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3 Cards in this Set
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- Back
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What is the site of nutrient transfer between a mother and a foetus called? |
Placenta. The placenta is where the baby’s and mother’s blood pass very close to each other (although they do not mix) and vital nutrients (glucose, oxygen etc.) diffuse from the mother’s blood into the baby’s blood. Waste products such as carbon dioxide and urea also pass back from the baby’s blood into the mother's blood. |
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How many chromosomes does a gamete have in relation to a "normal" parent cell? |
Half. During sexual reproduction, both parents must create a sex cell (gamete), which contains half of their DNA. Then one gamete from each parent must meet and fuse together in a process called "fertilisation". This can happen internally inside the female (e.g. in humans) or externally (e.g. in frogs). The fertilised egg is known as a "zygote" and this undergoes cell division to become an "embryo". Once the embryo develops further and becomes recognisable as a particular species, it is known as a "foetus". |
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How often is an egg released from the ovaries? |
Half a month. The ovaries produce the female gametes called "ova". Once a month, an egg is released from an ovary and slowly travels down the oviduct. During sexual intercourse sperm are deposited in the vagina and they swim up through the cervix, though the uterus and along the oviduct, where they are most likely to encounter an ovum. |
