Cell Division and Reproduction : Cell Division and Reproduction Slide 2: Objectives Explain how cells produce more cells.
Explain the difference between mitosis and meiosis. Slide 3: Asexual Reproduction In asexual reproduction, only one parent cell is needed. The structures inside the cell are copied, and then the parent cell divides, making two exact copies.
This type of cell reproduction is called mitosis. Most of the cells in your body and most single-celled organisms reproduce this way. Slide 4: The Life of a Cell The cell cycle begins when the cell is formed and ends when the cell divides and forms new cells.
Before a cell divides, it must make a copy of its DNA which is organized into structures called chromosomes. Slide 5: Making More Prokaryotic Cells
Cell division in bacteria is called binary fission, which means “splitting into two parts.”
Bacteria have a single circular DNA molecule (chromosome). Binary fission results in two cells that each contain one copy of the circle of DNA. Slide 6: Copyright © by Holt, Rinehart and Winston. All rights reserved. Eukaryotic Cells and Their DNA
The chromosomes of eukaryotic cells contain more DNA than those of prokaryotic cells.
In a eukaryotic cell, chromosomes are found in the nucleus and are made of DNA and protein.
Pairs of similar chromosomes are called homologous chromosomes. Slide 7: Making More Eukaryotic Cells
The cell cycle has three stages:
Interphase: The cell grows and copies its chromosomes. The two copies are now called chromatids.
Mitosis: The chromatids separate.
The cell splits into two identical cells. Slide 8: Mitosis Video Clip of Mitosis : Video Clip of Mitosis The clip can be found in the folder. Slide 10: Sexual Reproduction In sexual reproduction, two parent cells (sex cells) join together to form offspring that are different from both parents.
Chromosomes that carry the same sets of genes are called homologous chromosomes.
Each sex cell has only one of the chromosomes from the homologous pair. Slide 11: Meiosis
Process in which sex cells are made.
Meiosis is a copying process that produces cells with half the usual number of chromosomes. Video of meiosis : To watch the clip go to the folder and click on the meiosis video. Video of meiosis Slide 13: Meiosis Making sex cells - gametes
During meiosis, chromosomes are copied once, and then the nucleus divides twice.
The resulting sex cells (sperm and eggs) have half the number of chromosomes of a normal body cell. Slide 16: The following slide shows what happens to a pair of homologous chromosomes during meiosis and fertilization. Slide 18: Sex Chromosomes carry genes that determine sex.
Human females have two X chromosomes.
Human males have one X chromosome and one Y chromosome. Slide 19: Mitosis: Making more body cells
Human Cells contain 46 chromosomes (23 Pairs)
One division of the nucleus Meiosis: Making sex cellsHuman sex cells have 23 chromosomes (1 from each pair)Two divisions of the nucleus : Meiosis: Making sex cellsHuman sex cells have 23 chromosomes (1 from each pair)Two divisions of the nucleus Video comparing mitosis and meiosis : Video comparing mitosis and meiosis Watch the comparing mitosis and meiosis video .