Chapter 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

A single cell, the zygote, can develop into an entirely new organism with many different specialized cells. Which of the following statements about this process is false?

Additional genetic information for the formation of specialized cells is passed on to the developing embryo via the mother.

Which of the following statements regarding the comparison of DNA microarrays and qPCR is false?

Both methods use fluorescent DNA molecules and cDNA

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.

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

What is the proper order of events in the expression of a eukaryotic protein?

DNA unpacking, mRNA splicing, translation, protein folding

Which of the following statements about microarrays is false?

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

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

Why can some plants be cloned from a single cell

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

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.

Why don't the grafted hybrids produce apples with a blend of traits from the scion and the rootstock?

The rootstock regulates gene expression in the scion but contributes no genetic information for fruit production.

All of the trees in an orchard were derived from the same rootstock, but half had scion "A" grafted and the other half had a different scion, scion "B," grafted. The trees that were grafted with scion "A" developed large fruits. What characteristics do you think the fruit from the trees that were grafted with scion "B" will have and why?

There is not enough information to know what the fruit will look like

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

A scientist hypothesizes that a new drug turns on a certain gene in a skin cell. Which of the following experiments would be the best to test her hypothesis?

Use qPCR to measure the initial levels of gene expression in skin cells, treat skin cells with the drug and measure the levels of gene expression, and then compare the two measurements.

Scientists are attempting to make a chicken look like a dinosaur ("dino-chicken") by using drugs or proteins to turn on certain homeotic genes during the development of a chicken embryo. If the scientists are successful in creating both male and female "dino-chickens," and then the "dino-chickens" mate together, what type of offspring would the two "dino-chickens" have?

a male or female normal chicken

the expression of the tryptophan operan 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

A pancreatic cell normally produces low levels of the protein insulin, but after a meal it produces large levels of insulin before returning to its initial state. Which of the following figures would represent qPCR data obtained from a pancreatic cell that went through this cycle?

c, goes up in the middle

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

cell division will be increased

RNA interference (RNAi) can be used by

cells to prevent infections from double-stranded RNA viruses

the cloning of Dolly the sheep

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

Melanoma (skin cancer) can develop after several mutations occur in skin cells. If a woman is diagnosed with melanoma and becomes pregnant, what are the chances that her offspring will inherit melanoma?

it is unlikely that the offspring will be born with melanoma

There is a mutation in the operator of the lac operon in a cell such that the lac repressor always stays bound to the operator. If lactose is added to the cell, what will happen?

lactose wil bind to the repressor and lac enzymes will not be produced

In this drawing of the lac operon, which molecule is an inactive repressor?

molecule D

the term "gene expression" refers to the

process by which genetic info flows from genes to proteins

RNA splicing involves the

removal of introns from the molecule

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 structure in this figure shows one complete nucleosome

structure D

Two yeast cells, one of type a and the other type α, are in proximity to each other. The a yeast cell has a mutation in the gene for the α factor receptor protein such that the receptor does not translocate to the surface of the a cell. If both cells secrete their respective a and α factors, which of the following outcomes is most likely to occur?

the A cell will grow towards to a cell

A cell has a mutation in both alleles of its p53 gene that causes the p53 protein to be three times as effective as normal. What do you predict would happen to this cell?

the cell would divide into six daughter cells instead of two and would lead to cancer

In a muscle cell, the contractile protein myosin is present in larger quantities than the structural protein actin. Which of the following qPCR results would support this observation?

the fluorescent signal for myosin is higher than that of actin

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

tobacco

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.

Half the trees in an orchard were derived from rootstock "A" and half from rootstock "B,"but all the trees had the same scion. If the trees grafted onto rootstock "A" were infected by a parasite that causes blossom rot, the trees grafted onto rootstock "B"

would be very likely to become infected, because the remaining scions are genetically identical to those that are already infected.