Mitosis (cell division)
Eukaryotes Cells that have a nucleus and membrane-bound organelles, like… Mitochondria Ribosomes ER Golgi Apparatus
Nucleus Nucleus= Boss of the cell Contains DNA= the code of life
All living things contain cells Cells die and sometimes we need to make more. (We grow, get hurt, fight diseases, etc.) Cells are specialized to perform different functions Hearts are made of… Surprise! Heart cells
Mitosis The process by which the nucleus of a cell is divided into two new ones! Each daughter cell ends up with the same number and kinds of chromosomes as the parent cell!
Cytokinesis Division of the cytoplasm (after mitosis!)
DNA Deoxyribonucleic acid During mitosis, DNA gets reorganized from messy, spaghetti-like CHROMATIN into organized, neat CHROMOSOMES! Humans have 46 chromosomes (23 from your mom, 23 from your dad)
Chromosome number Just the way the DNA is packaged! How many do certain organisms have?? Amoeba= 50 Cat = 32 Goldfish =94 Earthworm= 36 Human = 46
Chromosomes Chromosomes are made up of material called chromatin Chromatin= DNA and protein coils Protein= spool DNA= Thread
Relaxed chromatin Neat & tidy chromosome
Chromosome structure After DNA replication the chromosomes become visible by condensing. This is the beginning of mitosis Chromosomes= 2 sister chromatids and a centromere holding them together (see next page!)
Chromosome
Cell Cycle= interphase and mitosis Interphase= the “ getting ready ” period between cell divisions. Contains G1, S, and G2 G1= Gap one phase. Cell grows to be able to divide. S Phase= DNA synthesis G2= Gap two phase. More growth! Specifically, the growth of new cell organelles and materials required for cell division
Mitosis Basic Cell Reproduction
Mitosis C entrioles in animal cells help in lining up the chromosomes and forming the spindle, (which is made of cytoskeleton microtubules)
Mitosis 4 stages: Prophase Metaphase Anaphase Telophase PMAT!
Prophase Centrioles move to opposite sides of cell Spindle starts to form The nuclear envelope breaks down Chromatin condenses into chromosomes
Metaphase Meta=middle The chromosomes line up in the middle of the cell Spindle continues to form and connects to each chromosome
Anaphase The centromeres that join the two chromatids split and they start to pull apart from each other
Telophase Chromosomes unwind to form chromatin Nuclear envelope reappears Cytoplasm begins to pinch apart Spindle breaks down See how it ’ s kind of the opposite of Prophase??
Cytokinesis After mitosis (nuclear division) the cytoplasm of the cell divides A cell membrane forms, separating the two new cells
Mitosis Basic Cell Reproduction
Let ’ s look at that again…
Early Prophase
Late Prophase
Early Metaphase
Late Metaphase
Anaphase
Telophase