1. Mutations are important in genetics because: A. they are the source of geneti
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1. Mutations are important in genetics because: A. they are the source of genetic variability for populations. B. they allow geneticists to investigate gene function. C. they are produced to allow adaptation. D. A and B. E. All of the above. 2. Mutations are characterized by all of the following criteria EXCEPT: A. forward vs. reverse. B. somatic vs. germ line. C. gene vs. chromosome. D. intergenic vs. intragenic. E. Actually, all of these are criteria used to characterize mutations. 3. A missense mutation could be described by each of the following EXCEPT: A. loss of function. B. silent. C. neutral. D. conditional. E. Actually, all of these can describe missense mutations. 4. A gene mutation could take any of the following forms EXCEPT: A. a transition mutation. B. a substitution mutation. C. a nonsense mutation. D. a reverse mutation. E. Actually, it could be any of these. 5. Suppressor mutations can be: A. intergenic. B. intragenic. C. reverse. D. A and B. E. All of the above. 6. Mutation can be caused by: A. replication errors. B. ionizing radiation. C. alkylating agents. D. A and B. E. All of the above. 7. Spontaneous replication errors can be caused by all of the following EXCEPT: A. tautomeric shift. B. wobble base pairing. C. intercalating agents. D. slippage. E. Actually, all of these can cause spontaneous errors. 8. Induced mutations can be caused by all of the following EXCEPT: A. wobble base pairing. B. base analogs. C. intercalating agents. D. oxidation. E. Actually, induced mutations can be caused by all of these. 9. Expanding nucleotide repeats are NOT: A. involved with genetic disorders such as fragile-X syndrome. B. reasonable explanations for the phenomenon of anticipation. C. induced by radiation. D. variable in size of the repeat. E. Actually, they are all of these. 10. Transposable elements can induce mutations by all of the following mechanisms EXCEPT: A. disrupting a gene when inserted into it. B. facilitating recombination between transposons, producing chromosomal mutations. C. producing double-stranded breaks during excision, leading to chromosomal mutations. D. Activating genes with their own promoter, dysregulating them. E. Actually, all of these mutations are induced by transposons. 11. Because transposons can induce mutations, organisms have been selected to suppress transposition. This suppression can be carried out by all of the following mechanisms EXCEPT: A. the attenuation of the transposase transcript. B. the use of methylation to silence the transposon. C. blocking translation of the transposase. D. the use of piRNA to block transposase transcription. E. Actually, all of these mechanisms are used. 12. Human transposons include: A. Alu, which is unique to Homo sapiens and Pan troglodytes (chimpanzee). B. Ac and Ds, the discovery of which earned Barbara McClintock a Nobel Prize. C. LINES (Long Interspersed Elements), which make up 21% of the genome. D. P elements, which are responsible for hybrid dysgenesis. E. None of the above. 13. Faulty repair mechanisms can lead to all of the following EXCEPT: A. xeroderma pigmentosum. B. Fanconi anemia. C. increase in rates of transposition. D. hereditary colon cancer. E. Actually, all of these are caused by faulty DNA repair. 1. Mutations are important in genetics because: A. they are the source of genetic variability for populations. B. they allow geneticists to investigate gene function. C. they are produced to allow adaptation. D. A and B. E. All of the above.Explanation / Answer
Answer:
1. (E) All of the above.
Mutations are the source of genetic variability for populations and they help geneticists to identify gene function by mutating the wild type gene. Mutation helps organisms to adapt in varying environments and thus facilitate evolution.
2. (E) Actually, all of these are criteria used to characterize mutations.
Forward vs Reverse: Forward mutations are the mutations which lead to the formation of mutants from the wild type, while reverse mutations refers to the mutations which revert the mutant form to its wild type.
Somatic vs Germline: Somatic mutations are those which occurs in the normal/somatic cells of the body and are not inheritable. Germline mutations are those which takes place in the gamete producing germline cells and are thus heritable.
Gene vs Chromosome: Gene mutations refers to the change in the DNA forming a gene leading to coding of non functional or pre-mature gene product. These are basically small scale mutations. Examples include missense mutation, non sense mutation, silent mutation, frameshift mutation, deletion, insertion, etc.
Chromosomal mutations involve large segments of DNA and include duplication of genes, deletion of large segments of DNA, large scale inversions (paracentric and pericentric), translocation, copy nuber variation, etc.
Intergenic vs intragenic: These are basically suppressor mutations.
Intergenic suppressor mutations are those which revert back the functional form of the mutant gene though a mutation at a distant site within the genome. It does not occur within the mutant gene under consideration.
Intragenic suppressor mutations are those which can revert the function of a mutant gene to its functional form. It generally occurs in the DNA sequence which is either in or in very close proximity to the mutant gene.
3. (E) Actually, all of these can describe missense mutations.
Missense mutations can result in null mutations. For example, a missense mutation that causes an amino acid substitution in a critical residue of the active site of a protein may result in complete loss of enzymatic activity. However, missense mutations may also result in a partially active (leaky) gene product, a conditional phenotype, or a silent change that does not disrupt protein function.
Missense mutation is a type of non synonymous substitution which results in a different amino acid.
4. (E) Actually, it could be any of these.
All types of mutations mentioned in the options can affect the function of the expressed proteins.
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