Chapter 11 - How Genes Control - Biol 1030

c

The tortoiseshell pattern on a cat a. usually occurs in males. b. is the result of a homozygous recessive condition. c. results from X chromosome inactivation. d. is a result of alleles on the Y chromosome.

organs

The ultimate aim of therapeutic cloning is to supply cells for the repair of damaged or diseased _________

tumor-supressor genes

This gene normally inhibits cell division or function in the repair of DNA damage, though mutations to this gene INACTIVATE it, allowing for uncontrolled division to occur

RNA interference

the use of miRNA to artificially control gene expression by injecting miRNAs (often called silencing RNAs or siRNA) into a cell to turn off a specific gene sequence

growth factor

A(n) _______ ___________ is a protein that promotes cell division. In excess, such a protein may lead to cancer.

d

Genes linked to Waardenburg syndrome in humans have also been discovered where? a. nematodes b. yeast c. plants d. jellyfish

better, therapeutic, endangered, conservation, diversity

Reproductive cloning is used to produce animals with desirable traits to: - produce _________ agricultural products - produce ____________ agents - restock populations of ___________ animals - belittle _____________ efforts - doesn't help with genetic ____________

acetylation

of DNA and histones causes nucleosomes to loosen and spread apart

oncogenes

cancer causing genes

plant cloning

a root cell can divide to form an adult plant

promoter

A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA.

methylated

genes can be passed to offspring cells; not permanent

tumor-suppressor gene

A(n) ________-__________ _______ is a gene that encodes proteins that inhibit cell division. Such proteins normally help prevent cells from becoming cancerous.

c

Adrenaline is a "fight-or-flight" hormone and is released when danger threatens or in an emergency. It binds to a protein receptor, which causes a number of reactions to occur inside the cell. Enzymes are produced that perform a number of functions, including release of sugar into the bloodstream. What function does adrenaline play in this pathway? a. receptor protein b. enzyme c. signal molecule d. relay protein

d

Adult stem cells have limited therapeutic potential a. because they are fully differentiated. b. because they lack a complete set of genes. c. due to their excessive numbers in tissues. d. because their developmental potential is limited to certain tissues.

mRNA, translation, activation, breakdown

After mRNA is fully processed and transported to the cytoplasm, gene expression can still be regulated by: - breakdown of _____ - initiation of ____________ -protein ______________ - protein _______________

c

All of the following mechanisms are used to regulate protein production except a. protein activation. b. protein breakdown. c. DNA editing. d. the breakdown of mRNA.

b

Both miRNAs and siRNAs are used in a. blocking transcription. b. blocking translation. c. enhancing transcription. d. enhancing translation.

proteins

Control of gene expression allows for cells to produce specific kinds of _______ when and where they are needed

contacting

DNA packing can PREVENT gene expression by preventing RNA polymerase and other transcription proteins from __________ the DNA

c

Enhancers are a. adjacent to the gene that they regulate. b. required to turn on gene expression when transcription factors are in short supply. c. DNA sequences to which activator proteins bind. d. required to facilitate the binding of DNA polymerases.

heterochromatin

Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed.

DNA packing

Eukaryotic chromosomes undergo multiple levels of folding and coiling, called _____ ____________

c

In multicellular eukaryotic cells, the control of gene expression is more complex because _____. a. prokaryotes are restricted to stable environments b. these cells have smaller chromosomes, so each gene must be multifunctional c. these cells are specialized for different functions d. the genes contain information for making proteins

on

Is an operon on or off when RNA polymerase is able to bind to promoter?

c

Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to a promoter are called a. regulators. b. operators. c. activators. d. repressors.

b

RNA polyerase binds where? a. Enhancer b. Promoter c. Initiation start site d. None of the above

c

RNA splicing involves the a. addition of a nucleotide "cap" to the molecule. b. addition of a nucleotide "tail" to the molecule. c. removal of introns from the molecule. d. removal of exons from the molecule.

a

Since the first cloned animal was produced using a fully differentiated cell, a number of observations have been made. Which of the following statements is true in regard to reproductive cloning? a. Only a small fraction of cloned embryos develop normally. b. Cloned animals are physically identical when compared to their parents. c. Cloned animals never stop growing because, similar to cancer cells, the cloned cells never stop dividing. d. Cloned animals are behaviorally identical to their parent animals.

c

The lac operon controls expression of three genes that produce lactose-digesting enzymes. What role does lactose play in regulating the lac operon? a. It is not directly involved in gene regulation in this system. b. It turns off the gene that produces the repressor protein, thereby allowing production of the three enzymes. c. It binds to and disables the repressor protein, thereby allowing production of the three enzymes. d. It binds to the promoter region of the operon, thereby allowing RNA polymerase to attach and begin transcription of the three genes.

euchromatin

The less condensed form of eukaryotic chromatin that is available for transcription.

tobacco

The only substance known to cause more cases and types of cancer than any other single agent is ___________

embryonic

_______________ stem cells are considered MORE promising than adult stem cells for medical application

LAC Operon

a gene system whose operator gene and three structural genes control lactose metabolism in E. coli

subset

a set that is part of a larger set

gene expression

overall process of information flow from genes to proteins

doesnt

Cloning ____________ increase genetic diversity

reproductive cloning

using nuclear transplantation to produce new organisms

carcinogen

A cancer-causing substance that alters DNA

mutagen

A chemical or physical agent that interacts with DNA and causes a mutation.

operon

A cluster of genes with related functions, along with the control sequences, is called an ________

barr body

A dense body formed from a deactivated X chromosome.

d

A gene operon consists of a. a transcribed gene only. b. a promoter only. c. a regulatory gene only. d. transcribed genes, an operator, and a promoter.

oncogene

A gene that causes a cell to become cancerous is called a(n) ______________

regulatory gene

A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.

proto-oncogene

A normal gene that, if mutated, can lead to cancer is called a(n) _______-_________

d

A proto-oncogene is a normal gene that can change into an oncogene. Oncogenes are potentially lethal genes that can cause cancer. Why do cells continue to maintain proto-oncogenes? a. Proto-oncogenes are unavoidable environmental carcinogens. b. Proto-oncogenes protect cells from infection by cancer-causing viruses. c. Proto-oncogenes are genetic junk that has not yet been eliminated by natural selection. d. Proto-oncogenes are necessary for normal control of cell division.

b

Anhydrotic dysplasia is a genetic disorder in humans that results in the absence of sweat glands in the skin. Some men have this defect all over their bodies, but in women it is usually expressed in a peculiar way. Women with this disorder typically have small patches of skin with sweat glands and other patches without sweat glands. This pattern of sweat-gland distribution can be explained by _____. a. a homeotic gene b. X chromosome inactivation c. a mutation d. alternative RNA splicing

homeotic genes

Any of the genes that control the overall body plan (anatomy) of animals by controlling the developmental fate of groups of cells.

prokaryotic

Are operons typically prokaryotic or eukaryotic?

environmental, random

Cloned animals can show differences in anatomy and behavior due to: - _______________ influences - ______________ phenomena

endangered

Cloning has been attempted to save ____________ species

nucleosomes

DNA coiled around histones

c

Dioxin is a by-product of various industrial chemical processes. It is suspected of causing cancer and birth defects in both humans and other animals. Apparently, it acts by entering cells and binding to proteins, altering the pattern of gene expression. Therefore, it is reasonable to propose that dioxin acts by mimicking _____. a. the action of DNA polymerase b. histones c. the role of transcription factors d. enhancers

x-chromosome

Either the maternal or paternal is randomly inactivated during ____-______________ inactivation

carcinogens, exercising, fiber, fat

Healthy lifestyles that reduce the risk of cancer include: 1. avoiding ____________ (ex: sun, tobacco) 2. ___________ adequately 3. high-_________, low-______ diet

linkers

Help stabilize the plasma membrane and attach cells together by joining consecutive nucleosomes

a

Hemoglobin is a molecule that is found in red blood cells. These molecules have to last for months because red blood cells have no nucleus and are unable to make more hemoglobin (they cannot transcribe from no template). However, most proteins are much shorter-lived. What is the advantage to this? a. This enables cells to maintain a precise and efficient control over their activities. b. Long-lasting proteins contribute toward tumor formation. c. Most cells have a short life span. d.Most proteins are used only once.

off

Is an operon on or off when a repressor is active?

off

Is an operon on or off when a repressor is bound to an operator?

on

Is an operon on or off when enzymes are produced?

on

Is an operon on or off when lactose is present?

subset

Most differentiated cells retain a full set of genes, even though only a ________ may be expressed

b

Mutations in the p53 gene can lead to cancer by a. causing the production of excessive amounts of relay proteins. b. causing the production of a faulty protein that is no longer able to inhibit cell division. c. promoting the expression of mRNA that can interact with DNA, resulting in new mutations. d. increasing the production of growth hormones, which trigger faster cell cycles.

division

Mutations to proto-oncogenes create cancer-causing oncogenes that stimulate cellular _________

a

Nuclear transplantation experiments provide strong evidence for which of the following? a. Differentiated vertebrate cells still maintain their full complement of DNA. b. Differentiated vertebrate cells do not maintain their full complement of DNA. c. Vertebrate cloning is not feasible. d. Cell differentiation is an irreversible process.

transcription

Once RNA polymerase attaches to the promoter once the activator proteins bind, ___________ begins

1.5%

Only about _____% of the human genome codes for proteins

c

Operons are a standard method for gene regulation in _____. a. all organisms b. eukaryotes but not prokaryotes c. prokaryotes but not eukaryotes d. E. coli, but they are rare in other organisms

c

Scientists have recently discovered a protein that seems to block HIV infection. It is called a chemokine. If expressed throughout the body, it is a possible promising treatment for HIV infection. Normal human cells contain a gene for chemokine. This single copy, however, does not get expressed enough to guard effectively against HIV infection. How could you increase the expression of the chemokine gene? a. Methylate the DNA that encodes for the chemokine gene. b. Inject a plasmid containing the chemokine gene directly into a skin cell with a needle. c. Inhibit the enzyme that removes acetyl groups from histones in the area of the DNA that encodes the chemokine gene. d. Accelerate the cell cycle in cells that contain the chemokine gene.

b

Some species of bacteria can either synthesize the amino acid glycine or absorb it from their surroundings. If glycine binds to a repressor protein, which then allows the repressor to bind to the bacterial chromosome, the operon will not be transcribed. If it is like other operons, the presence of glycine will result in the _____. a. manufacture of the repressor protein b. cessation of the synthesis of glycine c. breakdown of glycine d. inhibition of bacterial cell division

b

Spinal muscular atrophy (SMA) is caused by a mutation in the smn1 gene that is required to maintain the health of spinal motor neurons. A closely related protein, smn2, has the ability to rescue a person; however, it is often expressed in too little quantity to be beneficial. Choose the best predicted outcome if you treated an SMA patient with an miRNA complementary to the coding sequence of the smn2 gene (i.e., minus the introns). a. The miRNA would bind to the template strand of the gene and keep the DNA strand open, allowing for more copies of the gene to be made. b. The miRNA would bind to the smn2 mRNA, causing it to be broken down and fewer copies of the protein to be made. c. The miRNA would bind to the finished protein product, preventing it from doing its job and targeting it for degradation. d. The miRNA would bind to the coding strand of the smn2 gene, preventing it from being transcribed at all.

a

Stem cells could be immensely important in the treatment of which of the following conditions? a. spinal cord injuries b. lung cancer c. loss of a limb d. hardened arteries

d

Testosterone enters human cells and binds to a specific protein inside the cell. This testosterone-protein complex is then transported into the nucleus, where it binds to the cell's DNA. What is the function of the testosterone-protein complex? a. It alters the pattern of RNA splicing. b. It unwinds the DNA so that its genes can be transcribed. c. It inhibits transcription. d. It helps RNA polymerase transcribe certain genes.

genome, all

The ability to clone an animal from a single cell demonstrates that every adult body cell: 1. contains a complete __________ 2. capable of directing the production of ___ the cell types in an organism

regeneration

The ability to regrow a missing part of the body - ex: salamander

b

The basis of cellular differentiation is a. the operon. b. selective gene expression. c. cloning. d. mutation.

d

The carcinogen known to cause the most cases and types of cancer is a. plutonium. b. ultraviolet light. c. alcohol. d. tobacco.

selective

The difference between cell types are NOT due to the presence of different genes but instead due to _____________ gene expression

a

The gene for human growth factor is inserted into the E. coli lactose operon so that it replaces the structural genes with the gene for human growth factor. What substance must be added to the bacterial culture so that it produces human growth factor? a. lactose b. a repressor protein c. human growth factor d. an operator protein

c

The term "module" is often used to refer to a cluster of what? a. cells b. chromosomes c. genes d. nuclei

active, inactive, inactive, active

There are two types or repressor-controlled operons: 1. in the LAC operon, the repressor: - is ________ when alone - is __________ when bound to the lactose 2. in the TRP bacterial operon, the repressor: - is _________ when alone - is __________ when bound to the amino acid tryptophan (TRP)active,

b

To begin the process of gene transcription, RNA polymerase attaches to _____. a. the gene that will be transcribed b. the promoter associated with the target gene c. the operator associated with the target gene d. none of the above

X, UV

What are two of the most potent carcinogens? 1. _____ - rays 2. ______ radiation from sunlight

cancer

What is the second-leading cause of death in most industrialized nations?

a

Where have scientists found genes associated with breast cancer? a. nematodes b. yeast c. plants d. jellyfish

c

Which of the following is an example of homology? a. a shark tail and a whale tail b. a bird wing and a butterfly wing c. a cat forearm and a human forearm d. the body shape of a seal and the body shape of a penguin

b

Which of the following statements regarding DNA packing is false? a. A nucleosome consists of DNA wound around a protein core of eight histone molecules. b. DNA packing tends to promote gene expression. c. Highly compacted chromatin is generally not expressed at all. d. Prokaryotes have proteins analogous to histones.

a

Within an operon, repressors _____. a. block gene transcription to RNA by attaching to the operator b. block gene transcription to RNA by attaching to the promoter c. block mRNA translation by attaching to the mRNA for a specific gene d. block gene transcription to RNA by attaching directly to the gene itself

b

Your body is composed of a dazzling array of different cell types. Each cell type develops its own unique properties. How does this happen? a. Each cell type is provided with its own specialized set of genes during cell division. b. All cells (with very few exceptions) contain the same set of genes, but the process of gene expression determines which genes are active in each cell. c. none of the above d. The zygote contains one of each of the different cell types. These ancestor cells then divide to produce the diversity of cell types in the adult.

p53 gene

a tumor-suppressor gene that codes for a specific transcription factor that promotes the synthesis of proteins that inhibit the cell cycle

cloning

creation of an individual by asexual reproduction

transcription factor

eukaryotic RNA polymerase requires the assistance of proteins called ___________ _______

histone

protein molecule around which DNA is tightly coiled in chromatin

repressor

protein that binds to the operator in an operon to switch off transcription (blocks RNA polymerase action)

activator proteins

proteins that bind to enhancer sequences in eukaryotes to increase transcription

activators

proteins that turn operons on by binding to DNA and stimulating gene transcription by making it easier for RNA polymerase to bind to the promoter

silencers

repressor proteins that may bind to DNA sequences and inhibit the start of transcription

microRNA

small single stranded RNA molecules that bind to mRNA and can degrade mRNA or block its translation.

adult stem cells

stem cells that are found in adults that can differentiate and form a *LIMITED* number of cells

proto-oncogenes

the corresponding normal cellular genes that are responsible for normal cell growth and division

ras proto-oncogene

the most common oncogene abnormality in tumors

nuclear transplantation

the nucleus of an egg cell or zygote is replaced with a nucleus from an adult somatic cell

cell differentiation

the process by which a cell becomes specialized for a specific structure or function

gene regulation

turning on and off of genes - deciding which ones are transcribed