CELL DIVISION

What are the two types of cell division?

Mitosis (body cells) and meiosis (sex cells)

What is the purpose of mitosis?

Growth, repair, and to make identical body cells

What is the purpose of meiosis?

To make gametes (sperm and egg) with half the number of chromosomes

What is the result of mitosis?

2 genetically identical diploid cells

What is the result of meiosis?

4 genetically different haploid cells

What is a diploid cell?

A cell with a full set of chromosomes (46 in humans)

What is a haploid cell?

A cell with half the number of chromosomes (23 in humans)

What types of cells are made by mitosis?

Body cells (somatic cells)

What types of cells are made by meiosis?

Gametes (sex cells: sperm and egg)

Why is meiosis important for sexual reproduction?

It ensures the offspring get half their DNA from each parent

What is crossing over and when does it happen?

It’s the exchange of DNA between chromosomes in meiosis; it increases genetic variation (Prophase I)

What is asexual reproduction?

Reproduction involving one parent, making identical offspring

What is sexual reproduction?

Reproduction involving two parents, making genetically unique offspring

What is cancer?

Uncontrolled cell division (mitosis that doesn’t stop)

What is interphase?

The phase before division when the cell grows and copies its DNA

What are the stages of mitosis (in order)?

Prophase, Metaphase, Anaphase, Telophase (PMAT)

What happens in prophase?

DNA condenses into chromosomes; nuclear membrane breaks down

What happens in metaphase?

Chromosomes line up in the middle of the cell

What happens in anaphase?

Chromosomes are pulled apart to opposite ends

What happens in telophase?

Two new nuclei form; cell starts to split

What is cytokinesis?

The final split into two separate cells after mitosis

How many chromosomes do human body cells have?

46 chromosomes

How many chromosomes do human gametes have?

23 chromosomes

What is a zygote?

A fertilized egg (sperm + egg = zygote, 46 chromosomes)

What process makes a zygote divide into more cells?

Mitosis

How does mitosis relate to growth and repair?

It makes new identical cells to replace old or damaged ones

What happens in Meiosis II (PMAT II)?

Chromatids separate just like in mitosis, but from haploid cells, forming 4 unique gametes