Ch 10

A DNA molecule containing a gene has the sequence AACT on one strand. During replication, DNA polymerase synthesizes the sequence TTGT on the new strand. Which of these is the most likely new allele of the original strand after replication?

AACA

What is the role of BRCA1 in normal cells? BRCA1 is a tumor suppressor. BRCA1 is a carcinogen. BRCA1 is a mutagen. BRCA1 is a proto-oncogene. BRCA1 is an oncogene.

BRCA1 is a tumor suppressor

If a man, Bob, has one parent who smoked and died early in life from lung cancer, which of the following is most likely to be true?

Bob could inherit a mutation that leads to cancer early in life.

Predict what would most likely happen if both alleles of BRCA1 were mutated.

DNA errors would occur more frequently.

A test designed to look for different alleles of a gene (e.g., the BRCA1 gene) is based on differences in _____.

DNA sequences

What would be the best way to distinguish between two alleles and two genes?

Examine their DNA; the DNA sequences of two different alleles would be more similar than the sequences of two different genes.

A proto-oncogene is critical for a cell to respond to an external signal to divide. What would happen to a cell that sustains an inactivating mutation in this proto-oncogene?

It would not divide, even in the presence of a signal to divide.

Which statement is true for the younger brother of a 29-year-old woman with breast cancer?

The brother may have an increased risk for prostate cancer. The brother may not have an increased risk for cancer. The brother may develop cancer early in life. the brother may pass a mutated form of a tumor suppressor gene on to his children.

Which woman would be most likely to benefit from genetic testing for breast cancer? a 25-year-old woman whose mother, aunt, and grandmother had breast cancer a 55-year-old woman whose older sister was just diagnosed with breast cancer a 40-year-old woman who has a cousin with breast cancer All women can benefit from genetic testing for breast cancer. a healthy 75-year-old woman with no family history of breast cancer

a 25 year old woman whose mother, aunt, and grandmother had breast cancer

In an otherwise normal cell, what happens if one mistake is made during DNA replication? The mutation will be inherited by the individual's offspring. Nothing; mistakes just happen. The cell will begin to divide out of control, forming a malignant tumor. A cell cycle checkpoint detects the error and pauses the cell cycle so the error can be corrected. Mistakes are never made during DNA replication.

a cell cycle checkpoint detects the error and pauses the cell cycle so the error can be corrected

cell cycle checkpoint

a cellular mechanism that ensures each stage of the cell cycle is completed accurately

If an individual has a germ cell mutation, which of these is a possible source of that mutation? a maternal or paternal allele a paternal allele only overuse of alcohol a maternal allele only excessive sun exposure

a maternal or paternal allele

Which of these does not cause cancer to develop and progress? a tumor suppressor gene acting alone an oncogene and a BRCA1 acting together a proto-oncogene acting alone a proto-oncogene and a tumor suppressor gene acting together an oncogene acting alone

a proto-oncogene and a tumor suppressor gene acting together

We would all have many more mutations in our genes if not for the _____. death of all mutant cells, removing them from our bodies fact that mutations tend to cancel each other out, leaving mostly functional genes fact that everybody carries a "good" allele to counter every "bad" allele activity of repair enzymes fact that dividing cells remove all their mutations when they replicate their DNA

activity of repair enzymes

At which point does a mutation exert its potentially dysfunctional effects in a cell? only during cell division after a protein is produced during DNA replication during protein translation during DNA transcription

after the protein is produced

A mutation can cause a change _____. all of these in the shape of a protein in the way the cell cycle is regulated that is beneficial to the cell in the amino acid sequence of a protein

all of these

What would you say to a niece if she asked you how she could reduce her risk of breast cancer? (Assume there is no family history of breast cancer.) all of these Reduce sun exposure. Reduce alcohol consumption. Utilize early screening. Avoid tobacco.

all of these

Why is age a risk factor for cancer? none of these all of these Age extends the amount of exposures to environmental factors, which can lead to the progression of cancer. Age provides more time for the cancer cells to accumulate. Age causes additional mutations to be acquired that can predispose one to cancer.

all of these

Two copies of a gene have identical regulatory sequences, but different coding sequences. These copies can be referred to as _____.

alleles

allele

alternative version of the same gene that have different nucleotide sequences

mutagens

any chemical or physical agent that can damage DNA by changing its nucleotide sequence

carcinogen

any substance that causes cancer. most carcinogens are mutagens

DNA damage is usually repaired _____.

at cell cycle checkpoints

Put the following steps in order to indicate how a malignant tumor may develop. a - An environmental mutagen such as UV light mutates the p53 gene. b - A single mutation of BRCA1 is inherited. c - Mutation that allows invasion of other tissues develops. d - An oncogene forms when DNA mistakes are not corrected. Please choose the correct answer from the following choices, and then select the submit answer button.

b, d, a, c

How does an acquired mutation in a gene alter the function of a cell? Base pair mutations in a gene are passed directly into mRNA via transcription. Base pair mutations in a gene are passed directly into mRNA via translation. Base pair mutations in mRNA are passed directly into a protein via transcription. Base pair changes in the gene are passed directly into altered amino acids by a ribosome. Base pair mutations in a gene are passed from mRNA into a protein via transcription.

base pair mutations in a gene are passed directly into mRNA via transcription

Tumors that will not spread throughout the body are _____, and those that do spread are termed _____. mutagen; carcinogen benign; mutagen benign; malignant malignant; benign tumor suppressor; proto-oncogene

benign; malignant

Why do people with "inherited cancer" often develop cancer at a relatively young age? Cancer cannot be truly inherited, but certain alleles weaken the normal control points that prevent cancer, and this causes cancer to appear earlier in life. Younger people are exposed to more risk factors than older people. all of these All inherited alleles that are associated with cancer cause childhood cancers. Predisposition does not increase the chances that other risk factors will lead to the progression of cancer.

cancer cannot be truly inherited, but certain alleles weaken the normal control points that prevent cancer, and this causes cancer to appear earlier in life

Cancer cells have distinctive properties that set them apart and contribute to malignancy. Which characteristic is NOT one of those exhibited by cancer cells?

cancer cells exhibit anchorage dependence

A potential cancer-causing gene coding for a protein with cell cycle control responsibilities is a _____, and a gene coding for a protein that stimulates cell division is a _____. tumor suppressor; oncogene oncogene; proto-oncogene carcinogen; proto-oncogene oncogene; tumor suppressor oncogene; mutagen

carcinogen; proto-oncogene

mutation

chance in nucleotide sequence of DNA

You isolate cells from a tumor and study them. You observe that the cells continue dividing, even when DNA is damaged, when the cells become crowded, or even when nutrients run low. These observations lead you to suspect that the cells _____.

contain a mutated tumor suppressor gene

cancer

disease of unregulated cell division: cells divide inappropriately and accumulate, in some instances forming a tumor

DNA mutations can arise from uncorrected errors in DNA replication, inheritance, and _____. catching an influenza virus from a person with mutated genes chronic sleep deprivation a poor diet lacking in vitamins and minerals abnormal cell division environmental insults

environmental insults

Why would you need a gene to stop the cell cycle?

if a mutation occurred and the cell needed time to repair it before continuing, if there was no immediate need for more cells, and if a cell had mutated DNA

A person has the identical BRCA1 mutation in every somatic cell in her body. What is the most likely source of this mutation?

inheritance from one of her parents (via the sperm or egg)

Which is the correct order of events in which breast cancer might develop? inheritance of a mutant BRCA gene > mutation of p53 > additional mutations permit spreading > replication errors create an oncogene replication errors create an oncogene > mutation of p53 > inheritance of a mutant BRCA gene > additional mutations permit spreading inheritance of a mutant BRCA gene > replication errors create an oncogene > mutation of p53 > additional mutations permit spreading mutation of p53 > inheritance of a mutant BRCA gene > additional mutations permit spreading > replication errors create an oncogene inheritance of a mutant BRCA gene > additional mutations permit spreading > replication errors create an oncogene > mutation of p53

inheritance of a mutant BRCA gene > replication errors create an oncogene > mutation of p53 > additional mutations permit spreading

A woman with a BRCA1 mutation _____. is at increased risk of developing breast cancer must have inherited it from her mother because of the link to breast cancer none of these will also have a mutation in BRCA2 will definitely develop breast cancer

is at increased risk of developing breast cancer

Which statement accurately describes cancer development? It is a multistep process by which multiple mutations cause a series of events that lead to cancer. It is inherited and is independent of environmental factors. It is a multistep process by which multiple mutagens cause a series of cancer-causing alleles. It is a one-step process by which a mutation drives cancer development. It is a caused by carcinogens that act on inherited alleles that cause cancer.

it is a multistep process by which multiple mutations cause a series of events that lead to cancer

Which family history most strongly suggests a risk of inherited breast cancer due to BRCA1 mutations? many relatives with skin cancer many female relatives who were diagnosed with breast cancer in their 70s many relatives diagnosed with skin cancer at an early age many female relatives diagnosed with breast cancer at an early age many female relatives with both early breast cancer and ovarian cancer

many female relatives diagnosed with breast cancer at an early age

tumor

mass of cells resulting from uncontrolled cell division

A chemical that causes alterations in DNA is a _____, and if this chemical causes cancer it is called a(n) _____. tumor suppressor; mutagen tumor suppressor; oncogene carcinogen; mutagen tumor suppressor; proto-oncogene mutagen; carcinogen

mutagen; carcinogen

Which statement about decreasing a woman's breast cancer risk if she inherits one of the mutant BRCA genes is true? A woman cannot decrease her cancer risk, so she might as well live life to its fullest. Surgical removal of the breasts will decrease a woman's cancer risk to near zero. She can take several medications that make it almost impossible to get breast cancer, even if she inherits the BRCA gene. Diet and lifestyle changes will effectively decrease her risk to near zero. none of these

none of these

apoptosis

programmed cell death; often referred to as cellular suicide

Will a woman who inherits a BRCA1 mutation from her mother develop breast cancer?

she may develop breast cancer, but it depends on other factors, such as her lifetime estrogen exposure

Why does wearing sunscreen reduce cancer risk? Sunscreen can prevent cells with mutations from being destroyed. Sunscreen can repair damaged DNA. Sunscreen can reduce the chance of mutations caused by exposure to UV radiation present in sunlight. It does not reduce cancer risk; sunscreen causes mutation and actually increases cancer risk. Sunscreen can activate checkpoints in skin cells.

sunscreen can reduce the chance of mutations caused by exposure to UV radiation present in sunlight

A new gene is discovered, called SHOSH. It prevents a cell from entering mitosis if there are any signs of DNA damage. This means that SHOSH would be a type of _____ and that _____ mutations in SHOSH would be associated with cancer.

tumor suppressor gene; inactivating

An individual who inherits a mutation in a BRCA1 or BRCA2 gene is at higher risk for developing cancer because these genes are _____.

tumor suppressor genes that produce proteins to repair DNA damage