Concept explainers
HOW DO WE KNOW?
In this chapter, we have focused on DNA, the molecule that stores genetic information in all living things. In particular, we discussed its structure and delved into how we analyze this molecule. Based on your knowledge of these topics, answer several fundamental questions:
(a) How were we able to determine that DNA, and not some other molecule, serves as the genetic material in bacteria, bacteriophages, and eukaryotes?
(b) How do we know that the structure of DNA is in the form of a right-handed double-helical molecule?
(c) How do we know that in DNA G pairs with C and that A pairs with T as complementary strands are formed?
(d) How do we know that repetitive DNA sequences exist in eukaryotes?
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ESSENTIALS OF GENETICS-MODIFIED ACCESS
- Why do you think nucleic acids were originally not considered to be carriers of genetic information?arrow_forwardGiven the following DNA sequence: 5’-ATGCGGCCAAGGTCAGAGTGACA-3’ a) If this DNA strand represents the “Sense Strand” of DNA, what would be the RNA sequence? b) If this DNA strand represents the “Antisense Strand” of DNA, what would be the RNA Sequence? c) What would be the other strand of DNA?arrow_forwardWhy do higher salt concentrations stabilize the DNA double helix? Or What aspect of the structure of double-stranded DNA destabilizes the helix in the absence of salt?arrow_forward
- What properties of DNA make it especially well suited to serve as the genetic material?arrow_forwardIn what ways are DNA polymerase and RNA polymerase similar? How do they differ?arrow_forwardWhat are the key properties of the genetic code? Given that the genomes of all organisms are made up of As, Ts, Cs, and Gs, how does one account for diversity in organisms? What are some factors that could adversely affect diversity in nature?arrow_forward
- Does the design of the Hershey–Chase experiment distinguish between DNA and RNA as the molecule serving as the genetic material? Why or why not?arrow_forwardWhat is an Okazaki fragment? In which strand of replicating DNA are Okazaki fragments found? Based on the properties of DNA polymerase, why is it necessary to make these fragments?arrow_forwardWhile studying the structure of a small gene that was recently sequenced duringthe Human Genome Project, an investigator notices that one strand of the DNAmolecule contains 20 As, 25 Gs, 30 Cs, and 22 Ts. How many of each base isfound in the complete double-stranded molecule?arrow_forward
- A 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_forwardOn further analysis of the DNA described in conceptual questionC21, you discover that the triplex DNA in this alien organism iscomposed of a double helix with a third strand wound within themajor groove (just like the DNA in Figure shown). How would youpropose that this DNA is able to replicate itself? In your answer,be specific about the base-pairing rules within the double helixand which part of the triplex DNA would be replicated first.arrow_forwardLet’s assume the linker region of DNA averages 54 bp in length. How many molecules of H2A would you expect to find in a DNA sample that is 46,000 bp in length?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning