Biology Chapter 8: The Cellular Basis of Reproduction and Inheritance – Flashcards
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In sexually reproducing multicellular organisms, the main functions of mitosis are _____.
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growth and developmenttissue repair/replacement of damaged cells
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Which events occur during prophase?
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Chromosomes condense and are attached to spindle fibers. The nuclear envelope breaks down.
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Cytokinesis _____.
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finishes mitosis by dividing the cytoplasm and organelles of the original parent cell into two separate daughter cells
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During _____, the cell carries out its normal functions and the chromosomes are thinly spread out throughout the nucleus.
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interphase
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Looking through a light microscope at a dividing cell, you see two separate groups of chromosomes on opposite ends of the cell. New nuclear envelopes are taking shape around each group. The chromosomes then begin to disappear as they unwind. You are witnessing _____.
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telophase
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Most of a cell's life is spent in _________, when growth occurs. Cells that are about to divide replicate their DNA.
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interphase
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In _______ microtubules form the mitotic spindle, and the nuclear envelope breaks up.
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prophase
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At ________, the mitotic spindle is fully formed and chromosomes are lined up in the center of the cell.
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metaphase
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In _________, sister chromatids separate and become full-fledged chromosomes that move opposite poles.
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anaphase
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In ________, chromosomes become less condensed and new nuclear envelopes form. In _________ the cytoplasm divides.
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telophase... cytokinesis....
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A _____ _____ is a lump of abnormal cells that, although growing out of control, remains at its original site.
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benign tumor
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A _____ _____ is an abnormally growing mass of cells that is actively spreading through the body.
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malignant tumor
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_______ is the spread of cancer cells from their site of origin to other sites in the body.
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Metastasis
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An individual with a malignant tumor is said to have ______.
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cancer
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The most common type of cancer is_________; this type always originates in tissues that line organs.
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carcinoma
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The function(s) of meiosis is/are _____.
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a. reproduction (production of gametes)
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Looking through a light microscope at a cell undergoing meiosis, you see that the chromosomes have joined into XX-shaped tetrads. These tetrads are lined up along a plane that runs through the center of the cell. This cell is in _____.
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meiosis I
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Meiosis starts with _____ cells and produces _____ gametes.
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diploid ... haploid
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Meiosis is typically accomplished in _____.
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three steps. All of the chromosomes are duplicated in a diploid cell, and then there are two cell divisions to produce a total of four haploid gametes.
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The _____ separate in meiosis I; the _____ separate in meiosis II.
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homologous chromosomes ... sister chromatids
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During binary fission, one copy of the duplicating chromosome moves to the opposite end of the cell. What does this achieve?
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It ensures that each daughter cell receives one copy of the chromosome.
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A cell replicates its entire chromosomal DNA only _____.
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before it is about to divide
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Immune system cells enter a resting phase after undergoing mitosis. When activated - for example, by an infection - they can reenter the sequence of events in the cell cycle that leads to cell division. What would be the correct sequence of events?
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G1, S, G2, M
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Benign tumors differ from malignant tumors in that the cells of a benign tumor _____.
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remain confined to their original site
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Asexual reproduction _____.
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produces offspring genetically identical to the parent
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Asexual and sexual reproduction differ in that sexual reproduction _____.
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can produce great variation among the offspring
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The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called
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asexual reproduction.
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Strictly speaking, the phrase "like begets like" refers to
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asexual reproduction only.
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With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have
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a similar but not identical combination of genes.
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Which of the following statements regarding cell division is false?
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Cell division is common in eukaryotes but rare in prokaryotes.
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Which of the following statements regarding prokaryotes is false?
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Prokaryotic chromosomes are more complex than those of eukaryotes.
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Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?
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The sequences are identical.
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Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called
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sister chromatids.
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Which of the following statements correctly describes the timing of DNA synthesis?
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DNA is synthesized in the S phase of interphase.
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Eukaryotic cells spend most of their cell cycle in which phase?
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interphase
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At the start of mitotic anaphase,
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the centromeres of each chromosome come apart.
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Which of the following is a feature of plant cell division that distinguishes it from animal cell division?
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formation of a cell plate
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When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example ofWhen animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of
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density-dependent inhibition.
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In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____.
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are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
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Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are
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homologous chromosomes.
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Baker's yeast is an organism with 32 chromosomes that can perform asexual or sexual reproduction and exist as both a diploid and haploid cell. After meiosis, how many chromosomes will be present in each cell?
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16
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In meiosis II, _____.
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sister chromatids are separated
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During which stage of meiosis do synapsis and crossing over occur?
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prophase I
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Which of the following statements regarding mitosis and meiosis is false?
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Meiosis provides for asexual reproduction.
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Independent orientation of chromosomes at metaphase I results in an increase in the number of
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possible combinations of characteristics.
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During meiosis I, homologous chromosomes form a tetrad. What does this accomplish?
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This brings the chromosomes into alignment so that crossing over can create new combinations of genes present on a single chromosome.
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what maternal age does the incidence of Down syndrome begin to increase substantially?
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about 37 or 38
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Which of the following variations of the sentence "Where is the cat" is most like a chromosomal deletion?
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Where is cat?
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A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. There are _____ chromatids.
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92
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Cytokinesis refers to _____.
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division of the cell outside the nuclear material
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What is the difference between a benign tumor and a malignant tumor?
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Benign tumors do not metastasize; malignant tumors do.
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In humans, the _____ determines the sex of the offspring because _____.
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male ... the male can contribute either an X or a Y chromosome
