Biology- Genes and Variation

Question	Answer
How many chromosomes do sex cells (sperm and egg) have? Why is this?	Sex cells have 23 single chromosomes. This is so that when they fuse together to create a zygote it creates 23 pairs of chromosomes or 46 individual chromosomes.
True or false: genes are found in different places on different chromosomes?	False: Genes are found on the same place on each chromosome.
What are alleles?	Different versions or variations of the same gene.
Why do children only resemble their parents, not look identical to them?	Because half of the chromosomes come from each so they will look identical to neither as they do not have an identical genotype.
What happens to the chromosomes as the sex cells fuse?	Each of the 23 pairs separates. This means that around 8 million different combinations can be created.
Why are siblings never identical?	Because the man releases many millions of sperm, meaning there are many different alleles so it is almost impossible for siblings to be identical unless they are identical twins.

Resource summary

	Created by Laura Perry over 10 years ago