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40 Cards in this Set
- Front
- Back
What is a CELL DIVISION?
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The continuity of life is based on the reproduction of cells; for development from a fertilized cell, for growth and repair
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What is the CELL CYCLE?
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The life of a cell from when it is first formed from a dividing parent, until its own division into two cells; passing identical genetic material is crucial
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What is a GENE?
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A cell's endowment of DNA, its genetic information.
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How is the replication and distribution of so much DNA manageable during cell division?
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B/c DNA molecules are packed into CHROMOSOMES.
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What is a SOMATIC CELL?
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Encompass all human cells except reproductive cells; have two sets of chromosomes (Mt)
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What is a GAMETE?
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A human reproductive cell; sperm and eggs; have half as many chromosomes as somatic cells (MI and MII)
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What are eukaryotic cells made of?
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CHROMATIN (a complex of DNA and associated protein molecules). Two sister chromatids are made in Mt
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Does DNA go into the CHROMOSOMES?
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Each single chromosome contains one very long linear DNA molecule that carries several hundred to a few thousand genes.
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What is the CENTROMERE?
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A 'waist' region where the two sister chromatids are most likely joined.
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What is MITOSIS?
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The division of the nucleus.
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What follows MITOSIS?
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CYTOKINESIS (the division of the cytoplasm).
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What is MEIOSIS?
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A variation of cell division which yields nonidentical daughter cells that have only one set of chromosomes (23)
- MEIOSIS only occurs in the gonads (ovaries or testes) |
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What are PHASES OF THE CELL CYCLE?
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1. MITOTIC PHASE (the shortest part of the cycle)- includes both mitosis and cytokinesis - Mitosis occurs at the end where two daughter cells are produced
2. INTERPHASE (often accounts for up to 90% of the cycle) - alternates with the MITOTIC PHASE. - It is during this phase that the cell grows and copies its chromosomes in preperationf ro cell division. |
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Name the sub-phases that break up the INTERPHASE.
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1. G1 PHASE - "the first gap" - cell grows; longest part
2. S PHASE - synthesis - DNA replicates and grows more 3. G2 PHASE - "second gap" - grows more in prep for Mt |
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As the cell grows, what is going on?
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The cell grows by producing proteins, cytoplasmic organelles (mitrochondria and the ER...)
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When are CHROMOSOMES DUPLICATED?
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Only during the S phase.
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How long does cell division take in humans?
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One division in 24 hours
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How many phases are there in MITOSIS?
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FIVE:
1. Prophase 2. Prometaphase 3. Metaphase 4. Anaphase 5. Telophase. |
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What is the CENTROSOME?
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A nonmembraneous organelle that functions throughout the cell cycle to organize the cell's microtubules
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Why is CYTOKIONESIS different in plant celLs?
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B/c they have walls.
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What is CYTOKINESIS and why is it different in plant cells?
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the process known as cleavage in a animal cell and B/c they have they have walls. A Cleavage furrow forms and a cell plate forms
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What are PROTEIN KINASES?
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Enzymes that activate or inactivate other proteins by phophorylating them.
- Particular protein kinases give the go-ahead signals at the G1 and G2 checkpoints. |
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What makes a PROTEIN KINASES active, thus assisting with the driving of the cell cycle?
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PK are mostly inactive, unless they are attached to CYCLIN.
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What is CYCLIN?
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A protein that gets its name from its cyclically fluctuating concenration in the cell.
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What is CdK?
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CYCLIN DEPENDENT KINASES.
- The activity of CdK rises and falls with the changes in concentration of its cyclin partner. |
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What was the name of the CdK complex that was discovered first?
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MPF. (maturation promoting factor)
- It triggers the cell's passage past the G2 checkpoint into the M phase. |
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What is a GENOME?
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all the DNA in a cell; packaged in a chromosome
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P arm and Q arm
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p arm tends to be shorter on chromatid and always on top
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What is BINARY FISSION?
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process in which proks reproduce; the chromosomes (at beginning of origin of replication) replicate and two daughter chromosome actively move apart
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How do CANCER CELLS grow?
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they may make their own growth factor, they may convey a signal w/o the presence of a growth factor; they may have an abnormal cell cycle control
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What is TRANSFORMATION?
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a normal cell is converted to a cancerous cell
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What is a BENIGN TUMOR?
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abnormal cells remain at the original site, a lump forms
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What is a MALIGNANT TUMOR?
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abnormal cells invade surrounding tissues and can metastasize, exporting cancer cells to other parts of the body, where more tumors can grow
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What is the CELL CYCLE CONTROL SYSTEM?
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a cyclical set of molecules in the cell that both triggers and coordinates key events in the cell cycle
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What is a CHECKPOINT?
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in the cell cycle is the critical control point where stop and go-ahead signals can regulate the cycle; checking to see that all processes are completed correctly; 3 major ones found in G1, G2 and M phases
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PROPHASE
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sister chromatids condense and spindles start to form; nuclear membrane begin to dissociate
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METAPHASE
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sister chromatids align along the metaphase plate
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ANAPHASE
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sister chromatids separate and individual chromosomes move toward poles as kinetochore microtubules shorten
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TELOPHASE
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chromosomes decondense and nuclear membrane re-form; cleavage/cell plate separates the new cells with single chromatids identical from parent; 2 nuclei begin to form; mitosis is complete
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INTERPHASE
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chromosomes have replicated
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