Question 1

How does the transcription of structural genes in an inducible operon occur?

Accepted Answer

A)  It occurs continuously in the cell. 
B)  It starts when the pathway's substrate is present. 
C)  It starts when the pathway's product is present. 
D)  It stops when the pathway's product is present. 
A)  It occurs continuously in the cell. 
B)  It starts when the pathway's substrate is present. 
C)  It starts when the pathway's product is present. 
D)  It stops when the pathway's product is present.

Question 2

If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then

Accepted Answer

A)  the amino acid inactivates the repressor. 
B)  the repressor is active in the absence of the amino acid. 
C)  the amino acid acts as a corepressor. 
D)  the amino acid turns on transcription of the operon. 
A)  the amino acid inactivates the repressor. 
B)  the repressor is active in the absence of the amino acid. 
C)  the amino acid acts as a corepressor. 
D)  the amino acid turns on transcription of the operon.

Question 3

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Accepted Answer

A)  Proto-oncogenes first arose from viral infections. 
B)  Proto-oncogenes are mutant versions of normal genes. 
C)  Proto-oncogenes are genetic "junk". 
D)  Proto-oncogenes normally help regulate cell division. 
A)  Proto-oncogenes first arose from viral infections. 
B)  Proto-oncogenes are mutant versions of normal genes. 
C)  Proto-oncogenes are genetic "junk". 
D)  Proto-oncogenes normally help regulate cell division.

Question 4

How does extracellular glucose inhibit transcription of the lac operon?

Accepted Answer

A)  by strengthening the binding of the repressor to the operator 
B)  by weakening the binding of the repressor to the operator 
C)  by inhibiting RNA polymerase from opening the strands of DNA to initiate transcription 
D)  by reducing the levels of intracellular cAMP 
A)  by strengthening the binding of the repressor to the operator 
B)  by weakening the binding of the repressor to the operator 
C)  by inhibiting RNA polymerase from opening the strands of DNA to initiate transcription 
D)  by reducing the levels of intracellular cAMP

Question 5

Among the newly discovered small noncoding RNAs, one type helps to reestablish ethylation patterns during gamete formation and blocks expression of some transposons. Which of the following types of RNA is responsible for this function?

Accepted Answer

A)  miRNA 
B)  piRNA 
C)  lncRNA 
D)  siRNA 
A)  miRNA 
B)  piRNA 
C)  lncRNA 
D)  siRNA

Question 6

Which of the following are maternal effect genes that control the orientation of the egg and thus the Drosophila embryo?

Accepted Answer

A)  homeotic genes 
B)  segmentation genes 
C)  egg-polarity genes 
D)  morphogens 
A)  homeotic genes 
B)  segmentation genes 
C)  egg-polarity genes 
D)  morphogens

Exam 18: Regulation of Gene Expression

How does the transcription of structural genes in an inducible operon occur?

If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

How does extracellular glucose inhibit transcription of the lac operon?

Among the newly discovered small noncoding RNAs, one type helps to reestablish ethylation patterns during gamete formation and blocks expression of some transposons. Which of the following types of RNA is responsible for this function?

Which of the following are maternal effect genes that control the orientation of the egg and thus the Drosophila embryo?

Evolution, the Themes of Biology, and Scientific Inquiry

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Viruses

Dna Tools and Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonised Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Vascular Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signalling

Nervous Systems

Sensory and Motor Mechanisms

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