“Cell division is part of the cell cycle” Section 3.2 & 3.3
“Cell division is part of the cell
cycle”Section 3.2 & 3.3
Smart Notebook
Do Now
• Label the following diagram
• 1- chromosome
• 2- chromatid
• 3- centromere
Do Now
• Through a light microscope, what parts of the cell would you look at to determine what stage of mitosis the cell is in?
Objectives
• Describe the main events of the cell cycle
• Differentiate interphase from mitosis
• Construct a cell cycle model from paper plates.
Cell Cycle• “normal sequence of development and division of a cell”
• Two main phases: Interphase & M-phase (Mitosis)
Interphase• There is no division in interphase, just growth.
G1: organelles duplicate, cell grows
S: DNA replicates (is copied)
G2: cell grows, prepares to divide
M-phase (Mitosis)• Mitosis= “nuclear division”
• PMAT+ C
• Prophase
• Metaphase
• Anaphase
• Telophase
• Cyokinesis
Mitosis• Creates 2 genetically IDENTICAL daughter cells.
Prophase• DNA condenses to form chromosomes.
• Each chromosome has 2 chromatids and a centromere
• The nuclear membrane disappears
Metaphase – “Middle”
• Chromosomes line up in the middle of the cell at the “equator”
Anaphase – “away”• Chromatids split
• Spindles pull to opposite sides of the cell AWAY from each other
Telophase• 2 nuclei form
• Nuclear membrane forms around each group of chromosomes.
• The chromosomes become chromatin again.
Cytokinesis
• Division of the cytoplasm.
• Occurs differently in plant and animal cells.
• 2 new daughter cells!
Cytokinesis
• Animal Cells:
• Membrane pinches together and forms a cleavage furrow until the cells separate.
Cytokinesis
• Plant Cells:
• Cell plate forms which becomes the cell wall and divides the two cells.
Section 3.3
• Eukaryotic cells divide by mitosis and cytokinesis.
• Ex: skin cells apart of skin tissue (aren’t independent)
• Most unicellular organisms use cell division to reproduce through asexual reproduction.
• Asexual Reproduction: one organisms produces one or more new organisms that are identical to itself and that live independently of it
“Both sexual and asexual reproduction involve cell division”
Binary Fission
• A form of asexual reproduction occurring in prokaryotes.
• The parent organism splits in two, creating two independent daughter cells.
• Genetically all the same!
Budding - Organism develops tiny buds on its body.
• Genetic material the same!
• Can bud anywhere OR specialized cells in certain parts of the body.
• Detaches when it reaches a certain size
• Both unicellular and multicellular can reproduce by budding.
Hydra
Regeneration
The process of new tissue growth at sites with
wounds or lost limbs.
Bacteria
Many bacteria have a very short generation time.
Some can have a new generation of cells in less than 30 min.