Mitosis BIOLOGY 1 TURNER COLLEGE CAREER HIGH SCHOOL
Mitosis BIOLOGY 1 TURNER COLLEGE & CAREER HIGH SCHOOL
Mitosis is the process in which the nucleus divides to form two new nuclei. How does mitosis differ in plants and animals?
How do little elephants grow up to be BIG elephants?
Why do animals shed their skin?
Three reasons why cells reproduce by asexual reproduction: 1. Growth 2. Repair 3. Replacement Skin cancer: the abnormal growth of skin cells; most often develops on skin exposed to the sun. • Cell that reproduce by asexual reproduction reproduce constantly.
Mitosis Cycle • Interphase • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis
Interphase: Occurs Before Mitosis Begins • Each stage of interphase has a distinct set of specialized biochemical processes that prepares the cell for initiation of cell division.
Interphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
G 1 Phase o Growth and young cell maturation occurs. o G 1 phase is the phase during which the cell cycle starts with the production of RNA and proteins required by the young cells for their growth and maturity. o The time period of the G 1 phase of the interphase varies highly among the different species of eukaryotic cells. o Chromosomes begin to condense.
S Phase o All of the chromosomes are copied. o Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy change to sister chromatids at end of this phase. o Following replication, each chromosome now consists of two sister chromatids.
G 2 Phase o During G 2, the cell synthesizes a variety of proteins. o Of particular significance to the cell cycle, most microtubules – proteins that are required during mitosis – are produced during G 2.
Mitosis • Prophase • Metaphase • Anaphase • Telophase
1: Prophase o Chromosomes become more coiled and can be viewed under a light microscope. o Each duplicated chromosome is seen as a pair of sister chromatids joined by the duplicated but unseparated centromere. o The nucleolus disappears during prophase. o In the cytoplasm, the mitotic spindle, consisting of microtubules and other proteins, forms between the two pairs of centrioles as they migrate to opposite poles of the cell. o The nuclear envelope disappears at the end of prophase.
1: Prophase
Prophase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
2: Metaphase o The centrosomes are at opposite poles of the cell. o The chromosomes, now at their most highly coiled and condensed, become arranged on a plane equidistant from the two poles called the metaphase plate (or equator). o For each chromosome, the kinetochores of the sister chromatids face the opposite poles, and each is attached to a kinetochore microtubule coming from that pole.
2: Metaphase
Metaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
3: Anaphase o Begins when the duplicated centromeres of each pair of sister chromatids separate, and the nowdaughter chromosomes begin moving toward opposite poles of the cell due to the action of the spindle. o Depending where the centromere is located along the chromosome, a characteristic shape appears during chromosome movement. o At the end of anaphase, a complete set of chromosomes has assembled at each pole of the cell.
3: Anaphase
Anaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
4: Telophase o The chromosomes assemble in sets at the two poles. o The chromosomes begin to uncoil and eventually assume the extended state characteristic of interphase. o A nuclear envelope reforms around each chromosome set, the spindle disappears, and the nucleolus reforms. o Nuclear division by mitosis is complete at this point.
4: Telophase
Telophase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm
Cytokinesis, the division of the cytoplasm, usually is in progress before nuclear division is complete. ◦ In animal cells, cytokinesis involves the formation of a cleavage furrow resulting in the pinching of the cell into two. ◦ In plant cells, cytokinesis involves the formation of the cell plate resulting in formation of the cell wall, creating two cells.
Cytokinesis
Animal Mitosis: Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
Plant Mitosis: Review Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
REMEMBER! o o o Interphase Prophase Metaphase Anaphase Telophase Cytokinesis IPMATC I Picked More Apples Today Carefully.
- Slides: 30