BIO CH. 6 0 Mitosis – Flashcards
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Why do cells divide?
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To grow, reproduce, and replace damaged cells
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Tumors
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Are a mass of cells with no function.
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Are all tumors cancerous?
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No.
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Tumors are malignant they...
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Invade surrounding structures. They are cancerous.
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Tumors are metastatic if..
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Their cancer cells break from tumor and move to other locations. They are cancerous.
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Tumors are benign when they..
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Do not affect surrounding structures. They are not cancerous.
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What is cancer?
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Uncontrolled cell division
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Does DNA replication happen before cell division?
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Yes.
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What happens during DNA replication?
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One parent DNA molecule produces two daughter DNA molecules
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Which enzyme facilitates DNA replication?
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Polymerase
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How are duplicated chromosomes shaped?
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X shaped.
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What happens during mitosis?
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Duplicated chromosomes are separated into single chromosomes.
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What are the 4 stages of mitosis?
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Prophase, metaphase, anaphase, telophase
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What happens in prophase?
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Chromosomes are preparing to divide.
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What happens in metaphase?
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Chromosomes move to the middle/equator of the cell. (Meta means middle)
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What happens in anaphase?
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Chromosome is pulled apart
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What happens in telophase?
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Separate daughter cells are formed
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What is a mutation?
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A change in DNA. The enzyme polymerase mistakenly pairs the wrong nitrogenous bases together. (A with G)
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Are sister chromotids identical?
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Yes.
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What are the 3 stages of the cell cycle?
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Interphase Mitosis Cytokenisis
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Cytokenisis
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Division of cytoplasm
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What are the 3 components of interphase?
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G1 (organelles duplicate) S (DNA is synthesized) G2
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What is mitosis? What does it produce?
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Division of the nucleus. Produces daughter cells that are genetically identical to the parent cell.
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What are cell cycle control genes?
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Proteins that prevent cell division from occurring when it should not occur.
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Where do cells spend most of their time in the cell cycle?
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Cells spend most of their time in interphase.
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A certain species of animal has 8 pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase?
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So 16 chromosomes total. DNA replication is completed during S phase, which occurs prior to G2 phase. Since each single chromosome (16) is replicated, there are 32 DNA molecules in the nucleus during G2 phase.
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What are 3 checkpoints that occur late in G1?
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That the cell is large enough for division? Nutrients are sufficient? Growth factors are present? NOT a check that chromosome replication has been successfully completed.
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When are nucleoli present?
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Nucleoli are present during interphase.
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What phase does cytokinesis accompany?
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Cytokinesis often, but not always, accompanies telophase.
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When do chromosomes become visible?
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During prophase, the chromatin fibers become discrete chromosomes.
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During which stage do centromeres divide and sister chromosomes become full-fledged chromosomes?
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Anaphase, sister chromatids separate and migrate to opposite poles.
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During which stage do spindle fibers attach to kinetochores?
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Prometaphase
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Cytokinesis in animal cells involves the formation of what?
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Cleavage furrow
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What are 2 events of prophase?
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The condensation of chromatin and the dispersal of nucleoli.
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What happens during prometaphase?
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The attachment of spindle fibers to kinetochores.
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What happens during telophase?
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Both nuclear envelopes and nucleoli re-form.
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During prophase a pair of chromosomes consist of?
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2 chromosomes and 4 chromatids.
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What are 4 carcinogens?
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Cigarette smoke, testosterone, estrogen, UV light
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What is a carcinogen that promotes colon cancer?
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Fat
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3 ways cancer cells differ from normal cells?
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They divide when they're not supposed to, they invade surrounding tissue, and the move to other locations in the body.
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A diet high in ___ would tend to increase the levels of antioxidants in the body, and thus decrease the risk of cancer?
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High-fiber diets. They contain lots of fruits and vegetables will contribute lots of antioxidants.
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Do sister chromatids carry copies of the same genes?
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Yes. Each sister chromatid is composed of a DNA molecule that contains the same genes.
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Which of the following contains uncondensed chromosomes that have been duplicated? When do the chromosomes become condensed?
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A cell during the G2 phase of interphase. DNA is duplicated during the S phase, following the G1 phase of interphase. The chromosomes do not become condensed until prophase
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Do only individuals with cancer have proto-oncogenes? What are they?
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No. Proto-oncogenes are normal genes that enable organisms to regulate cell division.
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When do proto-oncogenes become oncogenes?
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When they are mutated, and can cause cancer.
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What is the most appropriate treatment to be used after metastasis?
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Chemotherapy. Chemotherapeutic drugs are injected into the bloodstream and circulate throughout the body; thus, they have the best chance of finding and killing the metastasized cells.
