Biology Exam 2 - Practice Questions

A man tests positive for BRCA2. Which of the following should he be monitored for?

breast and prostate cancer

A normal gene that, if mutated, can lead to cancer is called a(n) ____________.

proto-oncogene

Identify the evolutionary mechanism at work. - genetic drift - gene flow - natural selection A prominent tail helps the peacock attract a mate.

natural selection

Identify the evolutionary mechanism at work. - genetic drift - gene flow - natural selection Camouflage enables this insect to evade predators.

natural selection

Identify the evolutionary mechanism at work. - genetic drift - gene flow - natural selection The bird's beak is well-suited for cracking seeds.

natural selection

If Sophie has a brother or sister from the same parents, what are the chances that sibling would have cystic fibrosis?

25%

Sickle-cell disease is a rare genetic disorder. Which of the following statements regarding the gene for sickle-cell disease must be true?

sickle-cell is a mutant trait, but we cannot say whether it is dominant or recessive

Can you identify the type(s) of nucleic acid to which each of the following structures belong? RNA only

- ribose sugar - single-stranded - uracil base

DNA is considered to be the molecule of life. Which two functions make DNA uniquely suited to this role?

- DNA produces more of itself. - DNA directs the production of proteins.

Lipase is an enzyme (a type of protein) that breaks down fats. Which of the following statements about lipase are true?

- a specific sequence of bases in a DNA molecule codes for the lipase enzyme - a specific sequence of bases in a DNA molecule codes for the lipase enzyme

Can you identify the type(s) of nucleic acid to which each of the following structures belong? DNA only

- deoxyribose sugar - thymine base - double-stranded

You can estimate the deadliness of each type of cancer by dividing the number of deaths by the number of cases. If nearly everyone who received a diagnosis of one particular type of cancer dies, the ratio will be near 1 (or 100% deadly). If many more people receive a diagnosis than die, the ratio will be near 0 (or 0% deadly). Rank these three cancer types from the most deadly to the least deadly. - breast cancer - lung cancer - prostate cancer

- lung cancer - breast cancer - prostate cancer

The cellular processes that results in the production of protein begin in the ____________, where the DNA resides. There, the process of _____________ creates a molecule of RNA from a molecule of DNA. The enzyme that performs this process is called _____________. The RNA molecule, which exits the nucleus, is a specific kind of RNA called ____________. Once it exits the nucleus via the nuclear pores, this molecule travels to a cellular organelle called the _____________. There, the sequence of nucleotides on this molecule is used to create a molecule of protein through the process called ____________. This process is helped along by molecules of _____________, each of which recognizes one nucleotide triplet and carries the corresponding amino acid.

- nucleus - transcription - RNA polymerase - mRNA - ribosome - translation - tRNA

Can you identify the type(s) of nucleic acid to which each of the following structures belong? Both DNA and RNA

- phosphate - guanine base - nucleotides

___________ is a long linear polymer found in the nucleus of a cell, shaped like a double helix, and associated with the transmission of genetic information.

DNA

Human ABO blood type is determined by a single gene that comes in 3 distinct alleles: IA , IB , and i. The IA and IB alleles are each dominant to the i allele, but are codominant with each other, meaning that both phenotypes are expressed in the heterozygote. The Punnett square below shows a cross between two parents with different blood types. Drag the genotypes and phenotypes from the left to correctly complete the Punnett square.

a. IA IB b. type AB c. IA i d. type A e. IB i f. type B g. ii h. type O

There are five examples of a ___________: A, G, C, T, and U.

base

When are the chromosomes of a cell duplicated?

before a cell divides

Female fireflies choose mates based on the specific flash pattern displayed by males flying nearby. This is an example of ____________.

behavioral isolation

An individual with a malignant tumor is said to have ____________.

cancer

At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.

cytokinesis

A breeder wants to set up a program to produce zebrafish with long fins. Having long fins is a dominant trait compared to the short-finned wild type. Before she can market her zebrafish, she needs to perform a test cross on the long-finned fish she plans to use as a breeder. How can she tell whether her fish are homozygous or heterozygous for the long-finned trait?

do several test crosses between the long-finned fish and the short-finned fish; if the offspring are always long finned, the long-finned parent is probably homozygous

In a population with brown and green alleles for color, genetic drift

has more effect on the evolution of a small population

During prophase I of meiosis,

homologous chromosomes stick together in pairs

Which set of the biologically related individuals would have identical numbers of STRs at all 13 locations?

identical twins

What is the role of transcription factors?

initiate gene expression

The chromosomes line up in the center of the cell during which phase of mitosis?

metaphase

A researcher has identified a mutation in a gene for a protein that is usually 636 amino acids long. The protein product of the mutated gene is only 20 amino acids long. This mutation is probably a ____________.

nonsense mutation

Which of the following is LEAST likely to be a health problem for someone with cystic fibrosis?

obesity

In the Grand Canyon, fossils in rock layers at the bottom of the canyon are ___________ than those in layers closer to the top.

older

These new cancer therapies focus on using which of the following to help the patient?

the patient's immune system

A(n) ______________ is one particular variation of a character.

trait

One way that ___________ is different from DNA is that it contains Us instead of Ts.

RNA

The principal role of ___________ is to act as a messenger carrying instructions from DNA out of the nucleus for the synthesis of proteins.

RNA

The ____________ defines a ___________ as a group of populations whose members have the potential to interbreed with one another and produce fertile offspring.

biological species concept; species

RNA is produced from DNA via the process of ____________.

transcription

If Sophie conceives a child, and the father neither has cystic fibrosis nor is a carrier, what are the chances that the child would have cystic fibrosis?

0%, because the child must receive the bad gene from both parents

Suppose there is a population of 100 rabbits. In this population, 60 rabbits are FF, 20 are Ff, and 20 are ff. What is the allele frequency for the F allele in this population's gene pool?

0.7 explanation - There are 100 rabbits in the population, each with two alleles for the fur color gene, for a total of 200 alleles in the gene pool. Since there are 60 FF rabbits, there are 60 ×× 2 = 120 F alleles from these rabbits. Since there are 20 Ff rabbits, there are 20 ×× 1 = 20 F alleles from these rabbits. (There are zero F alleles from the 20 ff rabbits.) This gives a total of 120 + 20 = 140 F alleles in the gene pool. Since the gene pool has 200 total alleles, the allele frequency for the F allele is 140 / 200 = 0.7.

You discover that a type of skin cancer is very similar to typical cases of thyroid cancer in its cause. How many mutations cause this skin cancer?

1

You work for a company creating gene therapy treatments. Which of the following chromosomes do you focus on to work on a treatment for BRCA2?

13

DNA is a double helix composed of nucleotides. Suppose that a portion of one of the two strands of a DNA molecule has the sequence GCAGTAG. What is the sequence of the opposite strand?

CGTCATC

Identify the evolutionary mechanism at work. - genetic drift - gene flow - natural selection New individuals move into a population.

gene flow

The allele that causes cystic fibrosis is recessive. An individual who is heterozygous for cystic fibrosis _______________.

is a carrier

Translation begins when a _____________ molecule binds to a _____________.

mRNA; small ribosomal subunit

A woman tests positive for the BRCA2 mutation. Which of the following is true?

she inherited the gene from her mother or her father

Gorillas have 48 chromosomes. How does the number of chromosomes in a gorilla sperm compare with that of a human sperm?

gorilla sperm have one more chromosome than human sperm

____________ serves as the molecular basis for life.

DNA

How are DNA and RNA different?

DNA contains the bases A, G, C, and T; RNA contains the bases A, G, C, and U

Which of the following genes is most similar to BRCA2?

RB gene, a tumor-suppressing gene linked to retinoblastoma

The c-src gene in animals is turned on during periods of cell growth and division. The Rous sarcoma virus genome contains a mutated form of this gene, v-src, which produces a protein that is always activated. Infections of chickens with this virus cause cancers to develop. What type of gene is c-src?

a proto-oncogene

Puberty is caused by the release of follicle stimulating hormone and luteinizing hormone from the pituitary gland. These hormones are delivered to the ovary in girls and initiate the monthly release of mature egg cells. This is an example of what mechanism of regulation of gene expression?

a typical signal transduction pathway

Mendel discovered that the allele for green seed pods (G) is dominant to the allele for yellow seed pods (g). He crossed true-breeding (homozygous) parental plants with green (GG) and yellow (gg) seed pods to produce an F1 generation, all of which were heterozygous (Gg) with green seed pods. He then crossed two of these F1 plants to produce an F2 generation. Drag the genotypes and phenotypes from the left to correctly complete the Punnett square for the F2 generation.

a. GG b. green c. Gg d. green e. Gg f. green g. gg h. yellow

The disease hemophilia is caused by a single gene that is located on the X chromosome. Because human females have two X chromosomes (XX), they have two copies of this gene. Since hemophilia is recessive (h), a female must have two copies of the recessive allele to have the disease. A human male (XY), on the other hand, has only one X chromosome, and so needs only one copy of the recessive allele to have the disease. Complete the Punnett square below of a cross between a carrier mother (a female who carries one copy of the recessive allele and so appears normal herself) and a non-hemophiliac father.

a. female b. normal c. male d. normal e. female f. male g. carrier h. hemophiliac

Can you correctly label these images of chromosomes?

a. homologous chromosomes b. centromere c. sister chromatids d. autosomes e. sex chromosomes f. karyotype

Can you organize these terms that describe the different kinds of cell division?

a. mitosis b. meiosis c. asexual reproduction d. somatic cells e. gametes f. sexual reproduction

The process of macroevolution refers to major evolutionary changes over time, through which new types of organisms originate from previously existing, but different, ancestors. Drag the labels to complete the concept map about macroevolution.

a. speciation b. diversification c. mass extinctions d. branching e. non branching f. novel features g. fossil record

A(n) ___________ is an alternative version of a gene.

allele

Most human genes come in alternate versions called ______________.

alleles

The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?

anaphase

Cauliflower, broccoli, Brussels sprouts, cabbage, and kohlrabi are all the same species of plant. What is responsible for the differences in these vegetables?

artificial selection

A ____________ is a lump of abnormal cells that, although growing out of control, remains at its original site.

benign tumor

Sickle-cell disease is caused by a recessive form of hemoglobin. Two parents that do NOT have the disease give birth to a child that does. What are the genotypes of the mother and father for the hemoglobin gene?

both parents are heterozygous

A sudden volcanic eruption kills many members of a population of elk. By chance, the individuals that remain do not have the same mix of genes as the original population. The mechanism of evolution is ____________.

bottleneck effect

Although millions of prairie chickens once roamed the Midwest, their numbers dwindled to only 50 individuals in the 1990s. These few individuals have since produced a larger population. The genetic variation among the current population is quite low. The mechanism of evolution is _____________.

bottleneck effect

A(n) ______________ is an inherited feature that varies from individual to individual.

character

Which of the following is TRUE concerning benign tumors?

do not spread to other parts of the body

If an organism has two non-identical versions of a gene, the one that is expressed in the organism is called the _______________ allele.

dominant

Imagine that eye color in cats is controlled by a single gene and that there are two alleles: black eyes and orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele for black eyes is ______________ the allele for orange eyes.

dominant to

Evolution that occurs by ____________ results in a change in a population's gene pool due to the movement of individuals into and out of the population.

gene flow

After DNA replication, _____________.

each of the two daughter DNA molecules contains one strand from the original DNA molecule and one newly synthesized strand

What is the function of CRISPR-Cas9?

edit a specific nucleotide sequence in living cells

Tristan da Cunha is a remote island in the Atlantic Ocean. In 1814, 15 people formed a colony there, one of whom carried a rare gene for blindness. The frequency of this gene is now 10 times higher on the island than on the mainland from which the settlers arrived. The mechanism of evolution is ______________.

founder effect

Meiosis starts with a single diploid cell and produces ________________.

four haploid cells

Guar are increasingly rare wild oxen found in Asia. How would you clone this animal?

fusing a guar cell nucleus with an egg cell from a domestic cow that has had its nucleus removed

In addition to behavioral isolation, other reproductive barriers that may prevent populations from breeding and producing fertile offspring include: - Temporal isolation (mating or fertilization occurs at different seasons or times of day) - Habitat isolation (populations live in different habitats and do not meet) - Mechanical isolation (structural differences prevent fertilization) - Gametic isolation (female and male gametes fail to unite in fertilization) Match the following examples with the correct type of reproductive barrier. Many populations of clams release their sperm and eggs into the same region of a lake, but only the sperm and eggs from the same species successfully unite to form zygotes.

gametic isolation

As habitats change, populations of northern pine trees that were once separated can now exchange pollen. This exchange of genes between populations is allowing the previously isolated gene pools to mix. The mechanism of evolution is ___________.

gene flow

Consider a population of birds living on an island. Suppose several individuals of the same species from a different population migrate to the island. Due to the arrivial of the new birds, the allele frequencies in the original population change. What mechanism of microevolution is at work in this example?

gene flow

Insecticide resistance among mosquitos is spreading around the world after mutations that originate in one population are spread to other populations through matings. The mechanism of evolution is _____________.

gene flow

Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?

gene flow causes the frequency of the brown allele to increase

The total collection of alleles in a population at a given time is the population's ____________.

gene pool

How would you describe the current status of gene therapy research?

gene therapy has had limited success in a few cases. however, there is still a long way to go before gene therapy is deemed safe and effective enough for widespread use in curing genetic diseases.

Your aunt specializes in oncogenes. What does she study?

genes that trigger cancer

Evolution that occurs by ____________ results in a change in a population's gene pool due to chance.

genetic drift

Identify the evolutionary mechanism at work. - genetic drift - gene flow - natural selection By chance, some wildflowers in this population reproduce, while others do not.

genetic drift

The evolution of populations due to chance is ___________.

genetic drift

The ______________ is the genetic makeup of an organism.

genotype

The gene for the beta chain of normal human hemoglobin has the sequence CTC at the position for the seventh amino acid in the protein. A point mutation changing the sequence to CAC results in sickle cell hemoglobin. Use the genetic code to determine the change in the amino acid at position seven of the hemoglobin beta chain.

glutamic acid to valine

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

growth factor

In addition to behavioral isolation, other reproductive barriers that may prevent populations from breeding and producing fertile offspring include: - Temporal isolation (mating or fertilization occurs at different seasons or times of day) - Habitat isolation (populations live in different habitats and do not meet) - Mechanical isolation (structural differences prevent fertilization) - Gametic isolation (female and male gametes fail to unite in fertilization) Match the following examples with the correct type of reproductive barrier. Two populations of lobsters do not mate because one population lives in the Atlantic Ocean and the other lives in the Pacific Ocean.

habitait isolation

Imagine that a deaf male has a child with a hearing female. You know that the male must have the genotype dd, but the female could be either Dd or DD. If the couple's first child has hearing, can you determine the mother's genotype? (Hint: Draw Punnett squares for the two possible crosses.)

her genotype cannot be determined

How might global warming result in most grizzly bears having fur that is less dense in the future?

in any population of bears, some individuals have thick fur, some have thin fur, and some are in between. As temperatures increase with the passage of time, the survival of bears with thin fur will increase, and the number of bears in the population with thick fur will decrease

How did Darwin's ideas on evolution conflict with contemporary religious dogma?

in contrast to biblical teaching, Darwin argued that the earth was very old, and that species are constantly changing

If a woman with curly hair and a man with straight hair have a child with wavy hair, the gene for this characteristic of hair shows ______________.

incomplete dominance

A cell preparing to undergo meiosis duplicates its chromosomes during _______________.

interphase

Can you identify the molecules and processes involved in the flow of genetic information through a cell?

left -> right - DNA - transcription - RNA - translation - protein

A _____________ is an abnormally growing mass of cells that is actively spreading through the body.

malignant tumor

In addition to behavioral isolation, other reproductive barriers that may prevent populations from breeding and producing fertile offspring include: - Temporal isolation (mating or fertilization occurs at different seasons or times of day) - Habitat isolation (populations live in different habitats and do not meet) - Mechanical isolation (structural differences prevent fertilization) - Gametic isolation (female and male gametes fail to unite in fertilization) Match the following examples with the correct type of reproductive barrier. A male snail and a female snail from different species attempt to mate, but the orientation of their different types of shells prevents mating from occurring.

mechanical isolation

_____________ is the spread of cancer cells from their site of origin to other sites in the body.

metastasis

A change in allele frequencies in a population over a span of generations is ___________.

microevolution

Changes in allele frequencies in a population over time is ______________.

microevolution

A(n) __________ is a change in the nucleotide sequence of DNA.

mutation

Evolution that occurs by ___________ results in nonrandom reproductive success and adaptive change.

natural selection

Why is natural selection considered to be the most important mechanism of microevolution?

natural selection is the only mechanism that consistently leads to adaptive changes in populations

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

oncogene

If someone is a carrier of a recessive genetic disorder, it means he or she has ______________ of the allele, and ______________ exhibit symptoms of the disorder.

one copy; does not

During transcription of a specific gene, which of the following serves as a template for the formation of RNA?

one strand of DNA

The physical traits of an organism are called its _______________.

phenotype

A group of individuals of the same species that live in the same area and interact with one another is a ____________.

population

A(n) ___________ is a group of individuals of the same species living in the same area that interact with each other.

population

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?

prophase

During meiosis, segments of non-sister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur?

prophase I

The correct order of events during meiosis is

prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II

A ____________ is made up of hundreds or thousands of smaller units called amino acids, attached to one another in long chains.

protein

Fur color in rabbits is controlled by multiple alleles. What does this mean?

rabbit fur color is controlled by a single gene, but there are multiple versions of that gene

If an organism has two non-identical versions of a gene, the one that is not expressed in the organism is called the _______________ allele.

recessive

DNA copies itself via the process of ____________.

replication

A ____________ is anything that prevents successful interbreeding between species.

reproductive barrier

A ____________ serves as the site of protein synthesis in the cytoplasm.

ribosome

What process involving cell division results in daughter cells that are NOT identical to the parent cell?

sexual reproduction

Researchers discovered that female gray tree frogs prefer to mate with males who sound the longest mating calls. The mechanism of evolution is ____________.

sexual selection

You are a physician. A female patient tests positive for the BRCA2 gene. Which of the following would be best to tell her?

she has in increased risk of getting breast and ovarian cancer and should be monitored as such

Which of the following mutations is LEAST likely to result in harmful changes to cellular proteins?

silent mutation

As mitosis begins, ______________ are linked together at the centromere.

sister chromatids

The process that gives rise to new species is called ____________.

speciation

Which of the following could you be certain is NOT a GMO at the grocery store?

steak

Due to differences in mating times, two sub-populations of frogs form into separate species, even though they occupy the same pond. This overall process is known as ___________.

sympatric speciation

The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?

telophase

In addition to behavioral isolation, other reproductive barriers that may prevent populations from breeding and producing fertile offspring include: - Temporal isolation (mating or fertilization occurs at different seasons or times of day) - Habitat isolation (populations live in different habitats and do not meet) - Mechanical isolation (structural differences prevent fertilization) - Gametic isolation (female and male gametes fail to unite in fertilization) Match the following examples with the correct type of reproductive barrier. Two populations of flowers do not produce offspring because one blooms during early spring and the other blooms during late spring.

temporal isolation

Which part of a nucleotide molecule in DNA encodes genetic information?

the base

You are a research scientist for the pharmaceutical company AstraZeneca working on a tumor-agnostic treatment for lung cancer. This treatment will be based on which of the following?

the cancer's genetic make-up

What must happen before a cell can begin mitosis?

the chromosomes, or genetic material, must be copied, which occurs during interphase

Darwinian fitness is measured only in terms of _____________.

the contribution that an individual makes to the gene pool of the next generation in comparison to the contributions from other individuals

In viruses called retroviruses, the genetic information is contained in RNA; these viruses have no DNA. These viruses also have an enzyme called reverse transcriptase. What is its function?

the enzyme makes a DNA transcript of the viral RNA

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,

the frequency of the green allele will increase

PCR is used to copy just a relatively small region of DNA, not the entire genome. How do researchers specifically target the region of interest?

they use two primers, each about 15 to 20 nucleotides long, that flank the region of interest

____________ is the first step of gene expression, during which a particular segment of DNA is converted into RNA.

transcription

Proteins are produced from RNA via the process of ___________.

translation

_____________ is the process in which mRNA codons are converted into an amino acid sequence.

translation

If cancer treatment proceeds as this research indicates, which of the following is most likely?

treatment will be geared towards the type of cancer a patient has as well as the individual patient

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

tumor-suppressor gene

As in the previous question, suppose there is a population of 100 rabbits that have different fur patterns. - In this population several generations ago, there were 60 FF rabbits, 20 Ff rabbits, and 20 ff rabbits. - Over time, the population changed, and now there are 40 FF rabbits, 40 Ff rabbits, and 20 ff rabbits. Has microevolution occurred? Why or why not?

yes, because the allele frequencies have changed