2022 GCE O Level Bio Suggested Answer Edited (FPE)

2022 GCE O Level Biology Suggested Answer Paper 1 1 2 3 4 5 6 7 8 9 10 D B D B C B C D A D 11 12 13 14 15 16 17 18 19 20 B B C D D D A C A D 21 22 23 24 25 26 27 28 29 30 B B A C D B D D B A 31 32 33 34 35 36 37 38 39 40 B B D C C A D B A A Paper 2 (Section B) 1 (a) Any 3: - It contains haemoglobin which binds to oxygen and transports it around the body. [1] - It has a circular biconcave shape which increases the surface area to volume ratio to take in and release oxygen at a faster rate. [1] - It does not have a nucleus . This enables the cell to store more haemoglobin for transport of oxygen. [1] - It is flexible to squeeze through tiny capillaries and be transported to body cells. [1] (bi) When this person is walking up a flight of stairs, there will be a higher rate of aerobic respiration to release more energy for increased muscle contractions.[1] This individual with only 91% of oxygen saturation will have insufficient oxygen will be transported to the muscle cells and therefore will have a higher breathing rate.[1] Hence, this person will be breathless and will feel tired easily compared to a healthy person walking up the same flight of stairs.[1] (bii) Blood vessel: pulmonary vein [1] Reason: it is transporting blood from lungs after gaseous exchange/oxygenation.[1] (c) transported to the lungs where it is excreted from the body/ removed during exhalation [1] White blood cells [1] 2 (ai) palisade mesophyll cell [1] (aii) Vacuole [1] (aiii) Nucleus/ribosomes/mitochondrion [1] Questions to note: 15,33,40 Question to note:

(b) As the plant is placed in low light intensity, the chloroplast would move towards the source of light within the cell [1] So that chlorophyll in the chloroplast absorb maximum sunlight [1] for photosynthesis [1] which is essential for plants growth and development (c) Any 3: Both processes do not require energy[1] movement of water and carbon dioxide down the concentration gradient.[1] Movement of water requires the presence of a partially permeable cell membrane while movement of carbon dioxide from the air into the leaf does not require a membrane [1] The movement of water into a cell is via osmosis while the movement of carbon dioxide into the cell is via diffusion. [1] 3 (a) Long filament [1] Pendulous and protrude out of the flower [1] (bi) Carbon, hydrogen and oxygen [1] (bii) White flour has a lower mass of indigestible carbohydrates/ protein/ fat in 100g of flour as compared to brown flour.[1] (with data) [1] White flour has a higher mass of digestible flour in 100g of flour as compared to brown flour.[1] (with data) [1] (biii) Add 2 cm3 of biuret solution to 2cm3 of flour. Shake well and allow the mixture to stand for 5 minutes. [1] When the blue biuret solution turns violet, proteins are present.[1] (c) When the vili decreases in size and number, it reduces its the surface area to volume ratio [1]. This will