Flashcards
B5 - Growth and Development
Flashcards do conjunto (23)
- 1"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.
- 2What are groups of one cell type called?Tissues
- 3What is the main difference between an animal and a plant cell?Plant cells have cell walls.
- 4What is a fertilised egg called?A zygote.
- 5How does an embryo divide?Using mitosis.
- 6What are embryonic stems cells?The cells in the early embryo that can develop into whole individuals because they're unspecialised.
- 7What are the dividing cells that cause the plant to widen called?Meristem cells.
- 8Why do meristems work?Meristem cells are unspecialised so can develop into anything.
- 9What stem cells do adult humans have?Skin cells and blood cells from the bone marrow.
- 10What 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.
- 11Why do gardeners use cuttings?Quick, cheap and produces exactly the same features as the parent plant.
- 12What is phototropism?The bending of growing plant shoots towards the light.
- 13How 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.
- 14How 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.
- 15What is a chromosome?A long molecule of DNA wound around a protein framework.
- 16What is the first stage of mitosis?The chromosome develops an identical copy attached to itself and the membrane around the nucleus breaks down.
- 17What happens at the second stage of mitosis?The chromosomes uncoil and are dragged into the middle by protein fibres.
- 18Describe stage 3 of mitosis.The chromosomes are pulled apart by the protein fibres to opposite ends of the cell.
- 19What is the last stage in mitosis?New nuclear membranes form and chromosomes recoil. The cell then divides.
- 20What is a gamete?Sex cells.
- 21What 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.
- 22What was Watson and Crick's major discovery?That DNA had a double helix structure.
- 23What is base pairing?The bases of a DNA molecule always bond in the same way, A with T, G with C.
Informações
- Descrição
- Cambridge IGCSE Biology FlashCards sobre B5 - Growth and Development, criado por franimal em 13-11-2013.
- Criado por
- franimal
- Visualizações
- 101
- Tags
- Avaliação