3/6

0s myogenic / initiates each beat;1 ma

(ii) (AN #rod!ces electrical acti"ity that) ca!ses "entricles tocontract (a$ter atria);1 ma (Accept reference to causingdelay between (contraction of)atria and ventricles)

(iii) arries electrical acti"ity $rom AN to base o$ "entricles /ca!ses contraction $rom the base o$ "entricles;1 (Reject bottom of heart)

(c) (i) orrect answer o$ 1 beats #er min!te / 1.2 beats #er sec /1.2 beats #er sec gains & mar*s;(Remove 1 mark for correct answer but no units)rinci#le correct gains 1 mar* e.g. . secs $or 1 beat;

0$ 1. gi"en as answer, loo* atwor*ing and i$ 1.2 seen, b!tro!nding incorrect, then allow& mar*s

(ii) Damage to cells / tiss!e (in AN) that #rod!ce electricalacti"ity;o no / low #ea* o$ acti"ity / lower big s#i*e / less electricalacti"ity;(4ower AN s#i*e) red!ces the electrical acti"ity o$ the rest o$the heart;56(Damaged AN) less "entric!lar contraction;o less electrical acti"ity generated by heart m!scle;


(a)(i) hotorece#tors / rods / cones / light sensiti"e cells;Action #otentials/im#!lses, along sensory ne!rones/o#ticner"e/ tothe brain; &

(ii) (ii) 4ess light to enter / in bright light / #arasym#athetic,ca!sesconstriction o$ #!#il;ontraction o$ circ!lar m!scles;More light to enter / in dim light / sym#athetic, ca!ses dilationo$ #!#il;

ontraction o$ radial m!scles;orrect re$erences to %; 3 ma

(b) 1 4ens mo"es ($orward in the octo#!s) / h!man lens does notmo"e;& iliary m!scle ca!ses mo"ement / h!man m!scle contractsto change sha#e;3 4ens remains the same sha#e / h!man lensaccommodates/$atter/ ro!nder; No s!s#ensory ligaments / h!man eye s!s#ensoryligaments slac*en;


4/6

7 6e$raction/amo!nt o$ bending is the same / re$ractiongreater in h!mans; !#il becomes wider in octo#!s / h!mans stays the sameor constricts; ma


7 (a) (i) A mitochon!rion "# postsynaptic mem$rane "% myelin sheath & Sch'ann cell "

(ii) pro!uces ATP " (1)R pro!uces ener*yany t'o from2 (for) A%h pro!uction "+ (for) esicle formation "- (for) esicle moement "5 (for) e.ocytosis & !escri$e! "

/ (for) functionin* of ion pumps "R calcium ions (2 ma.)

(b) 1 myelin sheath insulates a.on "2 i!ea of !epolarisation & action potentials, only atno!es of Ranier "+ ref saltatory con!uction & AW "

(c) (i) 1 (impulse from TS) causes release ofen!orphins "2 en!orphins attach to morphine receptors "+ slo's & stops, A%h release "- no & less, $in!in* of A%h on receptors "


5/6

5 in postsynaptic mem$rane "/ fe'er & no, action potentials& impulses, to paincentre (in $rain) "3 A4P " e* ref role of %a2 6- ma.7

(ii) any t'o from1 no nee! to use !ru*s "2 no a!!iction to !ru*s "+ patient can control the treatment & AW "- fe'er & no, si!e e8ects "5 cheaper "


(a) 1. carbon dioide #rod!ced in res#iration / e8 ;&. a$$ects 9"ol!me / #ress!re: o$ gas / e8 ;3. allows meas!rement o$ oygen !sed / e8 ;

(b) (i) %wo mar*s $or correct answer. (mm min-1) ;;i$ incorrect allow one mar* $or correct wor*ing1. ; 56 1. 1& ;

&. < to gi"e answer ; 56 &. < 17 to gi"e answer(ii) 1. no oygen a"ailable/no oygen !#ta*e ;

&. re$erence to anaerobic res#iration ;3. carbon dioide #rod!ced is absorbed / e8 ;. no (net) change o$ 9"ol!me / #ress!re: o$ gas ;

(iii) &. !se same mass / e#ress res!lts #er !nit mass / e8 ;3. tem#erat!re changes / e8 ;. control tem#erat!re !sing a water bath / e8 ;7. #ress!re may a$$ect "ol!me o$ gas / e8 ;. !se o$ control with no organisms, at the same time / e8;


6/6

Documents

Mark Scheme Unit 5