Chapter 4 Section 3 Mitosis

The Cell Cycle Your body produces millions of cells in order for you to grow and to replace cells that have died Your body produces millions of cells in order for you to grow and to replace cells that have died Ex. Stomach lining is replaced every few days Ex. Stomach lining is replaced every few days

The Life of a Cell Cell Cycle Cell Cycle The life cycle of a cell The life cycle of a cell Begins when the cell is formed and ends when the cell divides and forms new cells Begins when the cell is formed and ends when the cell divides and forms new cells

It must first make a copy of its DNA It must first make a copy of its DNA DNA contains the information that tells a cell how to make proteins. DNA contains the information that tells a cell how to make proteins. DNA is organized into chromosomes DNA is organized into chromosomes Before a cell divides

Making More Prokaryotic Cells Prokaryotic cells and their DNA are relatively simple Prokaryotic cells and their DNA are relatively simple Bacteria have ribosomes and a single circular molecule of DNA Bacteria have ribosomes and a single circular molecule of DNA Therefore division for bacteria is simple Therefore division for bacteria is simple

Binary Fission Splitting into 2 parts Splitting into 2 parts Each resulting cells contain one copy of the DNA Each resulting cells contain one copy of the DNA

Binary Fission

Eukaryotic Cells and Their DNA Larger and more complex than prokaryotic cells Larger and more complex than prokaryotic cells Because of this, eukaryotic cells have MORE DNA Because of this, eukaryotic cells have MORE DNA Chromosomes contain DNA and Proteins Chromosomes contain DNA and Proteins

Eukaryotic Cells Number of chromosomes differs from one kind of organism to the next Number of chromosomes differs from one kind of organism to the next Number has nothing to do with the complexity of the organism Number has nothing to do with the complexity of the organism

Fruit Fly- 8 chromosomes Fruit Fly- 8 chromosomes Potato- 48 chromosomes Potato- 48 chromosomes Humans- 46 chromosomes Humans- 46 chromosomes

Homologous Chromosomes Chromosomes with matching information Chromosomes with matching information Pairs Pairs

Making More Eukaryotic Cells 3 main stages of cell cycle 3 main stages of cell cycle Stage 1 or Interphase - cell grows and copies its organelles and chromosomes, DNA and protein strands are loosely coiled pieces of thread Stage 1 or Interphase - cell grows and copies its organelles and chromosomes, DNA and protein strands are loosely coiled pieces of thread

Interphase continued After the chromosomes are duplicated, the two copies are called CHROMOTIDS which are held together at a region called a CENTROMERE After the chromosomes are duplicated, the two copies are called CHROMOTIDS which are held together at a region called a CENTROMERE Chromatids coil and condense into an X shape Chromatids coil and condense into an X shape

Mitosis, Stage 2 Chromatids separate Chromatids separate Mitosis – process of chromosome separation Mitosis – process of chromosome separation Two new nuclei are made Two new nuclei are made Each new cell receives a copy of each chromosome Each new cell receives a copy of each chromosome

Stage 3 of Cell Cycle Cytokinesis Cytokinesis The cell divides and produces 2 new cells that are identical to the original cell The cell divides and produces 2 new cells that are identical to the original cell