Chromosomes and Meiosis Vocabulary Biology 12

Hahahah…

What is meiosis? A special type of cell division. Only occurs in sex cells reproductive organs (humans: ovaries/testes) Produces sex cells (egg and sperm) Reduces the number of chromosomes in the nucleus (reduction division)

Chromosomes: All body cells (except egg and sperm) contain pairs of chromosomes called homologous chromosomes or homologues One member of each pair originally come from each parent (egg and sperm) Homologues contain DNA that codes for the same genes

Number of chromosomes: Diploid organism: two sets of chromosomes ( one from each parent) 2n Somatic cells Haploid organism: one set of chromosomes n Sex cells

What is the diploid number of corn? The haploid number of a chimp?

How many PAIRS of chromosomes do humans have?

Is the chromosome number related to the complexity of the organism?

Humans: Diploid =46 Haploid = 23 Zygote (fertilized egg) = 2n = 46 Female gamete = egg = n = 23 Male gamete = sperm = n = 23 Zygote (fertilized egg) = 2n = 46

Use your textbook to find definitions for the following meiosis vocabulary: Page 103-107, glossary and index will be helpful  Include an example and/or a diagram if appropriate Tetrad Zygote Gametes Fertilization Meiosis Synapsis Somatic cell Diploid haploid