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Mastering BIO 18

question

How do cells become differentiated? Different genes are expressed so that different proteins are produced. The DNA in each cell changes so that the appropriate proteins are produced. Paternal effect genes begin the process of differentiation by providing positional information. They differentiate through the process of mitosis. Some cells contain maternal chromosomes and some contain paternal chromosomes.
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Different genes are expressed so that different proteins are produced.
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By what mechanism might transposons contribute to gene duplication? Transposon insertion may disrupt an exon. Transposons may lead to slippage of DNA polymerase during DNA replication. Transposons may promote unequal crossing over during meiosis. Transposons cause failure of chromosomes to segregate during mitosis. Transposons may promote accidents in meiosis, leading to polyploidy.
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Transposons may promote unequal crossing over during meiosis.
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In humans, the hormone testosterone enters cells and binds to specific proteins, which in turn bind to specific sites on the cells’ DNA. These proteins probably act to do what? promote recombination cause mutations in the DNA unwind the DNA so that its genes can be transcribed alter the pattern of DNA splicing help RNA polymerase transcribe certain genes
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help RNA polymerase transcribe certain genes
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The fact that plants can be cloned from somatic cells demonstrates that the differentiated state is normally very unstable. differentiated cells contain masked mRNA. differentiated cells retain all the genes of the zygote. differentiation does not occur in plants. genes are lost during differentiation.
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differentiated cells retain all the genes of the zygote.
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What is considered to be the first evidence of differentiation in the cells of an embryo? cell division occurring after fertilization determination of specific cells for certain functions changes resulting from induction the occurrence of mRNAs for the production of tissue-specific proteins changes in the size and shape of the cell
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the occurrence of mRNAs for the production of tissue-specific proteins
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Which of the following would be most likely to lead to cancer? amplification of a proto-oncogene and inactivation of a tumor-suppressor gene hyperactivity of a proto-oncogene and activation of a tumor-suppressor gene failure of a proto-oncogene to produce a protein and amplification of a tumor-suppressor gene hyperactivity of both a proto-oncogene and a tumor-suppressor gene failure of both a proto-oncogene and a tumor-suppressor gene to produce proteins
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amplification of a proto-oncogene and inactivation of a tumor-suppressor gene
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All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs? Proto-oncogenes are necessary for the normal control of cell growth and division. Proto-oncogenes are genetic junk that has not yet been eliminated by natural selection. Cells produce proto-oncogenes as a by-product of mitosis. Proto-oncogenes are unavoidable environmental carcinogens. Proto-oncogenes protect cells from infection by cancer-causing viruses.
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Proto-oncogenes are necessary for the normal control of cell growth and division.
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Which of the following statements describes proto-oncogenes? Their normal function is to suppress tumor growth. They can code for proteins associated with cell growth. They are underexpressed in cancer cells. They are produced by somatic mutations induced by carcinogenic substances. They are introduced to a cell initially by retroviruses.
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They can code for proteins associated with cell growth.
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Which of the following is characteristic of the product of the p53 gene? It speeds up the cell cycle. It allows cells to pass on mutations due to DNA damage. It slows down the rate of DNA replication by interfering with the binding of DNA polymerase. It causes cell death via apoptosis. It is an activator for other genes.
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It is an activator for other genes.
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Tumor-suppressor genes are frequently overexpressed in cancerous cells. often encode proteins that stimulate the cell cycle. can encode proteins that promote DNA repair or cell-cell adhesion. are cancer-causing genes introduced into cells by viruses. do all of the above.
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can encode proteins that promote DNA repair or cell-cell adhesion.
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Muscle cells differ from nerve cells mainly because they have different chromosomes. use different genetic codes. contain different genes. have unique ribosomes. express different genes.
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express different genes.
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Cell differentiation always involves the movement of cells. the production of tissue-specific proteins, such as muscle actin. the cell’s sensitivity to environmental cues, such as light or heat. the transcription of the myoD gene. the selective loss of certain genes from the genome.
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the production of tissue-specific proteins, such as muscle actin.
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What characteristic of short tandem repeat DNA makes it useful for DNA fingerprinting? The sequence of DNA that is repeated varies significantly from individual to individual. The sequence variation is acted upon differently by natural selection in different environments. Every racial and ethnic group has inherited different short tandem repeats. The number of repeats varies widely from person to person or animal to animal.
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The number of repeats varies widely from person to person or animal to animal.