Why is the nucleus important to the cell?

Importance of Nucleus

• Controls all of the cell’s function• Contains genetic material- DNA and chromosomes

DNA

• Chemical that contains the information for an organism’s growth and function

• Deoxyribonucleic acid

Chromosomes

• DNA is packed together to make chromosomes

• Humans have 46 chromosomes in each cell

Cell Division

• Growth • Development • Repair

Growth

• Cells need to divide so multicellular organisms can grow.• Adults have about 100 trillion cells

Development

• Cells develop to become specialized to perform particular functions (skin cells, nerve cells, muscle cells…)

Repair

• Cells divide to repair the body (cuts-broken bones)• Cells repair and divide at different rates. Skin cells are

constantly repairing, while brain cells live a long time and don’t divide very often.

Nucleus-Chromosomes-DNA

Steps of Cell Cycle

1. Interphase

2. Prophase

3. Metaphase

4. Anaphase

5. Telophase

6. Cytokinesis

Interphase

• Cell begins to grow• Organelles double• DNA is copied• Cell prepare for mitosis-the division of the nucleus

Prophase

• DNA condenses into chromosomes

• Nuclear membrane begins to disappear

Metaphase

• Chromosomes line up across the center of the cell

Anaphase

• Chromosomes are split and pulled to opposite sides of the nucleus

Telophase

• A new nuclear membrane forms around the separated chromosomes

Cytokinesis

• The division of the cytoplasm

Mitosis

Types of Asexual Reproduction

• Binary Fission-division of prokaryotes• Budding-develop tiny buds that grow into a complete

identical organism• Regeneration-the growth of new cells at a site of lost

body parts