question

Cells must control gene expression so that a. their genes will only be expressed when needed. b. their genes will always be expressed. c. their genes will never be expressed. d. genetic disorders can be corrected.

answer

a. (their genes will only be expressed when needed)

question

Cells control the expression of their genes a. with regulatory sites found on each gene. b. with specific regulatory proteins. c. by determining when individual genes are to be transcribed. d. All of the above

answer

d. (all of the above)

question

In prokaryotic cells, a group of genes that code for functionally related proteins is a(n) a. exon. b. intron. c. operon. d. riboson.

answer

c. (operon)

question

The function of an operator is to a. regulate access of RNA polymerase to structural genes. b. turn on and off the molecules of tRNA. c. control the process of transcription within the nucleus. d. generate amino acids for protein synthesis.

answer

a. (regulate access of RNA polymerase to structural genes)

question

A repressor protein a. prevents DNA synthesis. b. blocks movement of RNA polymerase toward structural genes. c. attaches to ribosomes during translation. d. destroys amA repressor protein

answer

b. (blocks movement of RNA polymerase toward structural genes)

question

Inducer molecules allow transcription to proceed by a. destroying repressor proteins. b. unwinding the cell's DNA molecules. d. changing the shape of repressor proteins.

answer

d. (changing the shape of repressor proteins)

question

In order for RNA polymerase to attach to a DNA molecule, a. the RNA polymerase must recognize a promoter. b. an inducer must attach to the RNA polymerase molecule. c. transcription must first occur. d. translation must be completed.

answer

a. (the RNA polymerase must recognize a promoter)

question

What type of gene codes for a repressor protein? a. regulator b. promoter c. operon d. enhancer

answer

a. (regulator)

question

Which enzyme's action is prevented by the presence of a repressor protein? a. DNA polymerase b. lactase c. RNA polymerase d. permease

answer

c. (RNA polymerase)

question

Where on the lac operon does a repressor molecule bind when lactose is absent? a. to the operator b. to the promoter c. to a structural gene d. to the regulator

answer

b (the promoter)

question

The lac operon is shut off when a. lactose is present. b. lactose is absent. c. glucose is present. d. glucose is absent.

answer

b. (lactose is absent)

question

An inducer molecule functions by a. causing DNA replication. b. binding the rRNA subunits of a ribosome. c. removing a repressor molecule from an operator. d. digesting lactose molecules in bacterial cells.

answer

c. (removing a repressor molecule from an operator)

question

repressor : operator :: a. promoter : RNA polymerase b. promoter : DNA c. RNA polymerase : promoter d. termination signal : DNA

answer

c. (RNA polymerases : promoter)

question

The portions of DNA molecules that actually code for the production of proteins in eukaryotes are called a. mutons. b. exons. c. introns. d. exposons.

answer

b. (exons)

question

In eukaryotes, the noncoding portions of DNA are called a. mutons. b. exons. c. introns. d. exposons.

answer

c. (introns)

question

After mRNA has been transcribed, a. its introns are cut out. b. its exons are joined together. c. it leaves the nucleus. d. All of the above

answer

d. (all of the above)

question

A sequence of nucleotides in a DNA molecule that aids in arranging RNA polymerase in the correct position on the promoter is called a(n) a. repressor. b. operon. c. operator. d. enhancer.

answer

d. (enhancer)

question

Which of the following is not part of morphogenesis? a. the formation of cellular extensions in nerve cells and the functioning of these cells in receiving and transmitting signals b. the formation of long, thin muscle cells that are able to respond to the proper stimulus by contracting c. the formation of liver cells that produce enzymes that break down fat d. the formation of a zygote

answer

d. (the formation of a zygote)

question

Which of the following is not characteristic of homeoboxes? a. They are parts of genes. b. They produce regulatory proteins that switch on or off groups of developmental genes. c. They determine what species of organism will develop from a zygote. d. Each controls the development of a specific part of the adult organism.

answer

c. (they determine what species of organism will develop from a zygote)

question

A substance that causes cancer is known as a a. tumor. b. carcinogen. c. mutation. d. metastasis.

answer

b. (carcinogen)

question

Metastasis is characterized by a. the growth of a benign tumor. b. spread of malignant cells beyond their original site. c. localization of a tumor to a particular location. d. conversion of a malignant tumor to a benign tumor.

answer

b. (spread malignant cells beyond their original site)

question

Cells grow and divide at an abnormally high rate in a. diabetes. b. cancer. c. cytokinesis. d. mitosis.

answer

b. (cancer)

question

An oncogene a. metastasizes to other chromosomes. b. prevents a cell from reproducing. c. induces numerous mutations of the chromosome on which it is found d. may cause a cell to become a cancer cell.

answer

d. (may cause a cell to become a cancer cell)

question

Which of the following best describes the function of gene expression? A. It determines how a protein will be used. B. It is the activation, or "turning on," of a gene. C. It is the final appearance of a protein. D. It is a way of examining the entire set of genetic material in an individual.

answer

b. (it is the activation, or "turning on," of a gene)

question

An operon is A. the part of a gene that is translated. B. the part of a gene that is not translated. C. a series of genes, including some that code for specific protein products and others that regulate the production of those products. D. a repressor protein that prevents gene expression when the protein is in place.

answer

c. (a series of genes, including some that code for specific protein products and others that regulate the production of those products.)

question

Which of the following best describes how a lac operon is turned on in prokaryotes? A. An RNA polymerase binds with the operator to begin transcription. B. A repressor protein binds to the promoter to prevent transcription. C. Lactose binds with the repressor, which allows transcription to begin. D. The regulator gene codes for the production of the operator, which ultimately controls transcription.

answer

c. (lactos binds with the repressor, which allows transcription to begin)

question

In the lac operon, the inducer is the A. regulator gene. B. repressor protein. C. promoter. D. lactose.

answer

d. (lactose)

question

Which of the following is unique to eukaryotes? A. gene expression B. operons C. multiple chromosomes D. promoters

answer

c. (multiple chromosomes)

question

In eukaryotes, the portions of a gene that are actually translated into amino acids are called A. introns. B. exons. C. operons. D. euchromatin.

answer

b. (exons)

question

What must happen before the pre-mRNA can leave the nucleus? A. The exons must be spliced together. B. The introns must be spliced together. C. The exons must be removed. D. Translation must be completed

answer

a. (the exons must be spliced together)

question

Which of the following is not a true statement about enhancers in the control of gene expression? A. Enhancers must be activated for their associated genes to be expressed. B. An enhancer can be located some distance from the genes it activates. C. Enhancers are sometimes called transcription factors. D. Estrogen plays an important role in the activation of a certain enhancer.

answer

c. (enhancers are sometimes called transcription factors.)

question

Which of the following best describes how morphogenesis is achieved through the control of gene expression? A. The control of gene expression leads to cell differentiation, which leads to tissues, organs, and the overall form of an organism. B. The control of gene expression leads to evolution and new life forms. C. The control of gene expression causes enzymes to break down different food types. D. The control of gene expression can cause or eliminate certain types of genetic diseases.

answer

a. (The control of gene expression leads to cell differentiation, which leads to tissues, organs, and the overall form of an organism.)

question

Homeotic genes A. cause cancer when activated. B. help prevent cancer when activated. C. determine where anatomical structures will develop during morphogenesis. D. determine which proteins are made, which are destroyed, and which are stored for later use.

answer

c. (determine where anatomical structures will develop during morphogenesis

question

Which of the following statements about the influence of homeotic genes on Drosophila development is false? A. Regulatory proteins are made when a homeotic gene is translated. B. Each homeotic gene of Drosophila shares a common sequence of nucleotide pairs. C. Specific patterns of development in the Drosophila are regulated by the homeobox. D. The common nucleotide sequences in a Drosophila play an important role in the larva, but not in the development of adult body parts.

answer

d. (The common nucleotide sequences in a Drosophila play an important role in the larva, but not in the development of adult body parts.)

question

What is the role of the homeobox in development? A. The homeobox is a basic structure that develops into the key parts of a prokaryotic cell. B. The homeobox is a common sequence within the homeotic genes that regulates morphogenesis in specific regions of a developing eukaryote. C. The homeobox prevents mutations in the early, key stages of eukaryote development. D. The homeobox is a sequence of DNA that contains many of the most important homeotic genes, all of which regulate development.

answer

b. (The homeobox is a common sequence within the homeotic genes that regulates morphogenesis in specific regions of a developing eukaryote.)

question

Which of the following is not a key characteristic of cancer cells? A. Cancer cells divide uncontrollably. B. Cancer types are categorized by the types of tissues they affect. C. When cancer cells spread beyond their original site, the condition is known as metastasis. D. Benign tumor cells are what we commonly think of as cancer.

answer

d. (Benign tumor cells are what we commonly think of as cancer.)

question

Most carcinogens are also A. antigens. B. mutagens. C. growth factors. D. tumors.

answer

b. (mutagens)

question

What is the difference between oncogenes and tumor-suppressor genes? A. Oncogenes can cause cancer if they mutate to become tumor-suppressor genes. B. Oncogenes are mutated proto-oncogenes, which cause cancer. Normal tumor-suppressor genes code for proteins that prevent tumors. C. Oncogenes always lead to cancer. Tumor-suppressor genes always fight cancer. D. Under normal conditions, the tumor-suppressor genes code for proteins that activate the oncogenes.

answer

b. (Oncogenes are mutated proto-oncogenes, which cause cancer. Normal tumor-suppressor genes code for proteins that prevent tumors.)

question

1. __ oncogene 2. __ mutation 3. __ euchromatin 4. __ tumor supressor gene 5. __ enhancer 6. __ morphogenesis 7. __ homeotic gene 8. __ carcinogen a. prevents uncontrolled cell division b. substance that increases risk of cancer c. noncoding control sequence in a eukaryotic gene d. gene that causes cancer e. development of an organism's form f. regulates development during morphogenesis g. changes in a cells DNA h. uncoiled form of DNA

answer

1. D 2. G 3. H 4. A 5. C 6. E 7. F 8. B

question

The peice of DNA that overlaps the promoter and serves as an on and off switch in an operon is called an a. promoter site b. enhancer c. operator d. repressor

answer

c. (operator)

question

The first stage of gene expression is called ________________.

answer

transcription

question

Cancer occurs as a result of disorders in cell _________.

answer

division

question

A gene that, when mutated, can cause a cell to become cancerous is called ____________________.

answer

proto-oncogenes

question

A __________ ________ can be used as a tool to determine which genes are being expressed

answer

DNA chip

question

In the abscence of lactose, a repressor protein binds to a. operator b. enhancer c. another repressor d. an exon

answer

a. (operator)

question

In eukaryotic gene regulation proteins called _____________ _________ help arrange RNA polymerases in the correct position of the promoter.

answer

transcription factor

question

A great deal of research on the causes of and a possible cure of cancer focuses on the genes that control the cell cycle. Why?

answer

Cancer is a disease in which cells grow and undergo mitosis at an abnormally high rate. If mitosis or other stages of the cell cycle are cancerous cells could be better controlled, possibly could be slowed or cured

question

Gene may be made more accessible to RNA polymerases by a sequence of nucleotides called __________

answer

enhancers

question

A repressor protein can physically block _______ ___________ from binding to a promotor site on the lac operon

answer

RNA polymerase

question

When there is no lactose present in a bacterial cell, a ______ _______ turns the lac operon ___

answer

repressor protein, off

question

Liver cells differ from muscle cells in the same organism because of _________ _____________

answer

cell differentation

question

operons have been identified in a. prokaryotes only b. eukaryotes only c. both a and b d. structural gene

answer

a. (prokaryotes)

question

Which enzymes action is prevented by the prescence of a repressor protein?

answer

RNA polymerase

question

Because of its position on the operon the __________ is able to control RNA polymerases access to the structural gene

answer

operator

question

Transcription and translation are stages in the process of ______ __________

answer

gene expression

question

transcription begins when an ezymes called _____ _____________ binds to the beginning gene on a region of DNA called a promoter

answer

RNA polymerase

question

A _____________ __________ is a molevule that prevents transcription by blocking the path of RNA polymerase along a molecule of DNA

answer

repressor protein

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