Pathophysiology ch 5

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 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? Explanation: 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 macro- chromosomal level, or at the micro- base pair level.

Which of the following is the best definition of a haplotype?

A small variation in gene sequence Explanation: The human genome sequence is almost exactly the same in all people. There is a small variation of about 0.01% in gene sequence that is termed a haplotype that is thought to account for the individual differences in physical traits, behaviors, and disease susceptibility.

A nurse working in a genetic clinic understands that the process of transcription is initiated by which of the following?

RNA polymerase Explanation: The nurse knows that the process of transcription is initiated by RNA polymerase.

A client with a diagnosis of chronic renal failure receives regular injections of erythropoietin to stimulate red blood cell synthesis. This treatment:

is a direct application of recombinant DNA technology. Explanation: Complex proteins like erythropoietin are produced in mammalian cell culture using recombinant DNA techniques. The use of erythropoietin is not dependent on the characteristics of the client's haplotype map. Erythropoietin is not produced by cloning. The client's karyotype, or chromosome map, if not a clinically relevant consideration.

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?

"In situ hybridization focuses on genes that can express themselves in cell culture." Explanation: 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.

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?

"In the base pairs, adenine combines with thymine and guanine with cytosine." Explanation: 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.

The mother is heterozygous for blue eyes, a recessive trait. The father is homozygous for brown eyes, a dominant trait. What colour eyes will their four children have?

All will have brown eyes. Explanation: 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.

A healthcare 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?

Band 9, region 7 of the long arm of the X chromosome Explanation: 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.

Select the inactive chromatin mass used to identify the genetic sex of an unborn fetus under microscopic study.

Barr body Explanation: The inactive chromatin mass is seen as the Barr body in epithelial cells or as the drumstick body in the chromatin of neutrophils. The genetic sex of a child can be determined by microscopic study of cell or tissue samples, with a normal male having no Barr bodies. The other options do not apply.

A pregnant woman carrying both a dominant (brown) and a recessive (blue) gene has a husband who has a recessive gene that pairs with her recessive gene. The woman asks what color eyes their baby will have. The best response would be:

Blue Explanation: When two recessive genes combine for the lighter color eyes, the child would have the lighter (blue) eyes. Despite the woman having a recessive and dominant gene, it would not alter the color of the baby's eyes to a different shade.

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?

Brown Explanation: 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.

Which of the following statements is true?

Cell division involves the duplication of chromosomes. Explanation: The DNA stores 23 pairs of chromosomes. There are 22 pairs of autosomes, and there is one pair of sex chromosomes. The only true statement is that cell division involves the duplication of the chromosomes.

Which of the following statement is not true concerning chromosomes?

Chromosomes do not retain integrity between cell divisions. Explanation: Chromosomes retain integrity between cell divisions. All of the other statements are true.

There are two main approaches used in gene therapy: transferred genes can replace defective genes, or they can selectively inhibit deleterious genes. What are the compounds usually used in gene therapy?

Cloned DNA sequences Explanation: Cloned DNA sequences are usually the compounds used in gene therapy. Messenger RNA carries the instructions for protein synthesis. Sterically stable liposomes are stable liposomes with long circulation times. Sites in the DNA sequence where individuals differ at a single DNA base are called single nucleotide polymorphisms (SNPs, pronounced "snips")

Which feature of a DNA molecule allows for precise replication?

Double-stranded structure Explanation:

Which statement is true concerning chromosomes?

Each human somatic cell has 23 pairs of different chromosomes Explanation: Each human somatic cell has 23 pairs of different chromosomes, one pair derived from the individual's mother and the other from the father. One of the chromosome pairs consists of the sex chromosomes. Genes are arranged linearly along each chromosome. Each chromosome contains one continuous linear DNA helix.

Enzymes that assist in the repair of deoxyribonucleic acid (DNA) defects by recognizing the defect, cleaving the abnormal chain, and then removing the distorted regions are known as:

Endonucleases Explanation: Several repair mechanisms exist, and each depends on specific enzymes called endonucleases that recognize local distortions of the DNA helix, cleave the abnormal chain, and remove the distorted regions. The other options are not enzymes involved in this process.

A nurse is conducting a community education class on genetics. The nurse sees that the class understands the information when they say that the Human Genome Project involved sequencing of which of the following?

Entire human genetic complement Explanation: The nurse sees that the class understands the information when they identify that the Human Genome Project involved sequencing of the entire human genetic complement.

A nurse is assessing two children with the same genetic disorder. One child is severely impacted and the other is not. Of which of the following genetic characteristics is this the result?

Expressivity Explanation: Two children will be impacted differently based on the gene's expressivity, defined as the manner in which the gene is expressed in the phenotype.

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

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

The process of spermatogenesis results in which of the following?

Four spermatids Explanation: The process of spermatogenesis results in four daughter cells called spermatids. Polar bodies are the result of oogenesis. A karyotype is the completed pictorial representation of chromosomes.

A nurse teaches a client that genetic information is responsible for which body function? Select all that apply.

Function of body cells Appearance Response to the environment Reaction to drugs Explanation: Genetic information is responsible for the function of body cells, our appearance, how we respond to the environment, our disease susceptibility, and how we react to drugs.

A nurse conducting a community education class on genetics tells the class that meiosis occurs in which of the following types of cells?

Gamete producing Explanation: The nurse should say that meiosis occurs in gamete-producing cells. Spermatids are daughter cells formed by meiosis. Polar body cells are formed through the process of oogenesis. Daughter cells are the result of both meiosis and mitosis

A nurse recognizes that no two patients have the same susceptibility to disease and that this is partly due to which of the following?

Haplotype Explanation: The nurse knows that each patient's haplotype helps to account for individual patient differences in disease susceptibility.

The International HapMap Project was created with two goals. One is the development of methods for applying the technology of these projects to the diagnosis and treatment of disease. The other is to map the what of the many closely related single nucleotide polymorphisms in the human genome?

Haplotypes Explanation: The establishment of the International HapMap Project was to map the haplotypes of the many closely related single nucleotide polymorphisms in the human genome and the development of methods for applying the technology of these projects to the diagnosis and treatment of disease. Four bases—guanine, adenine, cytosine, and thymine (uracil is substituted for thymine in RNA)—make up the alphabet of the genetic code. A sequence of three of these bases forms the fundamental triplet code used in transmitting the genetic information needed for protein synthesis. This triplet code is called a codon. Alternate forms of a gene at the same locus are called alleles.

A nurse is counseling a patient on how recessive disorders are transmitted from parent to child. The nurse knows that recessive disorders occur when which of the following alleles are present?

Homozygous recessive Explanation: Recessive disorders occur when the patient has homozygous (two copies) of the recessive allele present.

An instructor is teaching students about recombinant DNA technology and the impact of its results on pharmacology. Select the response that best identifies a result of the technology.

Human insulin Explanation: Recombinant DNA technology has also made it possible to produce proteins that have therapeutic properties. One of the first products to be produced was human insulin. The remaining options have no reliance on recombinant DNA technology.

A nurse caring for an organ transplant patient understands that advances in which of the following have made organ transplants a reality?

Immunogenetic Explanation: The nurse understands that advances in immunogenetics have made organ transplants a reality.

Which of the following materials has been produced using recombinant DNA technology?

Insulin Explanation: Recombinant DNA technology has made it possible to produce several proteins that have therapeutic properties. One of the first products to be produced was human insulin. Cartilage, bone, and heart valves have all been synthetically made using different technologies.

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 this data on which new technology finding?

Interference RNA (RNAi) Explanation: 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 V.

Which of the following statements is not true concerning meiosis?

It has three distinct phases. Explanation: Meiosis has two distinct phases. The other statements are true.

Which of the following statements is true concerning mitochondrial DNA?

It is inherited from the mother by her offspring. Explanation: Part of the DNA of a cell resides in the mitochondria. Mitochondrial DNA is inherited from the mother by her offspring.

Which of the following is the purpose of messenger RNA (mRNA)?

It is necessary for protein synthesis. Explanation: mRNA provides the information needed for placing amino acids in their proper order for each specific type of protein.

Which of the following statements is true concerning DNA structure and function?

It is very stable. Explanation: The DNA that contains genetic information is extremely stable. Because of its stable structure, the genetic information carried in DNA can survive the many stages of cell division and the day-to-day process of cell renewal and tissue growth. It also allows the information to survive the many processes of reduction division, the fertilization process, and the mitotic cell divisions involved in the formation of a new organism.

Which term accurately describes the position of a gene on a chromosome?

Locus Explanation: The position of a gene on a chromosome is called its locus. Alternate forms of a gen at the same locus are called alleles.

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?

Messenger RNA Explanation: Messenger RNA results from the breakage and recombining of DNA strands that is known as transcription. Ribosomal RNA and Transfer RNA are not involved in the process of transcription, and translation RNA is not a type of RNA.

Which of the following statements is true concerning ribonucleic acid (RNA)?

Messenger RNA is the template for protein synthesis. Explanation: Messenger RNA is the template for protein synthesis. Ribosomal RNA is the physical structure in the cytoplasm where protein synthesis takes place. Transfer RNA is a clover-shaped molecule. RNA is synthesized in the nucleus and then moved into the cytoplasm.

A client has developed a large wound as a result of trauma sustained during an auto accident. The nurse is aware that wound healing depends on:

Mitosis Explanation: Mitosis is the cell cycle process in which nongerm cells are replicated, providing ways for the body to replace cells that have a limited life span—skin and blood cells; increase tissue mass during periods of growth; and repair tissue, such as in wound healing. Cytogenetics is the study of the structure and numeric characteristics of the cell's chromosomes. Meiosis is limited to replicating germ cells and results in the formation of gametes or reproductive cells. Cloning is a general term for the research activity that creates a copy of same biological entity.

A nurse understands that the cell cycle of duplicating somatic cells is called which of the following?

Mitosis Explanation: The duplication of somatic cells through the cell cycle is the process of mitosis. Meiosis is limited to replication of germ cells versus somatic cells. Transcription is the process by which RNA directs protein synthesis. Transduction is not part of cellular replication.

A nurse sees that a patient's disorder has a polygenic inheritance pattern. The nurse understands this involves which physiologic concept?

Multiple genes at different loci Explanation: The nurse understands a polygenic inheritance pattern to mean that the disorder was caused by multiple genes at differnt loci.

Which of the following is an error in DNA duplication?

Mutation Explanation: Rarely, accidental errors in duplication of DNA occur and are called mutations.

A client states, "Both of my parents were overweight, but I've never really had any problems maintaining a healthy weight." How should the nurse best interpret the role of genetics in the client's observation?

Obesity is a polygenic trait and does not result from a single gene at one locus. Explanation: Obesity is an example of a trait that has a genetic component but which is polygenic; it does not exist by virtue of one single genotype. As such, it is not considered to be a recessive or dominant trait. Because it is polygenic, the odds of having a child who is obese cannot be precisely determined.

Which of the following is the purpose of a chromosome?

Organize, store, and retrieve genetic information Explanation: Most genetic information of a cell is organized, stored and retrieved in small intracellular structures called chromosomes.

A nurse is completing a genetic map of a patient's family. The patient has brown eyes and his wife has blue eyes. Both the son and the daughter have brown eyes. Which of the following is the same in both children?

Phenotype Explanation: Both the son and the daughter have the same phenotype, which is defined as the recognizable traits associated with a specific genotype.

Which term defines visible, physical or biochemical, traits associated with a specific inheritance pattern that is recognizable?

Phenotype Explanation: The phenotype refers to the recognizable traits, physical or biochemical, associated with a specific genotype. The genotype of a person is the genetic information stored in the base sequence triplet code. Pharmacogenetics is the variability of drug response due to inherited characteristics in individuals. Somatic cell hybridization involves the fusion of human somatic cells with those of a different species (typically, the mouse) to yield a cell containing the chromosomes of both species. Penetrance represents the ability of a gene to express its function. Seventy-five percent penetrance means 75% of persons of a particular genotype present with a recognizable phenotype.

What is the term that refers to the recognizable traits associated with specific genetic information stored in an individual base sequence?

Phenotype Explanation: The phenotype refers to the recognizable traits, physical or biochemical, associated with a specific genotype. The genotype of a person is the genetic information stored in the base sequence triplet code. The position of a gene on a chromosome is called its locus, and alternate forms of a gene at the same locus are called alleles.

A nurse understands that karyotyping involves which characteristic of the cell's chromosone? Select all that apply.

Photographing chromosomes Arranging chromosomes in pairs Standardizing the classification system Explanation: Karyotyping is the process through which an individual's karyotype is determined. It involves culturing cells, staining them, photographing the chromosomes, cutting them out, and arranging them in pairs according to a standard classification system.

Most human traits are determined by multiple pairs of genes, many with alternate codes, accounting for some dissimilar forms that occur with certain genetic disorders. What type of inheritance involves multiple genes at different loci, with each gene exerting a small additive effect in determining a trait?

Polygenic inheritance Explanation: Polygenic inheritance involves multiple genes at different loci, with each gene exerting a small additive effect in determining a trait. Multifactorial inheritance is similar to polygenic inheritance in that multiple alleles at different loci affect the outcome; the difference is that multifactorial inheritance includes environmental effects on the genes. Monofactorial inheritance is nonexistent as is collaborative inheritance.

Select the statement that best describes polygenic inheritance.

Polygenic traits involve multiple genes. Explanation: Polygenic inheritance involves multiple genes at different loci, with each gene exerting a small additive effect in determining a trait. Most human traits are determined by multiple pairs of genes, many with alternate codes, accounting for some dissimilar forms that occur with certain genetic disorders. Polygenic traits are predictable, but with less reliability than single-gene traits. Multifactorial inheritance is similar to polygenic inheritance in that multiple genes at different loci affect the outcome; however, environmental effects on the genes also affect the outcome.

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?

Provide a restricted iron diet to prevent organ damage. Explanation: Postnatal linkage studies have been used in diagnosis 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.

Which of the following is the purpose of attempting to develop a HapMap (haplotype map)?

Providing a link between genetic variations and common diseases Explanation: An international effort has been organized to develop a HapMap of these variations to provide a link between genetic variations and common complex diseases such as cancer, heart disease, diabetes, and some forms of mental disease.

Select the option that best describes the nitrogenous group having two nitrogen rings and includes adenine and guanine.

Purine base Explanation: The purine bases, adenine and guanine, have two nitrogen rings. Thymine and cytosine are pyrimidine bases.

A client with hepatitis C is scheduled to begin a new therapy that would block the progression of the virus by interfering with its genetic replication. What type of therapy is this client beginning?

RNA interference Explanation: RNA interference will stop genes from making unwanted disease proteins by interfering with gene expression. Gene transfer and replacement are protocols that aim to fix the problem gene, not the gene product. DNA interference will silence a gene, not its product.

A client asks the health care provider if any technology exists to limit faulty gene activity from producing unwanted disease proteins. The best response would be:

RNA interference Explanation: Scientists are approaching faculty gene activity with the use of RNA interference (RNAi) to stop genes from making unwanted disease proteins. DNA forensic testing is being utilized to solve criminal cases. Gene cloning and translation do not assist with stopping faculty gene activity.

A technology that scientists are using to stop faulty gene activity from producing unwanted disease proteins is known as:

RNA interference. Explanation: Scientists are using RNA interference technology to stop genes from making unwanted disease proteins. DNA forensic testing is being utilized to solve criminal cases. Gene cloning and translation do not assist with stopping faulty gene activity.

A nurse conducting a genetics class explains that RNA differs from DNA in which of the following ways? Select all that apply.

RNA is a single-strand molecule. RNA sugar is ribose. RNA's pyrimidine base is uracil. Explanation: The nurse includes that RNA differs from DNA because RNA is a single-strand molecule, RNA's sugar is ribose, and RNA's pyrimidine base is uracil. Both RNA and DNA are made up of nucleotides.

Select the statement that best describes the difference between ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).

RNA is a single-stranded molecule. Explanation: RNA is a single-stranded molecule, while DNA is a double-stranded molecule. The sugar in each nucleotide of RNA is ribose instead of deoxyribose. The pyrimidine base thymine in DNA is replaced by uracil in RNA. RNA, like DNA, is a large molecule made up of a long string of nucleotides.

Gene therapy used to control viral infection by preventing the synthesis of viral proteins is recognized as:

RNAi Explanation: In viral infections, RNAi would serve to control the infection by preventing the synthesis of viral proteins. Cloned DNA sequences are usually the compounds used in gene therapy. Sterically stable liposomes are promising methods for the treatment of genetic disorders such as cystic fibrosis. Factor VIII used to treat hemophilia does not play any role in controlling viral infections.

Homozygotes are what people are called in whom the two alleles of a given pair are the same (AA or aa). Heterozygotes are what people are called who have different alleles (Aa) at a gene locus. What kind of trait is expressed only in homozygous pairing?

Recessive trait Explanation: A recessive trait is one that is expressed only when a two homozygous people have a child. A dominant trait is one expressed in either a homozygous or a heterozygous pairing. A single-gene trait and a penetrant trait do not exist. However, single-gene inheritance does exist.

A nurse seeing that a disorder has a Mendelian inheritance pattern interprets this to mean that the disorder is which of the following?

Single-gene disorder Explanation: The nurse should interpret a Mendelian inheritance pattern to mean that it is a single-gene disorder.

A nurse reading an epidemiological study sees that syndactyly is a genetic mutation with 75% penetrance. The nurse understands this to mean which of the following?

That 75% of the people with the gene for syndactyly will have webbed toes or fingers Explanation: When a gene has a 75% penetrance, it means that 75% of the people with a particular genotype present with a recognizable phenotype. In this instance, 75% of the people with the gene for syndactyly will have webbed toes or fingers.

Which of the following statements is true concerning gene expression?

The degree to which a gene is active is called gene expression. Explanation: The degree to which a gene or particular group of genes is active is called gene expression. A phenomenon termed "induction" is an important process by which gene expression is increased. Gene repression is a process by which a regulatory gene acts to reduce gene expression. Whenever product levels decrease, gene transcription is increased.

A researcher is involved in the production of insulin through recombinant DNA technology. Which statement about recombinant DNA is most accurate?

The gene fragment responsible for insulin production can be isolated and reproduced. Explanation: 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 microbase pair level.

Which of the following is the definition of cytogenetics?

The study of the structure and numeric characteristics of the cells' chromosomes Explanation: The study of cytogenetics is the study of the structure and numeric characteristics of the cells' chromosomes. The other statements are not true.

The production of proteins requires both DNA and a second type of nucleotide called ribonucleic acid (RNA). The process is accomplished by which of the following options? Select all that apply

The transcription of the DNA code onto messenger RNA The translation of messenger RNA code by transfer RNA Explanation:

Which of the following statements describes a difference between transcription and translation?

Transcription occurs in the cell nucleus and translation occurs in the cytoplasm. Explanation: Transcription occurs in the cell nucleus and involves the synthesis of RNA from a DNA template. Translation occurs in the cytoplasm of the cell and involves the synthesis of a protein using its messenger RNA template.

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 be most likely to involve an individual who has a genetic disorder?

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

Mendelian, or single-gene, patterns of inheritance include autosomal dominant and recessive traits that are transmitted from parents to their offspring in a predictable manner. A recessive trait occurs when:

Two copies (homozygous) of the recessive allele are present Explanation: A recessive trait is one expressed only when two copies (homozygous) of the recessive allele are present. Dominant traits are expressed with either homozygous or heterozygous pairing of the alleles.

Select the base used in transmitting genetic information needed for protein synthesis that replaces thymine in a ribonucleic acid (RNA) structure.

Uracil Explanation: A sequence of three of these bases forms the fundamental triplet code for 1 of the 20 amino acids used in protein synthesis in humans. This triplet code is called a codon. The molecular link between the DNA code of genes and the amino acid sequence of proteins is ribonucleic acid (RNA), a macromolecule similar in structure to DNA, except that uracil (U) replaces thymine (T) as one of the four bases.

A nurse is reading a report that refers to a gene on band 2, region 2 of the short arm of the X chromosome. The nurse understands that the location of the gene would typically be documented as which of the following?

Xp22 Explanation: Reference to a gene located on band 2, region 2 of the shrot arm of the X chromosome would typically be documented as Xp22. The X represents the X chromosome, the "p" refers to the short arm of the X. The first "2" represents the band and the second "2" represents the region of the short arm where the gene is located.

A male child asks the nurse what chromosomes he would receive from his father. The best response would be:

Y Explanation: Males (XY) get an X chromosome from their mother, and a Y chromosome from their father. If the father transmits an X chromosome, then the fetus would develop into a female (XX).

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

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