Exam 3

Question 1

Describe the genetic material of a prokaryote.

a. DNA is arranged in several linear chromosomes.

b. A circular piece of DNA is found in the nucleus.

c. Prokaryotic chromosomes can be found in their mitochondria.

d. Circular pieces of DNA are found in the cytoplasm.

e. One long strand of DNA is found in the nucleus.

Answer 1

Circular pieces of DNA are found in the cytoplasm.

Question 2

What is the typical sequence of events/information flow in gene expression and protein synthesis?

a. DNA > RNA > protein

b. RNA > DNA > protein

c. RNA > protein > DNA

d. DNA > protein > RNA

e. protein > RNA > DNA

Answer 2

DNA > RNA > protein

Question 3

Within interphase, which stage is defined by the active replication of the cell’s genetic material?

a. Gap 1

b. replication phase

c. S phase

d. Gap 2

e. mitotic phase

Answer 3

S phase

Question 4

You are working in a biotechnology lab, and you have only a small amount of DNA available for analysis. Which could you use to duplicate that small piece of DNA repeatedly?

a. polymerase chain reaction

b. cloning

c. gene libraries

d. plasmids

e. restriction enzymes

Answer 4

polymerase chain reaction

Question 5

The division of the cytoplasm during cell division is referred to as:

a. replication.

b. binary fission.

c. Gap 1

d. cytokinesis.

e. Gap 2

Answer 5

cytokinesis.

Question 6

Restriction enzymes perform which of the following functions?

a. They cause mutations that are essential for evolution.

b. They defend against bacterial infections in the gut.

c. They are involved in DNA replication.

d. They restrict the size of a cell’s nucleus.

e. They cut DNA at specific sequences

Answer 6

They cut DNA at specific sequences

Question 7

A diploid cell in a human male undergoes meiosis. What are the products of this division?

a. two diploid cells

b. two haploid cells

c. four diploid cells

d. four haploid cells

e. one polyploid gamete

Answer 7

four haploid cells

Question 8

You are a researcher who wants to inactivate the gene in mosquitoes that allows them to host the malarial parasite. What biotechnology tool would be best suited for this task?

a. polymerase chain reaction (PCR)

b. cloning

c. CRISPR

d. creating a gene library

e. chopping DNA with restriction enzymes

Answer 8

CRISPR

Question 9

DNA is a macromolecule that stores information. Which component of the DNA is the source of this information?

a. the phosphate group

b. the ladder

c. the base

d. the sugar

e. the histone

Answer 9

the base

Question 10

In the absence of glucose, how does the lac operon function when lactose is present?

a. Lactose binds to a repressor protein. The repressor protein then binds to RNA polymerase, which metabolizes the lactose and dismantles the repressor protein.

b. Lactose binds to the repressor protein and alters its shape so it can no longer bind to the operator. RNA polymerase is then able to bind to the promoter and transcribes genes necessary for metabolizing lactose.

c. A repressor protein binds to the operator, which prevents RNA polymerase from binding to the
promoter.

d. Lactose binds to the operator, preventing the repressor protein from binding to the promoter. RNA polymerase is then able to bind to the promoter and transcribes the genes necessary for metabolizing lactose.

e. A repressor protein binds to the operator, preventing lactose from binding to the operator. RNA polymerase then binds to the lactose and breaks it down.

Answer 10

Lactose binds to the repressor protein and alters its shape so it can no longer bind to the operator. RNA polymerase is then able to bind to the promoter and transcribes genes necessary for metabolizing lactose.

Question 11

Which statement does NOT represent a way in which meiosis and mitosis differ?

a. Mitosis can occur in most somatic cells, but meiosis only occurs in germ cells.

b. In mitosis, each cell divides once, whereas meiosis consists of two successive divisions.

c. In anaphase of mitosis, sister chromatids are separated, but in anaphase I of meiosis, homologous chromosomes are separated.

d. The daughter cells of a mitotic division are identical, but those of a meiotic division are not

e. Chromosome replication occurs before mitotic division but not before meiotic division.

Answer 11

Chromosome replication occurs before mitotic division but not before meiotic division.

Question 12

A mutation within the promoter region of a gene prevents RNA polymerase from recognizing and binding. What effect will this have on the expression of this gene?

a. The mutation will cause the protein produced by the gene to denature.

b. The mutation will prevent expression of the gene.

c. The mutation will cause the protein produced by the gene to fold more tightly into its tertiary structure.

d. The mutation will act as a positive control and increase expression of the gene.

e. The mutation will cause RNA polymerase to attach to the termination site, and gene expression will decrease.

Answer 12

The mutation will prevent expression of the gene.

Question 13

The complementary base pairs in a DNA molecule are stabilized by:

a. hydrogen bonds.

b. a salt bridge.

c. the electrostatic interactions of the charged backbone.

d. ionic bonds.

e. covalent bonds.

Answer 13

hydrogen bonds.

Question 14

A tomato plant that has pest-resistance genes inserted into its genome can be called a(n):

a. transgenic organism.

b. cloned organism.

c. poisonous organism.

d. mutated organism.

e. unnatural organism.

Answer 14

transgenic organism.

Question 15

About 0.1% of the DNA sequences of two individuals will differ. This difference translates to approximately how many base-pair differences?

a. 100

b. 1,000

c. 1 million

d. 3 million

e. 10 million

Answer 15

3 million

Question 16

Scientists have inserted a gene from the bacterium Bacillus thuringiensis into corn plants in order to:

a. increase the corn’s resistance to insects.

b. decrease the plant’s toxicity.

c. decrease the toxicity of Bacillus thuringiensis.

d. directly increase the growth rate of the corn

e. increase the plant’s tolerance to solar radiation.

Answer 16

increase the corn’s resistance to insects.

Question 17

Which aspect of cell division ultimately leads to cell death?

a. Genes in the telomere region fail to divide.

b. Telomeres impair the functioning of a protein that maintains the nucleus.

c. Telomeres become too short.

d. Cells die after 20-30 divisions.

e. Cells remain in the “resting phase” for too long.

Answer 17

Telomeres become too short.

Question 18

In asexual reproduction, daughter cells inherit their DNA from:

a. a single offspring.

b. alternating generations.

c. two separate parents.

d. a single parent.

e. multiple offspring

Answer 18

a single parent.

Question 19

In any DNA molecule, the number of thymine bases will:

a. always be equal to the number of cytosine bases.

b. sometimes be equal to the number of cytosine bases and sometimes equal to the number of adenine bases.

c. sometimes be equal to the number of guanine bases and sometimes equal to the number of cytosine bases.

d. always be equal to the number of adenine bases.

e. always be equal to the number of uracil bases.

Answer 19

always be equal to the number of adenine bases.

Question 20

During which phase of the mitotic cell cycle does reassembly of nuclear envelopes occur?

a. anaphase

b. metaphase

c. prophase

d. telophase

e. S phase

Answer 20

telophase

Question 21

The mRNA sequence GAU would code for which amino acid?

a. methionine

b. histidine

c. glycine

d. aspartate

e. “stop”

Answer 21

aspartate

Question 22

Bacteria use restriction enzymes to:

a. synthesize DNA.

b. synthesize RNA.

c. synthesize protein.

d. destroy foreign protein.

e. destroy foreign DNA.

Answer 22

destroy foreign DNA.

Question 23

In which situation might a cell not pass the G/S checkpoint?

a. Chromosomes are not correctly aligned on the metaphase plate.

b. The nuclear membrane has not disassembled.

c. Errors were detected during DNA synthesis.

d. Inappropriate tension is present on the cell spindle fibers.

e. A cell cultured in a lab has insufficient nutrients in its growth medium.

Answer 23

A cell cultured in a lab has insufficient nutrients in its growth medium.

Question 24

During which phase of the cell cycle do the chromosomes align in one plane at the center of the cell?

a. interphase

b. prophase

c. metaphase

d. anaphase

e. telophase

Answer 24

metaphase

Question 25

Why is trisomy 21 seen more frequently than other trisomies (such as trisomy 1)?

a. Trisomy 21 occurs more frequently than other trisomies because chromosome 21 is very small and more prone to nondisjunction.

b. Other trisomies are more likely to be detected by karyotyping and prevented.

c. Other trisomies are just as common as trisomy 21, but individuals are healthy and therefore go undetected.

d. Other trisomies are most often lethal; the fetuses are spontaneously aborted.

e. Trisomy 21 occurs more frequently than other trisomies because chromosome 21 determines the sex of the fetus.

Answer 25

Other trisomies are most often lethal; the fetuses are spontaneously aborted.

Question 26

Before an mRNA transcript exits the nucleus, may be added and removed.

a. introns; RNA polymerase

b. a termination site; a promoter site

c. DNA; RNA

d. a cap and a tail; introns

e. RNA polymerase; a cap and a tail

Answer 26

a cap and a tail; introns

Question 27

Which statement is true regarding the size of an organism’s genome and its complexity?

a. The larger the genome size, the more complex the organism.

b. No apparent relationship exists between the size of an organism’s genome and its complexity.

c. The smaller the genome size, the more complex the organism.

d. Any organism with a genome size larger than that of an amoeba is considered “complex.”

e. Any organism with a genome size larger than that of a fruit fly is considered “complex.”

Answer 27

No apparent relationship exists between the size of an organism’s genome and its complexity.

Question 28

The color of a daisy’s petals is a(n) _____ the instructions for which are found in a gene-controlling petal color. There may be many alternate versions of this gene, which are called _____.

a. base pair, traits

b. base pair, alleles

c. trait; chromosomes

d. allele; traits

e. trait; alleles

Answer 28

trait; alleles

Question 29

Gene therapy:

a. involves introducing non-defective genes into the cells of an individual with a genetic disorder.

b. relies on drug treatment of patients with genetic disorders at specific times that correspond with cell division.

c. involves no controversial or ethical questions.

d. is defined as the replacement of organs from patients with genetic disorders by transplant.

e. has been wildly successful in curing human diseases.

Answer 29

involves introducing non-defective genes into the cells of an individual with a genetic disorder.

Question 30

When a DNA fingerprint is created, what determines the size of each fragment?

a. the number of PCR cycles that are used

b. the size of the individual’s genome

c. the amount of time the electric current is applied during gel electrophoresis

d. the age of the individual from whom the sample was taken

e. the number of times the repeating sequence is repeated in each STR region

Answer 30

the number of times the repeating sequence is repeated in each STR region

Question 31

A specific region of DNA that contains the information to produce a complete protein is called a:

a. base

b. chromosome.

c. nucleotide.

d. codon.

e. gene.

Answer 31

gene.

Question 32

A 30-year-old woman has a 1 in 3,000 chance of giving birth to a child with trisomy 21; however, a 48- year-old woman has a 1 in 9 chance. Which statement is the most likely explanation for why a woman has a higher probability of giving birth to a child with trisomy 21 as she ages?

a. Older women have older oocytes, and the older the oocytes, the greater the chance they will experience failure of cytokinesis during cell division.

b. Older women have lived longer and have an increased percentage of toxins and oxidative damage in their bodies. Because these are the major causes of trisomy 21, the likelihood of giving birth to a child with trisomy 21 increases.

c. Older women have older oocytes, and the older the oocytes, the greater the chance that sister chromatids will duplicate genes incorrectly.

d. Older women have older oocytes, and the older the oocytes, the greater the chance they will experience a nondisjunction event during meiosis.

e. Older women are more likely to mate with older men, and the older the man, the older the sperm. Older sperm are more likely to experience a nondisjunction event during meiosis.

Answer 32

Older women have older oocytes, and the older the oocytes, the greater the chance they will experience a nondisjunction event during meiosis.

Question 33

In birds, sex determination is:

a. similar to that in humans, in which the father has one copy of each of two different sex chromosomes.

b. opposite of that in humans, because the mother has one copy of each of two different sex chromosomes.

c. based on temperature.

d. based on the males being haploid and the females being diploid.

e. based on the males being diploid and the females being haploid.

Answer 33

opposite of that in humans, because the mother has one copy of each of two different sex chromosomes.

Question 34

When comparing STR alleles of a biological father and son, what would you expect to find?

a. At each of the STR locations, the child would have at least one allele in common with his father.

b. The alleles at 11 of the 13 STR locations (>80%) would be identical.

c. It is impossible to predict similarities or differences between the alleles; STR locations can only be compared between unrelated individuals.

d. The son’s 26 alleles from the 13 STR locations would match the 26 alleles of his father.

e. None of the alleles would match because STR alleles are only maternally inherited.

Answer 34

At each of the STR locations, the child would have at least one allele in common with his father.

Question 35

A newly discovered bacterial protein consists of 300 amino acids. This protein would have been translated from an mRNA strand that was made up of at least:

a. 100 nucleotides.

b. 200 nucleotides.

c. 300 nucleotides.

d. 600 nucleotides.

e. 900 nucleotides.

Answer 35

900 nucleotides.

Question 36

Cancer cells are different from other cells in that they have lost their “contact inhibition.” Contact inhibition means:

a. DNA replication in most cells doesn’t begin until the double helix comes in contact with particular enzymes.

b. most cells stop dividing when they bump up against other cells or collections of cells.

c. DNA replication in most cells stops when the double helix comes in contact with particular enzymes.

d. most cells don’t begin to divide until they bump up against other cells or collections of cells.

e. most cells stop dividing when they have reached 50 cell divisions.

Answer 36

most cells stop dividing when they bump up against other cells or collections of cells.

Question 37

Why have scientists inserted the human insulin gene into the genome of E. coli bacteria?

a. A person who is unable to produce insulin can be cured if infected by a bacterium carrying the human insulin gene.

b. Bacteria express the human insulin gene and produce large quantities of the insulin protein, which is sold pharmaceutically.

c. Insertion of the human insulin gene into E. coli causes the cells to rupture, thereby controlling and reducing bacterial infections.

d. The recombinant bacteria can be used in gene therapy of individuals who have type 1 diabetes.

e. The engineered bacteria are used by the food industry as a supplement that improves the absorption of glucose.

Answer 37

Bacteria express the human insulin gene and produce large quantities of the insulin protein, which is sold pharmaceutically.

Question 38

What exactly does transfer RNA (tRNA) transfer?

a. amino acids to the RNA polymerase during transcription

b. carbohydrates throughout the cytoplasm during transcription

c. nucleotides that are to be added to a growing polypeptide chain

d. the two ribosomal subunits to the start sequence and initiates the start of translation

e. amino acids to the ribosome during translation

Answer 38

amino acids to the ribosome during translation

Question 39

A gene from a bacterium can be inserted into a corn plant, and the corn plant will make the same protein as the bacterium. This kind of gene transfer works because:

a. the bacterium and the corn plant are very closely related from an evolutionary perspective.

b. the bacterium and the corn plant use the same process and genetic code for synthesizing proteins.

c. the bacterium and the corn plant are able to interbreed and produce fertile offspring.

d. the bacterium infects the corn plant’s cells and uses its cellular machinery to produce the protein.

e. every organism’s DNA is identical.

Answer 39

the bacterium infects the corn plant’s cells and uses its cellular machinery to produce the protein.

Question 40

Which of these is NOT a common concern about genetically modified food crops?

a. They may cause unforeseen allergies in those who consume the genetically modified food.

b. They may cause a reduction of genetic diversity among food crops.

c. They may have unintended negative effects on surrounding organisms.

d. They may increase the number of human infections by transgenic E. coli.

e. They may cause the evolution of pesticide-resistant crop pests.

Answer 40

They may increase the number of human infections by transgenic E. coli.