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Chapter 18 Quiz 2

question

The cytoplasm of an unfertilized egg _____. A. Does not contain substances that are important in directing development. These substances are produced by the DNA of the fertilized zygote. B. Is an unevenly distributed mixture of mRNA, proteins, organelles, and other substances C. Is a homogeneous mixture of mRNA, proteins, organelles, and other substances D. Does not contain substances that are important in directing development. These substances are supplied by the sperm. E. Does not contain substances that are important in directing development. Development is directed solely by the surrounding cells.
answer

B. Is an unevenly distributed mixture of mRNA, proteins, organelles, and other substances
question

How do master regulatory genes function in cell differentiation? A. They may produce proteins that stimulate production of more of the master regulatory gene. B. They produce proteins that act as transcription factors to produce proteins specific to the function of the particular cell type. C. The transcription factors they produce coordinately control related genes. D. They are often capable of changing some fully differentiated cells of different types into their particular cell type. E. All of the above
answer

E. All of the above
question

How do cells become differentiated? A. Different genes are expressed so that different proteins are produced. B. The DNA in each cell changes so that the appropriate proteins are produced. C. Through the process of mitosis D. Some cells contain maternal chromosomes and some contain paternal chromosomes. E. Paternal effect genes begin the process of differentiation by providing positional information.
answer

A. Different genes are expressed so that different proteins are produced.
question

Which of the following would be most likely to lead to cancer? A. failure of a proto-oncogene to produce a protein and amplification of a tumor-suppressor gene B. hyperactivity of both a proto-oncogene and a tumor-suppressor gene C. failure of both a proto-oncogene and a tumor-suppressor gene to produce proteins D. amplification of a proto-oncogene and inactivation of a tumor-suppressor gene E. hyperactivity of a proto-oncogene and activation of a tumor-suppressor gene
answer

D. amplification of a proto-oncogene and inactivation of a tumor-suppressor gene
question

All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs? A. Cells produce proto-oncogenes as a by-product of mitosis. B. Proto-oncogenes are necessary for the normal control of cell growth and division. C. Proto-oncogenes protect cells from infection by cancer-causing viruses. D. Proto-oncogenes are unavoidable environmental carcinogens. E. Proto-oncogenes are genetic junk that has not yet been eliminated by natural selection.
answer

B. Proto-oncogenes are necessary for the normal control of cell growth and division.
question

Specific cells that appear undifferentiated under the microscope but are already fated to become muscle cells are called _____. A. meristematic cells B. bicoids C. myoblasts D. muscle cells E. myocytes
answer

E. myocytes
question

Instead of developing a head and a tail, an abnormal Drosophila embryo develops two tails. This is most likely due to _____. A. apoptosis B. a mutation in an operon C. a failure involving post-transcriptional modification of mRNA D. a mutation in a maternal effect gene E. destruction of the RNA polymerase molecules responsible for the transcription of genes that encode head-related proteins
answer

A. apoptosis
question

A cancer cell _____. A. is typically more than 10 times larger than a normal cell B. usually does not contain a nucleus C. does not respond to the chemical signals that control cell division D. requires less nutrients than a normal cell E. all of the above
answer

C. does not respond to the chemical signals that control cell division
question

What gene has been called the “guardian angel of the genome?” A. The p21 gene B. The BRCA1 gene C. The ras gene D. The myoD gene E. The p53 gene
answer

E. The p53 gene
question

Why is cancer more prevalent in older people? A. Cancer involves an accumulation of mutations, so older people have had more time to accumulate mutations in their DNA. B. Cancer is caused by viruses, and older people are more susceptible to viral infections. C. Cancer lies dormant for many years before causing problems. D. Most cancers are inherited as a recessive allele, so it takes time for the allele to be expressed. E. Cancer involves changes in gene expression, and it takes many years for gene expression to change.
answer

D. Most cancers are inherited as a recessive allele, so it takes time for the allele to be expressed.