Life Sciences Grade 12 Paper 1 NSC June 2013 Memo

Downloaded from hlayiso.com basic educatign _ Department: we OS Basic Education REPUBLIC OF SENIOR CERTIFICATE EXAMINATION BIOLOGY P1 HIGHER GRADE 2013 POSSIBLE ANSWERS MARKS: 200 Please turn over Copyright reserved

Downloaded from hlayiso.com Biology/HG/P1 2 DBE/2013 PRINCIPLES RELATED TO MARKING HG AND SG BIOL! 1. SCE — Memorandum If more information than marks allocated is given: 2013 -06- 9 5 Stop marking when maximum marks is reached and put a wavy line and ‘max’ in the right hand margin. : If, for example, three reasons are required and five ate RURLIC EXAMINATIONS _| 2. Mark the first three irrespective of whether all or some are correct/incorrect. 3. If the whole process is given when only part of it is required: Read all and credit relevant parts. 4. |f comparisons are asked for and descriptions are given: Accept if differences/similarities are clear. S tf tabulation is required but paragraphs are given: Candidates will lose marks for not tabulating. 6. If diagrams are given with annotations when descriptions are required: Candidates will lose marks. 7. If flow charts are given instead of descriptions: Candidates will lose marks. 8. If sequence is muddled and links do not make sense: Where sequence and links are correct, credit. Where sequence and links is incorrect, do not credit. If sequence and links becomes correct again, resume credit. 9. Non-recognized abbreviations: Accept if first defined in answer. If not defined, do not credit the unrecognised abbreviation but credit the rest of answer if correct. 10. Wrong numbering: If answer fits into the correct sequence of questions but the wrong number is given, it is acceptable. 11. If language used changes the intended meaning: Do not accept. 12. Spelling errors: If recognizable accept provided it does not mean something else in Biology or if it is out of context. Copyright reserved

Downloaded from hlayiso.com Biology/HG/P1 3 SCE - Memorandum 1 13. If common names given in terminology: Accept provided it is accepted at this memo sro} 14. If only letter is asked for and only name is given (and ae CAARMINATIONS No credit 15. If units are not given in measurements: Candidates will lose marks. Memorandum will allocate marks for units separately 16. Be sensitive to the sense of an answer, which may be stated in a different way: 17. Caption: All illustrations (diagrams, graphs, tables, etc.) must have a caption 18. Code-switching of official languages (terms and concepts): A single word or two that appears in any official language other than the learners’ assessment language used to the greatest extent in his/her answers should be credited, if it is correct. A marker that is proficient in the relevant official language should be consulted. This is applicable to all official languages. 19. No changes must be made to the marking memoranda without consulting the Provincial Internal Moderator who in turn will consult with the External Moderator/s. 20. Only memoranda bearing the signatures of the UMALUSI moderators and distributed by the National Department of Education via the Provinces must be used. Copyright reserved

da 1.2 1.3 1.4 Downloaded from hlayiso.com Biology/HG/P1 4 DBE/2013 SCE — Memorandum SECTION A QUESTION 1 Byv Avy Byy Dvv Byy Dvy Cvy Byy AvvY Avv Fe Cr Ce Ce GG Sa ae pr a as Cn nr Ser SOONMNORWN = co} (10 x 2) Co-enzymes “/ NAD Radiant ~’/ Sunlight / Solar / Light Alveoli ¥ MitochondrionY lleo-caecal valve ¥ Glottis ¥ Ciliated “Epithelium Squamous” (8x 1) None vv B only vv” Both A and BVY None vv B only vv (5 x 2) ae rorwnnan ONOORWNH = OhWNH > saw ow = a = Photosynthesis ~ 1.4.2 (a) The entire algal filament was exposed to light and photosynthesised therefore releasing oxygen” which attracted bacteria around the entire filament” (b) | Only the area of the algal filament exposed to light photosynthesised and released oxygenv’,, therefore bacteria concentrated only in this area ¥ Copyright reserved (20) (8) (10) (1) (2) (2) (5)

1.5 1.6 Downloaded from hlayiso.com Biology/HG/P1 5 1.5.1 1.5.2 1.5.3 1.5.4 1.5.5 1.6.1 1.6.2 SCE - Memorandum Person X - kwashiorkor ¥ i High carbohydratesv’ and low protein v (accept ally speeware £ x, + example) AMINATE NS Increasev of fatty tissue v/fat / cholesterol in the walls of the arteries V (Mark first ONE only) (1x2) Heart diseasev/ Heart attack High blood pressure”/ hypertension DiabetesY Stroke’ (Mark first ONE only) (any 1 x 1) Exercise VW Eat a diet lower in fatty foods v’/ balanced diet (Mark first ONE only) (a) Dv (b) Av (ce) DY Intra-specific competition in pot D “is competition between organisms Vv of the samev species Inter-specific competition in pot A or B or C vis competition between organisms V of different “species TOTAL SECTION A: Copyright reserved (2) (1) (2) (8) (1) (1) (1) 6) (9) 60

Downloaded from hlayiso.com Biology/HG/P1 6 SCE - Memorandum SECTION B QUESTION 2 2.1 244 - it is convoluted / folded/longY - has numerous internal folds“ on mucosa - contains numerous villi - presence of microvilli” on columnar cells of villi (Mark first TWO only) (any 2 x 1) (2) 2.1.2 - food remains longer in the intestinew/ slowed down by internal folds - more efficient/ time for digestion” - more efficient / time for absorption” (Mark first TWO only) (any 2 x 1) (2) 2.1.3 - secretes bile” - stores excess glucose in the form of glycogenvY - breaks down excess amino acids “/ deamination - converts glycogen into glucosev ” - stores vitamin A, D, E and KY” - stores iron’ ¥ - converts excess glucose / glycogen to lipids’ Vv - detoxifies poisonous substances VV” (Mark first TWO only) (any 2 x 2) (4) 2.1.4 In an active form pepsin will digest’ the cells in the stomach wall V because the cell membranes also contain proteins Vv (any 2) (2) 2.1.5 - acts as an antiseptic / kills bacteria vv - converts pepsinogen to pepsin / prorennin to rennin’v Y - facilitates the absorption of calcium and iron in the intestinevv - breaks down / converts/ hydrolyses sucrose to glucose and fructose”V - splits nucleoproteins into nucleic acid and protein’ Y (Mark first TWO only) (any 2 x 2) (4) 2.1.6 - these products are in abundance / high concentration “ in the small intestine - the blood capillaries also have a high / same concentration” of these substances - therefore diffusion of these products will be difficult / has to be absorbed against / without a concentration gradient “ - hence absorption is active and thereby preventing the non-absorption / wastage of these products / for maximum absorption” (any 3 x 1) (3) Copyright reserved

Biology/HG/P1 2.1.7 2.2 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.3 2.3.1 2.3.2 Copyright reserved Downloaded from hlayiso.com if DBE/2013 SCE — Memorandum - Both organs control / regulatesv the blood sugar levelv’/ by negative feedback mechanism - the pancreas / B will secrete insulin which will lower / decrease the blood sugar level” - by converting excess glucose to glycogen in the liver / C ¥ - the pancreas / B will secrete glucagon which will increase the blood glucose levels ¥ - by converting glycogen to glucose in the liver / C v(Max 4) Type of diet” - amount of exercise V - food eaten not observed by scientists v - volunteers cheated on exercise “ - volunteers cheated on food v - mass not controlled” - age not controlledv - genderv not controlled - occupation “not controlled - different proportions of subjects completed the course” -quantity of carbohydrates and fats used are not in same units” (Mark first TWO only) (any 2 x 1) Yes¥ - Low carbohydrate / group 1 lost more “body mass than group 2v -The greater percentage is due to the greater percentage v of volunteers who completed the trialv (Mark first ONE only) Neither diet constitutes a balanced diet vw Nuts~/Peanuts/almonds Brown bread /whole wheat bread Fresh fruity /dried fruit All raw and cooked vegetables” Cereal Vv (Mark first TWO only) (any 2 x 1) Provides volume/bulk to waste material in large intestinev Vv Stimulates peristalsis and movement of waste for defecationy “ Retains water and prevents constipationv “/diverticulitis/ cancer of colon/haemorrhoids Facilitates in the absorption of poisonous substancesv ” (Mark first TWO only) (any 2 x 2) (4) (2) (1) (2) (2) (8) (2) (4) ms.

Downloaded from hlayiso.com Biology/HG/P1 8 SCE — Memorandum QUESTION 3 3.1 3.1.1 The number of bubbles released at 35 °C over aperiod of time vv ony @ 6 68 6 Ss wy a VV rom ow 646 4 N Total number of bubbles released < 2 o a =) 10 Um 20 234 Time {Minutes} “ Rubric for the mark allocation of the graph A Correct type of graph 1 B Title of graph 2 Cc Correct label for X-axis 1 D Correct label for Y-axis 1 E Correct unit for X-axis 1 F Appropriate scale for X-axis 1 G Appropriate scale for Y-axis 1 H Plotting of points 3 = All points plotted correctly 2 = 3 to 4 points plotted correctly 1= 1 to 2 points plotted correctly | All plotted points joined 1 NOTE: If wrong type of graph drawn: - Marks will be lost for ‘correct type of graph’(A) and ‘plotting of points'(H) and all ‘plotted points joined'(!) - If axes are transposed, marks will ONLY be lost for labelling and units, X-axis(C) and Y- axis (D) (12) Copyright reserved

Biology/HG/P1 3.1.2 3.1.3 3.1.4 3.2 3.2.1 3.2.2 3.2.3 3.3 3.3.1 3.3.2 3.3.3 3.3.4 Copyright reserved Downloaded from hlayiso.com 9 DBE/2013 SCE - Memorandum At both temperatures) “’, with time there is an increase” in the number of bubbles released. However, the number of bubbles released is greater/faster at 35 °Cv Carbon dioxide / CO2 “ lime water v’/ Calcium hydroxide Equal amounts of yeast-glucose solution was used” Time intervals“/The time of the investigation Same quantity of water in beaker and test tube” Temperature Vv (Mark first TWO only) (any 2x 1) (2) (19) A-— vertebral column”/ backbone OR breastbone/ sternum B — breastbone/ sternum~ OR vertebral column/ backbone C - ribY (3) D - exhalation / expiration’ E — inhalation/ inspiration” (2) D - decreases” E - increases” (2) (7) Tissue FluidY (4) (a) BY (1) (b) BY (1) (c) AY (1) X - Carbon dioxide / CO2 V Y — Oxygen / 0.” (2) - bicarbonate ions” - in solution in plasmav/ carbonic acid - carb(amino)haemoglobinY (3) (9) [35]

Biology/HG/P1 QUESTION 4 41 4.1.1 4.1.2 4.13 4.1.4 4.1.5 4.2 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 Copyright reserved Downloaded from hlayiso.com 10 SCE — Memorandum Quadrat method’/ Simple sampling (34+34+6+2+1+2++0+3+2+0)V= 22/10V = 2.2V Total Area = L x B = 90m x 60m = 5 400 m? Total Number =Numbersin x Total area of field Sample Size of quadrat =6v¥x5 400 mv 1mv = 32 400 dandelions Nov Only one reading was taken VV Use more samples vv Use the average of more samples VY (Mark first ONE only) (any 1 x 2) geometric growth V / exponential / J-shaped curve/ Population growth is slow at first’, then increases rapidly ~ Lag phasev / establishment geometric phase / Exponential phase / Log / acceleration” death phase Vv (Mark first TWO only) (any 2x 1) Increase natality”’/ births / immigration / LOW mortality There will be overcrowding” leading to competition” Lack of foodv / iack of space / to grow will also lead to competition Environmental resistance sets in “and the carrying capacity has been reachedY Diseasev as a result of overcrowding “ (Mark first TWO only) (any 2x 2) (3) (4) (2) (11) (2) (1) (4) (10)

Biology/HG/P1 43 4.3.1 4.3.2 4.3.3 4.3.4 Copyright reserved Downloaded from hlayiso.com 1 SCE - Memorandum ProteasesY Amino acidY Babies are unable to produce proteases Vv to digest proteins” (zy (a) (b) (c) (d) 14¥minY Enzyme ZY Took shortest time/ 5 minutes v to pre-digest (i) Protein’ {ii) - Serve as structural components of cell membranesv ¥ - Serve as component of chromosomesv V - Many hormones are proteins, e.g. insulin and thyroxinv ¥ - Some proteins function as antibodiesv “ - Source of reserve energyvY “ (Mark first TWO only) (any 2 x 2) TOTAL SECTION B: 4 INS Q) (1) (2) (1) (4) (14) [35] 105

Downloaded from hlayiso.com Biology/HG/P1 12 SCE — Memorandum SECTION C QUESTION 5 5.1 5.1.1 - contains carbohydrates, protein and fat v v —~ ions “F - Large amount of fibre’ Vv met - low in fatsvv - low in kIV - has many vitaminsY Vv (Mark first ONE only) (any 1 x 2) (2) 5.1.2 - water’ - other vitamins / minerals” (Mark first ONE only) (any 1x 1) (1) 5.1.3 (a) Prevents night blindness VV Formation of rhodopsin Vv Protection of epithelial tissues VV (2) (Mark first ONE only) (any 1 x 2) (b) Absorbs caicium and phosphorus in the small intestine / formation of bone and teethY “ Prevents rickets Vv (2) (Mark first ONE only) (any 1 x 2) 5.1.4 (a) Haemoglobin’ (1) (b) Anaemiav (1) (9) 5.2 5.2.1 To determine the effect of pH” on enzyme activity” OR To determine the effect of saliva on starchy at different pH levelsY (2) 5.2.2 Amylase / ptyalin’ (1) 5.2.3 7.2¥ 1D (1) 5.2.4 it took the shortest time for the reaction to occur VY (2) 5.2.5 pH caused the enzyme to become denatured/ lost its shape/active site destroyed” Change is irreversible / could not be restored” Hence, no change in the result (2) (8) Copyright reserved

Downloaded from hlayiso.com Biology/HG/P1 13 7PBE2013 SCE - Memorandum 5.3 Benefits of photosynthesis Photosynthesis benefits all living organisms by forming energy-rich carbohydrates which are the basic source of j energy for all organisms” tn Maintains the balance of the atmospheric gasesv ks = Releases oxygen which is used by all organisms for cellul S| a respiration’ _ Ways in which the leaves are structured for efficient is wh photosynthesis: - Transparent cuticle and epidermis “allow light” into the mesophyll for photosynthesis - Single layer of epidermis V allows easy penetration of sunlight “ - Palisade mesophyll cells are elongated”in shape / allowing more cells to be arranged at right angles to the upper epidermis and in this way allowing more light v’to be absorbed for photosynthesis - Palisade mesophyll cells are elongated ~ allowing the chloroplast maximum absorption of sunlight / increase surface area. - Palisade mesophyll contains an abundance of chloroplasts” for maximum absorption of light” - Xylem v vessels present to supply water” to the leaf cells for photosynthesis - phloem” present to transport products ~glucose of photosynthesis to other parts of the plant - Spongy mesophyll cells — have an irregular shapev’/ numerous air spaces allows for gaseous exchange” - cell walls of mesophyll are thiny’ to allow for diffusion” of COz and water into the cells - Stomata ~ allows for gaseous exchange” - Leaf is flattened v’to increase the surfacev area for absorption of sunlight - Petiole” / veins hold the leaf in a suitable position “to absorb maximum sunlight (any 6 x 2) Copyright reserved Oy sy: ot JAN

Downloaded from hlayiso.com | Biology/HG/P1 14 ' SCE - Memorandum ‘ Synthesis: | Marks _| Descriptions ~ 3 Well structured - demonstrates insight and understanding of guestion 2 Minor gaps in the logic and flow of the answer 1 Attempted but with significant gaps in the logic and flow of answer 0 Not attempted/nothing written other than question number Factual content Synthesis. TOTAL SECTION C: GRAND TOTAL: Copyright reserved Please turn over (18) (3) (18) [35] 200