Genetics Exam 4

Cancer cells may carry gain-of-function mutations that increase the activity of an oncogene. In which of the following ways could the expression of the protein encoded by the oncogene be altered by this type of mutation?

-The amount of protein produced from the oncogene is significantly increased. -The structure of the protein is altered so that it is overly active. -The protein is expressed in a cell type where it is not normally found.

Four types of genetic changes that can convert a proto-oncogene to an oncogene are?

-mussense mutation -gene amplification -chromosomal translocation -vira integration

How many reading frames are possible in a cloned DNA fragment?

6

Which of the following accurately describes the genetic change(s) leading to malignancy?

A series of successive gene changes occurs, involving oncogene activation and inactivation of tumor-suppressor genes.

What is the normal role of Rb protein during the process of cell division?

Unphosphorylated Rb protein prevents progress through the cell cycle by binding to transcription factor E2F

During pyrosequencing, the release of pyrophosphate after addition of a nucleotide is monitored through a series of chemical reactions. In the first reaction, pyrophosphate and adenosine 5' phosphosulfate are the substrates for ATP synthesis by the enzyme ATP sulfurylase. The ATP produced in this reaction is combined with luciferin by the enzyme luciferase?

luciferase to produce light

The p53 protein functions as an activator of

transcription

Proto-oncogenes that can mutate into oncogenes fall into which of the following categories?

transcription factors growth factor receptors growth factors intracellular signaling proteins

The region of the p53 protein that corresponds to its main function is the ______ domain.

transcriptional activation

When a proto-oncogene is converted to an oncogene, which pattern of inheritance is usually observed for the mutated allele?

Dominant

Ras protein is in its active form when it is bound to ______

GTP

Ras protein is in its active form when it is bound to ______.

GTP

Orthologs are

Genes in different species that evolved from a common ancestor while retaining the same function (homologous genes in different species)

Which represent outcomes of using the RNA-sequencing (RNA-seq) method?

Genes that are expressed in a specific cell type can be identified. Patterns of RNA splicing found in a particular cell type can be determined.

Which of the following categories of proto-oncogenes would encode a product that would be released from one cell and would travel to and affect another cell?

Growth factor

Which type of growth has cells that can invade other tissues and migrate to other areas of the body to form secondary tumors?

Malignant growth

For the inherited tendency to develop retinoblastoma in the first few years of life, which correctly describes inactivation of the rb tumor-suppressor alleles by the "two-hit" model?

One allele is inactivated prior to birth, the other becomes inactivated early in life.

Which event activates progression through the cell cycle?

Phosphorylation of Rb protein so that it no longer binds to transcription factor E2F.

In which two ways have tumor-suppressor genes been shown to act within cells?

Regulating the rate of cell division and maintaining genomic integrity

Which change from proto-oncogene to oncogene occurred by a missense mutation?

Substitution of valine for glycine at position 12 in the amino acid sequence of the rasH protein

What is the goal of a genome-sequencing project?

To determine the DNA sequence of the entire genome of a given species

What is the goal of functional genomics?

To understand the roles of genetic sequences in a given species

Uncontrolled cell division may result from ______.

a decrease in the expression of tumor suppressor genes

conserved site

a short DNA sequence or amino acid sequence that is identical or similar across multiple species.

During the initial stage of cancer development, cells with a precancerous genetic change form a(n)

benign growth

In the development of retinoblastoma, a retinal cell is more likely to divide if ______.

both copies of the rb gene are inactivated

In the RNA-sequencing (RNA-Seq) method, next generation sequencing is used to find the order of nucleotides in

cDNAs produced from RNAs

Chromatin Immunoprecipitation (ChIP)

can determine if proteins can bind to a particular region of DNA in the chromatin of living cells

Most cancer cells are descendants of an original cell that acquired genetic changes. Therefore, cancerous growths are considered to be ______ in origin.

clonal

In the technique of chromatin immunoprecipitation, the formaldehyde serves to ______.

cross-link the protein to the DNA

Homologous genes are those?

derived from the same ancestral gene and so have similar sequences

The tumor-suppressor gene p53 has a significant role in ______.

detecting DNA damage in a cell

A carcinogen is a(n) ______?

environmental agent that causes cancer

The ERBB2 receptor normally plays a role in promoting cell division. Cells from many breast cancer patients show an increase in the number of ERBB2 receptors available on the plasma membrane. The type of mutation that contributed to cancer development in these cases would be called a ______-of-function mutation in a(n) ______

gain; oncogene

Gene families arise via?

gene duplications followed by sequence divergence

As an outcome of the RNA-sequencing (RNA-Seq) method, a cDNA sequence was shown to align with a specific region within the genome. This means that the sequence at that region is a(n) ______?

gene that is expressed

Organisms that have a close evolutionary relationship tend to have

genes with similar DNA sequences

A signaling molecule that can promote division of cells throughout the body of a multicellular organism is called a(n) ______.

growth factor

A signaling molecule that can promote division of cells throughout the body of a multicellular organism is called a(n) ______?

growth factor

An individual who is heterozygous for a defect in a tumor-suppressor gene ______.

has inherited an increased susceptibility to develop cancer

Genes that are derived from the same ancestral gene are called?

homologous

Paralogs are ______?

homologous genes within a single species that constitute a gene family.

oncogne

is a mutant gene that is over expressed and contributes to cancerous growth.

A benign tumor is a(n)

localized growth with a precancerous genetic change

The AMER1 gene encodes APC membrane recruitment protein 1 that regulates the Wnt intracellular signaling pathway involved with cell division. Functional copies of the AMER1 gene product can repress the pathway and prevent cells from growing and dividing in an uncontrolled way. Mutations in the AMER1 gene are observed in childhood kidney cancer and in breast, stomach and colon cancers in adults. The type of mutation that contributed to cancer development in these cases would be called a ______-of-function mutation in a(n) ______?

loss; tumor-suppressor gene

A series of genetic changes, involving oncogene activation and tumor-suppressor gene inactivation, leads to ______.

malignancy

If the function of Rb protein is lost in a retinal cell, that cell is ______.

more likely to divide

Li-Fraumeni syndrome is an inherited tendency toward cancer development that relates to changes in the tumor-suppressor protein p53. A common change is the substitution of tryptophan for arginine at position 248 in the amino acid sequence. This is an example of inactivating a tumor-suppressor gene through ______.

mutation

The majority of carcinogens promote cancer development by increasing the rate of ______ in somatic cells.

mutation

An oncogene is formed when a proto-oncogene gains a ______

mutation that causes its expression to be abnormally active

Tumor-suppressor genes normally act to ______.

negatively regulate cell division maintain genome integrity

A mutant gene that is overexpressed and contributes to cancerous growth is called a(n) ______.

oncogene

A region of a nucleotide sequence that does not contain any stop codons is called a(n)?

open reading frame

Which gene plays a significant role in detecting DNA damage in a cell?

p53

Tumor-suppressor genes whose normal gene products help maintain genome integrity are ______.

p53 BRCA-1

Multiple homologous genes within a single species are known as?

paralogs

An oncogene is formed by mutation that increases the expression of a normal gene called a(n)

proto-oncogene

In pyrosequencing, the incorporation of a nucleotide into a growing DNA strand is monitored by measuring the release of?

pyrophosphate (PPi)

A cancer-causing mutation in the ras gene leads to an altered Ras protein that ______?

remains bound to GTP

RNA-Seq is a method used to?

sequence complementary DNAs derived from RNAs

A growth factor is a ______.

signaling molecule that can stimulate cells throughout the organism's body to divide

growth factors

signaling molecules that bind to cell surface receptors and influence cell division.

What is high-throughput sequencing?

the ability to rapidly sequence large amounts of DNA

The set of all RNA molecules that are transcribed in one cell or a population of cells is called the?

transcriptome

True or false: Conserved sites within a polypeptide are more likely to be functionally important than non-conserved sites.

true-Natural selection will favor the retention of amino acids at conserved sites to preserve the function of the polypeptide.

Which type of gene normally prevents cancers but can allow cancerous growth when mutated?

tumor-suppressor gene