The Cell Cycle What are your cells doing

The Cell Cycle

What are your cells doing right now? • Your body is made of trillions of cells • At any given point approximately 1 million of your cells are dividing. • The rest of your cells are growing or just carrying out their functions Your cells Their functions Red blood cells Carry oxygen White blood cells Fight infection by killing intruders (viruses and bacteria) Muscle cells Contract and relax Intestine cells Absorption of nutrients

Cell Cycle

Cell Cycle

Cell Cycle

Cell Cycle

Phase Interphase Prophase What happens in this phase? -Working and growing -Cell duplicates all organelles -Cell duplicates DNA to forms two identical pairs called sister chromatids

Phase Interphase Prophase What happens in this phase? -Working and growing -Cell duplicates all organelles -Cell duplicates DNA to forms two identical pairs called sister chromatids - First stage of mitosis (Cell Division) - Sister chromatids bunch together - sister chromatids join near the center to form an “x” shape (each side of the x is a sister chromatid) - Nuclear membrane starts to break down - Centrioles move to opposite ends of the cell - Spindles (fibres) grow from the centrioles towards the chromatids

Phase Metaphase Anaphase What happens in this phase? - The sister chromatids line up along the center of the cell - Each spindle connects to one of the sister chromatids

Phase Metaphase Anaphase What happens in this phase? - The sister chromatids line up along the center of the cell - Each spindle connects to one of the sister chromatids - - Sister chromatids are pulled apart by the spindles - Each one of the sister chromatids is pulled to each side of the cell - cleavage furrow forms (the cell membrane is pinching into two cells) Chromatids are called chromosomes after this point

Phase Telophase Cytokinesis What happens in this phase? - The new chromosomes have reached the opposite ends of the cell - 2 nuclear membranes form - The chromosomes unravel - The spindle disappears - nucleolus reforms

Phase Telophase Cytokinesis What happens in this phase? - The new chromosomes have reached the opposite ends of the cell - 2 nuclear membranes form - The chromosomes unravel - The spindle disappears - nucleolus reforms - Divides the cytoplasm and organelles - once the cytoplasm is divided the cell pinches in tow You now have two daughter cells