Biology

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Biology textbook- pg. 80
3) Distinguish between the autotrophic and heterotrophic nature of plants and animals. Animals have heterotrophic cells; hence, they live off nutrients of other species by eating. Most plants have autotrophic cells, which allow them to generate their own food with photosynthesis. 4) Explain the following statement: ‘All living things depend on plants’. As animals are heterotrophs, they need to eat other species to survive. If mammals only depended on other mammals, there would be no animal with nutrients. Only plants have self-feeding systems which is similar to ‘free food’ to the animals. 5) Write out the word equation that summarises the process of photosynthesis. Water + Carbon Dioxide –(with the presence of chlorophyll, starch and sunlight)-> glucose and oxygen. 6) Compare aquatic and terrestrial plants in relation to the site of water and mineral uptake. In an aquatic environment, water and minerals can be absorbed across the whole surface of the plant. In most terrestrial plants, water and minerals are obtained through root systems, which also anchor the plants in the soil. Plants root need a large surface area over which absorption can occur. They achieve this by having a branching structure, and root hairs just behind the root tips. 7) Explain how the structure of typical leaves and the distribution of specialised tissue within them are adaptations to photosynthesis. Use clearly labelled diagrams in your answers.

Water, air and glucose must move around the leave for it to photosynthesise. The water is transported through the xylem while the glucose is transported through the phloem. The epidermis allows the sunlight to readily penetrate through the leave for photosynthesis.

8) Explain the difference between mechanical and chemical digestion. Mechanical digestion is the actual physical break down of food into smaller pieces; for example, using teeth to grind food into smaller bits for it to go down throats. Chemical...
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