Human Heredity: Principles and Issues (MindTap Course List)
11th Edition
ISBN: 9781305251052
Author: Michael Cummings
Publisher: Cengage Learning
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Chapter 11, Problem 20QP
The cystic fibrosis gene encodes a chloride channel protein necessary for normal cellular functions. Let us assume that if at least 5% normal channels are present, the affected individual has mild symptoms of cystic fibrosis. Having less than 5% normal channels produces severe symptoms. At least 50% of the channels must be expressed for the individual to be
Predict the percent of functional channels and severity of symptoms for the following genotypes:
- a. heterozygous for CF100
- b. homozygous for CF100
- c. heterozygous, with one copy of CF100 and one of CF3
- d. heterozygous, with one copy of CF1 and one copy of CF3
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Troponin is a complex composed of Troponin C (TnC), Troponin I (TnI), and Troponin T (TnT); the complex is found in skeletal and cardiac muscle, but not smooth muscle. Two "isoforms" of TnI and two "isoforms" of TnT are expressed in human skeletal muscle tissue.
Q:The isoforms of TnI in the sentence above mean:
A:One single TnI gene encodes two different TnI proteins as a result of alternative splicing of the TnI pre-mRNA.
B:There are two different TnI genes, each produces a TnI protein.
In humans, the disease cystic fibrosis is caused by a recessive allele for a gene that encodes a specific type of channel protein. Using C as a “normal” allele for the disease, under what conditions is it possible for a child with cystic fibrosis to have biological parents who do not have the disease?
Both parents have the genotype Cc
It is not possible for this to occur
Both parents have the genotype CC
Hurler syndrome is due to a mutation in a gene that encodes aprotein called α-l-iduronidase. This protein functions withinlysosomes as an enzyme that breaks down mucopolysaccharides(a type of polysaccharide that has many acidic groups attached).When this enzyme is defective, excessive amounts of the mucopolysaccharides dermatan sulfate and heparin sulfate accumulatewithin the lysosomes, especially in liver cells and connectivetissue cells. This accumulation leads to symptoms such as anenlarged liver and spleen, bone abnormalities, corneal clouding,heart problems, and severe neurological problems. The pedigreebelow contains three members affected with Hurler syndrome,indicated with black symbols. Based on this pedigree, does thissyndrome appear to follow autosomal recessive, autosomaldominant, X-linked recessive, or X-linked dominant inheritance?Explain your reasoning.
Chapter 11 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
Ch. 11.4 - Consumer products including bandages, cotton...Ch. 11.4 - Prob. 2EGCh. 11 - Prob. 1CSCh. 11 - Prob. 2CSCh. 11 - Prob. 3CSCh. 11 - Prob. 1QPCh. 11 - Achondroplasia is an autosomal dominant form of...Ch. 11 - Why is it almost impossible to directly measure...Ch. 11 - What are the factors that influence the mutation...Ch. 11 - Achondroplasia is a rare dominant autosomal defect...
Ch. 11 - Although it is well known that X-rays cause...Ch. 11 - Prob. 7QPCh. 11 - Bruce Ames and his colleagues have pointed out...Ch. 11 - Define and compare the following types of...Ch. 11 - If the coding region of a gene (the exons)...Ch. 11 - Two types of mutations discussed in this chapter...Ch. 11 - Prob. 12QPCh. 11 - A frameshift mutation is caused by a: a....Ch. 11 - In the gene-coding sequence shown here, which of...Ch. 11 - Prob. 15QPCh. 11 - Familial retinoblastoma, a rare autosomal dominant...Ch. 11 - Tay-Sachs disease is an autosomal recessive...Ch. 11 - Replication involves a period of time during which...Ch. 11 - Our bodies are not defenseless against mutagens...Ch. 11 - The cystic fibrosis gene encodes a chloride...
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- A human gene called theCFTR gene (for cystic fibrosis transmembrane regulator) encodes aprotein that functions in the transport of chloride ions across the cellmembrane. Most people have two copies of a functional CFTR geneand do not have cystic fibrosis. However, a mutant version of the CFTRgene is found in some people. If a person has two mutant copies ofthe gene, he or she develops the disease known as cystic fibrosis. Arethe following descriptions of this disease related to genetics at themolecular, cellular, organism, or population level?A. People with cystic fibrosis have lung problems due to a buildupof thick mucus in their lungs.B. The mutant CFTR gene encodes a defective chloride transporter.C. A defect in the chloride transporter causes a salt imbalance inlung cells.D. Scientists have wondered why the mutant CFTR gene is relativelycommon. In fact, it is the most common mutant gene that causesa severe disease in persons of Northern European descent. Onepossible explanation why…arrow_forwardIndividuals with the hereditary disorder ataxia telangiectasia suffer from neurodegeneration, immunodeficiency, and an increased incidence of cancer. The genetic basis for ataxia telangiectasia is a loss-of-function mutation in the gene encoding ATM (ATM; ataxia telangiectasia mutated). Besides p53, what other substrate is phosphorylated by ATM? How does the phosphorylation of this substrate lead to inactivation of CDKs to enforce cell cycle arrest?arrow_forwardDuring periods of sustained demand and in the presence of sufficient nutrients, muscle cells can increase in size. When the size of muscle cells increases, they will often develop additional nuclei in their intracellular environment. Which of the following is the most likely explanation for the expression of additional nu- clei in growing muscle cells? A B с D Nutrients entering the cells will be digested and recycled more quickly by the additional nuclei to better support the subcellular components in the cell as its size increases. The ATP molecules that are produced in the additional nuclei will be able to better sup- port the increased energetic demands on the muscle cell as its size increases. The addition of more nuclei to the cell will allow more genetic information to be stored in the cell and allow the cell to produce additional types of proteins as its size increases. Additional nuclei allow subcellular components to continue to be sufficiently expressed and transferred…arrow_forward
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