Chapter 8 And 9 Test Questions – Flashcards
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What type of cell division produces two new, bacterial cells?
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Binary fission
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When newly produced cells from a single - celled organism create two identical cells, this is known as
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Asexual reproduction
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What introduces different variations to offspring?
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Sexual reproduction
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What statement describes cell theory?
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This states that "all cells come from pre - existing cells" so a new cell cannot be made without a pre - existing cell and a new organism cannot be born without a pre -existing organism
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Cellular reproduction involves two important processes. What are they?
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Growth and Cell Division
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What happens during cellular growth?
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A cell duplicates its contents including the organelles and its DNA
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What happens during cellular division?
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the DNA and other cellular contents of the parent cell are distributed to the daughter cells.
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What occurs in preparation for cell division?
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DNA replication which is the process by which a cell copies its DNA
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Cells cannot continue to live without what?
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A copy of their genetic material
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What are chromosomes?
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A structure that consists of DNA complexed with proteins that transmits genetic information from the previous generation to the next
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What are histones?
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Protein molecule responsible for packaging chromatin
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What are nucleosomes?
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Units composed of DNA that's wound around a core of eight histone proteins
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What's chromatin?
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Network of fibris consisting of DNA and associated proteins observed within a nucleus that is not dividing
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What are sister chromatids?
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One or two genetically identical chromosomal units that are the result of DNA replication and are attached to each other at the centromere
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What is the centromere?
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Constricted region on a chromosome joining two sister chromatids
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What is the cell cycle?
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Repeating sequence of events in eukaryotes that involves cell growth and nuclear division
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What are the phases of interphase?
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Prophase, Metaphase, Anaphase and Telophase
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What is mitosis?
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Process in which a parent nucleus produces two daughter nuclei, each having the same number of chromosomes
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What are the 4 phases of mitosis?
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Prophase, Metaphase, Anaphase, and Telophase
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What happens during prophase?
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Mitotic phase during which chromatin condenses, so that chromosomes reappear
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What happens during metaphase?
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Mitotic phase during which chromosomes are aligned at the spindle equator
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What happens during anaphase?
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Mitotic phase during which daughter chromosomes move towards the pole of the spindle
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What happens during telophase?
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Mitotic phase during which daughter cells are located at each pole
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What happens with the spindle?
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Microtubule structure that brings about chromosomal movement during nuclear division
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What are centrosomes?
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Central microtubule organizing center of cells. In animal ells, it contains two centrioles
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What are centrioles?
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Cell organelles that occurs in the centrosome and may help organize a mitotic spindle for chromosome movement during animal cell division
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What is cytokinesis?
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Division of the cytoplasm
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What are checkpoints?
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In the cell cycle, one of several points where the cell cycle can stop or continue on, depending on the internal signal it receives; ensures that each step of the cell cycle is completed before the next one begins
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What are cyclins?
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Protein that cycles in quantity as the cell cycle progresses; combines with and activates the kinases that promote the events of the cycle
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What are kinases?
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Enzymes that activates another enzyme by adding a phosphate group
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What is contact inhibition?
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In cell culture, the point where cells stop dividing when they become a one - cell thick sheet
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What are telomeres?
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Long, repeating DNA sequences at the ends of chromosomes; functions as a cap
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What is apoptosis?
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Programmed cell death involving a cascade of specific cellular events, leading to death and destruction of the cell
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What are somatic cells?
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Body cells
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What are proto - oncogenes?
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Normal gene that can become an oncogene through inhibition
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What are growth factors?
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Chemical signals that regulates mitosis and differentiation of cells that have receptors for it
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What are tumor suppressor genes?
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Genes that code for a protein that ordinarily suppresses cell division. Inactivity can lead to a tumor
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What are trans-locations?
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Movement of a chromosomal segment from one chromosome to another non-homologous chromosome, leading to abnormalities
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What are carcinogenesis?
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Development of cancer
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What are benign tumors?
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Tumor that does not invade adjacent tissue and stays at the site of origin
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What are malignant tumors?
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Invasive tumor that may spread
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What is angiogenesis?
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Formation of new blood vessels
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What is metastasis?
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Spread of cancer from the place of origin throughout the body; caused by the ability of cancer cells to migrate and invade tissues
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What is meiosis?
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Type of nuclear division that occurs as part of sexual reproduction in which the daughter cells receive the haploid number of chromosomes in varied combinations
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What are homologous chromosomes?
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Homologues, member of a pair of chromosomes that are alike and come together in synapsis during prophase of the first meiotic division
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What are alleles?
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Alternative form of a gene. Alleles occur at the same locus on homologous chromosomes
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What are autosomes?
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Any chromosome other than the sex determining pair
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What are sex chromosomes?
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Chromosomes that determines the sex of an individual.
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What is the haploid number?
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Cell condition in which only one of each type of chromosome is present
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What is the diploid number?
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Cell condition in which two of each type of chromosome is present
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What is the life cycle?
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Recurring pattern of genetically programmed events by which individuals grow, develop, maintain themselvs, and reproduce
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What is meiosis I?
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cell division that produces reproductive cells in sexually reproducing organisms; the nucleus divides into four nuclei each containing half the chromosome number (leading to gametes in animals and spores in plants)
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What is meiosis II?
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The second of the two consecutive divisions of the nucleus of eukaryotic cell during meiosis, and composed of the following stages: prophase II, metaphase II, anaphase II, and telophase II.
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What is synapsis?
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Pairing of homologous chromosomes during meiosis I
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What are tetrads?
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Homologous chromosomes, each having sister chromatids that are joined during meiosis
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What are dyads?
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Chromosomes composed of two sister chromatids
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What is crossing - over?
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Exchange of segments between nonsister chromatids of a tetrad during meiosis
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What are non-sister chromatids?
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A tetrad consists of four chromatids. Only the chromatids belonging to a homologue are sister chromatids and the others, belonging to the other homologue, are nonsister chromatids
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What is interkinesis?
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Period of time between meiosis I and meiosis II during which no DNA replication takes place
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What is nondisjunction?
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Failure of homologous chromosomes or daughter chromosomes to separate during meiosis I and meiosis II, respectively
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What is Down syndrome?
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Trisomy 21. The individual has 3 copies of chromosome 21
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What is Turner syndrome?
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Condition caused by the inheritance of a single X chromosome
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What is Klinefelter syndrome?
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Condition caused by the inheritance of XXY chromosomes
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What is Barr body?
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Dark-staining body in the nuclei of female mammals that contains a condensed, inactive X chromosme
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Turner syndrome is associated with which karyotypes?
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45, XO
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Unicellular organisms undergo mitotic division to
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Unicellular organisms (e.g. bacteria, yeast, some fungi) undergo mitosis as their means of reproduction. Instead of "having children" or "laying eggs" the single-celled organism simply divides itself into 2 single-celled organisms.
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Cancer is a disorder in which some cells have lost the ability to control their
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growth rate
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4. Crossing over between sister chromatids does not result in recombination of genetic material while crossing over between non-sister chromatids does because
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A. sister chromatids have the same alleles while non-sister chromatids have different ones.
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5. Cytokinesis usually, but not always, follows mitosis. If a cell undergoes mitosis and not cytokinesis, this would result in
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A. A cell with two or more nuclei
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6. Which phases results in separation of sister chromatids into daughter chromosomes?
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A. anaphase II and anaphase of mitosis
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7. Know the events of the cell cycle from interphase to mitosis
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A. G1: Growth occurs as organelles double; S: DNA replication occurs as chromosomes duplicate; G2: Growth occurs as cell prepares to divide; M: Mitosis and cytokinesis occur
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8. differences between meiosis I and meiosis II is that
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A. In Meiosis I, the homologous chromosomes separate. In Meiosis II, sister chromatids separate
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9. The failure of sister chromatids to separate during meiosis is called
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A. Nondisjunction
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10. What is apoptosis
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A. Programmed cell death
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11. DNA and histones form beadlike globules known as
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A. Nucleosome
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12. How does apoptosis occur
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A. When the protein p53 can stop the cell cycle
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13. The human life cycle consists of
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A. Mitosis and Meiosis
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14. The term metastasis refers to the fact that cancer cells tend to
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A. Travel through the blood or lymph to start new tumors elsewhere within the body
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15. What is the importance of meiosis in germ cells
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A. Germ cells undergo meiosis to form gametes
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16. The G2 checkpoint prevents the cell cycle from continuing until
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A. DNA replication is complete
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17. A tetrad is composed of
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A. Four chromatids (two homologous chromosomes with two chromatids each)
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18. If a cell has 46 chromosomes at the beginning of mitosis, then at the end of anaphase there would be a total of
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46
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19. Metaphase II is more similar to metaphase of mitosis than to metaphase I because
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A. In metaphase II, dyads align separately at the spindle equator.
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20. ___________ are a type of internal signal molecule used in controlling the cell cycle.
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A. Kinases
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21. If there are twenty centromeres in a cell, how many chromosomes are there?
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A. 20
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22. Phases of mitosis in their proper sequence?
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A. Prophase, Metaphase, Anaphase, Telophase
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23. Down syndrome is associated with which of the following karyotypes?
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A. 47, XY, trisomy 21
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24. Which human syndrome is a monosomy?
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A. Turner syndrome
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25. Multicellular organisms undergo mitotic cell division to
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A. To make new kinds of organisms, to reproduce
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26. Plant cells and animal cells differ in cytokinesis because
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A. Animal cells divide by a cleavage furrow. Plant cells divide by a cell plate that eventually becomes the cell wall.
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27. A dyad consists of
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A. Two chromatids
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28. Chromosomes that occur in pairs and code for the same traits are called _____________ chromosomes; these do not include the __________________ chromosomes which code for gender.
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A. Homologous: sex
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29. An individual with the karyotype 48, XYYY would have how many Barr bodies?
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A. 0
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30. Which organelle would be abundant and in close proximity to the cell plate in a plant cell undergoing cytokinesis?
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A. Golgi Apparatus
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31. Know the functions of meiosis
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A. Meiosis, or reductional division, is a process during which exchange of genetic material between the homolog chromosomes (crossing-over and recombination) takes place
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32. Cyclins function with which other internal signal
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A. G1 phase to the S phase
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33. How do the daughter cells at the end of mitosis and cytokinesis compare to their parent cell when it was in G1 of the cell cycle?
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A. The daughter cells have the same number of chromosomes and the same amount of DNA.
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34. An egg with 22 chromosomes that is fertilized by a normal sperm will result in
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A. A zygote with monosomy
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35. What happens during crossing over
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A. An exchange of genetic material between homologous chromosomes that results in an recombinant chromosomes during sexual reproduction.
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36. Following meiosis I, the daughter cells are ______; following meiosis II, the daughter cells are ______; and following mitosis, the daughter cells are _______.
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A. 46,23,23
