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| Questão | Responda |
| "Every kind of cell in the human body is specialised" - explain. | Different types of cells do different jobs and they can only do that particular job. |
| What are groups of one cell type called? | Tissues |
| What is the main difference between an animal and a plant cell? | Plant cells have cell walls. |
| What is a fertilised egg called? | A zygote. |
| How does an embryo divide? | Using mitosis. |
| What are embryonic stems cells? | The cells in the early embryo that can develop into whole individuals because they're unspecialised. |
| What are the dividing cells that cause the plant to widen called? | Meristem cells. |
| Why do meristems work? | Meristem cells are unspecialised so can develop into anything. |
| What stem cells do adult humans have? | Skin cells and blood cells from the bone marrow. |
| What is rooting powder and what is the active ingredient? | Auxin - it causes new cells at the base of the stem to develop into roots, and so is used in cuttings. |
| Why do gardeners use cuttings? | Quick, cheap and produces exactly the same features as the parent plant. |
| What is phototropism? | The bending of growing plant shoots towards the light. |
| How does phototropism occur? | Auxin is a plant hormone that causes cells to expand. It diffuses away from light and makes the shaded area bend towards the light. |
| How was phototropism proved to be only in the tips? | Darwin put caps that blocked light on different areas of the plant. When the tips were covered, the plant remained upright. |
| What is a chromosome? | A long molecule of DNA wound around a protein framework. |
| What is the first stage of mitosis? | The chromosome develops an identical copy attached to itself and the membrane around the nucleus breaks down. |
| What happens at the second stage of mitosis? | The chromosomes uncoil and are dragged into the middle by protein fibres. |
| Describe stage 3 of mitosis. | The chromosomes are pulled apart by the protein fibres to opposite ends of the cell. |
| What is the last stage in mitosis? | New nuclear membranes form and chromosomes recoil. The cell then divides. |
| What is a gamete? | Sex cells. |
| What is meiosis? | The type of division that splits a normal cell into four sex cells, each with half the amount of chromosomes of the parent. |
| What was Watson and Crick's major discovery? | That DNA had a double helix structure. |
| What is base pairing? | The bases of a DNA molecule always bond in the same way, A with T, G with C. |
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