H-Bio Ch. 11

During an experiment assessing the development of a fly embryo, a scientist artificially turns on a homeotic gene that controls eye development in somatic cells that develop into the wings. Which of the following is the most likely outcome of this experiment?

A mutant adult fly will develop that has eyes on its wings.

Which of the following statements regarding DNA packing is false?

DNA packing tends to promote gene expression

All of the following mechanisms are used to regulate protein production except

DNA replication.

Enhancers are

DNA sequences to which activator proteins bind.

The lac operon consists a promoter, regulator, and an operator and series of genes that code for enzymes.

Describe the physical structure of the lac operon

Which of the following statements about microarrays is false?

Microarrays use tiny portions of double-stranded RNA fragments from a large number of genes.

Which of the following statements regarding cancer risk factors is false?

Mutagens are usually not carcinogens.

Mutations in the p53 gene can lead to cancer by

Mutations in the p53 gene can lead to cancer by

A normal muscle cell produces the myosin protein, which allows muscles to contract. You discover a single muscle cell that has tRNAs that do not bind to amino acids. Will the myosin gene be expressed in this muscle cell? Why or why not?

No, because if the tRNAs do not bind amino acids, then translation cannot occur.

Which of the following statements regarding skin cells and muscle cells in your body is true?

Skin cells and muscle cells each contain information about both muscle proteins and skin color.

A stomach cell is producing pepsin, an enzyme that hydrolyzes proteins. Which of the following events suggests that gene expression of pepsin has been turned off in the cell?

The chromosome with the pepsin gene is tightly coiled.

Which of the following statements about fruit fly development is false?

The location of the head and tail ends of the egg is primarily determined by the location of sperm entry during fertilization.

Genes control cellular activities through a two-step process known as gene expression. Name and discuss the significance of the two steps.

Transcription copies DNA to mRNA Translation copies mRNA to Protien

There is a mutation in the operator of the trp operon in a cell such that the trp repressor is unable to bind to the operator. If tryptophan is added to the cell, what will happen?

Tryptophan will bind to the repressor, and trp enzymes will be produced.

In plants, most differentiated cells retain

a complete set of their genes and retain the ability to express those genes under certain circumstances

the expression of the tryptophan operon is controlled by

a repressor that is active when it binds to tryptophan.

Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to a promoter are called

activators

Which of the following permits a single gene to code for more than one polypeptide?

alternative RNA splicing

In a prokaryote, a group of genes with related functions, along with their associated control sequences, defines

an operon.

Adult stem cells have limited therapeutic potential

because their developmental potential is limited to certain tissues.

In female mammals, the inactive X chromosome in each cell

becomes a Barr body.

RNA interference (RNAi) can be used by

cells to prevent infections from double-stranded RNA viruses.

Which of the following processes occurs when a salamander regenerates a lost limb?

certain cells in the limb dedifferentiate, divide, and then redifferentiate to form a new limb.

The cloning of Dolly the sheep

demonstrated that the nuclei from differentiated mammalian cells can retain their full genetic potential.

Mutations in the proto-oncogene ras and the tumor suppressor gene p53

disrupt normal regulation of the cell cycle.

Transcription factors attach to

dna

The coding regions of a gene are called

exons

In thinking about their role in cell division, oncogenes are like the ________ of a car, while tumor suppressor genes are like the ________ of a car.

gas pedal, brakes

Which of the following mammals has not yet been cloned and brought through the complete gestation cycle?

human

The figure below shows a normal cell transduction pathway. If the receptor wasn't there, which of the following is the most likely outcome?

increased.

Small pieces of RNA that can regulate translation of mRNA are called

microRNA.

Part complete What is the correct order of structures in a chromosome from smallest to largest?

nucleotide, histone, nucleosome, tight helical fiber, supercoil, chromosome

A gene that can cause cancer when present in a single copy in a cell is called a/an

oncogene.

To initiate a signal transduction pathway, a signal binds to a receptor protein usually located in the

plasma membrane

The lac operon in Escherichia coli

prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment.

The term "gene expression" refers to the

process by which genetic information flows from genes to proteins.

Both prokaryotic and eukaryotic cells use ________ to turn certain genes on or off.

proteins

Which of the following molecules are not required to express a gene in eukaryotic cells?

repressor protein

5. Describe the role of THREE of the following in the regulation of protein synthesis (gene expression). (5 points) • RNA splicing • Repressor proteins • Methylation • miRNA

repressor proteins-a gene product encoded by a regulatory gene\methyl-addition of methyl groups to the cytosine of CG doublets

The basis of cellular differentiation is

selective gene expression.

A homeotic gene

serves as a master control gene that functions during embryonic development by controlling the developmental fate of groups of cells.

Which of the following is not a factor that contributes to normal cells becoming cancerous?

the production of more effective tumor-suppressor gene products

4. What is the function of the regulator gene in the lac operon

the regulator gene produces a repressor protein, which interacts with the operator to shut off transcription.

Which of the following possible uses of reproductive cloning is still considered by most to be an unresolved ethical issue?

the reproductive cloning of humans

The use of cloning to produce special embryonic stem cells is called

therapeutic cloning.

The relationship between DNA and chromosomes is most like

thread wrapped around a spool.

Yeast are able to communicate with each other

through chemical signaling.

The carcinogen known to cause the most cases and types of cancer is

tobacco

2 steps of gene expression

transcription and translation

Which of the following mechanisms of controlling gene expression occurs outside of the nucleus?

translation

The development of colon cancer occurs slowly, and colon cancer is more frequently seen in the elderly than the young. This is most likely because

usually six or more somatic mutations must occur to give rise to the cancer, which takes time.