MEIOSIS AND SEXUAL REPRODUCTION Cell Division Of Sex Cells MEIOSIS AND SEXUAL REPRODUCTION
What Are Sex Cells Sex cells, or gamates, are different from body cells. Body cells produce new tissues. Sex cells produce new organisms!
What Are Sex Cells The male sex cell is a SPERM The female sex cell is an EGG
Sexual Reproduction Sexual Reproduction – two sex cells, usually an egg and a sperm, come together.
Sexual Reproduction Fertilization – the joining of an egg and a sperm, generally from two different organisms of the same species.
After Fertilization When fertilization occurs, a zygote forms!
? Question ? Will the offspring resulting from sexual reproduction be identical to the parents?
How Do Sex cells divide? Sex cells DO NOT divide by mitosis. They divide though another process called meiosis.
Sex cells have HALF the number of chromosomes compared to body cells! Mitosis Meiosis Happens in BODY CELLS. These are called diploid cells because they contain 23 pairs of chromosomes (46 single chromosomes) Happens in SEX CELLS. These are called haploid cells because they contain 23 single chromosomes Sex cells have HALF the number of chromosomes compared to body cells!
What is Diploid What is Haploid Diploid cells (2N) have two complete sets of chromosomes. The body cells of animals are diploid. Haploid cells have one complete set of chromosomes. In animals, gametes (sperm and eggs) are haploid.
What is Meiosis Meiosis uses two cell divisions. Meiosis In A Nutshell
Meiosis Meiosis deals only with sex cells. Each sex cell (sperm or egg) has a chromosome from each parent. Before division, these cells duplicate. Arthur’s sex cell
Meiosis I In Meiosis I, the nucleus divides and produces two new cells. Each new cell has one duplicated chromosome from each similar pair.
Meiosis I
Meiosis I
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Meiosis II In Meiosis II, the nuclei divide and the chromatids separate, producing four cells with half the number of chromosomes of the original nucleus.
Meiosis II
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Meiosis Il
Meiosis Il
Meiosis Il Thanks to Meiosis, Arthur now has 4 sex cells! Yay! Will these sex cells become sperm or eggs? Thanks to Meiosis, Arthur now has 4 sex cells! Yay!
To Simplify Meiosis In A Nutshell
2n Meiosis I n n Meiosis II n n n n