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63 Cards in this Set
- Front
- Back
What is cell division?
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- reproduction of a cell through duplication of the genome and division of the cytoplasm.
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What are chromosomes?
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- threadlike, gene carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis
- main gene carrying structure of a prokaryotic cell - consists of 1 very long piece of chromatin; combination of DNA and protein |
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What is asexual reproduction?
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creation of genetically identical offspring by a single parent, without the participation of sperm and egg
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- in the amoeba it does reproduction
- in the body it does development, growth, and repair |
What function does cell division play in amoeba? What function does it play in your body?
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What is binary fission?
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means of asexual reproduction in which a parent organism, often a single cell, divides into 2 gentically identical individuals of about equal size.
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because the genetically identical offspring inherit their DNA from a single parent.
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Why is binary fission classified as asexual reproduction.
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What are sister chromatids?
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- 1 of the 2 identical parts of a duplicated chromosome in a Eukaryotic cell.
- prior to mitosis, they remain attached to each another at the centromere |
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What is a centromere?
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- region of a duplicated chromosome where 2 sister chromatids are joined and where spindle microtubules attach during meiosis and mitosis
- divison at the onset of anaphase during mitosis and anaphase 2 during meiosis. |
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- when the cell is preparing to divide and has duplicated its chromosomes, but before the duplicate actually separate.
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When does a chromosome consist of 2 identical chromatids?
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What is cell cycle?
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ordered sequence of events (including the interphase and the mitotic phase) that extends from the time a eukaryotic cell is first formed from a dividing parent until its own division into 2 cells.
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What is interphase?
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- period in the eukaryotic cell cycle when the cell is not actually dividing.
- constitutes the majority of the time spent in the cell cycle |
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What is the mitotic phase?
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- part of the cell cycle when the nucleus divides (via mitosis), its chromosomes are distributed to the daughter nuclei, and the cytoplasm divides (via cytokineses), producing 2 daughter cells
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What is mitosis?
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- divison of a single nucleus into 2 genetically identical nuclei
- this and cytokinesis make up the mitotic (M) phase of the cell cycle. |
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What is cytokinesis?
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- division of the cytoplasm to form 2 separate daughter cells
- usually occurs in conjunction with telophase of mitosis - this and mitosis make up the mitotic (M) phase of the cell cycle |
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What are the 5 stages of mitosis?
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- Prophase
- Prometaphase - Metaphase - Anaphase - Telophase |
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What is prophase?
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first stage of mitosis, during which the chromatin condenses to form strucutres (sister chromatoids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact
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What is prometaphase?
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- second stage of mitosis, during which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatoids
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What is the metaphase?
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- third stage of mitosis, during which all the cell's duplicated chromososmes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle
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What is the anaphase?
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- fourth stage of mitosis, beginning when sister chromatoids separate from each other and ending when a complete set arrive at each of the 2 poles of the cell.
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What is the telophase?
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- fifth and final stage of mitosis, during which daughter nuclei form at the 2 poles of a cell
- usually occurs together with cytokinesis |
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What is mitotic spindle?
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- football-shaped structure formed of microtubules, and associated proteins that is involved in the movement of chromosomes during mitosis and meiosis.
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What are centromeres?
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- material in the cytoplasm of a Eukaryotic cell that gives rise to microtubules; important in mitosis and meiosis
- aka microtubule organizing center |
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What is a cleavage furrow?
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- 1st sign of cytokinesis during cell division in an animal cell
- shallow groove in the cell surface near the old metaphase plate |
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What is cell plate?
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double membrane across the midline of a dividing plant cell, between which the new wall forms during cytokinesis.
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- in animals, cytokinesis involves a cleavage furrow in which the contractuary microfilaments pinch the cells in two.
- in plants, it involves formation of a cell plate, a fusion of vesicles that forms new plasma membranes and new cell walls between the cells |
What is the difference in cytokineses between plant and animal cells?
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What is growth factor?
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protein secreted by certain body cells that stimulates other cells to divide
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What is density-dependent inhibition?
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- ceasing of cell divison that occurs when cells touch one another
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What is anchorage dependence?
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requirement that to divide, a cell must be attach to a solid surface
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What is cell cycle control system?
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cyclically operating set of proteins that triggers and coordinate events in the eukaryotic cell cycle
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What is a tumor?
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abnormal mass of rapidly growing cells that forms within otherwise normal tissue
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What is a benign tumor?
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abnormal mass of cells that remains at its orginal site in the body
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What is a malignant tumor?
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- abnormal tissue mass that can spread into neighboring tissue and to other parts of the body
- cancerous tumor |
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What is cancer?
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disease characterized by the presence of malignant tumors (rapidly growing and spreading of abnormal body cells) in the body
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What is metastasis?
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spread of cancer cells beyond their original site
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What is carcinomas?
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cancer that originates in the coverings of the body, such as skin or the lining of the intestinal tract
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What are sarcomas?
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cancer of the supportive tissues, such as bone, cartillage, and muscle
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What is leukemia?
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- type of cancer of the blood forming tissues, characterized by an excessive production of white blood cells and an abnormally high number of them in the blood
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What is lymphocytes?
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- type of white blood cell that is chiefly responsible for the acquired immune response and is found mostly in the lymphatic system
EX: b-cell, t-cell |
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What is a somatic cell?
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any cell in a multicellular organism except a sperm/egg or a cell that develops into sperm/egg
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What is homologus chromosome?
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- two chromosomes that make up a matched pair in a diploid cell
- are of the same length, centromere position, and and staining pattern and posesses genes for the same characteristic at corresponding loci - one inherited from the father, the other is from the mother |
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What is locus?
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- particular site whre a gene is found on a chromosome
- have corresponding gene loci |
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What are sex chromosomes?
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chromosome that determines whether an individiual is a male or female
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What are autosomes?
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- chromosome not directly involved in determining the sex of an organism
EX: any chromosome other than X and Y |
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What is life cycle?
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entire sequence of stages in the life of an organism, from the adults of 1 generation to the adults of the next
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What is a diploid?
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- orgnaism that reproduces sexually, a cell containing two homologous sets of chromosomes, one set inherited from each parent
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What are gametes?
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- sex cell; haploid egg/sperm
- union of two of these of opposite sex (fertilization) produces a zygote |
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What is fertilization?
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union of the nucleus of a sperm cell with nucleus of an egg cell, producing a zygote
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What is zygote?
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diploid fertizlized egg, which results from the union of the sperm and egg cell nucleus
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What is meiosis?
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- in a sexually reproducing organism, the divison of a single diploid nuclues into 4 haploid daughter nuclei
- this and cytokinesis produce haploid gamets from diploid cells in the reproductive organs of the parents |
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What are tetrads?
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- paired set of homologous chromosomes, each composed of two sister chromatids
- some may form during prophase 1 of meiosis, when crossing over may occur |
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What is a chiasma?
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microscopically, visible iste where crossing over has occured between chromatids of homologous chromosomes during prophase 1 of meiosis
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What does crossing over mean?
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- exchange of segments between chromatids of homologus chromosomes during synapsis in prophase 1 of meiosis
- also the exchange of segments between DNA molecules in prokaryotes |
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What is genetic recombination?
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- production, by crossing over and or interdependent assortment of chromosomes during meiosis, of offspring with allele combinations different from those in the parents
- the term may also be used more specifically to mean the production by crossing over of eukarytoic or prokaryotic chromosomes with gene combinations different from those in the original chromosome |
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What is a karyotype?
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- display of micrographs of the metaphase chromomes of a cell, arranged by size and centromere position
- used to identify certain chromosomal abnormalities |
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What is down syndrome?
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- human genetic disorder resulting from the presence of an extra chromsome 21.
- chracterized by heart and respiartorial defects and varying degrees of mental retardation |
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What is nondisjunction?
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- accident of meiosis or mitosis in which a piar of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase
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diploid gamete would result if the nondisjunction affects all the chromosomes during one of the miotic division.
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How could nondisjunction result in diploid gamete?
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What is a polyploid organism?
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1 with more than 2 sets of homologous chromosomes in its body cells
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What is deletion?
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- loss of 1 or more nucleotides from a gene by mutation
- loss of a fragment of a chromosome |
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What is duplication?
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- repetition of part of a chromosome resutling from fusion with a fragment from a homologous chromosome
- result from an error in meiosis or from mutagenesis |
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What is inversion?
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- change in a chromosome resulting from reattachment of a chromosme fragment to the original chromosome, but in a reverse direction
- mutagens and erros during meiosis can cause these |
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What is translocation?
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- during protein synthesis, the movement of tRNA molecule carrying a growing polypeptide chain from the A site tot he P site on a ribosome
- change in a chromosome resulting from a chromosomal fragment attach to a nonhomologous = can result of an error in meiosis or from mutagenesis |
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- reciprical translocation swaps chromosome segments between nonhomologous chromosome
- crossing over normally exchangers corresponding segments between homologus chromosmes |
How is recipricol translocation different from normal crossing over?
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