Cell division How one cell becomes two Mitosis

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Cell division How one cell becomes two

Cell division How one cell becomes two

Mitosis + Cytokinesis = Cell division • Most cells in all eukaryotic organisms will

Mitosis + Cytokinesis = Cell division • Most cells in all eukaryotic organisms will divide many times throughout the life of the organism – ________ is the process by which a cell duplicates its genetic materials (chromosomes and prepares for cell division – ________ is the division of the rest of the cell into two separate but identical daughter cells – ___________________________________________ • In animals, cell division occurs during embryonic development, growth, and wound healing • Errors during cell division cause cell death or cancer

Mitosis reorganizes DNA in the cell • ______________________________________ • During mitosis, the two copies

Mitosis reorganizes DNA in the cell • ______________________________________ • During mitosis, the two copies are reorganized, repackaged into two sets of chromosomes, and divided to opposite ends of the cell • In most organisms, ______________________________________ _(the cell body dividing in two) • The original cell (mother cell) is identical to the two resulting cells (daughter cells)

Mitosis vocabulary • • • Nucleus – location of DNA inside the cell Nuclear

Mitosis vocabulary • • • Nucleus – location of DNA inside the cell Nuclear envelope – the membrane that separates the nucleus from the cytoplasm DNA – an incredibly long molecule that contains genetic blue prints for cell behavior Chromatin – a loosely bundled coil of DNA. Most of the time, DNA is organized in this form, “ a loose rope” Histones – proteins which hold a DNA strand together in the form of chromatin Chromosome – a highly organized form of chromatin, “a tightly wrapped and carefully knotted rope ” – – • • Each chromosome is composed of two identical parts called chromatids Chromatids: two halves of a chromosome which contain the same genetic information DNA exists in the form of chromosomes only during mitosis Each chromosome looks like an X Centromere – a bundle of proteins which connects the two chromatids of a chromosome, the “knot at the center of the X“ Microtubules – part of a cell’s cytoskeleton. These are tubes of protein which use to pull chromosomes apart and to opposite ends of a cell during mitosis. They are powered by ATP! Mitotic spindle – How microtubules are organized during mitosis. This is a collection of microtubule fibers which is formed to coordinate the pulling of apart of chromosomes. Metaphase plate – the line along which chromosomes are lined up during mitosis. This arrangement is coordinated by the mitotic spindle.

Chromosome Structure

Chromosome Structure

5 Phases of Mitosis • Mitosis is composed of five phases – – –

5 Phases of Mitosis • Mitosis is composed of five phases – – – ___________________ __________ • During each phase, different proteins in the cell perform specific roles to divide the two copies of genetic material • _________________________________________

Prophase • ________________________ into chromosomes inside the nucleus • Microtubules are organized into ___________

Prophase • ________________________ into chromosomes inside the nucleus • Microtubules are organized into ___________ in the cytoplasm • Nuclear envelope is dissolving • By the end of prophase – Chromosomes and mitotic spindle are fully organized – Nuclear envelope has disappeared

Prometaphase • Chromosomes move towards each other and into the center of the cell

Prometaphase • Chromosomes move towards each other and into the center of the cell • Microtubules move into the nuclear region and begin to connect to chromosomes • ____________________

Metaphase • The mitotic spindle is fully organized, and has pulling the chromosomes to

Metaphase • The mitotic spindle is fully organized, and has pulling the chromosomes to the center of the cell • The spindle aligns chromosomes so that each centromere is lined up along the metaphase plate (the center of the cell)

Anaphase • _______________________ • Microtubule fibers contract (__________), pulling chromatids to opposite ends of

Anaphase • _______________________ • Microtubule fibers contract (__________), pulling chromatids to opposite ends of the cell towards the two spindles

Telophase • _________________________ • New nuclear envelopes begin to form around the chromatin to

Telophase • _________________________ • New nuclear envelopes begin to form around the chromatin to create two nuclei • Spindle fibers disperse into the cytoplasm • The cell membrane begins to cleave in preparation for cytokinesis

Cytokinesis • The cell membrane is being pinched off to form two separate compartments

Cytokinesis • The cell membrane is being pinched off to form two separate compartments • Cytoplasm and organelles are being divided between the two forming cells • __________________________________ • Cell division is complete!

Cell division movies • http: //www. youtube. com/watch? v=Vl. N 7 K 19 QB

Cell division movies • http: //www. youtube. com/watch? v=Vl. N 7 K 19 QB 0 • http: //www. youtube. com/watch? v=Cz. PGh Yi. Gy. Z 8&feature=related • Embryonic division in the worm c. elegans: http: //www. youtube. com/watch? v=zsg. Ol 04 PESI&NR=1 • http: //www. cellsalive. com/mitosis. htm