Biology Exam 3
Why do scientists pursue several methods to get stem cells to grow into specific tissue types? A. Each method or approach used in stem cell research adds to our knowledge of how stem cells work. B. More research on stem cells will be less expensive, over the long term. C. Scientists are trying to maximize their profit margin. D. Science is not a collaborative work, so individuals must develop their own method of growing tissue types. E. The more scientists are involved in stem cell research, the less people will think any research on embryos is unethical.
A
Why don't engineered bladders get rejected by the patient's immune system when they are implanted? A. Engineered bladders are grown from the patient's own cells. B. The bladder is not as functional as a regular bladder, making it less susceptible to immune rejection. C. The patient takes strong immunosuppressive drugs to prevent rejection. D. Engineered bladders are made of sections from the patient's bowels. E. The bladders are taken from another member of the same family.
A
Mendel observed that crossing a purple-flowered pea plant with a white-flowered pea plant always produced purple-flowered offspring in the F1 generation. Select TWO inferences could he make from this observation? A. The purple trait is dominant, and the white trait is recessive. B. The two parental traits were blended in the F1 generation. C. The purple-flowered pea plants cannot successfully mate with white-flowered pea plants. D. The two parental traits were not blended in the F1 generation. E. The purple trait is recessive, and the white trait is dominant.
A and D
What does Mendel's law of segregation tell us about meiosis and formation of gametes? A. Plants segregate their genes in a manner different from humans and other animals, such as mice. B. Maternal and paternal chromosomes separate during meiosis, giving each gamete half the amount of DNA of the parent. C. Gametes have exactly double the amount of DNA as the parent cell. D. Genes are linked, and the probability of inheriting traits from parents is random and cannot be predicted. E. Particles from each parent come together and blend during meiosis and formation of gametes.
B
What is different about red blood cells from a person with type AB blood, compared to those from other blood types? A. They carry A and B type surface markers, so they cannot receive or donate blood. B. They carry A and B type surface markers, so they are universal acceptors of blood. C. They carry A and B type surface markers, so they are universal donors of blood. D. They carry Rh markers, whereas other blood types have none. E. They have no surface markers from the ABO blood type alleles.
B
Children often have many of the phenotypes of their parents because _____. A. they carry the same combinations of alleles that their parents have B. they have the exact same genotypes as their parents C. they inherit mutations that make their bodies appear identical to one or both parents D. the cells of embryos divide by meiosis, a process that yields genetic duplicates E. they inherit half of their genetic material from each parent
E
DNA mutations can arise from uncorrected errors in DNA replication, inheritance, and _____. A. a poor diet lacking in vitamins and minerals B. abnormal cell division C. catching an influenza virus from a person with mutated genes D. chronic sleep deprivation E. environmental insults
E
How does an acquired mutation in a gene alter the function of a cell? A. Base pair changes in the gene are passed directly into altered amino acids by a ribosome. B. Base pair mutations in a gene are passed from mRNA into a protein via transcription. C. Base pair mutations in mRNA are passed directly into a protein via transcription. D. Base pair mutations in a gene are passed directly into mRNA via translation. E. Base pair mutations in a gene are passed directly into mRNA via transcription.
E
Would it be sufficient to just replace the neurons in someone who suffered nervous tissue damage? Why or why not? A. Yes, replacement neurons convert into stem cells when transplanted and repair damaged tissue. B. Yes, replacement neurons will co-exist with remaining endogenous neurons and make all other cells. C. Yes, replacement neurons will make the correct connections with cells in their surroundings. D. No, replacement neurons will reject the remaining endogenous neurons. E. No, replacement neurons must also make the correct connections with cells in their surroundings.
E
A diploid cell of baker's yeast has 32 chromosomes. How many chromosomes are in each of its haploid spores? A. 16 B. 64 C. 8 D. 1 E. 32
A
A gamete is aneuploid if _____. A. all of these B. one or more homologous chromosomes fail to separate in meiosis I C. there are fewer than 23 chromosomes in the cell D. there are more than 23 chromosomes in the cell E. one or more sister chromatids fail to separate in meiosis II
A
A hematopoietic stem cell turns on genes that direct it to become a white blood cell. This process is known as _____. A. cell differentiation B. meiosis C. regeneration D. mitosis
A
A woman is heterozygous for the CF-associated gene (the alleles are represented here by the letters A and a. Assuming that meiosis occurs normally, which answer choice represents eggs that she can produce? A. A or a B. a C. A D. Aa E. AA
A
An alien has 82 total chromosomes in each of its body cells. The chromosomes are paired, making 41 pairs. If the alien's gametes undergo meiosis, what are the number and arrangement (paired or not) of chromosomes in one of its gametes? A. 41 unpaired chromosomes B. 164 paired chromosomes C. 41 paired chromosomes D. 82 unpaired chromosomes E. 82 paired chromosomes
A
By happenstance, Mendel chose traits located on different chromosomes for his studies. How would his results have been different, with regard to independent assortment, had he chosen to follow two traits carried on the same chromosome? A. His results would show that one trait was always co-inherited with another trait. B. His results would be easier to interpret and would better demonstrate his dominant/recessive principles and concepts. C. The two recessive traits would have assorted into one out of every four offspring independently of each other. D. There is not enough information to make predictions about his results in this type of cross. E. The offspring would display any and every possible combination of dominant and recessive traits.
A
Consider your brother and your son. If you are male, which statement is correct? A. You and your brother inherited the same Y chromosome from your dad, and you passed the same Y chromosome on to your son. B. You cannot tell the inheritance pattern with the information given. C. You and your brother inherited the same Y chromosome from your dad, and you passed a different Y chromosome on to your son. D. The inheritance of the Y chromosome is dependent on which X chromosome is inherited. E. You and your brother inherited different Y chromosomes from your dad, and you passed your Y chromosome on to your son.
A
Engineering a bladder is more challenging than engineering skin because a bladder _____. A. requires a scaffold on which to grow B. is an internal tissue C. does not contain differentiated cells D. contains a single cell type E. does not receive signals for cell division
A
How do the two alleles of the CFTR gene in a lung cell differ? A. They are inherited from different parents. B. They are inherited from different parents, they are on different chromosomes, and only one is expressed. C. There is no difference because they are both the same gene. D. Only one is expressed. E. One is on chromosome 7 and one is on chromosome 3.
A
Predict the sex of a baby with an XXY combination of sex chromosomes. A. male B. female C. This cannot be determined with the chromosome information given.
A
Use the following information for this question: Phenylketonuria is considered to be an inborn error of metabolism. It is a recessive genetic condition in which the enzyme that breaks down the amino acid phenylalanine is defective or missing. Testing of all newborns allows this condition to be detected at birth. A special diet that severely minimizes phenylalanine (e.g., by avoiding diet sodas and most usual sources of protein) can treat the condition. In this scenario, two carriers of both cystic fibrosis and phenylketonuria have a child. What is the probability that the child will have cystic fibrosis and be a carrier for phenylketonuria? A. 12.5% B. 6.25% C. 56.25% D. 0% E. 18.75%
A
Which of these can be determined by amniocentesis and karyotyping? A. trisomy 21 B. Duchenne muscular dystrophy C. blood type D. cystic fibrosis E. hair color
A
Which of these can result in a trisomy such as Down syndrome? A. an egg with 24 chromosomes fertilized by a sperm with 23 chromosomes B. an egg with 23 chromosomes fertilized by a sperm with 23 chromosomes C. an egg with 23 chromosomes fertilized by a sperm with 22 chromosomes D. an egg with 22 chromosomes fertilized by a sperm with 23 chromosomes E. an egg with 22 chromosomes fertilized by a sperm with 24 chromosomes
A
Which of these does not cause cancer to develop and progress? A. a proto-oncogene and a tumor suppressor gene acting together B. an oncogene and a BRCA1 acting together C. an oncogene acting alone D. a proto-oncogene acting alone E. a tumor suppressor gene acting alone
A
Which statement is true of a single human liver cell? A. all of these B. The number of chromosomes in this liver cell is referred to as diploid. C. There are two alleles for each gene. D. There are 46 chromosomes present. E. There is one allele on each chromosome.
A
Why are more males than females affected by X-linked recessive genetic diseases? A. Males have a Y chromosome that cannot mask the X-linked recessive allele. B. Females have no Y chromosome to mask the X-linked recessive allele. C. Females have an additional Y chromosome to mask the X-linked recessive allele. D. Males and females are affected equally by X-linked recessive genetic conditions. E. Females have two Y chromosomes and cannot be affected by X-linked traits.
A
A mutation can cause a change _____. A. in the way the cell cycle is regulated B.all of these C. in the shape of a protein D. that is beneficial to the cell E. in the amino acid sequence of a protein
B
Human skin color ranges from very light to dark black, with many distinct skin tones in between. What type of inheritance pattern governs skin color? A. multifactorial inheritance B. polygenic inheritance C. X-linked inheritance D. incomplete dominance E. codominance
B
If two women have identical alleles of the suspected 20 height-associated genes, why might one of those women be 5 feet 5 inches tall and the other 5 feet 8 inches tall? A. because the identical 20 alleles cause variation in the phenotype B. because environmental factors also play a role in the phenotype of this trait C. all of these D. because phenotype dictates genotype E. none of these
B
In an otherwise normal cell, what happens if one mistake is made during DNA replication? A.Mistakes are never made during DNA replication. B.A cell cycle checkpoint detects the error and pauses the cell cycle so the error can be corrected. C. The cell will begin to divide out of control, forming a malignant tumor. D. Nothing; mistakes just happen. E. The mutation will be inherited by the individual's offspring.
B
In diploid organisms, having two homologues of each chromosome can be beneficial if one allele of a gene encodes a nonfunctional protein. Can haploid organisms avoid the negative effects of nonfunctional alleles? A. No, because there are two chromosomes each with a single allele that is always the same, and one cannot compensate for the other being nonfunctional. B. No, because there is only one allele for the gene in each cell, and the nonfunctional allele has no other allele to mask it. C. Yes, because there are two chromosomes each with a single allele that is always the same, and one can compensate for the other being nonfunctional. D. Yes, because there is only one allele for the gene in each cell, and the nonfunctional allele will be masked by another allele of a different kind. E. Yes, because there are always other alleles for other genes that will compensate for a nonfunctional allele.
B
Meiosis differs from mitosis in the _____. A. way in which sister chromatids separate B. number of chromosomes in each ending cell C. number of sister chromatids in the starting cells D. number of chromosomes in the starting cells E. number of cells produced immediately after the starting cells divide
B
Organs can perform unique functions that differ from those that the tissues from which they are made can perform individually. Why is this? A. The cells of a tissue are flat, whereas the cells of an organ are round; round cells create more functionality. B. Tissues cannot form the same shapes that organs can; organs, therefore, have more functions than tissues. C. Organs are always made of more cells than are tissues. D. The cell types of an organ work together to create new, unique functions. E. Organs have stem cells, whereas tissues do not; organs can grow new cells with functions that are different from tissues.
B
Relative to one of your liver cells, one of your skin cells has _____. A. the same genome (i.e., the same genetic material) B. the same genome and a different pattern of gene expression C. a different pattern of gene expression and the same function D. the same function E. a different pattern of gene expression
B
What are the chances that a curly-haired father and a straight-haired mother can give birth to a child with curly hair? A. 75% B. 0% C. 25% D. 100% E. 50%
B
What is the genotype of a person with cystic fibrosis? A. The genotype includes 2 additional chromosomes with the mutant CFTR gene, making a total of 25 chromosomes. B. The genotype includes two mutant CFTR genes, one each on the homologous chromosomes for chromosome 7. C. The genotype includes only one homologous chromosome 7; the second chromosome 7 is missing. D. The genotype includes one mutant CFTR gene and one normal gene, one each on the homologous chromosomes for chromosome 7. E. The genotype includes two mutant CFTR genes, both on a single homologous chromosome 7; the other homologous chromosome 7 is normal
B
Which couple could have a boy with Duchenne muscular dystrophy (DMD)? A. all of these B. a male without DMD and a carrier female C. a male without DMD and a homozygous dominant female D. none of these E. a male with DMD and a homozygous dominant female
B
Which family history most strongly suggests a risk of inherited breast cancer due to BRCA1 mutations? A. many female relatives who were diagnosed with breast cancer in their 70s B. many female relatives diagnosed with breast cancer at an early age C. many relatives with skin cancer D. many female relatives with both early breast cancer and ovarian cancer E. many relatives diagnosed with skin cancer at an early age
B
Which inheritance pattern includes an environmental contribution? A. none of these B. multifactorial C. polygenic D. X-linked recessive E. X-linked dominant
B
Which statement applies to tissues? A. Tissues contain a single cell type. B. Cells within a tissue cooperate, and each tissue has a specific function. C. Each tissue has a specific function. D. Cells within a tissue cooperate. E. Tissues contain a single cell type, and cells within a tissue cooperate.
B
Why do people with "inherited cancer" often develop cancer at a relatively young age? A. All inherited alleles that are associated with cancer cause childhood cancers. B. 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. C. all of these D. Younger people are exposed to more risk factors than older people. E. Predisposition does not increase the chances that other risk factors will lead to the progression of cancer.
B
Why do some people have unusual chromosome combinations, such as XYY and XXX? A. Genetic disease causes a spontaneous increase in the number of sex chromosomes in mature gametes. B. Errors occurred in chromosome segregation during meiosis in their fathers or mothers. C. People who inherit large numbers of short tandem repeats (STRs) also inherit extra sex chromosomes. D. It is not known why these unusual chromosome combinations occur. E. A mistake in mitosis during embryonic development leads to extra sex chromosomes in every cell.
B
Why is age a risk factor for cancer? A. none of these B. all of these C. Age provides more time for the cancer cells to accumulate. D. Age causes additional mutations to be acquired that can predispose one to cancer. E. Age extends the amount of exposures to environmental factors, which can lead to the progression of cancer.
B
You shed skin cells every day. Those cells are replaced by _____. A. meiotic division and differentiation of connective tissue cells B. mitotic division and differentiation of tissue stem cells C. mitotic division and specialization of embryonic stem cells D. differentiation of blood cells that migrate into deeper layers of the skin E. differentiation of neighboring neurons into skin cells
B
Which statement is true about Y chromosome analysis? A. It can be used to determine whether a person has a genetic disease caused by a mutant allele on an autosome. B. It can be used to determine whether a man is carrying traits such as hemophilia and Duchenne muscular dystrophy. C. It is commonly used to determine paternity and ancestry. D. It is commonly used to determine the sex of an individual. E. It can be used to determine whether a man is likely to pass on traits such as hemophilia and Duchenne muscular dystrophy.
C
Assume that Emily (who has CF, a recessive disease (aa)) decides to have children with a man who does not have CF and who has no family history of CF. What combination of gametes can each of them produce, and what is the probability that they will have a child who is a carrier for CF? A. Emily: aa, man: AA; 50% probability B. Emily: Aa, man: Aa; 100% probability C. Emily: aa, man: Aa; 100% probability D. Emily: Aa, man: AA; 50% probability E. Emily: aa, man: AA; 100% probability
E
"Reprogramming" genes erase the pattern of gene expression in a differentiated cell. When scientists insert "reprogramming" genes into differentiated cells, these cells will _____. A. hunt and destroyed damaged body cells B. be stimulated to divide into more differentiated cells C. be converted into stem cells D. become more specialized
C
A woman with a BRCA1 mutation _____. A. none of these B. will definitely develop breast cancer C. is at increased risk of developing breast cancer D. must have inherited it from her mother because of the link to breast cancer E. will also have a mutation in BRCA2
C
An adult stem cell called a hematopoietic stem cell from bone marrow is most useful in treating a _____. A. large burn on the upper thigh B. heart attack C. disorder affecting the development of blood cells D. degenerative eye disease affecting the retina E. degenerative nervous system disease such as Alzheimer's disease
C
Hematopoietic stem cells are _____ cells that develop into _____ cells. A. differentiated; liver B. differentiated; muscle C. undifferentiated; blood D. undifferentiated; urinary bladder E. undifferentiated; liver
C
If a man has an X-linked recessive disease, can his sons inherit that disease from him? A. Yes, all his sons have one X chromosome. B. Yes, all his sons inherit their X chromosomes maternally. C. No, all his sons inherit their X chromosomes maternally. D. No, all his sons have one X chromosome. E. Yes, all his sons inherit their Y chromosomes maternally.
C
If meiosis were to fail and a cell skipped meiosis I, so that meiosis II was the only meiotic division, how would you describe the resulting cells? A. haploid cells with 23 pairs of chromosomes B. haploid cells with 23 unpaired chromosomes C. diploid cells with 23 pairs of chromosomes D. diploid cells with 23 unpaired chromosomes E. none of the above
C
One could determine whether a cell is differentiated by determining whether _____ A. the cell contains membrane-bound organelles such as mitochondria. B. the cell contains all of the DNA found in other body cells. C. some genes are turned "off." D. the cell responds to growth factors. E. the cell is capable of undergoing mitosis.
C
One of the purposes of meiosis is to _____. A. increase genetic diversity in the diploid-starting cells B. double the number of chromosomes per gamete C. reduce the chromosome number in each resulting cell by half D. produce four zygotes instead of only two (as produced in mitosis) E. increase the number of embryos per fertilization
C
Predict the sex of a baby with an X sex chromosome. A. This cannot be determined with the chromosome information given. B. male C. female
C
Predict the sex of a baby with an XX pair of sex chromosomes. A. male B. This cannot be determined with the chromosome information given. C. female
C
What does it mean to say that a person has a heterozygous genotype for a disease and no disease phenotype? A. It means that the person exhibits the symptoms of the disease if the disease allele is recessive. B. It means that the person has two copies of the normal allele. C. It means that the person does not show symptoms of the disease if the disease allele is recessive. D. It means that the person is a carrier who has already sired children who show symptoms of the disease. E. It means that the person has two copies of the disease allele.
C
What is an advantage of receiving a replacement organ grown from one's own cells versus receiving an organ transplant from a donor? A. Cells in donor organs divide at a slower rate. B. Grown organs are cheaper than organ transplants. C. There is less chance of organ rejection and there is no need to wait on a transplant list. D. Replacement organs from one's own cells function better than donated organs. E. Cells in donor organs do not undergo cell division after they are transplanted.
C
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.) A. Reduce sun exposure. B. Avoid tobacco. C. all of these D. Reduce alcohol consumption. E. Utilize early screening.
C
When Mendel self-pollinated plants from the purple-flowered F1 generation, he saw that one out of every four plants in the F2 had white flowers. What reasoning did Mendel use to explain how the white, hidden trait reappeared? A. He reasoned that the recessive or hidden allele only shows up in offspring with two copies of the recessive allele. B. He reasoned that two parental elements separate during gamete formation, and each gamete receives only one of the two parental alleles. C. All of the answers are correct. D. He reasoned that, during gamete formation, the two elements separate randomly. E. He reasoned that each parent had two elements, one representing purple and one white.
C
Why is it possible for two healthy parents to give birth to a child with a genetic defect such as cystic fibrosis? A. CF is not passed to children from their parents; it comes from their grandparents. B. CF is caused by the inheritance of too many "normal" genes; the parents would be unaffected. C. CF is only evident in individuals with two mutant alleles; a healthy parent could carry both a defective allele and a normal allele. D. CF is normally caused by a mutation that occurs in the fetus during pregnancy, and it does not affect the mother. E. CF is normally caused by a mutation that occurs only in the sperm and eggs of the parents, so their bodies are not affected.
C
At which point does a mutation exert its potentially dysfunctional effects in a cell? A. only during cell division B. during DNA transcription C. during DNA replication D. during protein translation E. after a protein is produced
E
A human female has _____ chromosomes in each skin cell and _____ chromosomes in each egg. A. 23; 46 B. 46; 46 C. 92; 46 D. 46; 23 E. 23; 23
D
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 _____. A. tumor suppressor; oncogene B. oncogene; tumor suppressor C. oncogene; proto-oncogene D. carcinogen; proto-oncogene E. oncogene; mutagen
D
Besides recombination, what other event in meiosis increases the genetic diversity of the gametes? A. the random way in which gametes fuse together to make uniquely different sperm and eggs B. the random exchange of DNA segments between maternal chromosomes C. the random exchange of DNA segments between paternal chromosomes D. the random line-up and separation of maternal and paternal chromosomes E. the way in which chromosomes are replicated in meiosis II
D
Cellular differentiation, or cell specialization, results from _____. A. cellular division; when cells divide by mitosis, the daughter cells are specialized B. fertilization of an egg; the fusion of the sperm and egg initiates cell specialization within minutes C. the birth process; all the cells of a fetus differentiate by the time it is born D. the "turning off" of some genes and the "turning on" others E. the separation of stem cells from each other, so they do not "know" what their "neighbors" are becoming
D
How are embryonic stem cells different from adult stem cells? A. Embryonic stem cells are mature cells that are fully differentiated, whereas stem cells are immature cells that can differentiate. B. Embryonic stem cells are immature cells that can differentiate, whereas adult stem cells are mature cells that are fully differentiated. C. Embryonic stem cells can develop into a limited array of cell types, whereas adult stem cells can become a wide range of cell types. D. Embryonic stem cells can develop into a wide range of cell types, while adult stem cells can become only limited cell types.
D
How are polygenic and multifactorial traits different? A. Polygenic traits are influenced by the number of traumatic life events, whereas multifactorial traits are influenced by the levels of brain chemicals. B. There are more kinds of polygenic traits than multifactorial traits. C. Polygenic traits are influenced by nutrition and diet, whereas multifactorial traits are not. D. Polygenic traits are genetically based, whereas multifactorial traits have both genetic and environmental influences. E. Polygenic traits show a continuous range of phenotypic variation, whereas multifactorial traits show several distinct phenotypes.
D
If an individual has a germ cell mutation, which of these is a possible source of that mutation? A. a paternal allele only B. a maternal allele only C. excessive sun exposure D. a maternal or paternal allele E. overuse of alcohol
D
Mendel's law of independent assortment was best demonstrated when he crossed true-breeding plants and followed two traits at a time. What did he observe when following two traits that helped him formulate this law? A. He observed that the wrinkled and smooth traits always blended to produce semiwrinkled seeds. B. He observed that the dominant traits are always inherited together and the recessive traits are always inherited together; no offspring displayed one dominant and one recessive trait. C. All of the answers are correct observations. D. He observed that both dominant traits always hid the recessive traits in these double crosses. E. None of the answers are correct observations.
D
Some cancer chemotherapy blocks the formation of the mitotic spindle during prophase. Why would cancer chemotherapy limit the ability of adult stem cells to perform the normal cell turnover in a tissue? A. Cancer chemotherapy blocks both meiosis and mitosis. B. Cancer chemotherapy causes adult stem cells to lyse (burst open). C. Cancer chemotherapy blocks meiosis. D. Cancer chemotherapy blocks mitosis.
D
A recipient of a liver transplant has a high risk of bacterial infections because _____. A. the surgery poses a high risk for introducing bacteria into the recipient B. the liver plays a critical role in the immune response C. donor livers are often contaminated with disease-causing bacteria D.the immune system may reject the liver E. a transplant recipient has to take drugs that suppress his or her immune system
E
Use the following information for this question: Phenylketonuria is considered to be an inborn error of metabolism. It is a recessive genetic condition in which the enzyme that breaks down the amino acid phenylalanine is defective or missing. Testing of all newborns allows this condition to be detected at birth. A special diet that severely minimizes phenylalanine (e.g., by avoiding diet sodas and most usual sources of protein) can treat the condition. In this scenario, two carriers of both cystic fibrosis and phenylketonuria have a child. What is the probability that the child will have both cystic fibrosis and phenylketonuria? A. 18.75% B. 0% C. 12.5% D. 6.25% E. 56.25%
D
Which combination contains the normal chromosome number? A. a human egg - 23; a human sperm - 23; a human zygote - 23 B. a human egg - 46; a human sperm - 46; a human zygote - 23 C. a human egg - 46; a human sperm - 23; a human zygote - 23 D. a human egg - 23; a human sperm - 23; a human zygote - 46 E. a human egg - 46; a human sperm - 46; a human zygote - 46
D
Which of these is a likely result of nondisjunction in human meiosis? A. an egg that can develop into a child without fertilization by a sperm B. a sperm that can develop into a child without fertilization with an egg C. a genetic disorder (such as hemophilia or color blindness) caused by a faulty allele D. aneuploid eggs or sperm E. an increased risk of clinical depression
D
Which statement about decreasing a woman's breast cancer risk if she inherits one of the mutant BRCA genes is true? A. Surgical removal of the breasts will decrease a woman's cancer risk to near zero. B. She can take several medications that make it almost impossible to get breast cancer, even if she inherits the BRCA gene. C. A woman cannot decrease her cancer risk, so she might as well live life to its fullest. D. none of these E. Diet and lifestyle changes will effectively decrease her risk to near zero.
D
Which woman would be most likely to benefit from genetic testing for breast cancer? A. a 40-year-old woman who has a cousin with breast cancer B. a healthy 75-year-old woman with no family history of breast cancer C. All women can benefit from genetic testing for breast cancer. D. a 25-year-old woman whose mother, aunt, and grandmother had breast cancer E. a 55-year-old woman whose older sister was just diagnosed with breast cancer
D
A chemical that causes alterations in DNA is a _____, and if this chemical causes cancer it is called a(n) _____. A. carcinogen; mutagen B. tumor suppressor; proto-oncogene C. tumor suppressor; oncogene D. tumor suppressor; mutagen E. mutagen; carcinogen
E
Women can inherit alleles of a gene called BRCA1 that puts them at higher risk for breast cancer. The alleles associated with elevated cancer risk are dominant. Of the genotypes listed below, which carries the lowest genetic risk of developing breast cancer? A. BB B. Bb C. Bb and bb D. All of these genotypes carry equal risk. E. bb
E
How is codominant inheritance different from incomplete dominant inheritance? A. In codominance, all genes are recessive; in incomplete dominance, one gene is recessive to two dominant genes. B. In codominance, the two alleles cooperate to make an intermediate phenotype; in incomplete dominance, the heterozygote shows the recessive phenotype. C. In codominance, two alleles are expressed equally; in incomplete dominance, there is only one allele in the system. D. In codominance, one gene is recessive to two dominant genes; in incomplete dominance, all genes are recessive. E. In codominance, two alleles are expressed equally; in incomplete dominance, heterozygotes have an intermediate phenotype.
E
In order for a child to develop cystic fibrosis _____. A. more than one egg in the mother must carry the CF allele B. more than one sperm in the father must carry the CF allele C. genetic recombination must occur in the mother but not the father D. genetic recombination must occur in the father but not the mother E. a sperm carrying a CF allele must fertilize an egg that also has that allele
E
Is the genome of stem cells larger than that of specialized cells? A. No; they have a smaller genome, because stem cells are equivalent to gametes (which are haploid) in that they can potentially create an entire individual. B. No; they have a smaller genome because stem cells express only a subset of genes. C. Yes, because they need the genes found in every cell type, whereas specialized cells need only a subset of all the genes. D. Yes, because they express more genes than specialized cells express. E. No, because all of a person's cells have the identical set of genes in their genome.
E
The biological function of stem cells is to _____. A. replenish existing stem cells and form eggs and sperm for reproduction B. replenish existing stem cells C. form eggs and sperm for reproduction D. differentiate into specific cell types E. replenish existing stem cells and differentiate into specific cell types
E
Tumors that will not spread throughout the body are _____, and those that do spread are termed _____. A. tumor suppressor; proto-oncogene B. malignant; benign C. mutagen; carcinogen D. benign; mutagen E. benign; malignant
E
We would all have many more mutations in our genes if not for the _____. A. fact that everybody carries a "good" allele to counter every "bad" allele B. fact that mutations tend to cancel each other out, leaving mostly functional genes C. fact that dividing cells remove all their mutations when they replicate their DNA D. death of all mutant cells, removing them from our bodies E. activity of repair enzymes
E
What is the role of BRCA1 in normal cells? A. BRCA1 is an oncogene. B. BRCA1 is a proto-oncogene. C. BRCA1 is a carcinogen. D. BRCA1 is a mutagen. E. BRCA1 is a tumor suppressor.
E
Which is the correct order of events in which breast cancer might develop? A. replication errors create an oncogene > mutation of p53 > inheritance of a mutant BRCA gene > additional mutations permit spreading B. inheritance of a mutant BRCA gene > mutation of p53 > additional mutations permit spreading > replication errors create an oncogene C. inheritance of a mutant BRCA gene > additional mutations permit spreading > replication errors create an oncogene > mutation of p53 D. mutation of p53 > inheritance of a mutant BRCA gene > additional mutations permit spreading > replication errors create an oncogene E. inheritance of a mutant BRCA gene > replication errors create an oncogene > mutation of p53 > additional mutations permit spreading
E
Which of these most influences the development of a female fetus? A. the presence of a Y chromosome B. none of these C. the presence of two X chromosomes D. the presence of any two sex chromosomes E. the absence of a Y chromosome
E
Which of these occurs during anaphase of mitosis? A. Replicated chromosomes line up in the middle of the cell. B. Two nuclear membranes form around two groups of chromosomes. C. The nuclear membrane disassembles. D. Chromosomes are replicated. E. Sister chromatids move to opposite ends of the cell.
E
Which phase of mitosis is correctly matched? A. interphase - replicated chromosomes condense into visible structures B. telophase - nuclear membrane disassembles C. prophase - each chromosome replicates D. interphase - chromatids move to opposite ends of the cell E. metaphase - replicated chromosomes align in the middle of the cell
E
Which phrase accurately describes meiosis? A. ends with four gametes that are not the same genetically B. contains two rounds of division (meiosis I and meiosis II) C. none of these D. takes one diploid cell to make four haploid cells E. all of these
E
Which statement accurately describes cancer development? A. It is inherited and is independent of environmental factors. B. It is a multistep process by which multiple mutagens cause a series of cancer-causing alleles. C. It is a caused by carcinogens that act on inherited alleles that cause cancer. D. It is a one-step process by which a mutation drives cancer development. E. It is a multistep process by which multiple mutations cause a series of events that lead to cancer.
E
Which statement is true of a single human gamete? A. all of these B. none of these C. There are two alleles per trait on each chromosome. D. There are 46 chromosomes present. E. There is one allele per trait on each chromosome.
E
Why does wearing sunscreen reduce cancer risk? A.Sunscreen can activate checkpoints in skin cells. B. Sunscreen can prevent cells with mutations from being destroyed. C. Sunscreen can repair damaged DNA. D. It does not reduce cancer risk; sunscreen causes mutation and actually increases cancer risk. E. Sunscreen can reduce the chance of mutations caused by exposure to UV radiation present in sunlight.
E
Why is type O Rh-negative the "universal donor"? A. The O and Rh surface markers on the donor red blood cells block immune reactions in the recipient. B. Three surface markers are present on the donor blood cells (A, B, and O) that are recognized as compatible in all recipients. C. More people have type O blood than any other blood type. D. Three surface markers are present on the donor blood cells (A, B, and O), which block immune reactions in the recipient. E. No surface markers are present on the O Rh-negative blood cells to react with the recipient's immune system.
E
