MARK SCHEME MAXIMUM MARK : 40 SYLLABUS/COMPONENT : 0610/6 BIOLOGY (ALTERNATIVE TO PRACTICAL)

Transcription

1 NOVEMBER 2001 INTERNATIONAL GCSE MARK SCHEME MAXIMUM MARK : 40 SLLABUS/COMPONENT : 0610/6 BIOLOG (ALTERNATIVE TO PRACTICAL)

2 Page 1 of 4 Mark Scheme Syllabus Paper 1 (a) (i) potato strip A in water to remain horizontal; potato strip B in concentrated sugar solution to be curved downwards; ignore the width and length of the potato strips accept description in the correct place [2] (ii) 1 potato strip has lost turgor / has become flaccid / wilted / plasmolysed; R change in length / floppy / soft 2 due to water moving out of tissue / sugar solution absorbs water; NB direction is important 3 ref to concentration gradient or clear comparative statement identifying where the higher or lower part is located; 4 osmosis / exosmosis; [4] (iii) to show cell wall with contents pulled away from the wall; R cells without a cell wall (double line) / nuclei in the middle of vacuoles / cells without a vacuole I shape. Need smooth outline, not crenate margins [1] (b) cells swell or increase / expand in size / turgid / cells gain water / absorb water; concentration gradient explained and comparative; no cell wall; cells burst / lyse / red blood cells not visible; R water goes red / cells die [max 3] [Total : 10]

3 Page 2 of 4 Mark Scheme Syllabus Paper 2 (a) (i) Drawing : S complete fish more than 15 cm in length; O complete clear outline and reasonable shape; R fuzzy lines, artistic sketches and shading I visible patterns F fins - correct number and location; (pectoral and caudal / tail fin to be shown) T tail symmetrical; [4] (ii) ON DRAWING label X and from : fins (once) / tail, even if label caudal fin / streamlined body; [2] (iii) appropriate for structure labelled X and : role of any fin - prevent rolling / yawing / pitching, or to enable steering / braking / balance / turning, or to increase stability; R cut / penetrate through water role of tail / caudal fin for forward movement; role of body shape - streamlined for ease of movement; ignore ref to scales / slime / oxygen [max 2] (iv) location in region of operculum; THIS IS ON THE DRAWING CIRCLE ON THE DRAWING BUT AWARD MARK B (iv) [1] (b) photograph length range 16.8 upwards (no mark for measurement alone) the candidates stated length by size given in question 17 70; = 0.24 / 0.25 or ratio 1 to 4; [2] if measurements outside this range then check for mathematical skill [Total : 11] 3 (a) line graph : A axes orientation and labelled plus units; S suitable scale so ½ of the graph paper is used; P points plotted; (look for cross lines on left and bottom lines parallel) L 4 clear lines joining all of the points; K each line labelled or include use of a key; [max 4] (b) (i) accept neither surface alone; (candidate must have done calculation) [1] (ii) transpiration; loss of water (vapour); through stomata; no replacement as leaves are detached; [max 3] (iii) use of microscope; observe stomata distribution; some on the upper surface; OR place leaf in (warm) water; observe release of bubbles; from upper surface; OR leaves placed in a water tight container; condensation of water / water loss from leaves; loss from upper surface; OR use of dry / blue cobalt chloride paper; change in colour / blue to pink / purple; due to water loss from upper surface; [3] [Total : 11]

4 Page 3 of 4 Mark Scheme Syllabus Paper 4 (a) asexual reproduction / budding / vegetative reproduction / mitosis / binary fission / cell division / reproduction / cloning; R meiosis / cell splitting / sexual reproduction / growth [1] (b) (i) two from *warm /suitable temperature; R temperature alone and boil *nutrients / named nutrient eg sugars / food / minerals; *water / moisture / damp / humid; [2] (ii) drawing to show: L yeast (labelled or drawn) growing in a liquid; A apparatus air tight to collect gas; D collection by downward displacement of water / inflation of balloon / use of a gas syringe with plunger; [3] APPARATUS TO BE ASSEMBLED allow 1 mark for yeast in solution in a container O 2 gas collects air D A to collect B D D C D D plant D E yeast and water CO 2 collects in syringe pipe thro hole bud delivery tube covered beaker D F G D water H gas collects testtube D

5 Page 4 of 4 Mark Scheme Syllabus Paper (iii) limewater / bicarbonate or hydrogencarbonate indicator / ph indicator; appropriate colour change for end result; limewater - white / cloudy hydrogencarbonate - red to yellow ph indicator - green to yellow [2] [Total : 8]