Concept explainers
Videos
Working on the Amazon River, a biologist isolated DNA from two unknown organisms, P and Q. He discovered that the adenine content of P was 15% and the cytosine content of Q was 42%. This means that:
a. the amount of guanine in P is 15%.
b. the amount of guanine and cytosine combined in P is 70%.
c. the amount of adenine in Q is 42%.
d. the amount of thymine in Q is 21%.
e. it takes more energy to unwind the DNA of P than theDNA of Q.
Introduction:
The genetic material in DNA (deoxyribonucleic acid) contains four types of nucleotides. These nucleotides consist of sugar, deoxyribose, a phosphate group, and a nitrogen base. There are four types of nitrogenous bases that are present in DNA. These are guanine, adenine, cytosine, and thymine. The guanine and adenine are purines and cytosine and thymine are pyrimidines.
Answer to Problem 1TYK
Correct answer:
The content of guanine and cytosine combined in P is 70%.
Explanation of Solution
Justification for the correct answer:
Option (b) states that the amount of guanine and cytosine combined in P is 70%. The amount of adenine content of P was 15%, which means that the amount of thymine must also be 15%. This makes up 30%, which means that the other two bases guanine and cytosine constitute 70% of the content. Hence, option (b) is correct.
Justification for the incorrect answers:
Option (a) states that the amount of guanine in P is 15%. The amount of adenine and thymine is 15% and the sum of the other two bases guanine and cytosine is 70%. The amount of guanine is equal to that of cytosine, so each base must be 35% and not 15%. So, it is an incorrect option.
Option (c) states that the amount of adenine in Q is 42%. The amount of cytosine in Q is 42% and because the amount of guanine is equal to that of cytosine, the sum of cytosine and guanine in Q must be 84%. The other two bases adenine and thymine, thus constitute 16% of the content, which means that adenine must be 8% and not 42%. So, it is an incorrect option.
Option (d) states that the amount of thymine in Q is 21%. The amount of cytosine in Q is 42% and because the amount of guanine is equal to that of cytosine, the sum of cytosine and guanine in Q must be 84%. The other two bases adenine and thymine constitute 16% of the content, which means that thymine must be 8% and not 21%. So, it is an incorrect option.
Option (e) states that it takes more energy to unwind the DNA of P than to unwind the DNA of Q. There are three hydrogen bonds between guanine and cytosine and two between adenine and thymine. It will take more energy to break three hydrogen bonds than to break two hydrogen bonds. The sum of guanine and cytosine content in P is 70% of the content and in Q is 84% of the content. Thus, it takes more energy to unwind the DNA of Q than to unwind the DNA of P. So, it is an incorrect option.
Hence, options, (a), (c), (d), and (e) are incorrect.
Thus, it can be concluded that the total content of guanine and cytosine in the organism P is 70%. This is because the amount of adenine is equal to that of thymine and the amount of adenine is equal to that of thymine in DNA. The total amount of adenine and thymine in the organism P is 30%.
Want to see more full solutions like this?
Chapter 14 Solutions
Biology: The Dynamic Science (MindTap Course List)
- If a virus particle contained double-stranded B-DNA of 400,000 base pairs, A. How many complete helical turns would occur on each strand? B. How many atoms of phosphorus would be present? C. If the mole % of G in this genome is 17%, what is the mole % of A?arrow_forwardA researcher sequences the genome of a variety of bacterial and eukaryotic cells. She finds that the bacterial genome is smaller, but that there are more genes for a given number of base pairs in the eukaryotic cells. In other words, there are fewer genes per unit of length of DNA in the eukaryotic cells. What do you predict she will find if she examines the DNA more closely? A. All of the bacterial DNA consists of coding sequences, but this is not true of the eukaryotic DNA. B. There are more repetitive sequences in the eukaryotic DNA than in the bacterial DNA. C. There are densely packed genes in the eukaryotic DNA that were not immediately distinguishable during the first analysis. D. The bacteria have larger quantities of noncoding DNA than the eukaryotic cells.arrow_forwardyou performed a sanger sequencing on a particular segment of DNA. Explain at the molecular level what your gel profile would look like due to this mistake. a. you forgot to add ddNTPs to your test tube. b. you added too much ddNTPs to your test tubearrow_forward
- Bacteriophages are viruses that infect bacteria. Depending on the bacteriophage, their genome can be made of either single or double stranded DNA or RNA. The composition of genetic material found in a bacteriophage is found to be 25% A, 33% T, 24% G, and 18% C. What can you conclude about the genetic material of this virus? a. It is double-stranded DNA. b. It is single-stranded DNA. c. It is single-stranded RNA. d. It is double-stranded RNA.arrow_forwardWhen performing Sanger sequencing a scientist accidentally forgot to include ddGTP in his sequencing reaction (he did include ddATP, ddCTP, and ddTTP along with all the other needed components). Which of the following statements are true? A.All DNA fragments will terminate at the first G base pair B.A color will be missing from the chromatogram. C.The sequencing primer will not contain G base pairs. D.There will be gaps in the chromatogram.arrow_forwardwhat is the difference between human DNA and strawberry DNA?arrow_forward
- What is the effect of incubating a mixture of RNA and DNA with 0.1 M NaOH? A. DNA is hydrolyzed to nucleoside monophosphates. B. No effect. RNA and DNA are resistant to base hydrolysis. C. RNA is hydrolyzed to nucleoside monophosphates. D. Both RNA and DNA are hydrolyzed to nucleoside monophosphates. Stem-loop structures in RNA resemble the ________ form of double-helical DNA. A. A B. B C. supercoiled circular D. Zarrow_forwardWhich of the following experimental results was NOT evidence that DNA is the genetic molecule rather than proteins? a. When a virus was radioactively labelled, and the virus was allowed to infect a bacteria cell, radioactive virus DNA was found inside the bacteria cell while radioactive virus proteins were found outside the cell. b. Dead pathogenic bacteria cells combined with living nonpathogenic bacteria cells caused the creation of living pathogenic cells and thus the death of the host animal. c. Proteins are a class of macromolecules with the diversity and specificity needed for hereditary material. d. Nucleotide bases occur regularly, such that the number of adenines = number of thymines, and the number of guanines = number of cytosines.arrow_forwardSome restriction enzymes produce DNA fragments with overhanging stretches called sticky ends on each strand. Sticky ends are useful in making recombinant DNA because Select one: a. Sticky ends contain the exact same nucleotides that allows fragments to splice together. b. Sticky ends contain nucleotides with complementary bases that allows fragments to splice together. c. Sticky ends contain the exact same nucleotides that can form hydrogen bonds. d. Sticky ends contain nucleotides with complementary bases that can form hydrogen bonds.arrow_forward
- Place the steps of sanger sequencing in order.A. A fluorescent laser excites the fragments and records the wavelength consistent with a single nucleotide. B. ddNTPs bind and stop chain extension.C. DNA fragments are separated by size through a capillary tube. D. DNA polymerase copies the target region of template DNA.E. The final nucleotide of each fragment is labeled with a fluorescent tag.arrow_forward3) Erwin Chargaff is considered one of the pioneering scientists in the field of molecular biology. In one of his studies, Chargaff observed that a sample of human DNA contained approximately 30% adenine and 20% guanine. Based on DNA structure, what are the expected percentages of the other nitrogenous bases in the sample? A. 10% thymine, 40% cytosine B. 20% thymine, 30% cytosine C. 30% thymine, 20% cytosine D. 40% thymine, 10% cytosinearrow_forwardWhich of the following best describes the process of DNA seqencing. a. DNA is seperated on a gel and the different bands are labled with flouroscent nucleotides and scanned with a laser. b. A laser is used to flurorescently label the nucleotides present with in the DNA , the DNA is run on a gel and then the DNA is droken into fragments c. Nucleotides are scanned with a laser and incrprorated into the DNA that has been seperated on a gel and then DNA is amplified with PCR. d. fragments of DNA are produced in a reaction that lables them with any of four different fluroscent dyes and the fragmented then are run on a gel and scanned with laser e. DNA is broken down into its constituents nucleotides and the nucleotides are then run on a gel and purified with a laserarrow_forward
Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSON
Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax
Anatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education