Stomata are usually present on both sides of leaves. Plants make carbohydrates from carbon dioxide and water. They absorb minerals from the soil for the synthesis of essential substances, such as proteins. In the daytime, plants carry out both respiration and photosynthesis.
Thick cuticle on the upper epidermis of leaves is an adaptive feature to prevent rapid water loss. 7. B When the rate of photosynthesis is higher than the rate of respiration, there is a net uptake of carbon dioxide and a net release of oxygen from the plants to its surroundings. . A Under dim light, the rate of photosynthesis would not exceed the rate of respiration. Therefore, option A is the best answer. . A During period X, the concentration of carbon dioxide was higher than 0.
04%. It means that there was a net release of carbon dioxide from the plant. The light was absent during period X, and the plant only carried out respiration. 10.
A If light intensity is a limiting factor for photosynthesis, the increase in light intensity will increase the rate of photosynthesis.However, if light intensity is no longer a limiting factor, the increase in light intensity will not increase the rate of photosynthesis. Short Question Plants carry out photosynthesis in the presence of light.
They use water and 11. Arbor dioxide to produce carbohydrates and release oxygen as a by-product. (3) Animals cannot make organic food substances themselves. They must obtain food substances by eating plants or other animals. Therefore, plants are the direct or indirect energy source of animals. Moreover, animals need to use oxygen released by plants for aerobic respiration. (1) 12. A) phosphorus; (b) large; (c) chlorophyll; (d) membrane 13.
At time O, the tree carries out respiration only and takes up oxygen from its surroundings. It results of the highest oxygen uptake. (1) From time O to noon, light intensity increases gradually, the rate of photosynthesis f the tree is increasing, more and more oxygen is released. (1) The highest oxygen release occurs at noon, because the rate of photosynthesis of the tree reaches the maximum.
From noon to midnight, light intensity gradually decreases, the rate of photosynthesis of the tree is decreasing, less oxygen is released.At m don gnat, the tree carries out respiration only and takes up oxygen trot its (1) Structured Questions 14. (a) (I) This can prevent bacterial and fungal infections that may kill the plant seedlings. (l) (it) The tubes covered with aluminum foil could eliminate the growth f algae, which may use the minerals in the culture solution. Acts as a control. (c) Mineral X may be nitrogen. (1) (b) Tube A Nitrogen is an important component of amino acids, which are the building blocks of proteins. Proteins are known for synthesizing the cell membrane and cell organelles.
They are also necessary for the formation of chlorophyll. Plant deficient in nitrogen usually has small and yellow leaves. Correct labeling: Stomata (it) correct labeling: Guard cells (1) The 15. (a) 0) In herbaceous plants, gas exchange takes place mainly through the stomata of leaves and stems, and the epidermis of roots.
In woody plants, gas exchange takes place mainly through the stomata of leaves, lentils of stems and the epidermis of roots. (c) Plants make their own food by photosynthesis.They carry out photosynthesis in the presence of light. They use water and carbon dioxide to produce carbohydrates and release oxygen as a by-product. 16. Correct title correct labeling of axes correct drawing and labeling of graph (b) (I) At 0000, the concentration of carbon dioxide is the highest. Light intensity is the lowest.
The plant carries out respiration only and releases carbon dioxide to its surroundings. Ii) At 1200, the concentration of carbon dioxide is the lowest. Light intensity at noon is the highest.
The rate of photosynthesis reaches the maximum, which results in the maximum net uptake of carbon dioxide. (iii) At 1800, the concentration of carbon dioxide is 320 pump. Rate of photosynthesis gradually decreases when light intensity decreases in the evening, so the net uptake of dioxide decreases. (c) respiration (1) carbon (d) Two suggested reasons (accept other reasonable answers): – In July, the day length is longer and the night is shorter than that in December. (1)- The light intensity in July is higher than that in member.
Control. B) Tube 1- orange red; Tube 2-purple; Tube 3-yellow (a) Tube 1 acts as a (3) (c) Tube 2 – In the presence of light, the leaf carries out both photosynthesis and respiration. But the rate of photosynthesis is higher than the rate of respiration.
The carbon dioxide level in the tube decreases and thus changes the indicator solution from orange red to purple. (1) Tube 3 -In the absence of light (the tube covered with aluminum foil), the leaf only carries out respiration. The carbon dioxide level in the tube increases and thus changes the indicator solution from orange red to yellow. )
