Question 1

How could a health care professional most accurately explain an aspect of the underlying structure of DNA to a colleague who is unfamiliar with genetics?
A) "DNA consists of nucleotides plus one of the four nitrogenous bases."
B) "In the base pairs, adenine combines with thymine and guanine with cytosine."
C) "Thymine and cytosine are considered the purine bases."
D) "The backbone of a DNA molecule consists of either deoxyribose or phosphoric acid."

Accepted Answer

The base pairings of DNA are such that adenine combines with thymine and guanine with cytosine. DNA also includes the sugar deoxyribose, while thymine and cytosine are considered the pyrimidine bases. The backbone of DNA includes both deoxyribose and phosphoric acid.

Question 2

A student is trying to understand the possible reasons that a genetic abnormality might exist in an individual. Which of the following reasons is most plausible?
A) DNA has combined with several types of protein and a small amount of RNA.
B) Histones have exerted control on the folding of DNA strands.
C) DNA has blocked genetic transcription by preventing access of nucleotides to the DNA surface.
D) Chromatin has maintained its stable structure during the DNA replication process.

Accepted Answer

To facilitate DNA replication and gene expression, chromatin must change its structure through the process of chromatin remodeling. Answers A, B, and C all denote normal genetic processes.

Question 3

A 45-year-old client who experienced exposure to radiation during an industrial accident several years prior is being assessed. Which of the following phenomena may underlie the genetic changes that have been noted in the client?
A) Base pairs may have been rearranged by the radiation in the accident.
B) Endonucleases may have influenced the DNA structure following exposure.
C) Two paired bases may have exchanged helical position after the accident.
D) The radiation may have produced a redundant or degenerate genetic code.

Accepted Answer

Radiation exposure can cause the rearrangement of base pairs and resultant mutation. Endonucleases facilitate gene repair, and base pairs are not noted to swap positions from their respective sides of the helical strand. Redundant or degenerate genetic code is a normal trait.

Question 4

A researcher is involved in the investigation of an individual's genetic abnormality. Which of the following situations could the researcher most likely rule out as the genetic cause of a mutation?
A) Loss of a cytosine-guanine base pair
B) Formation of an adenine-uracil base pair
C) Substitution of an adenine-thymine base pair for a cytosine-guanine base pair
D) Insertion of an extra adenine-thymine base pair

Accepted Answer

RNA contains uracil instead of thymine. Formation of an adenine-uracil base pair is a normal event during assembly of messenger RNA.

Question 5

In the context of an explanation of how human growth occurs, a student is explaining to a colleague the necessity and roles of different types of RNA in protein synthesis. Which of the following types of RNA is a result of the process of transcription?
A) Ribosomal RNA
B) Messenger RNA
C) Translation RNA
D) Transfer RNA

Accepted Answer

Messenger RNA results from the process of breakage and recombination of DNA strands, which is known as transcription Ribosmal RNA and transfer RNA are not involved in the process of transcription, and translation RNA is not a type of RNA.

Question 6

A 31-year-old male has been newly diagnosed with early-onset Parkinson disease. As the nurse is educating the patient and family, they ask how this happened so early in his life. The nurse will base the response on which of the following statements listed below?
A) "No one really knows why some patients get this diagnosis in their 30s, while others are in their 50s before they begin to have symptoms."
B) "Sometimes exposure to too much ultraviolet radiation causes changes in your gene sequencing and therefore mutations occur."
C) "Disruption in some proteins called molecular chaperones causes intracellular molecules to become denatured and insoluble leading to clumping and the development of inclusion bodies."
D) "Gene repression is a process by which a regulatory gene acts to reduce or prevent gene expression, thereby confusing the negative feedback mechanisms that could prevent disease formation."

Accepted Answer

An international project was charged with developing genetic and physical maps that allowed the precise location of genes and with exploring technologies that would enable the sequencing of large amounts of DNA with high accuracy and low cost. It is still undergoing experimental testing. The function of a chaperone is to assist a newly synthesized polypeptide chain to attain a functional conformation as a new protein and then assist the protein's arrival at the site in the cell where the protein carries out its function. Disruption of chaperoning mechanisms causes intracellular molecules to become denatured and insoluble. These denatured proteins tend to stick to one another, precipitate, and form inclusion bodies. The development of inclusion bodies is a common pathologic process in Parkinson's. Gene repression is a process by which a regulatory gene acts to reduce or prevent gene expression.

Question 7

While discussing embryogenesis to a group of students moving through the maternity ward, the nurse quizzes them to see if they know what is happening during sonic hedgehog signaling. Which of the following answers would be considered accurate? Select all that apply.
A) Development of the eyes
B) Separation of the brain into two cerebral hemispheres
C) A carrier system for delivering the appropriate amino acids to the ribosomes
D) Development of the correct number of fingers and toes
E) Bone formation leading to macrocephaly

Accepted Answer

Sonic hedgehog signaling is involved in many key developmental events at multiple times during embryogenesis. It participates in such diverse developmental steps as establishment of the left-to-right axis responsible for the rostral-caudal orientation of the nervous system, the separation of the brain into two cerebral hemispheres, right and left eye orientation, and the separation and development of the correct number of fingers and toes. The PAX family of transcription factors is responsible for the development of the eye. Transfer RNA acts as a carrier system for delivering the appropriate amino acids to the ribosomes. Bone formation leading to macrocephaly is caused by fibroblast growth factors.

Question 8

A physician is working with a family whose daughter has been recently diagnosed with the chromosomal disorder Turner syndrome. The physician would recognize that which of the following statements about the characteristics of human chromosomes is accurate?
A) Individual variations are attributable to differences in appearance in autosomes.
B) Chromosomes undergo variations during each episode of cell division.
C) Autosomes contain the determination of an individual's sex.
D) Each of the 22 pairs of autosomes has a homolog.

Accepted Answer

Each of the 22 autosomes contains a homolog in the diploid cell. Autosomes are consistent from individual to individual with regard to appearance. Chromosomes retain their integrity in cell divisions, and sex determination is found in the 23rd chromosome.

Question 9

A man and woman are eager to determine the sex of their unborn child and have asked the nurse at the fertility clinic how this is possible at an early stage of in vitro development. Which of the nurse's responses best captures the genetic rationale for early sex identification through tissue samples?
A) "The inactive X chromosome can be visible in a female."
B) "The cells of a male contain a Barr body that can be visualized."
C) "A normal female lacks Barr bodies."
D) "The number of visible Y chromosomes indicates the sex."

Accepted Answer

The fact that the inactive X chromosome can be visible as a Barr body in a female allows for the extrapolation of the number of X chromosomes and thus the sex associated with the cells. Normal male cells lack Barr bodies, but they are present in females. The number of X chromosomes ultimately determines the sex of an individual.

Question 10

A health care researcher has identified the gene of interest in a particular genetic disorder as well as the gene's location Xq97. Where would one find a gene named Xq97?
A) Band q, region 97 of the Y chromosome
B) Band 7, region 9 of the short arm of the X chromosome
C) Band 9, region 7 of the long arm of the X chromosome
D) Band 9, region 7 of the short arm of the Y chromosome

Accepted Answer

In gene names, the first letter stands for the chromosome. The second indicates the arm of the chromosome, p (short) or q (long). The first numeral indicates the band, and the second one indicates the region within that band.

Question 11

A child possesses a trait that is the result of the interaction of two different genes, neither of which could have produced the trait independently. Which of the following explanations best captures the genetic explanation for this?
A) The trait is an expression of multiple alleles.
B) Epistasis has dictated the phenotypic outcome.
C) The phenomenon is an example of polygenic inheritance.
D) The outcome is the result of the interaction between collaborative genes.

Accepted Answer

The expression of two genes influencing the same phenotype, neither of which could have produced it alone, is an example of collaborative genes. Multiple alleles involve more than one gene at a particular locus affecting the same trait, and in epistasis, a gene masks the phenotypic effects of another nonallelic gene. Polygenic inheritance involves multiple genes each affecting a small influence on a genetic outcome.

Question 12

A health care professional works in a context where there are a large number of clients who live with genetic disorders. Which of the following circumstances would most likely involve an individual who has a genetic disorder?
A) The primordial germ cells of both of the individual's parents have undergone meiosis.
B) Two chromosomes of the same number have been inherited from one parent.
C) The individual possesses 22 pairs of autosomes.
D) The individual's karyotype indicates separate X and Y chromosomes at chromosome 23.

Accepted Answer

When two chromosomes of the same number are inherited from one parent, the result can be the disorder of uniparental disomy. Answers A, C, and D all relate normal genetic processes.

Question 13

Mary is heterozygous for blue eyes, a recessive trait. John is homozygous for brown eyes, a dominant trait. What color eyes will their four children have?
A) Brown
B) Blue
C) Some will have blue, and some will have brown
D) Impossible to tell

Accepted Answer

A heterozygote with a dominant and a recessive allele will have the dominant phenotype. In Mary's case, this will manifest itself in her brown eyes. A homozygote with two dominant alleles will have the dominant phenotype, so John also has brown eyes. To have blue eyes, the children would have to inherit two alleles for blue eyes. Because they will inherit, at most, one recessive allele for blue eyes, the children's eyes will be brown.

Question 14

Knowing that persons with blonde hair exhibit the phenotype of a recessive gene, which of the following genetic scenarios would most likely underlie such a trait?
A) aa
B) A heterozygous pairing
C) Either AA or Aa
D) Different alleles at a gene locus

Accepted Answer

A recessive trait is expressed solely in a homozygous pairing, such as aa. A heterozygous pairing, in which there are two different alleles at a gene locus, will not express a recessive trait. Aa is an example of a heterozygous pairing.

Question 15

A group of researchers have identified that the prevalence of two particular genetic disorders shares a statistical correlation. Which of the following statements best conveys the genetic rationale for this situation?
A) There is likely a cause-and-effect relationship between the two genes responsible.
B) The chromosomes containing each gene are likely closely situated.
C) The genes causing each disorder are likely in the same section of the same chromosome.
D) The disorders likely share the same locus.

Accepted Answer

The genes causing these problems are likely proximate in the same chromosome. They would not likely be correlated if they were in different chromosomes, and the situation is not indicative of a cause-and-effect relationship. The genes are likely closely situated, but they could not share the same locus.

Question 16

When educating the parents of an infant diagnosed with hemochromatosis, the nurse should consider which of the following topics a priority for the parents to know?
A) Provide a restricted iron diet to prevent organ damage
B) How to check their infants' stools for blood
C) Where to look for lesion development on the skin
D) How to assess an infant for blood loss and anemia

Accepted Answer

Postnatal linkage studies have been used in the diagnosis of hemochromatosis, which is closely linked to another HLA type. People with this disorder are unable to metabolize iron, and it accumulates in the liver and other organs. It cannot be diagnosed by conventional means until irreversible damage has been done. Dietary restriction of iron intake may be used to prevent organ damage.

Question 17

A student is explaining to her colleague the different methods that are available for genetic mapping. Which one of the colleague's following statements indicates a need for further teaching?
A) "I know that linkage studies are rooted in the exchange of genes that occurs during meiosis."
B) "Gene dosage studies involve the measurement of enzyme activity as a reflection of genetic activity."
C) "If hybrid cells were stable, somatic cell hybridization would not be viable."
D) "In situ hybridization focuses on genes that can express themselves in cell culture."

Accepted Answer

In situ hybridization examines genes that do not express themselves in cell culture. The rationale for linkage studies exists in the genetic exchange of genes that occurs during meiosis, and gene dosage is a reflection of gene activity. Somatic cell hybridization necessitates the fact that hybrid cells degrade during division.

Question 18

A researcher is involved in the production of insulin through recombinant DNA technology. Which of the following statements could the researcher best provide as a rationale for her work?
A) The gene fragment responsible for insulin production can be isolated and reproduced.
B) Particular bacteria are capable of insulin production.
C) It is possible to reproduce the chromosome responsible for insulin production.
D) Recombination of DNA base pairs can result in a gene that will produce insulin.

Accepted Answer

The gene fragment that initiates and controls the production of several human proteins, including insulin, can be identified, separated, and reproduced by recombinant technology. Bacteria are used as a medium of reproduction, but they are not inherently capable of insulin production. Recombinant technology does not take place at the macrochromosomal level or at the micro- base pair level.

Question 19

Which of the following patients are receiving treatment that has been developed utilizing recombinant DNA techniques? Select all that apply.
A) Patient undergoing detection of gene location by chemically tagging DNA or RNA sequences
B) Mother undergoing amniocentesis to diagnose a congenital adrenal hyperplasia
C) End-stage renal disease patient receiving erythropoietin to stimulate RBC production
D) Stroke victim receiving tissue plasminogen activator (tPA) to dissolve the thrombi
E) Couple going to an infertility clinic for diagnostic testing

Accepted Answer

Recombinant DNA technology has made it possible to produce proteins that have therapeutic properties. These include erythropoietin, which is used to stimulate RBC production, and tissue plasminogen activator (tPA), which is frequently administered to dissolve thrombi. In situ hybridization involves the use of specific sequences of DNA/RNA to locate genes. Prenatally, the autosomal recessive disorder congenital adrenal hyperplasia is diagnosed through amniocentesis.

Question 20

While the nurse is educating a fellow nurse about some new research being developed to treat hepatitis C, specifically to identify disease-related drug targets on the cells, the nurse will be basing these data on which new technology finding?
A) Recombinant DNA technology
B) Haplotype mapping
C) The human genome project
D) Interference RNA (RNAi)

Accepted Answer

Pharmaceutical companies are using RNAi to identify disease-related drug targets. There is considerable interest in harnessing RNAi for therapeutic purposes, linking the treatment of HIV infection and hepatitis C.

Quiz 4: Genetic Control of Cell Function and Inheritance

How could a health care professional most accurately explain an aspect of the underlying structure of DNA to a colleague who is unfamiliar with genetics?

A student is trying to understand the possible reasons that a genetic abnormality might exist in an individual. Which of the following reasons is most plausible?

A 45-year-old client who experienced exposure to radiation during an industrial accident several years prior is being assessed. Which of the following phenomena may underlie the genetic changes that have been noted in the client?

A researcher is involved in the investigation of an individual's genetic abnormality. Which of the following situations could the researcher most likely rule out as the genetic cause of a mutation?

In the context of an explanation of how human growth occurs, a student is explaining to a colleague the necessity and roles of different types of RNA in protein synthesis. Which of the following types of RNA is a result of the process of transcription?

A 31-year-old male has been newly diagnosed with early-onset Parkinson disease. As the nurse is educating the patient and family, they ask how this happened so early in his life. The nurse will base the response on which of the following statements listed below?

While discussing embryogenesis to a group of students moving through the maternity ward, the nurse quizzes them to see if they know what is happening during sonic hedgehog signaling. Which of the following answers would be considered accurate? Select all that apply.

A physician is working with a family whose daughter has been recently diagnosed with the chromosomal disorder Turner syndrome. The physician would recognize that which of the following statements about the characteristics of human chromosomes is accurate?

A health care researcher has identified the gene of interest in a particular genetic disorder as well as the gene's location Xq97. Where would one find a gene named Xq97?

A child possesses a trait that is the result of the interaction of two different genes, neither of which could have produced the trait independently. Which of the following explanations best captures the genetic explanation for this?

A health care professional works in a context where there are a large number of clients who live with genetic disorders. Which of the following circumstances would most likely involve an individual who has a genetic disorder?

Mary is heterozygous for blue eyes, a recessive trait. John is homozygous for brown eyes, a dominant trait. What color eyes will their four children have?

Knowing that persons with blonde hair exhibit the phenotype of a recessive gene, which of the following genetic scenarios would most likely underlie such a trait?

A group of researchers have identified that the prevalence of two particular genetic disorders shares a statistical correlation. Which of the following statements best conveys the genetic rationale for this situation?

When educating the parents of an infant diagnosed with hemochromatosis, the nurse should consider which of the following topics a priority for the parents to know?

A student is explaining to her colleague the different methods that are available for genetic mapping. Which one of the colleague's following statements indicates a need for further teaching?

A researcher is involved in the production of insulin through recombinant DNA technology. Which of the following statements could the researcher best provide as a rationale for her work?

Which of the following patients are receiving treatment that has been developed utilizing recombinant DNA techniques? Select all that apply.

While the nurse is educating a fellow nurse about some new research being developed to treat hepatitis C, specifically to identify disease-related drug targets on the cells, the nurse will be basing these data on which new technology finding?