BIO 160 - CHAPTER 11

In prokaryotes, a group of genes with related functions is called _____. a. an operon b. a constitutive area c. a repressor d. an activator e. RNA polymerase

a. an operon An operon is a group of structural genes with related functions.

Within an operon, repressors _____. a. block gene transcription to RNA by attaching to the operator b. block gene transcription to RNA by attaching to the promoter c. block mRNA translation by attaching to the mRNA for a specific gene d. block gene transcription to RNA by attaching directly to the gene itself

a. block gene transcription to RNA by attaching to the operator

Which of the following molecules would bind to an operator? a. a histone b. a transcription factor c. a nucleosome d. an active repressor e. RNA polymerase

d. an active repressor The binding of an active repressor to an operator inhibits gene expression.

_____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell's cytoplasm. a. Adenylyl cyclase ... cyclic AMP ... Ca2+ b. Phospholipase C ... IP3 .... Ca2+ c. Phospholipase C ... cyclic AMP ... Ca2+ d. Protein kinase ... PIP2 ... Na+ e. Adenylyl cyclase ... IP3 .... Ca2+

b. Phospholipase C ... IP3 .... Ca2+

Why can some plants be cloned from a single cell? a. Plant cells can produce genes to replace those lost during development. b. Plant cells can dedifferentiate and give rise to all of the specialized cells required to produce an entire plant. c. Plant cells do not differentiate even when mature, so any cell can grow into an entire plant. d. Plant cells are capable of self-renewal by utilizing cellular components from adjacent cells.

b. Plant cells can dedifferentiate and give rise to all of the specialized cells required to produce an entire plant.

Which of the following permits a single gene to code for more than one polypeptide? a. retention of different introns in the final version of the different mRNA strands b. alternative RNA splicing c. genetic differentiation d. addition of different types of caps and tails to the final version of the mRNA strands

b. alternative RNA splicing

In a prokaryote, a group of genes with related functions, along with their associated control sequences, defines a. an allele. b. an operon. c. a locus. d. a transposon.

b. an operon.

Some glucose transport molecules are controlled by levels of insulin. When insulin binds to a specific _____, the signal is relayed to a(n) _____ , which then controls gene expression. a. signal molecule ... silencer b. receptor ... transcription factor c. relay protein ... activator protein d. plasma membrane ... transcription factor e. activator ... silencer

b. receptor ... transcription factor Insulin binds to the insulin receptor. The signal is then relayed through a series of proteins to activate a specific transcription factor. This then triggers production of specific genes.

To begin the process of gene transcription, RNA polymerase attaches to _____. a. the gene that will be transcribed b. the promoter associated with the target gene c. the operator associated with the target gene d. none of the above

b. the promoter associated with the target gene

All of the following mechanisms are used to regulate protein production except a. protein activation. b. controlling the start of polypeptide synthesis. c. DNA editing. d. the breakdown of mRNA. e. protein breakdown.

c. DNA editing.

When are DNA molecules the least tightly coiled? a. telophase b. G2 phase of interphase c. S phase of interphase d. metaphase

c. S phase of interphase In order for replication to occur during the cell cycle, the DNA must unwind.

Which of these acts as a second messenger? a. adenylyl kinase b. G-protein-linked receptor c. cyclic AMP d. protein kinase e. G protein

c. cyclic AMP

The coding regions of a gene (the portions that are expressed as polypeptide sequences) are called a. introns. b. proto-oncogenes. c. exons. d. redundant coding sections.

c. exons.

To initiate a signal transduction pathway, a signal binds to a receptor protein usually located in the a. ER. b. nucleus. c. plasma membrane. d. cytoplasm.

c. plasma membrane.

Operons are a standard method for gene regulation in _____. a. all organisms b. eukaryotes but not prokaryotes c. prokaryotes but not eukaryotes d. E. coli, but they are rare in other organisms

c. prokaryotes but not eukaryotes

The tortoiseshell pattern on a cat a. is the result of a homozygous recessive condition. b. usually occurs in males. c. results from X chromosome inactivation. d. is a result of alleles on the Y chromosome.

c. results from X chromosome inactivation.

_____ bind(s) to DNA enhancer regions. a. RNA polymerase b. Promoters c. Introns d. Activators e. Exons

d. Activators

A researcher performs a DNA microarray but forgets to add the enzyme reverse transcriptase. This is important because the enzyme makes _____ from a(n) _____ template. a. mRNA ... RNA b. cDNA ... DNA c. mRNA ... DNA d. cDNA ... mRNA

d. cDNA ... mRNA Reverse transcriptase uses mRNA to make cDNA. This DNA is complementary, as RNA processing has already occurred and the template had no introns.

In embryonic mice, a homeotic gene controls development of the neck, which includes the larynx and thymus. If this gene were deleted, a full-term mouse would show _____. a. development of the larynx and thymus in the lower body b. normal development of the larynx and thymus, because other genes would take over c. inability of the embryo to form an adult mouse d. lack of development of the larynx and thymus

d. lack of development of the larynx and thymus By deleting this critical control gene, the correct signals to form the anatomy normally seen in full-term mice would be missing.

A signal transduction pathway is initiated when a _____ binds to a receptor. a. G protein b. tyrosine kinase c. calmodulin d. signal molecule e. cyclic AMP

d. signal molecule The binding of a signal molecule to a receptor initiates a signal transduction pathway.

Calcium ions that act as second messengers are stored in _____. a. lysosomes b. mitochondria c. peroxisomes d. chloroplasts e. endoplasmic reticula

e. endoplasmic reticula

Eukaryotes have the ability to switch gene expression on or off. If a repressor protein binds to a DNA sequence called a(n) _____, it may block gene expression. a. operon b. histone c. enhancer d. promoter e. silencer

e. silencer The binding of a repressor to a silencer inhibits transcription.