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Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
MULTIPLE CHOICE
- A student is observing a cell under the microscope. It is observed to have supercoiled DNA with histones. Which of the following would also be observed by the student? a. (^) A single circular chromosome b. (^) A nucleus c. (^) Free-floating nuclear material d. (^) No organelles
ANS: B The cell described is a eukaryotic cell, so it has histones and a supercoiled DNA within its nucleus; thus, the nucleus should be observed. A single circular chromosome called a prokaryote contains free-floating nuclear material but has no organelles.
- A nurse is instructing the staff about cellular functions. Which cellular function is the nurse describing when an isolated cell absorbs oxygen and uses it to transform nutrients to energy? a. (^) Metabolic absorption b. (^) Communication c. (^) Secretion d. (^) Respiration ANS: D The cell’s ability to absorb oxygen is referred to as respiration while its communication ability
involves maintenance of a steadNy dynamic stat e, metabolic absorption provides nutrition, and
secretion allows for the synthesizing of new substances.
- A eukaryotic cell is undergoing DNA replication. In which region of the cell would most of the genetic information be contained? a. (^) Mitochondria b. (^) Ribosome c. (^) Nucleolus d. (^) Nucleus cytoplasm
ANS: C The region of the cell that contains genetic material, including a large amount of ribonucleic acid, most of the DNA, and DNA-binding proteins, is the nucleolus, which is located within the cell’s nucleus. Mitochondria is associated with cellular respiration while ribosomes are involved with protein manufacturing. Cytoplasm is a fluid filling that is a component of the cell.
- Which of the following can remove proteins attached to the cell’s bilayer by dissolving the layer itself? a. (^) Peripheral membrane proteins b. (^) Integral membrane proteins c. (^) Glycoproteins d. (^) Cell adhesion molecules
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
ANS: B Proteins directly attached to the membrane bilayer can be removed by the action of integral membrane proteins that dissolve the bilayer. Peripheral membrane proteins reside at the surface while cell adhesion molecules are on the outside of the membrane. Glycoprotein marks cells and does not float.
- Which of the following can bind to plasma membrane receptors? a. (^) Oxygen b. (^) Ribosomes c. (^) Amphipathic lipids d. (^) Ligands
ANS: D Ligands are the only specific molecules that can bind with receptors on the cell membrane.
- A nurse is reviewing a report from a patient with metastatic cancer. What alternation in the extracellular matrix would support the diagnosis of metastatic cancer? a. (^) Decreased fibronectin b. (^) Increased collagen c. (^) Decreased elastin d. (^) Increased glycoproteins
ANS: A Only a reduced amount of fibronectin is found in some types of cancerous cells, allowing them to travel or metastasize.
- Which form of cell communication is used to relate to other cells in direct physical contact?
a. Cell junction N
b. (^) Gap junction c. (^) Desmosome d. (^) Tight junction
ANS: A Cell junctions hold cells together and permit molecules to pass from cell to cell. Gap junctions allow for cellular communication between cells. Neither desmosomes nor tight junctions are associated with cellular communication.
- Pancreatic beta cells secrete insulin, which inhibits secretion of glucagon from neighboring alpha cells. This action is an example of which of the following signaling types? a. (^) Paracrine b. (^) Autocrine c. (^) Neurohormonal d. Hormonal ANS: A Paracrine signaling involves the release of local chemical mediators that are quickly taken up, destroyed, or immobilized, as in the case of insulin and the inhibition of the secretion of glucagon. None of the other options involve signaling that is associated with a local chemical mediator like insulin.
- In cellular metabolism, each enzyme has a high affinity for a:
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
b. (^) substrate. c. (^) receptor. d. (^) ribosome.
ANS: B Each enzyme has a high affinity for a substrate, a specific substance converted to a product of the reaction. Cellular metabolism is not dependent on an attraction between an enzyme and any of the remaining options.
- An athlete runs a marathon, after which his muscles feel fatigued and unable to contract. The athlete asks the nurse why this happened. The nurse’s response is based on the knowledge that the problem is result of a deficiency of: a. (^) GTP. b. (^) AMP. c. (^) ATP. d. (^) GMP.
ANS: C When ATP is deficient, impaired muscle contraction results. None of the other options are involved in muscle contraction.
- Which phase of catabolism produces the most ATP? a. (^) Digestion b. (^) Glycolysis c. (^) Oxidation d. (^) Citric acid cycle
ANS: D N
While some ATP is produced during the oxidation and glycolysis phases, most of the ATP is generated during the citric acid cycle. Digestion does not produce any ATP.
- A nurse is teaching the staff about the phases of cellular catabolism. Which phases should the nurse include? a. (^) Digestion, glycolysis, oxidation, and the citric acid cycle b. Diffusion, osmosis, and mediated transport c. (^) S phase, G phase, and M phase d. (^) Metabolic absorption, respiration, and excretion
ANS: A Only digestion, glycolysis, oxidation, and the citric acid cycle are the phases of cellular catabolism.
- A runner has depleted all the oxygen available for muscle energy. Which of the following will facilitate his continued muscle performance? a. (^) Electron-transport chain b. (^) Aerobic glycolysis c. (^) Anaerobic glycolysis d. (^) Oxidative phosphorylation
ANS: C
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
When no oxygen is available, anaerobic glycolysis occurs. The electron-transport chain is part of the citric acid cycle. Aerobic glycolysis involves the presence of oxygen. Oxidative phosphorylation is the mechanism by which the energy produced from carbohydrates, fats, and proteins is transferred to ATP. It is not part of muscle performance.
- A faculty member asks a student to identify the appropriate term for the movement of a solute from an area of greater to lesser concentration. Which answer indicates the nursing student understood the teaching? a. (^) Osmosis b. (^) Diffusion c. (^) Hydrostatic pressure d. (^) Active transport
ANS: B Diffusion is the movement of a solute molecule from an area of greater solute concentration to an area of lesser solute concentration through a permeable membrane. Osmosis is the movement of water across a semipermeable membrane from a region of higher water concentration to one of lower concentration. Hydrostatic pressure is the force of fluid against a cell membrane. In active transport, molecules move up a concentration gradient.
- Which description accurately describes electrolytes? a. (^) Small lipid-soluble molecules b. (^) Large protein molecules c. (^) Micronutrients used to produce ATP d. (^) Electrically charged molecules ANS: D
Electrolyte s are electrically chaNrged molecules. They are not lipid sol uble, they are not made
up of protein, and they do not play a role in ATP production.
- A nurse is reading a chart and sees the term oncotic pressure. The nurse recalls that oncotic pressure (colloid osmotic pressure) is determined by: a. (^) the concentration of sodium. b. (^) plasma proteins. c. (^) hydrostatic pressure. d. (^) the availability of membrane transporter proteins.
ANS: B Oncotic pressure is determined by the effect of colloids or plasma proteins. The concentration of sodium plays a role in tonicity. Hydrostatic pressure is the force within a vessel. Membrane transporter proteins are involved in active transport within a concentration gradient.
- A patient has a body fluid of 300 mOsm/kg. This lab result is measuring: a. osmolality. b. (^) osmolarity. c. (^) osmotic pressure. d. (^) oncotic pressure.
ANS: A
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
ANS: C Phagocytosis (cell eating) involves the ingestion of large particles, such as bacteria, through the formation of large vesicles. Endocytosis involves the formation of vesicles to facilitate movement into the cell. Pinocytosis is a type of endocytosis in which fluids and solute molecules are ingested through the formation of small vesicles. Exocytosis occurs when coated pits invaginate and internalize ligand-receptor complexes in coated vesicles.
- Some cancer drugs work during the cell cycle phase where nuclear and cytoplasmic divisions occur. What is this cell cycle phase called? a. (^) G 1 b. (^) S c. (^) M d. (^) G 2 ANS: C The M phase includes both nuclear and cytoplasmic divisions. The G 1 phase includes the period between the M phase and the start of DNA synthesis. The S phase includes synthesis of DNA in the cell nucleus. The G 2 phase includes RNA and protein synthesis.
- Which causes the rapid change in the resting membrane potential that initiates an action potential? a. (^) Potassium gates open, and potassium rushes into the cell, changing the membrane potential from negative to positive. b. (^) Sodium gates open, and sodium rushes into the cell, changing the membrane potential from negative to positive. c. (^) Sodium gates close, allowing potassium into the cell to change the membrane
potential from positive to nNegative.
d. (^) Potassium gates close, allowing sodium into the cell to change the membrane potential from positive to negative. ANS: B When the threshold is reached, the cell will continue to depolarize with no further stimulation. The sodium gates open, and sodium rushes into the cell, causing the membrane potential to reduce to zero and then become positive (depolarization). Sodium is involved in creating the action potential, not potassium. The sodium gate and channel must be open, not closed. The action potential is not affected by a change in the potassium gate.
- A cell is isolated, and electrophysiology studies reveal that the resting membrane potential is
- 70 mV. The predominant intracellular ion is Na+, and the predominant extracellular ion is K+. With voltage change, which of the following would result in an action potential? a. (^) K+^ rushing into the cell b. (^) Na+^ rushing into the cell c. (^) Na+^ rushing out of the cell d. (^) K+^ rushing out of the cell
ANS: A With voltage change, potassium rushes into, not out of, the cell. Sodium movement is not related to this process.
- A nurse teaching the staff about platelet-derived growth factor includes information that platelet-derived growth factor (PDGF) stimulates the production of:
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
a. (^) platelets. b. (^) epidermal cells. c. (^) connective tissue cells. d. fibroblast cells. ANS: C Different types of cells require different growth factors; for example, PDGF stimulates the production of connective tissue cells, but not platelets, epidermal cells, or fibroblast cells.
- The phase of the cell cycle during which the centromeres split and the sister chromatids are pulled apart is referred to as: a. (^) anaphase. b. (^) telophase. c. (^) prophase. d. (^) metaphase.
ANS: A Anaphase begins when the centromeres split and the sister chromatids are pulled apart. During telophase, a new nuclear membrane is formed around each group of 46 chromosomes, the spindle fibers disappear, and the chromosomes begin to uncoil. During prophase, the first appearance of chromosomes occurs. Metaphase occurs when two centrioles located at opposite poles of the cell pull the chromosomes to opposite sides of the cell.
- What is the role of cytokines in cell reproduction? a. (^) Provide growth factor for tissue growth and development. b. (^) Block progress of cell reproduction through the cell cycle. c. (^) Restrain cell growth and development.
d. Provide nutrients for cell grNowth and development.
ANS: A Cytokines play a major role in the regulation of tissue growth and development but do not restrain it. Cytokines help overcome intracellular braking mechanisms that restrain cell growth and promote cell growth, but they do not provide nutrients.
- A student is reviewing functions of the cell. The student would be correct in identifying a chief function of the nerve cell as: a. (^) sensory interpretation. b. (^) conductivity. c. (^) maintenance of homeostasis. d. communication. ANS: B Conductivity, not sensory interpretation, homeostasis, or communication, is one of the eight chief functions of nerve cells.
MULTIPLE RESPONSE
1. A nurse recalls that the basic types of tissues are: (Select all that apply.) a. (^) nerve. b. (^) epithelial. c. (^) mucosal.
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
Chapter 02: Genes and Genetic Diseases
Huether: Understanding Pathophysiology, 7th Edition
MULTIPLE CHOICE
- A nurse recalls the basic components of DNA are: a. (^) pentose sugars and four phosphate bases. b. (^) a phosphate molecule, deoxyribose, and four nitrogenous bases. c. (^) adenine, guanine, and purine. d. (^) codons, oxygen, and cytosine.
ANS: B The three basic components of DNA are deoxyribose; a phosphate molecule; and four types of nitrogenous, not phosphate, bases. DNA does not contain condone.
- Which of the following mutations have the most significant effect on protein synthesis? a. (^) Base pair substitutions b. (^) Silent mutations c. (^) Intron mutations d. (^) Frameshift mutations
ANS: D The frameshift mutation involves the insertion or deletion of one or more base pairs of the DNA molecule. This greatly alters the amino acid sequence, which affects protein synthesis. The base pair substitution is a type of mutation in which one base pair replaces another. Silent mutations do not change amino acids or protein synthesis. Intron mutations are part of RNA
sequencing. N
- The base components of DNA are: a. (^) A, G, C, and U. b. (^) P, G, C, and T. c. (^) A, G, C, and T. d. (^) X, XX, XY, and YY.
ANS: C The four base components of DNA are cytosine, thymine, adenine, and guanine, and are commonly represented by their first letters (A, C, T, and G) and not components identified as P or U. X, XX, XY, and YY are components of human chromosomes.
- A DNA strand has a region with the sequence ATCGGAT. Which of the following would be a complementary strand? a. (^) CGATACGT b. (^) TAGCCTAG c. (^) TUGCCTUG d. (^) UAGCCUAG
ANS: B
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
The consistent pairing of adenine with thymine and of guanine with cytosine is known as complementary base pairing; thus, A complements to T and C to G and vice versa throughout the strand. A complements to T; thus, the first letter must be a T. U does not represent a complement in the sequence.
- A biologist is explaining how RNA directs the synthesis of protein. Which process is the biologist describing? a. Termination b. (^) Transcription c. (^) Translocation d. (^) Translation
ANS: D In translation, RNA directs the synthesis of a polypeptide, interacting with transfer RNA (tRNA), a cloverleaf-shaped strand of about 80 nucleotides. Termination does not involve synthesis of protein. Transcription is the process by which DNA specifies a sequence of messenger RNA (mRNA). Translocation is the interchange of genetic material between nonhomologous chromosomes.
- What is the result of homologous chromosomes failing to separate during meiosis? a. (^) Neurofibromatosis b. (^) Nondisjunction c. (^) Polyploidy d. (^) Conjoined twins ANS: B Nondisjunction is an error in which homologous chromosomes or sister chromatids fail to
separate normally during meiosNis or mitosis. Neurofibromatosis is not due to chromosome
failure during meiosis. Polyploidy occurs when a euploid cell has more than the diploid number of chromosomes. Conjoined twins are not due to chromosome failure during meiosis.
- A cell that does not contain a multiple of 23 chromosomes is called a cell. a. (^) diploid b. (^) euploid c. (^) polyploid d. (^) haploid
ANS: C A polyploid cell is one in which a euploid cell has more than 23 pairs of chromosomes. A diploid cell is when the somatic cell nucleus has 46 chromosomes in 23 pairs. A euploid cell is a cell with multiples of the normal number of chromosomes. A haploid cell has only one member of each chromosome pair, for a total of 23 chromosomes.
- A 20-year-old pregnant female gives birth to a stillborn child. Autopsy reveals that the fetus has 92 chromosomes. What term may be on the autopsy report to describe this condition? a. (^) Biploidy b. (^) Triploidy c. (^) Tetraploidy d. Aneuploidy ANS: C
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
The primary risk for Down syndrome is pregnancy in women over 35. Down syndrome is a trisomy and not due to fetal exposure or paternal age. Down syndrome is a chromosomal abnormality and is not related to family history.
- A 13-year-old girl has a karyotype that reveals an absent homologous X chromosome with only a single X chromosome present. What medical diagnosis will the nurse observe on the chart? a. Down syndrome b. (^) Cri du chat syndrome c. (^) Turner syndrome d. (^) Fragile X syndrome
ANS: C A condition with the presence of a single X chromosome and no homologous X or Y chromosome, so the individual has a total of 45 chromosomes, is known as Turner syndrome. Down syndrome is a change in one arm of a chromosome. Cri du chat syndrome is due to a chromosome deletion. Fragile X syndrome is due to a break or a gap in a chromosome.
- What genetic disorder is the result if an individual possesses an XXY chromosome configuration? a. (^) Turner b. (^) Klinefelter c. (^) Down d. (^) Fragile X ANS: B Individuals with at least two X chromosomes and one Y chromosome in each cell (47 XXY
karyotype) have a disorder knoNwn as Klinefelter s yndrome. A condition wit h the pre sence of a
single X chromosome and no homologous X or Y chromosome, so the individual has a total of 45 chromosomes, is known as Turner syndrome. Down syndrome is a trisomy. Fragile X syndrome is due to a break or a gap in a chromosome, not an extra chromosome.
- A patient demonstrates severe mental retardation caused by a deletion of part of chromosome
- What genetic disorder will the nurse see documented in the chart? a. (^) Prader-Willi syndrome b. (^) Down syndrome c. (^) Cri du chat syndrome d. (^) Trisomy X ANS: C Cri du chat syndrome means “cry of the cat” and describes the characteristic cry of the affected child. Another symptom of the disorder is mental retardation. The disease is caused by a deletion of part of the short arm of chromosome 5. Prader-Willi syndrome is characterized by short stature, obesity, and hypogonadism. Down syndrome does cause mental retardation but is due to chromosome 21, not chromosome 5. Trisomy X can result in mental retardation but is due to an extra X chromosome.
- An aide asks the nurse why people who have neurofibromatosis will show varying degrees of the disease. Which genetic principle should the nurse explain to the aide? a. (^) Penetrance b. (^) Expressivity
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
c. (^) Dominance d. (^) Recessiveness
ANS: B Expressivity is the extent of variation in phenotype associated with a particular genotype. For neurofibromatosis, a variety of manifestations occur among individuals. The penetrance of a trait is the percentage of individuals with a specific genotype who also exhibit the expected phenotype. Dominance refers to observable traits and risk of transmission. Recessiveness refers to silent strains with reduced risk of occurrence.
- Cystic fibrosis is caused by what gene abnormality? a. (^) X-linked dominant b. (^) X-linked recessive c. (^) Autosomal dominant d. (^) Autosomal recessive
ANS: D Cystic fibrosis is an autosomal recessive disorder. It is not a result of X links or dominant pathology.
- A 15-year-old female is diagnosed with Prader-Willi syndrome. This condition is an example of: a. (^) genomic imprinting. b. (^) an autosomal recessive trait. c. (^) an autosomal dominant trait. d. (^) a sex-linked trait.
ANS: A N
Prader-Willi, an example of gene imprinting, is not associated with any autosomal sex-linked abnormality.
- A patient, age 9, is admitted to a pediatric unit with Duchenne muscular dystrophy. When planning care, the nurse recalls the patient inherited this condition through a trait that is: a. (^) X-linked dominant. b. X-influenced. c. (^) X-limited. d. (^) X-linked recessive.
ANS: D Duchenne muscular dystrophy is a relatively common X-linked recessive, not dominant, disorder. While it is sex linked, it is not X-limited or X-influenced.
- A child is diagnosed with cystic fibrosis. History reveals that the child’s parents are siblings. Cystic fibrosis was most likely the result of: a. (^) X-inactivation. b. (^) genomic imprinting. c. (^) consanguinity. d. (^) obligate carriers.
ANS: C
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
a. (^) a polygenic trait. b. (^) a multifactorial trait. c. (^) crossing over. d. recombination. ANS: B The gradual increase in height is an example of multifactorial traits influenced by genes and also by environment. Polygenic traits result from several genes acting together. Crossing over is an abnormal chromosome structure. Recombination results from new arrangements of alleles.
- When discussing DNA replication, which enzyme is most important? a. (^) RNA polymerase b. (^) Transfer RNA c. (^) Messenger RNA d. (^) DNA polymerase
ANS: D DNA polymerase, not RNA polymerase, is the primary enzyme involved in replication. It adds bases to the new DNA strand and performs “proofreading” functions. Neither messenger RNA nor transfer RNA is as important to DNA replication.
- The regions of the heterogeneous nuclear RNA that must be spliced out to form functional RNA are called: a. (^) promoter sites. b. (^) introns. c. (^) exons.
d. anticodon. N
ANS: B When the mRNA is first transcribed from the DNA template, it reflects exactly the base sequence of the DNA. In eukaryotes, many RNA sequences are removed by nuclear enzymes, and the remaining sequences are spliced together to form the functional mRNA that migrates to the cytoplasm. The excised sequences are called introns (intervening sequences), and the sequences that are left to code for proteins are called exons. In translation, RNA directs the synthesis of a polypeptide, a cloverleaf-shaped strand of about 80 nucleotides. The tRNA molecule has a site where an amino acid attaches. The three-nucleotide sequence at the opposite side of the cloverleaf is called the anticodon.
- A 50-year-old male was recently diagnosed with Huntington disease. Transmission of this disease is associated with: a. (^) penetrance of a trait. b. (^) recurrence risk. c. (^) expressivity. d. delayed age of onset. ANS: D
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
A key feature of Huntington disease is its delayed age of onset such that symptoms are not seen until 40 years of age or later. The penetrance of a trait is the percentage of individuals with a specific genotype who also exhibit the expected phenotype. Recurrence risk is the percentage of family members who will inherit the disease. Expressivity is the extent of variation in phenotype associated with a particular genotype.
- What type of mutation does not change the amino acid sequence and thus has no observable consequence? a. (^) Frameshift b. (^) Spontaneous c. (^) Silent d. (^) Missense
ANS: C Silent mutations do not change the amino acid sequence and therefore have no consequences. Frameshift mutations involve the insertion or deletion of one or more base pairs of the DNA molecule. They alter the amino acid sequence. Spontaneous mutations occur in the absence of exposure to a mutagen and produce changes in the amino acid sequence. Missense mutations, a form of base pair substitution, alter amino acids, which produce a change (i.e., the “sense”) in a single amino acid.
- A nurse is reviewing the pedigree chart. When checking for a proband, what is the nurse looking for? a. (^) The person who is first diagnosed with a genetic disease. b. (^) The individual who has a disease gene but is phenotypically normal. c. (^) The phenotype of genetic material.
d. The codominance. N
ANS: A The pedigree chart summarizes family relationships and shows which members of a family are affected by a genetic disease. The pedigree begins with the proband. The person who has a disease gene but is phenotypically normal is a carrier. The phenotype is the result of both genotype and environment; it is not a proband. Codominance is not represented by a proband, but it occurs when the heterozygote is distinguishable from both homozygotes.
- Which of the following disorders is manifested primarily in males? a. (^) Cystic fibrosis b. (^) Neurofibromatosis c. (^) Muscular dystrophy d. (^) Klinefelter syndrome
ANS: C Muscular dystrophy is manifested primarily in males. Cystic fibrosis, neurofibromatosis, and Klinefelter syndrome are manifested in both males and females.
MULTIPLE RESPONSE
1. When the nurse is teaching the staff about X-linked recessive disorders, which information should the nurse include? (Select all that apply.) a. (^) The trait is seen much more often in females than in males.
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
Chapter 03: Epigenetics and Disease
Huether: Understanding Pathophysiology, 7th Edition
MULTIPLE CHOICE
- When considering abnormal epigenetic modifications, what factor is currently being viewed as strongly associated with the development of some cancers? a. (^) Family genetics b. (^) Lifestyle choices c. (^) Environmental stressors d. (^) Emotional coping skills
ANS: C Environmental stressors can markedly increase the risk of aberrant epigenetic modification and are strongly associated with some cancers. While genetics, lifestyle choices, and coping skills can affect the development and management of cancer, they are not currently considered as being the primary factors in the epigenetic modification that occurs.
- Housekeeping genes are vital to the function and maintenance of all the body’s cells. What characteristic is associated with these genes? a. (^) They lack encoding histones. b. (^) They are transcriptionally active. c. (^) Ribosomal RNA genes are absent. d. (^) Epigenetic silencing has occurred. ANS: B
A small percentage of genes, teNrmed housekeeping genes, are necessar y for the function and
maintenance of all cells. These genes escape epigenetic silencing and remain transcriptionally active in all or nearly all cells. Housekeeping genes include encoding histones, DNA and RNA polymerases, and ribosomal RNA genes.
- What characteristic of Prader-Willi syndrome is not a characteristic of Angelman syndrome? a. (^) It is inherited from the father. b. (^) Mental retardation is observable. c. (^) Imprinting of an abnormal chromosome 15. d. (^) Seizure disorder is present.
ANS: A A well-known disease example of imprinting is associated with a deletion of about 4 million base (Mb) pairs of the long arm of chromosome 15. When this deletion is inherited from the father, the child manifests Prader-Willi syndrome, whose features include short stature, hypotonia, small hands and feet, obesity, mild to moderate mental retardation, and hypogonadism. The same 4 Mb deletion, when inherited from the mother, causes Angelman syndrome, which is characterized by severe mental retardation, seizures, and an ataxic gait.
- Research has demonstrated that neural stem cells have an impaired ability to differentiate into functional neurons when subjected to: a. (^) ethanol. b. (^) marijuana.
Chapter 01: Cellular Biology
Huether: Understanding Pathophysiology, 7th Edition
Latest Updated 2023 Examination Study Guide.
c. (^) insufficient nutrients.
