9. All organisms have the ability to repair DNA damage caused by mutagenic chemicals. To find genes that encode enzymes that repair DNA damage, scientists isolate mutants that have an abnormally high sensitivity to mutagenic chemicals. Suppose that five different true-breeding mutagen sensitive strains of fruit fly Drosophila melanogaster were isolated (mus mutants). Call these strain #1, strain #2, strain #3, strain #4, and strain #5. Complementation tests were performed with all of these strains and the results are given in the table below. A "+" symbol indicates that when the two indicated strains were crossed, the hybrid was wild-type and a "-" symbol indicates that the hybrid was mutagen sensitive. Assume that each strain has a mutation in just one gene. strain 1 strain 2 + strain 3 + strain 1 strain 2 strain 3 strain 4 strain 5 strain 4 + A. Which mutant strains have mutations in the same gene? B. How many different mus genes are represented here? strain 5 + + + +

9. All organisms have the ability to repair DNA damage caused by mutagenic chemicals. To find genes that encode enzymes that repair DNA damage, scientists isolate mutants that have an abnormally high sensitivity to mutagenic chemicals. Suppose that five different true-breeding mutagen sensitive strains of fruit fly Drosophila melanogaster were isolated (mus mutants). Call these strain #1, strain #2, strain #3, strain #4, and strain #5. Complementation tests were performed with all of these strains and the results are given in the table below. A "+" symbol indicates that when the two indicated strains were crossed, the hybrid was wild-type and a "-" symbol indicates that the hybrid was mutagen sensitive. Assume that each strain has a mutation in just one gene. strain 1 strain 2 + strain 3 + strain 1 strain 2 strain 3 strain 4 strain 5 strain 4 + A. Which mutant strains have mutations in the same gene? B. How many different mus genes are represented here? strain 5 + + + +

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter14: Dna Structure And Function

Section: Chapter Questions

Problem 20RQ: A scientist creates fruit fly larvae with a mutation that eliminates the exonuclease function of DNA...

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A scientist creates fruit fly larvae with a mutation that eliminates the exonuclease function of DNA pol III. Which prediction about the mutational load in the adult fruit flies is most likely to be correct? The adults with the DNA pol III mutation will have significantly more mutations than average The adults with the DNA pol III mutation will have slightly more mutations than average The adults with the DNA pol III mutation will have the same number of mutations as average The adults with the DNA pol III mutation will have fewer mutations than average.
4. A recent estimate of the rate of base substitutions atSNP loci is about 1 × 10−8 per nucleotide pair pergamete.a. Based on this estimate, about how many de novomutations (that is, mutations not found in the genomes of your parents) are present in your own genome?b. Where and when did these de novo mutations inyour genome most likely occur?
1. Every time a human cell divides, over 50 new mutations can be found in the daughter cells 2. Mutations can accumulate over the course of successive cell divisions 3. In every new kid, over 50 new mutations can be found when comparing them to their parents 4. Most of the new mutations in gametes are probably silent*, but there's a good chance that one of them might occur in a gene, and alter that gene in such a way as to potentially create a mutation *Note: by 'silent' we mean that the mutation doesn't have the potential to alter phenotype, either because it is not in a gene, or is in a gene but in the middle of an intron, or is in the coding sequence but is a silent substitution, etc., etc. 5. Most new gene mutations (i.e. mutations that occur in genes that alter gene expression, splicing or protein sequence) are recessive
7) A patient has discovered a lump in their breast. The doctors decide to biopsy (take tissue samples from) the lump. They take 7 tissue samples from different regions of the lump. Would you expect the genetic profile/mutations in every single sample of cells to be the same? Why or why not?
1. Through observing the sequence of events (A → B → C → D) found below, describe how reproductive cloning is made possible. Your response should consist of 3—5 complete sentences. SENTENCE STARTER: The process of cloning may look quite tricky, but it can actually be broken down into 4 individual steps. In step A, the cells of the organism we want to be cloned are isolated and the… 2. What is an ADVANTAGE of engaging in cloning practices similar to the one highlighted above? What reason might a farmer, livestock owner, or someone else use as justification for cloning? 3. What is a DISADVANTAGE (or potential drawback) of cloning plants, livestock, or pets?
You are working with a strain of mutant flies that have no wings. You apply gamma rays to your strain of wingless files to induce further mutations and cross these flies. Remarkably, in your progeny a small proportion of the flies now have wild type wings. You conclude that the second round of mutations must have induced a new mutation called a?
2. Null mutations are valuable genetic resources becausethey allow a researcher to determine what happens to anorganism in the complete absence of a particular protein. However, it is often not a trivial matter to determinewhether a mutation represents the null state of the gene.a. Geneticists sometimes use the following test forthe nullness of an allele in a diploid organism: If theabnormal phenotype seen in a homozygote for theallele is identical to that seen in a heterozygote(where one chromosome carries the allele in question and the homologous chromosome is known tobe completely deleted for the gene) then the alleleis null. What is the underlying rationale for thistest? What limitations might there be in interpreting such a result?
7. Why recombinant DNA is very useful in improving our health conditions?A. Human insulin can be reproduced by bacteria?B. Vaccine can be reproduced by fungi or bacteriaC. Human growth hormone can be obtained from E. ColiD. All of the above 8. Which of the following is/are example of genetic engineering?A. A farmer choose a breed of cow for greater milk production.B. The use of bacteria in order to produce human insulinC. The insertion of clone genes to plant cellsD. Cross pollination of squash flowers. 9. Bacterial cells as host organisms may expose the gene to make protein products such as insulin and growth hormone . Which of the following processes are involved?A. replication and transcription. B. Transcription and replication C. Transcription and transformation. D. Replication and transformation
6) If you had the ability to do gene editing with ONE gene for the betterment of human kind, which one would you choose, and why? Assume you could either change an abnormal allele associated with a disease, such as the cystin gene associated with Cystic Fibrosis to its normal wild type, or add a pre-existing human allele to a genome
8. As explained in the text, the cause of many geneticdiseases cannot yet be discerned by analyzing wholeexome/genome sequences. But in some of theseseemingly intractable cases, important clues can beobtained by looking at mRNAs or proteins, ratherthan at the DNA.a. As you will see in more detail in later chapters, it ispossible to use single-molecule methods to sequence cDNA copies of millions of mRNA molecules from any particular tissue cheaply. Howcould you sometimes use such information to finda disease gene? When would this information benoninformative?b. A technique called Western blotting allows you toexamine any protein for which you have an antibody; it is possible to see differences in size oramount of that protein. How could you sometimesuse such information to find a disease gene? Whenwould this information be noninformative?
1.what Human diseases that result from variations in multiple genes? 2.what Alternate forms of nitrogenous bases in which a proton has migrated to an alternative position.? 3. what Stereoisomers of furanose and pyranose rings which differ in the orientation of the hydroxyl group at the C1 position? 4.which Highly compacted strongly staining region of the chromosome with no transcriptional activity? 5. what DNA sequences that specify the transition between euchromatin and heterochromatin? 6. Once cells have passed the restriction point in this phase of the cell cycle they are committed to go through the entire cell cycle. 7.which Cdks belong to a family of serine/threonine? 8. what is A protein that tags another protein for proteolysis?
2. a. You want to create a genetic construct that will express GFP in Drosophila. In addition to the GFPcoding sequence, what DNA element(s) must youinclude in order to express this protein in flies if theconstruct were integrated into the Drosophila genome? Where should such DNA element(s) be located? How would you ensure that GFP is expressedonly in certain tissues of the fly, such as the wing?b. Suppose you insert the GFP coding region plus allof the DNA elements required by the answer to part(a)—except the enhancer—between inverted repeatsfound at the ends of a particular transposable element.Because all of the DNA sequences located betweenthese inverted repeats can move from place to placein the Drosophila genome, you can generate manydifferent fly strains, each with the construct integrated at a different genomic location. You now examine animals from each strain for GFPfluorescence. Animals from different strains showdifferent patterns: some glow green in the eyes,others in…