In what body organs does meiosis occur?
How many chromosomes are there in each of the specialized sex cells (sperm or egg)?
What is the difference between homologous and non homologous pairs of chromosomes?
What is an allele of a gene?
How many chromosomes are there in each of the specialized sex cells (sperm or egg)?
What is the difference between homologous and non homologous pairs of chromosomes?
What is an allele of a gene?
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Meiosis occurs only in the gonads, so the ovaries in females and testes in males. 2 total, but one per person.
23 chromosomes are in each specialized sex cell (Meiosis separates homologs, and leaves half as many chromosomes as a normal autosome).
Homologous chromosomes share analogous genes. When a sperm and egg fuse, they each contribute 23 chromosomes to make a cell with 46 chromosomes total. Each chromosome has a homolog, a partner if you want to think of it that way, from the other sex cell. You probably heard in your bio class that we have two alleles for a certain trait. These two alleles are on your pairs of homologous chromosomes. Non homologous pairs are just any two random chromosomes that don't share the same alleles.
An allele of a gene is most simply put a version of that gene. You have two alleles for each gene, one from your mom and one from your dad. If you say that for the cystic fibrosis gene you got one dominant allele from your mom and one recessive allele from your dad, you have two different versions (on two different chromosomes that are homologous as explained before), and because you have at least one dominant allele, you don't have cystic fibrosis.
23 chromosomes are in each specialized sex cell (Meiosis separates homologs, and leaves half as many chromosomes as a normal autosome).
Homologous chromosomes share analogous genes. When a sperm and egg fuse, they each contribute 23 chromosomes to make a cell with 46 chromosomes total. Each chromosome has a homolog, a partner if you want to think of it that way, from the other sex cell. You probably heard in your bio class that we have two alleles for a certain trait. These two alleles are on your pairs of homologous chromosomes. Non homologous pairs are just any two random chromosomes that don't share the same alleles.
An allele of a gene is most simply put a version of that gene. You have two alleles for each gene, one from your mom and one from your dad. If you say that for the cystic fibrosis gene you got one dominant allele from your mom and one recessive allele from your dad, you have two different versions (on two different chromosomes that are homologous as explained before), and because you have at least one dominant allele, you don't have cystic fibrosis.