Chapter 18

_____ bind(s) to DNA enhancer regions. RNA polymerase Promoters Introns Activators Exons

Activators Activators are a type of transcription factor that bind to enhancer regions.

How are genes coordinately controlled in eukaryotic cells? Select all that apply. Select all that apply. Coordinately controlled genes in eukaryotic cells are activated by the same chemical signals. Coordinately controlled genes in eukaryotic cells share a set of control elements. Coordinately controlled genes in eukaryotic cells are located together on the same chromosome.

Coordinately controlled genes in eukaryotic cells are activated by the same chemical signals. Coordinately controlled genes in eukaryotic cells share a set of control elements. In eukaryotes, specific transcription factors bind to control elements, promoting transcription of coordinately controlled genes, even if the genes are on separate chromosomes. Read about coordinately controlled genes in eukaryotes.

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

Different genes are expressed so that different proteins are produced. Cell differentiation results from changes in gene expression.

Which of these is true of the cytoplasm of an unfertilized egg? It does not contain substances that are important in directing development. These substances are produced by the DNA of the fertilized zygote. It is an unevenly distributed mixture of mRNA, proteins, organelles, and other substances. It does not contain substances that are important in directing development. Development is directed solely by the surrounding cells. It does not contain substances that are important in directing development. These substances are supplied by the sperm. It is a homogeneous mixture of mRNA, proteins, organelles, and other substances.

It is an unevenly distributed mixture of mRNA, proteins, organelles, and other substances. Many proteins are found concentrated at one end of the cell or another and provide positional information to the developing embryo.

It is possible for a cell to make proteins that last for months; hemoglobin in red blood cells is a good example. However, many proteins are not this long-lasting; they may be degraded in days, hours, or even minutes. What is the advantage of short-lived proteins? Cells lack the raw materials to make most of the proteins they need. Short-lived proteins enable the cells to control their activities precisely and efficiently. Most cells have a short life span. Most proteins are used only once. Long-lasting proteins are likely to make the cell cancerous.

Short-lived proteins enable the cells to control their activities precisely and efficiently. Some proteins are needed only for short-term use.

Which of the following mechanisms is (are) used to coordinate the expression of multiple, related genes in eukaryotic cells? A single repressor is able to turn off several related genes. The genes share a single common enhancer, which allows appropriate activators to turn on their transcription at the same time. Environmental signals enter the cell and bind directly to promoters. The genes are organized into a large operon, allowing them to be coordinately controlled as a single unit.

The genes share a single common enhancer, which allows appropriate activators to turn on their transcription at the same time.

Imagine that you've isolated a yeast mutant that contains histones resistant to acetylation. What phenotype do you predict for this mutant? The mutant will show low levels of gene expression. The mutant will grow rapidly. The mutant will show high levels of gene expression. The mutant will require galactose for growth.

The mutant will show low levels of gene expression.

Not long ago, it was believed that a count of the number of protein-coding genes would provide a count of the number of proteins produced in any given eukaryotic species. This is incorrect, largely due to the discovery of widespread _____. chromatin condensation control translational control transcriptional control alternative splicing

alternative splicing

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

amplification of a proto-oncogene and inactivation of a tumor-suppressor gene Excess copies of the proto-oncogene could stimulate cell division abnormally, and the inactivation of a tumor-suppressor gene would eliminate a brake on cell division.

What is the event that IMMEDIATELY follows the last event of this animation? unbending of the DNA and the release of RNA polymerase from the promoter binding of the activators to enhancers transcription binding of mRNA to the smaller ribosomal subunit binding of RNA polymerase to the promoter

binding of RNA polymerase to the promoter The bending of the DNA allows for the interaction of transcription factors and RNA polymerase.

The trp repressor blocks transcription of the trp operon when the repressor _____. is not bound to tryptophan binds to the inducer is not bound to the operator binds to tryptophan

binds to tryptophan

Forms of the Ras protein found in tumors usually cause which of the following? excessive cell division cell-to-cell adhesion to be nonfunctional cell division to cease DNA replication to stop

excessive cell division

DNA methylation is a mechanism used by eukaryotes to do what? cause apoptosis increase the rate of transcription facilitate the binding of DNA to intermediate filaments terminate transcription inactivate genes

inactivate genes DNA methylation, involving the attachment of methyl groups to certain bases, is a mechanism for the long-term inactivation of genes during development.

The product of the p53 gene _____. causes cells to reduce expression of genes involved in DNA repair allows cells to pass on mutations due to DNA damage inhibits the cell cycle slows down the rate of DNA replication by interfering with the binding of DNA polymerase

inhibits the cell cycle