The processes that make new cells! Mitosis and Meiosis The processes that make new cells!

DNA DNA – blueprint for life, determines how the living thing will look and behave

Chromosomes The chromosomes hold and organize the DNA in living cells Each human cell has 46 chromosomes in the nucleus

What is Mitosis? Nucleus divides The process that makes more cells in our body

Why Mitosis? Growth Replace dead cells Repair damaged cells

Facts About Mitosis Mitosis is asexual reproduction Each new cell is completely identical to the parent cell (clones)

Facts About Mitosis (cont.) Each new cell has a full set of DNA (46 chromosomes in humans) As a result of mitosis, the parent cell splits into two identical daughter cells Occurs in all body cells (heart, lung, skin, etc)

Cytokinesis The process where the cell actually splits in two

What is Meiosis? The process that makes egg and sperm cells

Gametes Cells with half the usual number of chromosomes Eggs in females, sperm in males

Facts About Meiosis Sexual reproduction Makes 4 unique daughter cells (gametes) Each new cell has half the number of chromosomes (23 in humans) Occurs only in the reproductive organs Goes through PMAT twice!

Crossing Over When making gametes, chromosome pairs “swap parts” This ensures each egg and sperm cell is unique

Fertilization Occurs AFTER meiosis! NOT THE SAME AS MEIOSIS!

Fertilization When sperm and egg cells combine to create one new offspring 23 chromosomes (egg) + 23 chromosomes (sperm) = 46 chromosomes (new human)

Haploid vs Diploid Cells Diploid (2n) – Any cell with a full set of DNA Made by mitosis Body cells Haploid (1n) – Any cell with half a set of DNA Made by meiosis Egg and sperm cells