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29 Cards in this Set
- Front
- Back
Why is cell division necessary?
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For growth and repair |
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How many cells are produced in mitosis?
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Two identical cells are produced from the original cell |
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What do chromosomes contain?
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What happens in mitosis?
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A copy of each chromosome is made before the cell divides and one of each chromosome goes to each new cell. |
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What are stem cells? |
Unspecialised cells are called stem cells.
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What happens to differentiated cells which cannot divide? |
They are replaced with adult stem cells, such as the ones found in bone marrow. |
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For how long can plant cells differentiate?
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Plant cells can differentiate throughout the life of the plant as it continues to grow. |
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What are actively dividing plant tissues called?
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Meristems |
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By which form of division are cells of offspring produced by asexual reproduction produced by?
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Mitosis from the parent cell |
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How do cells in reproductive organs divide to form gametes?
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They divide by meiosis |
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How many chromosomes from each pair of chromosomes do gametes have? |
Only one chromosome from the original pair |
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Why does sexual reproduction result in variation? |
The gametes from each parent fuse so half the genetic information comes from the mother and half from the father. |
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What happens in meiosis? |
Before each division a copy of each chromosome is made. The cell divides twice to form four gametes. |
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Where are stem cells found?
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In the human embryo and adult bone marrow |
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What do stem cells have the potential to do in science? |
To treat previously incurable diseases. We may be able to grow nerve cells to cure paralysis or whole new organs for people who need them |
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What is a tumour |
A mass of abnormally growing cells . |
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What are benign tumours? |
Tumours that form in one place and do not spread to other tissues |
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What are malignant tumours? |
Tumours that can spread to healthy tissue. Some malignant cells may enter the bloodstream and circulate to other parts of the body, forming secondary tumours. |
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What are carcinogens? |
Cancer causing chemicals, including asbestos and the chemicals found in tobacco smoke. |
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What might ionising radiation do? |
Cause cancer tumours to form |
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What is a tissue? |
A group of cells with a similar structure and function. |
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Give some examples of animal tissues |
Muscular tissue, which can contract to bring about movement. Glandular tissue, to produce substances such as enzymes or hormones. Epithelial tissue, which covers some parts of the body. |
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Give some examples of plant tissue
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Palisade mesophyll, which contains many chloroplasts and can photosynthesise. Spongy mesophyll, which has some chloroplasts, many air spaces between cells and a large SA for diffusion of gasses. Xylem and phloem which transport substances around the plant. |
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What are organs made up of? |
Tissues |
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What is the stomach made up of? |
Glandular tissue, to produce digestive juices. Epithelial tissue, to cover the outside and inside of the stomach. |
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Give some examples of organs in plants |
The leaf, stem and root |
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What are multicellular organisms made up of? |
Organ systems which work together |
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What are organ systems made up of? |
several organs that work together to perform a particular function. |
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What is the digestive system responsible for? |
Changing the food you each from insoluble molecules into soluble molecules and absorbing them into the blood. |