(a) To absorb carbon (IV) oxide; (b) to provide moisture to germinating seeds; (c) (i) (Left – right direction ); (ii) Oxygen in the tube is taken up by the seeds for germination; the Carbon (IV Oxide Produced during respiration and the one in the tube reacts with potassium hydroxide pellets; lowering the pressure inside the set-up; the higher pressure from outside the tube forces the dye in the direction shown; 26. (i) Lag phases; Dry mass increases slowly; became in plant has not developed leaves; for photosynthesis hence is depending on stored food; Reflex action Conditioned reflex action Single stimulus to bring about response. Simplest form of behaviouir and is independent of experience Sensory and mother component are the same at all times Repeatal stimulus to bring about response Involves modifications of behaviour and dependent experience . Primary sensory component is repeat by a sensory component bat the motor. Component remains unchanged.
(ii) Expontial phase; Rapid growth /increase in dry mass, leaves developed; photosynthesis taking place leading to accumulation of food and rapid cell division / plant adapted to the environment (iii) Death phase/ senescence; Negative growth/decrease in dry mass as some tissues die after reaching maximum maturity; Fall in photosynthesis activity; toxic wastes poison tissues; (c) (i) When dry mass was first recorded/at germination (ii) Dry mass would decrease first because food is oxidized to produces energy; water and carbon dioxide/utilized in respiration; (d) (i) Harvest every week about five seedlings; dry in oven to a constant dry mass; Calculate the average mass for one seedling and record the results. (ii) Advantage; Dry mass is not affected by environmental conditions while fresh weight is dependent on the amount of water in the plant which fluctuate with environmental factors affecting transpiration rate. 27. a)klinostat/clinostat; b)i)the radicle remains /grow horizontally; ii)rotation of klinostal causes uniform distribution of auxins/ indoleacetic acid; hence uniform growth/clongations (no curvature formed); c)the experiment repeated but with stationary klinostat; d)-(tropism)enable plants to get water-hydrotropism; -chemotropism aids plants in fertilization and nutrients absorption; -thigmotropism enable weak plants to obtain support -phototropism enable plants to obtain light for photosynthesis; -geotropism enables the roots grow down the soil towards the centre of the earth thus providing support to the plant 28. a)graph -axes have to be labelled- ½ [email protected] No axes marking stops there. -scale-should be appropriate and workable- ½ mk @-1mk -plotting [email protected]*RCH* ∗ wrong scale stop marking. -curve-smooth and not extrapolated beyond 3 small squares- ½ [email protected] -identity- ½ mk each-*RCH* Note/ -axes reversed-award only for identity -no origin-award only for one scale/vertical one.
b) i)bamboo; ii)(bamboo)have higher average weigh c) i)average height of maize plant between weeks 14 and 18 constant (at 2.1m); maximum height attained; average weight increased; because there was slight increased in the girth;
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- Fall '12
- Photosynthesis, red blood cells