Exam 4 Genetics

Cancer can result from a failure of

a cell cycle checkpoint

Oncogenes may block

apoptosis

Genetic drift is most likely to occur in populations with a _____ size

small

If mating is nonrandom for a trait, then the alleles of genes that influence the trait

will not be in Hardy-Weinberg equilibrium

If the population mates at random, then in the next generation, the frequency of genotype dd will be

0.01

If the frequency of an autosomal recessive disease allele is 1 in 100, what is the frequency of carriers in the population?

0.0198

If the population mates at random, then in the next generation, the frequency of genotype Dd will be

0.18

If the population mates at random, then in the next generation, the frequency of genotype DD will be

0.81

If the frequency of an autosomal recessive disease is 1 in 10,000, what is the frequency of the disease allele?

1/100

If the frequency of an X-linked recessive disease in males is 1 in 2500, what is the frequency of the disease allele?

1/2500

If the frequency of an X-linked recessive disease in females is 1 in 1600, what is the frequency of the disease allele?

1/40

Which of the following would be a biotic factor that zebras might have to contend with

Antelope that feed on the same grassy plains as the zebras

Which of the following events at the cellular level can result in development of cancer

Dedifferentiation, Activation of cancer stem cells, Increase in the proportion of stem cells within a tissue, Defective tissue repair

A Poodle and a Great Dane are members of the same species because

They can interbreed to produce fertile offspring

is targeted based on genetic information.

Tryosine kinase inhibitor

What types of DNA sequences are most commonly used in forensics and to identify victims of natural disasters?

Variable number of tandem repeats (VNTRs), Short tandem repeats (STRs)

The frequency with which a particular variant of a gene occurs in a population is called the

allele frequency

can be maintained in a population when the heterozygotes have the greatest fitness

balanced polymorphism

Balanced polymorphism is a type of ________ selection.

balancing

is a change in allele frequencies from one neighboring population to another.

cline

A barnacle grows on a whale, doing it no harm. This is an example of

commensalism

A mating between close relatives, such as cousins, is called

consanguinity

According to the theory of evolution, over time animals who are more "fit" will generally

contribute more alleles to the gene pool

Which of the following helps a prey species avoid being detected by a predator?

cryptic coloration

Some species of frogs produce a toxic chemicals, which makes any predator who eats them quite ill. The frogs are colored green and brown on their backs to blend in to leaves and grass. If they are about to be eaten, the frogs flip onto their backs to reveal a black, yellow, and red belly. The back colors are an example of ______________ coloration while the belly colors are an example of _____________ coloration.

cryptic, aposematic

The mutation that causes ___________ provides protection from diarrheal disease

cystic fibrosis

A tumor suppressor gene mutation that causes cancer is usually a

deletion

Marriage within a community is called

endogamy

Activation of a proto-oncogene into an oncogene could occur due to a mutation or a change in the _____ of the wild-type gene

expression

Chromosomes in cancer cells exist in normal numbers.

fa;lse

A mutation in the APC gene occurs commonly in colon cancer. Everyone who inherits the APC mutation will develop colon cancer.

false

All tumors are cancerous

false

Cancer begins when a cell divides less frequently than it should.

false

Duplication of a chromosome in a cancer cell reduces the copies of an oncogene.

false

If a population is in Hardy-Weinberg equilibrium, all allele frequencies are equal.

false

In human populations, most genes are in Hardy-Weinberg equilibrium.

false

Macroevolution is the change of allele frequencies within a population.

false

Most cancers are the result of a single genetic change.

false

Most cases of cancer are are caused by normal chromosomes.

false

Most cases of cancer are inherited as single-gene disorders.

false

Oncogenes cause cancer when they are inactivated.

false

Phenotypic frequencies, such as the frequency of PKU, are the same in all human populations.

false

Positive eugenics interferes with reproduction of individuals considered inferior.

false

The alleles used for DNA profiling occur with the same frequency in all ethnic groups

false

The thirteen STRs that are used in the CODIS database are all on the same chromosome.

false

To determine the likelihood that DNA profiles from two sources match one another by chance, the frequencies of the VNTR and STR alleles within the population are added together.

false

Wars may have eugenic consequences if the fighting groups are genetically similar.

false

Every person has at least_________ lethal equivalents, which are alleles or allele combinations that would be lethal in the homozygous state.

five

may occur when a small group of individuals forms a new settlement.

founders effect

In the eighteenth century, European Caucasians traveled to South Africa and had children with native women. The population today has alleles from both groups

gene flow

is the collection of all alleles in a population.

gene pool

Random changes in allele frequencies are called

genetic drift

Several rare genetic disorders are unusually common in the relatively small Old Order Amish community in Pennsylvania

genetic drift

The cheetah population has declined, and there is little genetic diversity left among cheetahs today.

genetic drift

Migration between populations may be prevented by ___________ barriers such as mountain ranges

geographical

Cancer susceptibility is passed onto future generations when a(n) _________ mutation has occurred.

germline

All populations have some deleterious alleles because harmful recessive alleles can be maintained in

heterozygous individuals

Clines may form as a result of communication difficulties due to _______ differences between groups.

language

When enough genetic changes accumulate in a new population, __________ the formation of a new species, can occur.

macroevolution

Sickle cell disease causes anemia in the recessive state, but carriers of the disease allele are resistant to

malaria

Changes in the allele frequencies in a population are called

microevolution

When individuals enter or leave a population, ____ occur

migration

A continual source of genetic variation that produces new alleles is

mutation

alleles that adversely affect reproduction are eliminated by

natrual selection

The sickle cell allele is maintained as a balanced polymorphism in geographical areas where malaria is prevalent

natural selection

The use of antibiotics has led to an increase in antibiotic resistance in bacteria.

natural selection

Selection that acts to eliminate a deleterious trait is called

negative selection

When some individuals contribute more to the next generation than other individuals, mating is

nonrandom

Autosomal recessive disorders occur at a high frequency when matings are consanguineous

nonrandom mating

Which of the following is a characteristic of parasitism

one organism lives in or on another and benefits at the expense of the other

The frequency with which a particular condition or trait occurs in a population is the

phenotypic frequency

is a group of individuals of the same species in a given area who are able to mate and produce fertile offspring.

population

occurs when many members of a population die, leaving only a few survivors.

population bottleneck

Selection that acts to retain a favorable trait is called

positive selection

Genes that normally stimulate cell division when it is appropriate are called

proto-oncogenes

is a method of treatment that causes adverse effects by harming healthy cells.

radiation

A mutation that occurs in cells that do not develop into gametes is called a(n)

somatic

Sporadic cancer is due to ____ mutation

somatic

The oldest approach to treating cancer is

surgery

Natural selection is based on the differential ability of individuals to

survive and reproduce

Cancer cells often have longer telomeres due to reactivation of the enzyme

telomerase

The theory of evolution requires all of the following except

the environment is robust enough to support as many animals as can possibly be produced

An individual's fitness is based on

the number of offspring he or she has

Animals evolve to fit a particular niche. This means that

they adapt to the amount of sunlight, water, oxygen and other organisms present

Traditional treatments for cancer, such as radiation and chemotherapy, are effective because

they kill rapidly dividing cells

A fusion protein can be produced due to the _______ of a proto-oncogene to a site next to another gene.

translocation

A mutation present in all stages of a tumor acts early in the disease process.

true

Animals sometimes use camouflage to become more effective predators.

true

Chromosomes in cancer cells may bear translocations

true

Chromothripsis shatters several chromosomes and may kill the cell—or trigger cancer.

true

Eugenic programs attempt to change the genetic structure of a population.

true

Eugenic programs control human reproduction.

true

Except for identical twins, every person has a unique DNA profile.

true

In DNA profiling, the sequences that are used for analysis are assumed to be in Hardy-Weinberg equilibrium

true

Somatic cells may develop mutations in cancer-causing genes.

true

Some countries have practiced eugenics through forced sterilization

true

The older a tumor is, the more genetic changes it will have.

true

The process of a tumor spreading is called metastasis

true

Translocations that join parts of nonhomologous chromosomes turn genes into oncogenes.

true

When a population is in Hardy-Weinberg equilibrium, allele frequencies are constant.

true