Question 1

What is predicted to occur if the operator is removed from the lac operon?

Accepted Answer

A) The lac operon would be transcribed continuously. 
B) Only lacZ would be transcribed. 
C) Only lacY would be transcribed. 
D) Galactosidase permease would be produced, but would be incapable of transporting lactose. 
E) None of the proteins coded by the lac operon would be produced. 
A) The lac operon would be transcribed continuously. 
B) Only lacZ would be transcribed. 
C) Only lacY would be transcribed. 
D) Galactosidase permease would be produced, but would be incapable of transporting lactose. 
E) None of the proteins coded by the lac operon would be produced.

Question 2

Drosophila larvae (wt)showing segmentation and anterior-posterior axis.
Refer to the image above to answer the following questions.
-Which gene is definitely functioning in the mother of this larva?

Accepted Answer

A) ras 
B) p53 
C) bicoid 
D) myoD 
E) You cannot tell from this larva. 
A) ras 
B) p53 
C) bicoid 
D) myoD 
E) You cannot tell from this larva.

Question 3

Use the following information to answer the questions below.
A researcher introduces double-stranded RNA into a culture of mammalian cells,and can identify its location or that of its smaller subsections experimentally,using a fluorescent probe.
-In addition,she finds what other evidence of this single-stranded RNA piece's activity?

Accepted Answer

A) She can measure the degradation rate of the remaining single strand. 
B) She can measure the decrease in the concentration of Dicer. 
C) The rate of accumulation of the polypeptide to be translated from the target mRNA is reduced. 
D) The amount of miRNA is multiplied by its replication. 
E) The cell's translation ability is entirely shut down. 
A) She can measure the degradation rate of the remaining single strand. 
B) She can measure the decrease in the concentration of Dicer. 
C) The rate of accumulation of the polypeptide to be translated from the target mRNA is reduced. 
D) The amount of miRNA is multiplied by its replication. 
E) The cell's translation ability is entirely shut down.

Question 4

Within a cell,the amount of protein made using a given mRNA molecule depends partly on

Accepted Answer

A) the degree of DNA methylation. 
B) the rate at which the mRNA is degraded. 
C) the presence of certain transcription factors. 
D) the number of introns present in the mRNA. 
E) the types of ribosomes present in the cytoplasm. 
A) the degree of DNA methylation. 
B) the rate at which the mRNA is degraded. 
C) the presence of certain transcription factors. 
D) the number of introns present in the mRNA. 
E) the types of ribosomes present in the cytoplasm.

Question 5

Use the following information to answer the questions below.
A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome.In four of the lines,the transgene is expressed strongly,but in the fifth there is no expression at all.
-Of the lines that express the transgene,one is transcribed but not translated.Which of the following is a likely explanation?

Accepted Answer

A) no promoter 
B) no AUG in any frame 
C) no compatible ribosome 
D) high histone acetylation 
E) missing transcription factor 
A) no promoter 
B) no AUG in any frame 
C) no compatible ribosome 
D) high histone acetylation 
E) missing transcription factor

Question 6

Most repressor proteins are allosteric.Which of the following binds with the repressor to alter its conformation?

Accepted Answer

A) inducer 
B) promoter 
C) RNA polymerase 
D) transcription factor 
E) cAMP 
A) inducer 
B) promoter 
C) RNA polymerase 
D) transcription factor 
E) cAMP

Question 7

Muscle cells differ from nerve cells mainly because they

Accepted Answer

A) express different genes. 
B) contain different genes. 
C) use different genetic codes. 
D) have unique ribosomes. 
E) have different chromosomes. 
A) express different genes. 
B) contain different genes. 
C) use different genetic codes. 
D) have unique ribosomes. 
E) have different chromosomes.

Question 8

Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?

Accepted Answer

A) Eukaryotic mRNAs get 5' caps and 3' tails. 
B) Prokaryotic genes are expressed as mRNA, which is more stable in the cell. 
C) Eukaryotic exons may be spliced in alternative patterns. 
D) Prokaryotes use ribosomes of different structure and size. 
E) Eukaryotic coded polypeptides often require cleaving of signal sequences before localization. 
A) Eukaryotic mRNAs get 5' caps and 3' tails. 
B) Prokaryotic genes are expressed as mRNA, which is more stable in the cell. 
C) Eukaryotic exons may be spliced in alternative patterns. 
D) Prokaryotes use ribosomes of different structure and size. 
E) Eukaryotic coded polypeptides often require cleaving of signal sequences before localization.

Question 9

What causes an increase in CAP?

Accepted Answer

A) increase in glucose and increase in cAMP 
B) decrease in glucose and increase in cAMP 
C) increase in glucose and decrease in cAMP 
D) decrease in glucose and increase in repressor 
E) decrease in glucose and decrease in repressor 
A) increase in glucose and increase in cAMP 
B) decrease in glucose and increase in cAMP 
C) increase in glucose and decrease in cAMP 
D) decrease in glucose and increase in repressor 
E) decrease in glucose and decrease in repressor

Question 10

Since Watson and Crick described DNA in 1953,which of the following might best explain why the function of small RNAs is still being explained?

Accepted Answer

A) As RNAs have evolved since that time, they have taken on new functions. 
B) Watson and Crick described DNA but did not predict any function for RNA. 
C) The functions of small RNAs could not be approached until the entire human genome was sequenced. 
D) Ethical considerations prevented scientists from exploring this material until recently. 
E) Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible. 
A) As RNAs have evolved since that time, they have taken on new functions. 
B) Watson and Crick described DNA but did not predict any function for RNA. 
C) The functions of small RNAs could not be approached until the entire human genome was sequenced. 
D) Ethical considerations prevented scientists from exploring this material until recently. 
E) Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible.

Question 11

Use the following figure to answer the questions below.
  
-What is chemically different between A and B in the above image?

Accepted Answer

A) A is acetylated. 
B) A is methylated. 
C) B is acetylated. 
D) B is methylated. 
E) A has histones. 
A) A is acetylated. 
B) A is methylated. 
C) B is acetylated. 
D) B is methylated. 
E) A has histones.

Question 12

Use the following information to answer the questions below.
A researcher has arrived at a method to prevent gene expression from Drosophila embryonic genes.The following questions assume that he is using this method.
-The researcher measures the concentration of the polypeptides from different regions in the early embryo and finds the following pattern (darker shading = greater concentration):
 
Which of the following would be his most logical assumption?

Accepted Answer

A) The substance has moved quickly from region 5 to region 1. 
B) Some other material in the embryo is causing accumulation in region 1 due to differential binding. 
C) The cytosol is in constant movement, dispersing the polypeptide. 
D) The substance is produced in region 1 and diffuses toward region 5. 
E) The substance must have entered the embryo from the environment near region 1. 
A) The substance has moved quickly from region 5 to region 1. 
B) Some other material in the embryo is causing accumulation in region 1 due to differential binding. 
C) The cytosol is in constant movement, dispersing the polypeptide. 
D) The substance is produced in region 1 and diffuses toward region 5. 
E) The substance must have entered the embryo from the environment near region 1.

Question 13

In humans,the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults.This is due to

Accepted Answer

A) nonidentical genes that produce different versions of globins during development. 
B) identical genes that generate many copies of the ribosomes needed for fetal globin production. 
C) pseudogenes, which interfere with gene expression in adults. 
D) the attachment of methyl groups to cytosine following birth, which changes the type of hemoglobin produced. 
E) histone proteins changing shape during embryonic development. 
A) nonidentical genes that produce different versions of globins during development. 
B) identical genes that generate many copies of the ribosomes needed for fetal globin production. 
C) pseudogenes, which interfere with gene expression in adults. 
D) the attachment of methyl groups to cytosine following birth, which changes the type of hemoglobin produced. 
E) histone proteins changing shape during embryonic development.

Question 14

Two potential devices that eukaryotic cells use to regulate transcription are

Accepted Answer

A) DNA methylation and histone amplification. 
B) DNA amplification and histone methylation. 
C) DNA acetylation and methylation. 
D) DNA methylation and histone modification. 
E) histone amplification and DNA acetylation. 
A) DNA methylation and histone amplification. 
B) DNA amplification and histone methylation. 
C) DNA acetylation and methylation. 
D) DNA methylation and histone modification. 
E) histone amplification and DNA acetylation.

Question 15

The product of the bicoid gene in Drosophila provides essential information about

Accepted Answer

A) lethal genes. 
B) the dorsal-ventral axis. 
C) the left-right axis. 
D) segmentation. 
E) the anterior-posterior axis. 
A) lethal genes. 
B) the dorsal-ventral axis. 
C) the left-right axis. 
D) segmentation. 
E) the anterior-posterior axis.

Question 16

Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts.This is evidence that the product of the bicoid gene

Accepted Answer

A) is transcribed in the early embryo. 
B) normally leads to formation of tail structures. 
C) normally leads to formation of head structures. 
D) is a protein present in all head structures. 
E) leads to programmed cell death. 
A) is transcribed in the early embryo. 
B) normally leads to formation of tail structures. 
C) normally leads to formation of head structures. 
D) is a protein present in all head structures. 
E) leads to programmed cell death.

Question 17

There is a mutation in the lac repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently.Which of these would characterize such a mutant?

Accepted Answer

A) It cannot bind to the operator. 
B) It cannot make a functional repressor. 
C) It cannot bind to the inducer. 
D) It makes molecules that bind to one another. 
E) It makes a repressor that binds CAP. 
A) It cannot bind to the operator. 
B) It cannot make a functional repressor. 
C) It cannot bind to the inducer. 
D) It makes molecules that bind to one another. 
E) It makes a repressor that binds CAP.

Question 18

Use the following information to answer the questions below.
A few decades ago,Knudsen and colleagues proposed a theory that,for a normal cell to become a cancer cell,a minimum of two genetic changes had to occur in that cell.Knudsen was studying retinoblastoma,a childhood cancer of the eye.
-In colorectal cancer,several genes must be mutated in order to make a cell a cancer cell,supporting Knudsen's hypothesis.Which of the following kinds of genes would you expect to be mutated?

Accepted Answer

A) genes coding for enzymes that act in the colon 
B) genes involved in control of the cell cycle 
C) genes that are especially susceptible to mutation 
D) the same genes that Knudsen identified as associated with retinoblastoma 
E) the genes of the bacteria that are abundant in the colon 
A) genes coding for enzymes that act in the colon 
B) genes involved in control of the cell cycle 
C) genes that are especially susceptible to mutation 
D) the same genes that Knudsen identified as associated with retinoblastoma 
E) the genes of the bacteria that are abundant in the colon

Question 19

Use the following information to answer the questions below.
A researcher has arrived at a method to prevent gene expression from Drosophila embryonic genes.The following questions assume that he is using this method.
-The researcher in question measures the amount of new polypeptide production in embryos from 2-8 hours following fertilization and the results show a steady and significant rise in polypeptide concentration over that time.The researcher concludes that

Accepted Answer

A) his measurement skills must be faulty. 
B) the results are due to building new cell membranes to compartmentalize dividing nuclei. 
C) the resulting new polypeptides are due to translation of maternal mRNAs. 
D) the new polypeptides were inactive and not measurable until fertilization. 
E) polypeptides were attached to egg membranes until this time. 
A) his measurement skills must be faulty. 
B) the results are due to building new cell membranes to compartmentalize dividing nuclei. 
C) the resulting new polypeptides are due to translation of maternal mRNAs. 
D) the new polypeptides were inactive and not measurable until fertilization. 
E) polypeptides were attached to egg membranes until this time.

Question 20

Use the following information to answer the questions below.
A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture.
-She tried decreasing the amount of methylation enzymes in the embryonic stem cells and then allowed the cells to further differentiate.Which of the following results would she most likely see?

Accepted Answer

A) increased chromatin condensation 
B) decreased chromatin condensation 
C) abnormalities of mouse embryos 
D) decreased binding of transcription factors 
E) inactivation of the selected genes 
A) increased chromatin condensation 
B) decreased chromatin condensation 
C) abnormalities of mouse embryos 
D) decreased binding of transcription factors 
E) inactivation of the selected genes

Exam 18: Regulation of Gene Expression

What is predicted to occur if the operator is removed from the lac operon?

Drosophila larvae (wt)showing segmentation and anterior-posterior axis. Refer to the image above to answer the following questions. -Which gene is definitely functioning in the mother of this larva?

Within a cell,the amount of protein made using a given mRNA molecule depends partly on

Most repressor proteins are allosteric.Which of the following binds with the repressor to alter its conformation?

Muscle cells differ from nerve cells mainly because they

Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?

What causes an increase in CAP?

Since Watson and Crick described DNA in 1953,which of the following might best explain why the function of small RNAs is still being explained?

Use the following figure to answer the questions below. -What is chemically different between A and B in the above image?

In humans,the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults.This is due to

Two potential devices that eukaryotic cells use to regulate transcription are

The product of the bicoid gene in Drosophila provides essential information about

Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts.This is evidence that the product of the bicoid gene

There is a mutation in the lac repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently.Which of these would characterize such a mutant?

Introduction: Evolution and Themes of Biology

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

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 Colonized 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

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

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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