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6 Cards in this Set
- Front
- Back
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Define sexual reproduction |
A process involving the fusion of two gametes (sex cells) to form a zygote and the production of offspring that are genetically different from each other |
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Define fertilisation |
The fusion of gamete nuclei |
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Diploid |
Somatic cells (normal body cells) the chromosomes are present in the nucleus in pairs Humans have 46 chromosomes (23 pairs)- this is known as the diploid number
During fertilisation (when the nuclei of each sex cell fuse) a zygote is formed. It gains the chromosomes from both gametes, so it is a diploid cell
Nucleus of a zygote is diploid
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Haploid |
When gametes are formed, the number of chromosomes in the nucleus of each sex cell is halved This is the haploid number |
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Advantages of Sexual Reproduction |
Variation in the offspring, adaptation to a changing or new environment is likely, enabling survival New varieties can be created which may have resistance to disease In plants, seeds are produced, which allow dispersal from the parent plant, reducing competition |
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Disadvantages of sexual reproduction |
Two parents usually needed (not always, some plants can elf pollinate) Growth of new plant to maturity from a seed is slow |
