420 likes | 522 Views
Cells and Growth. When do cells divide?. Replacement Repair Growth. The Cell Cycle. What is it? It is the life cycle of cell. The Cell Cycle. Composed of 2 main division: Interphase Mitosis. Interphase – Resting Stage. Cells carrying on normal activities
E N D
When do cells divide? • Replacement • Repair • Growth
The Cell Cycle What is it? It is the life cycle of cell
The Cell Cycle Composed of 2 main division: Interphase Mitosis
Interphase – Resting Stage • Cells carrying on normal activities • Chromosomes aren’t visible – DNA is in the form of chromatin • Cell metabolism is occurring • Occurs before mitosis
Chromatin vs Chromosomes ? Chromatin – long strands (strings) of DNA Chromosomes – the chromatin strands all condensed (scrunched) together into distinct pieces
G1 Phase • GAP 1 • First growth stage • Cell increases in size • Cell prepares to copy its DNA
Synthesis Phase • Copying (synthesizing)of all of DNA’s instructions • Chromatin duplicated
G2 Phase • GAP 2 • Time between DNA synthesis & mitosis • Cell continues growing • Needed proteins produced
M Phase • Cell growth & protein production stop • Cell’s energy used to make 2 daughter cells • Called mitosis
Stages of Mitosis • Prophase • Metaphase • Anaphase • Telophase
Prophase • Nuclear envelope disappears • Centrioles move to opposite poles • Spindle fibers start to form • Chromosomes condense
Metaphase • Chromosomes line up on the equator of the cell • Spindle fibers attached to the centromeres
Anaphase • Chromosomes split • Spindle fibers pull chromosomes apart
Telophase • Cell divides • Spindle fibers disintegrate • Nuclear envelopes re-form around 2 sets of chromosomes
Cytokinesis • Organelles get divided up into 2 daughter cells • Plant cells--a new cell wall made of cellulose forms between the two cells • Animal cells--fibers pinch the cell in two
Summary of Mitosis • Prophase: • Chromosomes condense • Nuclear envelope disappears • centrioles move to opposite sides of the cell • Spindle forms and attaches to centromeres • Metaphase • Chromosomes line up on equator of spindle
Anaphase • Centromeres divide • Chromosomes pulled to opposite poles by the spindle • Telophase • Chromosomes de-condense • Nuclear envelope reappears • Cytokinesis: the cytoplasm is divided into 2 cells
Mitosis: Can you name the stages? 1 2 3 4 5
Mitosis: Can you name the stages? Prophase 2 3 4 5
Mitosis: Can you name the stages? Prophase Metaphase 3 4 5
Mitosis: Can you name the stages? Prophase Metaphase Anaphase 4 5
Mitosis: Can you name the stages? Prophase Metaphase Anaphase Telophase 5
Mitosis: Can you name the stages? Prophase Metaphase Anaphase Telophase Cytokinesis