Farida says that she got her straight hair from her mother only, so her father's genes had nothing…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Farida says that she got her straight hair from her mother only, so her father's genes had nothing to do with it. Explain, using genes, why both parents contribute to each of her traits.
Need a reminder? The key ideaShow
DNA is the information source for making proteins; a gene is a section of DNA for one protein. Enzymes are proteins, and an enzyme can make a growth hormone that decides the height of a plant. Each body cell has two copies of every gene, one from each parent.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The zygote. Farida began as a zygote formed from her father's sperm and her mother's egg.
Step 2. Two copies. So she has two copies of every gene, one from each parent.
Step 3. The trait. Her hair type depends on how both copies act together. The mother's version may be the one that shows, but the father's copy is still there and may pass to her children.
Answer: each parent gave one copy of every gene, so both contribute to each trait, even when only one version shows.
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