6009907
Beschreibung
Karteikarten von Chelsi Souch, aktualisiert more than 1 year ago
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Erstellt von Chelsi Souch
vor etwa 8 Jahre
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| Frage | Antworten |
| PROKARYOTES vs EUKARYOTES reproduction | PROKARYOTIC CELL (e.g. Bacteria) Cells divide by BINARY FISSION (less complex) Chromosomes are replicated forming SISTER CHROMATIDS (identical copies of each chromosome) Sister chromatids assigned to daughter cells by MITOSIS |
| THE CELL CYCLE | The cell cycle multiplies cells – The cell cycle consists of two major phases: INTERPHASE: Occupies the major portion of the cell cycle: G1 , S & G2 Mitotic Phase: Mitosis and Cytokinesis |
| During interphase: Chromosomes.... | duplicate and cell parts are made |
| G1 phase of cell cycle | Cell continues to grow • Organelles replicate (so that there is plenty to distribute among the daughter cells) |
| S phase (Synthesis phase) | DNA replication Each chromosome forms TWO SISTER CHROMATIDS joined by a CENTROMERE |
| G2 phase cell cycle | Cell continues to grow • Structures such as microtubules that are directly involved in cell division are synthesized and organized |
| MITOSIS | Asexual reproduction of cells 2 daughter cells that are identical to the original cell (mutations: some variation) MITOSIS has 4 PHASES PROPHASE METAPHASE ANAPHASE TELEOPHASE |
| 1. PROPHASE | Centrioles duplicate and separate Mitotic spindle apparatus starts to form Chromosomes (already duplicated) condense (why is it necessary?) Nucleolus disappears Nuclear membrane breaks down Microtubules attach to the KINETOCHORE Duplicated chromosomes are pulled towards the center of the cell |
| 2. METAPHASE | CHROMOSOMES align at the center of the cell (METAPHASE PLATE) MITOTIC SPINDLES linking CHROMOSOMES to each pole are completed |
| 3. ANAPHASE | • Microtubule spindles contract • SISTER CHROMATIDS separate • They are pulled towards opposite poles |
| 4. TELEOPHASE | SISTER CHROMATIDS (now can refer to as non-duplicated chromosomes) reach the poles of the cell Chromosomes (non duplicated) de-condense Nucleus reforms CYTOKINESIS initiated |
| CYTOKINESIS | Division of the cytoplasm into 2 new cells DIFFERENT between ANIMAL & PLANT cells CYTOKINESIS in an ANIMAL CELL Analogy: Fluid-filled balloon - string around it is pulled tight |
| What Is Cancer? | Cancer is unrestrained cell growth and division caused by damage to genes regulating the cell division cycle. Ex. The “guardian Angel gene” p53 (tumor suppressor gene) • This gene plays a key role in G1 check point. The gene’s product p53 protein monitors the integrity of DNA. • If damage detected, halts the cell division and stimulates the activity of enzymes to repair the damage then allows to divide. • If can’t be repaired, p53 directs the cell to “commit suicide”, activating the cell’s apoptosis program. |
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