Meiosis

Meiosis

Take C-Notes on the Video and the following 4 slides. Pay particular attention to the steps of meiosis, especially what happens in Prophase 1. Make sure you understand what "Crossing Over" is.

Meiosis

Study this picture. Notice how a cell with four chromosomes turns into four different cells, each containing two chromosomes.

Crossing Over

Remember, the steps of Meiosis are similar to the steps to Mitosis. The major differences is that "Crossing Over" of the DNA occurs in Meiosis.

During Prophase 1 and Metaphase 1 of Meiosis, the DNA next to each other can SWITCH chromosomes, making a completely new strand of DNA.

Meiosis results in half the original DNA

Each new sperm or egg cell has a different set of DNA, which is why you are different than your siblings.

Meiosis Practice Problems

Use your notes to answer the following questions

Multiple Choice

How many chromosomes does a human somatic (body) cell have?

• 2

• 14

• 23

• 46

Multiple Choice

Why do sexually reproducing organisms need meiosis?

• To double the number of chromosomes in a new organism

• So that gametes have half the number of chromosomes of the organism

• So that offspring are identical

• So that human sperm and egg cells will each have 46 chromosomes.

Multiple Choice

What process, and which types of cells are represented by the diagram?

• Mitosis, somatic cells

• Mitosis, gametes

• Meiosis, somatic cells

• Meiosis, gametes

Multiple Choice

Meiosis makes sperm and egg cells. In humans, sperm and egg cells each have _____ chromosomes. Therefore a fertilized human egg cell (sperm and egg cell combined) would create a cell with _____ chromosomes.

• 23, 46

• 2, 4

• 4, 2

• 46, 23

Multiple Choice

This image shows chromosomes during Prophase 1. Which of the following correctly describes the process shown?

• segregation of sister chromatids

• mutation in which the DNA content of the gene is altered

• condensation and segregation of alleles

• crossing - over in which alleles are exchanged

How Are Sperm And Egg Cells Made?

Type up your notes into the "How Are Sperm And Egg Cells Made" C-Notes in your INB