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 (9th Edition) - Standalone book
- 1) How many bases are found (on one of the strands) in a single twist of a DNA helix: a) 3.4 b) 10 d) 0.34 2)Which of the following is a correct representation of a segment of DNA: a) I b) I and III c) IV and V 3)Consider the following sequence: 5' - AUGGCUACAGAUAGCUGGGGCUGAAAAAAAAAAAAAAA..3'Translated, the corresponding protein contains how many amino acids: a) 6 b) 7 c) 8arrow_forwardThe image below shows the base cytosine and a methylated form of cytosine that occurs frequently in the human genome. Use your knowledge of DNA structure to answer the following questions: a) Does methylation of cytosine affect its ability to base-pair with guanine? Explain your answer. b) Would methylation of cytosine affect the binding of a protein that interacts with a C-G base-pair in the major groove?arrow_forward1) How many bases are found (on one of the strands) in a single twist of a DNA helix: a) 3.4 b) 10 c) 2 d) 0.34 1)Consider the following sequence: 5' - AUGGCUACAGAUAGCUGGGGCUGAAAAAAAAAAAAAAA..3'Translated, the corresponding protein contains how many amino acids: a) 6 b) 7 c) 8 d) 13arrow_forward
- You have a sample of genetic material. The nitrogenous base content is 29% guanine. a) If the sample is DNA, what are the amounts of the other bases? Explain your thought process b) Why can you not determine the amounts of the other bases if the sample is RNA? Explain your answer c) How did Watson and Crick make use the relationships between base pairs as they constructed the model for DNA?arrow_forward1) RNA lacks the stability of DNA. Why? a) It has an unmethylated uracil. b) It is originally produced as a single-strand. c) It has one more hydroxyl group that DNA does. d) All the answers are correct! 2) As a newly hired researcher at Johns Hopkins, the nation's leading medical institute, your new boss asks you what would be the quickest mechanism to separate a sample of RNA molecules into siRNA versus lncRNA. Your response to her would be... a) 'Lady, are you crazy! It's not possible!' b) 'I can run them out on a gel and the smaller siRNA molecules will gravitate further down the gel while the larger lncRNA will stay behind!' c)'I can run them out on a gel and the larger siRNA molecules will gravitate further down the gel while the smaller lncRNA will stay behind!' d) 'I can design primers and amplify the RNA samples, which we can then sequence to get the actual RNA reads to determine which ones are shorter like siRNA and which ones are longer like lncRNA.'arrow_forwardThe following diagrams represent DNA molecules that are undergoing replication. Draw in the strands of newly synthesized DNA and identify (a) the polarity of the newly synthesized strands, (b) the leading and lagging strands, (c) Okazaki fragments, and (d) RNA primers.arrow_forward
- As 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: Question: How do we know that in DNA G pairs with C and that Apairs with T as complementary strands are formed?arrow_forward2)Which of the following is a correct representation of a segment of DNA: a) I b) I and III c) IV and V d) V and I 3)Consider the following sequence: 5' - AUGGCUACAGAUAGCUGGGGCUGAAAAAAAAAAAAAAA..3'Translated, the corresponding protein contains how many amino acids: a) 6 b) 7 c) 8 d) 13arrow_forwardIn the early 1950s, it became clear to many researchers that DNAwas the cellular molecule that carries genetic information. However,an understanding of the genetic properties of DNA couldonly be achieved through a detailed knowledge of its structure.To this end, several laboratories began a highly competitive raceto discover the three-dimensional structure of DNA, which endedwhen Watson and Crick published their now classic paper in 1953.Their model was based, in part, on an X-ray diffraction photographof DNA taken by Rosalind Franklin (Figure 9.10). Two ethical issuessurround this photo. First, the photo was given to Watson and Crickby Franklin’s co-worker, Maurice Wilkins, without her knowledge orconsent. Second, in their paper, Watson and Crick did not creditFranklin’s contribution. The fallout from these lapses lasted fordecades and raises some basic questions about ethics in science. What vital clues were provided by Franklin’s work to Watsonand Crick about the molecular structure…arrow_forward
- Why do you think nucleic acids were originally not considered to be carriers of genetic information?arrow_forwarda) If you isolated DNA from the ear and the tail of the same mouse, would you expect the DNA, isolated from the two tissue types, to be the same? Why? b) Provide one difference between DNA replication in eukaryotes and prokaryotes with regard to their origin (s) of replication.arrow_forward(1) Which end (5' or 3') of the molecule is here? (2) Which enzyme is probably functioning here to deal with supercoils in the DNA? (3) Which enzyme is probably functioning here to unwind the DNA? (4) Which nucleic acid is probably depicted here? (5) What are these short DNA fragments usually called? (6) Which enzyme probably functions here to couple these two newly synthesized fragments of DNA? (7) Is this strand the leading or lagging strand? (8) Which end (5' or 3') of the molecule is here?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning