Cell DivisionCell Cycle Cells Make New Cells Hey

Cell Division/Cell Cycle Cells Make New Cells Hey teacher, I keep counting, but that’s not the answer I come up with…

TEAM QUESTION 1: What are the stages that people go through during their life, starting with infancy (newborn) and ending in their elderly years (old age)?

Cells undergo life cycles too. It is called a CELL cycle. UNLIKE the life cycle, it begins again when the cell divides.

MITOSIS Skin Blood Muscle Mother Cell Daughter Cells A cell makes EXACT replicas or copies of itself.

MEIOSIS ENTIRE organism reproduces. FOUR cells NOT two.

Two types of cell division Mitosis Happens in all body cells Produces 2 cells that are identical to the parent cell

Cell Division Overview Process cells go through in order to make new cells The cell cycle has 3 parts 1. Interphase 2. Mitosis/Meiosis 3. Cytokinesis Cell Animation

Interphase is where the cell spends most of its life. During this stage the cell is performing its normal functions and is not dividing. It is growing and getting prepared to divide

Interphase has 3 stages 1. G 1 –Cell doubles in size and organelles get larger or duplicate 2. Synthesis –DNA replicates (makes a copy) 3. G 2 –Cell double checks to make sure it is ready to divide

Mitosis –Making an exact copy Mitosis is where the nucleus divides into two. Happens in body cells (skin, liver, stomach etc. ) Creates cells with the same number of chromosomes as original cell (humans=46) Needed for growth and repair of cells Has 4 stages(PMAT)

Mitosis -Prophase Nucleolus disappears Nuclear membrane breaks down and starts to disappear Chromatin (DNA strands) shorten and thicken into chromatids and connect together at the centromere to form chromosomes Spindle Fiber Apparatus (SFA) forms

Mitosis - Metaphase Chromosomes move to the center of the cell and attach to spindle fibers

Mitosis -- Anaphase Chromatids separate and move to opposite side of the cell The spindle fibers pull them apart

Mitosis -- Telophase Animal Cells – cell membrane pinches in and reforms Plant Cells – plate forms in middle of the cell Nuclear membrane reforms Chromosomes uncoil back to chromatin

Meiosis – Making Sex Cells Happens when sperm and egg cell are being formed. A type of cell division that results in ½ the chromosomes needed (humans =23) Goes through 2 divisions, but only makes one copy of DNA (PMAT)

Cytokinesis The cell is completely split. In mitosis 2 cells are formed that are identical (diploid = 46 chromosomes) In meiosis 4 cells are formed that contain half of the DNA (haploid = 23 chromosomes)