Mastering Biology Reading Quiz #14 and #15

The action of helicase creates _____.

replication forks and replication bubbles

True or false? Single-stranded DNA molecules are said to be antiparallel when they are lined up next to each other but oriented in opposite directions.

True

Hershey and Chase used _____ to radioactively label the T2 phage's proteins. A. 35S B. 14C C. 222Ra D. 92U E. 32P

A. 35S. Hershey and Chase used radioactive sulfur to label the phage's proteins.

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments? A. DNA polymerase can assemble DNA only in the 5' to 3' direction B. it is more efficient than assembling complete new strands C. only short DNA sequences can extend off the RNA primers D. DNA polymerase can assemble DNA only in the 3' to 5' direction E. the replication forks block the formation of longer strands

A. DNA polymerase can assemble DNA only in the 5' to 3' direction.

_____ is a carcinogen that promotes colon cancer. A. Fat B. UV Light C. Estrogen D. A Virus E. Testosterone

A. Fat

What would be the consequence(s) for DNA synthesis if DNA ligase were defective? A. Lagging strand synthesis would be incomplete; leading strand synthesis would be largely unaffected. B. Leading strand synthesis would be mostly incomplete; lagging strand synthesis would be unaffected. C. Both leading and lagging strand synthesis would be mostly incomplete. D. Both leading and lagging strand synthesis would be unaffected.

A. Lagging strand synthesis would be incomplete; leading strand synthesis would be largely unaffected.

Telomerase is needed to ______. A. prevent the loss of DNA bases at the ends of linear chromosomes B. open the two strands of DNA in front of the replication fork C. create repetitive DNA sequences that allow the assembly of the kinetochore D. synthesize telomere proteins E. allow DNA replication at the ends of chromosomes to occur in the 3' to 5' direction

A. Prevent the loss of DNA bases at the ends of linear chromosomes.

Why does telomerase have to have a built-in template for DNA synthesis? A. Telomerase is involved in adding DNA to the end of the lagging strand. B. Telomerase is involved in adding DNA to the end of the leading strand. C. All of lagging strand synthesis requires genetic information that is not present in the parent DNA molecule. D. All of leading strand synthesis requires genetic information that is not present in the parent DNA molecule.

A. Telomerase is involved in adding DNA to the end of the lagging strand.

Okazaki Fragments

Are the short sections of DNA that are synthesized on the lagging strand of the replicating DNA.

What would be the consequence(s) for DNA synthesis if primase were defective? A. Both leading and lagging strand synthesis would be unaffected. B. Both leading and lagging strand synthesis would be incomplete. C. Leading strand synthesis would be incomplete; lagging strand synthesis would be unaffected. D. Lagging strand synthesis would be incomplete; leading strand synthesis would be unaffected

B. Both leading and lagging strand synthesis would be incomplete.

You are trying to discover if the pesticide atrazine is a mutagen. Where are you looking for mutations? A. Glucose Molecules B. DNA C. Mitochondria D. RNA

B. DNA

Which of the following codes for proteins? A. Chromosomes B. Genes C. RNA D. Enzymes

B. Genes

The first step in the replication of DNA is catalyzed by _____. A. ligase B. helicase C. DNA polymerase D. primase E. single-strand binding protein

B. Helicase

During _____ both the contents of the nucleus and the cytoplasm are divided. A. S B. Mitotic Phase C. G1 D. G2 E. Mitosis

B. Mitotic Phase

Did doctors ask Henrietta Lacks' permission to take her cells, and was she paid for them? A. She was never told that her cells were being taken, but her family has since been compensated. B. She was never told that her cells were being taken, and neither she nor her family has been compensated. C. She granted her permission and was paid. D. She granted her permission but was not paid.

B. She was never told that her cells were being taken, and neither she nor her family has been compensated.

When cells were first taken from Henrietta Lacks, she was _____. A. Only two years old B. Suffering from cervical cancer C. In high school D. Already dead

B. Suffering from cervical cancer.

Which of the following statements about Okazaki fragments in E. coli is true? A. They are sealed together by the action of helicase. B. They are formed on the lagging strand of DNA. C. They are usually 50 to 500 bases long. D. They are synthesized in the 3' to 5' direction.

B. They are formed on the lagging strand of DNA.

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. A. uracil ... cytosine B. thymine ... cytosine C. guanine ... adenine D. cytosine ... uracil E. cytosine ... thymine

B. Thymine ... Cytosine

Which of the following enzymes is important for relieving the tension in a helix as it unwinds during DNA synthesis? A. Helicase B. Topoisomerase C. Single-strand binding proteins D. Ligase

B. Topoisomerase

A tumor would not be able to have its own blood supply if it weren't for which of the following? Choose all that apply. A. Immune System Cells B. Parafollicular Cells C. Endothelial Cells D. Fibroblast

Both A and C

How did doctors harvest and culture cells from Henrietta Lacks? A. A kidney that she donated to someone else was recovered when that patient died, and cells from the kidney were used to create a culture. B. Her body was recently exhumed from her grave, and cells were taken and grown in the lab. C. Cells were taken while she was being treated for cancer many years ago, and these cells have been cultured in the lab ever since. D. Her cells were frozen for many decades and have recently been thawed and grown in the lab.

C. Cells were taken while she was being treated for cancer many years ago, and these cells have been cultured in the lab ever since.

Two important checkpoints that regulate the cell's progression through the cell cycle occur in the _____ and _____ phases of the cell cycle. A. prophase, telophase B. G1, S C. G1, G2 D. S, M

C. G1, G2

Who demonstrated that DNA is the genetic material of the T2 phage? A. Watson and Crick B. Franklin C. Hershey and Chase D. Darwin and Wallace E. Meselson and Stahl

C. Hershey and Chase

The synthesis of a new strand begins with the synthesis of a(n) _____. A. short pieces of DNA B. poly(A) tail C. RNA primer complementary to a preexisting DNA strand D. Okazaki fragment E. single-strand binding protein

C. RNA primer complementary to a preexisting DNA strand.

Which of the following best summarizes current scientific opinion regarding cellphones and brain cancer? A. Cellphones do not cause brain cancer B. While most studies indicate that cellphones cause brain cancer, the studies are not statistically sound. C. While most studies indicate that cellphones do not cause brain cancer, more research needs to be done as cellphone use increases. D. Cellphones cause brain cancer.

C. While most studies indicate that cellphones do not cause brain cancer, more research needs to be done as cellphone use increases.

For the Meselson-Stahl experiment shown in Figure 15.5, what would be the composition of the DNA after three generations? A. 7/8 low-density and 1/8 high-density B. 1/2 low-density and 1/2 intermediate-density C. All intermediate-density D. 3/4 low-density and 1/4 intermediate-density

D. 3/4 low-density and 1/4 intermediate-density

What is the difference between a chromatid and a chromosome? A. A chromatid always consists of two linear DNA molecules, whereas a chromosome always consists of just one linear DNA molecule. B. Chromosomes are always replicated, whereas chromatids are not. C. Chromatids consist of DNA, whereas chromosomes consist of proteins. D. A chromatid is one half of a replicated chromosome, whereas a chromosome consists of DNA wrapped around proteins in a highly organized manner.

D. A chromatid is one half of a replicated chromosome, whereas a chromosome consists of DNA wrapped around proteins in a highly organized manner.

Cells taken from Henrietta Lacks have been used for experiments leading to _____. A. Tests of the effects of atomic radiation on life B. New treatments for cancer C. The development of a polio vaccine D. All of the above

D. All of the above

Mitosis is responsible for what key process in multicellular eukaryotes? A. Asexual Reproduction B. Growth C. Wound repair D. All of the responses are correct

D. All of the responses are correct

Which of the following is true? A. A cancer-causing substance always directly damages DNA. B. A cancer-causing substance never directly damages DNA. C. No substance has ever been determined to cause cancer. D. Cancer-causing substances work in many different ways.

D. Cancer-causing substances work in many different ways.

An environmental substance that is known to cause cancer is called a what? A. Mutagen B. Teratogen C. Mitogen D. Carcinogen

D. Carcinogen

The radioactive isotope 32P labels the T2 phage's _____. A. Tail B. DNA C. Head D. Base Plate E. Protein Coat

D. DNA. The T2 phage consists of a protein coat and DNA. It is the DNA that contains P.

Which answer correctly identifies a cell-cycle checkpoint with a criterion for passing it? A. Metaphase checkpoint: DNA is undamaged. B. G1 checkpoint: Chromosomes have replicated successfully. C. S checkpoint: DNA is undamaged. D. G2 checkpoint: Chromosomes have replicated successfully.

D. G2 checkpoint: Chromosomes have replicated successfully.

During _____ the cell grows and replicates both its organelles and its chromosomes. A. S B. cytokinesis C. G1 D. interphase E. Mitosis

D. Interphase

Radiation emitted from which of the following two sources are most alike? A. Cellphones and Cosmic Rays B. X-Rays and Microwaves C. Cosmic Rays and Lightbulbs D. Microwaves and Cellphones

D. Microwaves and Cellphones

The action of helicase creates _____. A. DNA fragments and replication forks B. DNA fragments and replication bubbles C. primers and DNA fragments D. replication forks and replication bubbles E. primers and replication bubbles

D. Replication Forks and Replication Bubbles

During what phase of the cell cycle does the DNA become replicated? A. M B. G1 C. G2 D. S

D. S

What property of Henrietta Lacks' cells was most unusual when they were grown in the laboratory? A. They never divided B. They did not require nutrients C. They grew to more than 10 times their normal size D. They continue to divide and multiply after decades of culture.

D. They continue to divide and multiply after decades of culture

You are developing a new drug that damages the cells that provide the supportive structure required by a tumor. Which type of cell are you targeting? A. endothelial cell B. parafollicular cell C. immune system cell D. fibroblast

D. fibroblast

The enzyme that can replicate DNA is called

DNA Polymerase

What catalyzes DNA synthesis?

DNA Polymerase

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?

DNA polymerase can assemble DNA only in the 5' to 3' direction.

After replication is complete, the new DNAs, called ________________, are identical to each other.

Daughter DNA

Replication Fork

During DNA replication, an open section of DNA, in which a DNA polymerase can replicate DNA.

Which of these is NOT a carcinogen? A. Fat B. Cigarette Smoke C. Testosterone D. UV light E. All of the above are carcinogens

E. All of the above are Carcinogens.

After DNA replication is completed, _____. A. each of the four DNA strands consists of some old strand parts and some new strand parts B. one DNA double helix consists of two old strands and one DNA double helix consists of two new strands C. there are four double helices D. each new DNA double helix consists of two new strands E. each new DNA double helix consists of one old DNA strand and one new DNA strand

E. Each new DNA double helix consists of one old DNA.

After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that they contained _____, which demonstrated that _____ is the phage's genetic material. A. Labeled Protein ... DNA B. Labeled Protein ... Protein C. Labeled DNA ... Labeled Protein D. Labeled DNA ... Protein E. Labeled DNA ... DNA

E. Labeled DNA ... DNA

The primers used for DNA synthesis are ______. A. Short DNA sequences B. Short amino acid sequences (peptides) C. RNA polymers D. Proteins that bind to a single strand DNA E. Short RNA sequences

E. Short RNA sequences

An old DNA strand is used as a _____ for the assembly of a new DNA strand. A. primer B. source of nucleotides C. complement D. model E. template

E. Template

The first step in the replication of DNA is catalyzed by _____.

Helicase

The new DNA strand that grows continuously in the 5' to 3' direction is called the

Leading Strand

Short segments of newly synthesized DNA are joined into a continuous strand by _____.

Ligase

Which part of a deoxynucleoside triphosphate (dNTP) molecule provides the energy for DNA synthesis?

Phosphate Groups

Which of the following enzymes creates a primer for DNA polymerase?

Primase

Which of the following statements about DNA synthesis is true? A. Primers are short sequences that allow the initiation of DNA synthesis. B. DNA polymerase adds dNTP monomers in the 3' to 5' direction. C. As DNA polymerase moves along the template strand, each new nucleotide provides a 5' hydroxyl group for the next reaction to occur. D. Nucleotides are added in a random fashion to single-stranded DNA.

Primers are short sequences that allow the initiation of DNA synthesis.

The synthesis of a new strand begins with the synthesis of a(n) _____.

RNA primer complementary to a preexisting DNA strand.

An old DNA strand is used as a _____ for the assembly of a new DNA strand.

Template

After DNA replication is completed, _____.

each new DNA double helix consists of one old DNA strand and one new DNA strand