1. 2. 3. 4. bellwork: identify which “phase” the cells are going through and draw that cell
TRANSCRIPT
Standard: (B.6G) recognize the significance of meiosis in sexual
reproduction
Essential Question: What is meiosis and how is it different than
mitosis?
Chromosomes are coiled DNA located in the cell
nucleus.
An organism inherits one chromosome from each
parent.
How many parents do you have?
So you have ____ sets of each chromosome.
2 copies of each chromosome =
homologous chromosomes
A cell that contains 2 sets of homologous chromosomes is said to be diploid.
2N = diploid cell.Because N = number of chromosomes
Sexual reproduction combines DNA from 2
parents.
Gametes are sex cells, also known as the sperm and the
egg.
When each parent forms gametes (egg, sperm) in their
body, they can only have 1 set of chromosomes instead
of 2.
During fertilization, 1 + 1 = 2 sets of chromosomes.
When gametes (sex cells) are formed, there must be a process that separates the two sets of genes so that each gamete ends up with just one set.
Because gametes contain only 1 set of chromosomes they are said to be haploid.
N = haploid N= number of sets of chromosomes in the cell
Meiosis is a process in which the number of
chromosomes per cell is cut in half through the
separation of homologous
chromosomes in a diploid cell.
** Meiosis is how gametes are produced**
Meiosis usually involves two divisions.
By the end of meiosis, the 1 diploid cell that entered meiosis has become four haploid cells.
In male animals, the haploid gametes produced by meiosis are called sperm.
In female animals, the haploid gametes produced by meiosis are called eggs.
Mitosis results in two genetically identical diploid cells. Mitosis is used for growth.
Meiosis results in four genetically different haploid cells.
Meiosis is used for gamete production and increased genetic variation.