The Cell Cycle Interphase, Mitosis,and Cytokinesis

The Cell Cycle Cell Theory: all cells come from pre- existing cells Cell Theory: all cells come from pre- existing cells Prokaryotes: Divide by binary fission Prokaryotes: Divide by binary fission Eukaryotes: Divide by mitosis or meiosis Eukaryotes: Divide by mitosis or meiosis Mitosis: Replication of somatic cells (body cells) Mitosis: Replication of somatic cells (body cells) Meiosis: Division of germ cells (sex cells) Meiosis: Division of germ cells (sex cells)

The Cell Cycle Interphase Interphase Normal cell functions and preparation for division Normal cell functions and preparation for division Mitosis Mitosis Separation of chromosomes Separation of chromosomes Cytokinesis Cytokinesis Division of cytoplasm and cell membrane Division of cytoplasm and cell membrane

The Cell Cycle

G 1 : First Growth Phase G stands for Gap G stands for Gap Normal cell function such as metabolism, protein synthesis, and growth Normal cell function such as metabolism, protein synthesis, and growth Typically represents the majority of cell cycle Typically represents the majority of cell cycle Chromosomes are not replicated Chromosomes are not replicated G 0 : resting phase, no growth or division. G 0 : resting phase, no growth or division.

S: Synthesis Phase Relatively short period of time Relatively short period of time DNA chromosomes are replicated within the nucleus DNA chromosomes are replicated within the nucleus Chromosomes are uncondensed and not clearly visible Chromosomes are uncondensed and not clearly visible Replicated pairs of chromosomes are connected at DNA region called centromere Replicated pairs of chromosomes are connected at DNA region called centromere

Sister Chromatids Two identical DNA molecules Two identical DNA molecules Attached together at the DNA sequence called centromere Attached together at the DNA sequence called centromere

G2: Second Growth Phase G stands for Gap G stands for Gap Normal cell function and cell growth continue Normal cell function and cell growth continue Organelles replicate in final preparation to cell division Organelles replicate in final preparation to cell division

Mitosis Division of cell nucleus into two nuclei Division of cell nucleus into two nuclei 4 phases 4 phases Prophase Prophase Metaphase Metaphase Anaphase Anaphase Telophase Telophase

Mitosis

Prophase Chromatin condenses into well defined chromosomes Chromatin condenses into well defined chromosomes Nuclear envelope dissolves Nuclear envelope dissolves Replicated centrioles separate across cell Replicated centrioles separate across cell Spindle apparatus forms Spindle apparatus forms

Spindle Apparatus Microtubules generated from centriole pair extend across cell and attach to proteins at chromatid centrosome

Centrosome = Centriole Pair

Metaphase Chromatids are pulled between centrosomes Chromatids are pulled between centrosomes Aligned across equator of cell Aligned across equator of cell Midline of cell is called metaphase plate Midline of cell is called metaphase plate

Anaphase Microtubules attached to chromatids shorten Microtubules attached to chromatids shorten Chromatids are pulled apart Chromatids are pulled apart Chromosomes separate to poles of cell Chromosomes separate to poles of cell

Telophase Non-kinetochore microtubules continue to length Non-kinetochore microtubules continue to length Nuclear envelope reforms at each pole Nuclear envelope reforms at each pole Chromosomes unfold back to chromatin Chromosomes unfold back to chromatin

Cytokinesis Cytoplasm is divided between two new cells Cytoplasm is divided between two new cells In animal cells plasma membrane pinches close In animal cells plasma membrane pinches close In plant cells cell wall is constructed between nuclei In plant cells cell wall is constructed between nuclei

Cancer When cells lose control of the cell cycle they become cancerous When cells lose control of the cell cycle they become cancerous A tumor is a mass of cells that cannot stop dividing A tumor is a mass of cells that cannot stop dividing Can occur in any organ or tissue Can occur in any organ or tissue

Animations & Videos Basic Mitosis Basic Mitosis Basic Mitosis Basic Mitosis Condensation of Chromatin Condensation of Chromatin Condensation of Chromatin Condensation of Chromatin Cancer Documentary Cancer Documentary Cancer Documentary Cancer Documentary