Molecular Biology Genetics HW 2 - Homework

You will receive no credit for items you complete after the assignment is due. Chapter 7 Reading Quiz Question 2 Part A In 1944, Avery, Macleod, and McCarty provided direct evidence that DNA was the hereditary molecule. They treated heat-killed extracts fr upon treatment with _______. ANSWER: Protease RNase Lipase DNase Correct DNase is an enzyme that degrades DNA. When DNA was removed from the extract, non-lethal RII recipient cells were not genetica DNA as Genetic Material: The Hershey and Chase Experiment Part A The Hershey and Chase experiments involved the preparation of two different types of radioactively labeled phage. Which of the following Hint 1. Recall the composition of T2 phages. ANSWER: It was necessary that each of the two phage components, DNA and protein, be identifiable upon recovery at the end of the experim Establishing the identity of the genetic material required observation of two phage generations. The bacteriophage used in the experiments was a T2 phage. Each scientist had his own method for labeling phage, so each conducted the same experiment using a different isotope. Correct Because it was concluded that the component associated with bacteria at the end of the experiment must be the genetic material, Part B Which of the following statements best represents the central conclusion of the Hershey-Chase experiments? ANSWER: Phage T2 is capable of replicating within a bacterial host. Some viruses can infect bacteria. When radioactive sulfur is supplied in a growth medium, it is primarily DNA that incorporates radioactive label. DNA is the identity of the hereditary material in phage T2. Correct Because phage DNA and not protein was associated with bacteria at the end of the experiment, it could be concluded that DNA - n Part C Which of the following outcomes would be most likely if the Hershey-Chase experiments were repeated without the step involving the blen Hint 1. Once phage had infected bacteria, the blender caused the attached phage heads to separate from bacterial cells. ANSWER: Both preparations of infected bacteria would contain both P32 and S35. Neither preparation of infected bacteria would exhibit radioactivity. The phage would fail to infect bacteria. Both preparations of infected bacteria would exhibit radioactivity. Correct Instead of being removed from the preparation, the "ghosts" would be retained. Because both bacterial preparations would include Chapter 1 Question 44 Fill in the Blank Part A DNA replication is called ________ because the newly replicated DNA consist of a parental strand (from the original DNA) and a newly sy ANSWER: semiconservative Correct DNA Structure - Copy Click here to launch the activity. Part A Guanine and adenine are pyrimidines found in DNA. Hint 1. Recall the structures of purines and pyrimidines. ANSWER: True False Correct A and G are PURINES found in both DNA and RNA. Part B Which of the following statements about DNA structure is true? Hint 1. How are nucleic acids formed? ANSWER: The pentose sugar in DNA is ribose. The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions. Nucleic acids are formed through phosphodiester bonds that link nucleosides together. Hydrogen bonds formed between the sugar‑phosphate backbones of the two DNA chains help to stabilize DNA structure. Correct This statement is true; the 5′–3′ orientation of each chain runs in opposite directions. Part C What is the complementary DNA sequence to 5′ GTCAGTTCGTA 3′? Hint 1. Make sure the sequence is in the correct orientation. ANSWER: 5′ TACGAACTGAC 3′ 5′ ACTCTACGTAG 3′ 5′ CAGTCAAGCAT 3′ 5′ ATGCTTGACTG 3′ Correct This sequence is complementary and in the correct (anti-parallel) orientation. Part D Drag and drop each base to match with its partner in order to maximize hydrogen bonding. ANSWER: Reset Correct Adenine and thymine are complementary and join via two hydrogen bonds. Guanine and cytosine are complementary and join via Part E What is the complementary DNA sequence for the DNA strand shown in the figure below? Enter your answer in the following format: e.g. ATGCAT ANSWER: TAACGTCATGG 5'- -3' Correct This sequence is complementary and in the correct orientation. Problem 1.10 - Copy - Copy Part A Define the following terms. Drag and drop the words into the appropriate blanks to complete the sentences. ANSWER: Re 1. Adenine binds to thymine, guanine binds to cytosine. This is known as complementary base pairing . 2. A purine is a base with a two-ring structure. 3. Complementary strands of DNA are antiparallel and the other from 3' to 5'. 4. A(n) gene is the physical unit of heredity. 5. A pyrimidine is a base with a single ring. meaning that one strand is oriented fro 6. The phosphate group at the 5'-end of DNA and the hydroxyl group at the 3'-end of DNA es DNA strand polarity . 7. The difference between deoxyribose and ribose is the absence/presence of an hydroxyl at C2 of the sugar. 8. Any one of the alternative forms of a particular gene is called a(n) allele . Correct Problem 1.13 Part A If thymine makes up 21% of the DNA nucleotides in the genome of a plant species, what are the percentages of the other nucleotides in th Express your answer as a numbers separated by comma. Enter your answer in the following order: % of adenine, % of cytosine, ANSWER: 21,29,29 Correct Chapter 1 Question 7 Multiple Choice Part A What kind of bond is formed between the 5 phosphate group of one nucleotide and the 3 hydroxyl (OH) group of the adjacent nucleotide? ANSWER: hydrogen bond hydroxyl bond disulfide bond ionic bond phosphodiester bond Correct Chapter 1 Reading Quiz Question 3 Part A Watson and Crick derived their model of DNA structure not from their own laboratory research but rather through the analysis and interpre Maurice Wilkins. Which of the following provides evidence that DNA nucleotides are arranged as complementary base pairs? ANSWER: Percentages of adenine and thymine are approximately equal to one another, and the percentages of cytosine and guanine are ap DNA nucleotides contain a five-carbon deoxyribose sugar, a phosphate group, and one of four possible nitrogenous bases. Complementary strands of DNA are antiparallel. The nucleotides forming a single strand of DNA are linked together by covalent phosphodiester bonds. Correct Correct. Chargaff's rule confirms the base-pairing rules of A-T and C-G. Chapter 7 Question 12 Multiple Choice - Copy Part A In their famous experiment, which of the following would Meselson and Stahl have observed after one cycle of replication in 14N medium i ANSWER: DNA molecules containing two 14N-DNA strands only DNA molecules containing two 15N-DNA strands only An equal number of DNA molecules containing two 15N-DNA strands and DNA molecules containing two 14N-DNA strands. DNA molecules containing one strand of 15N-DNA and one strand of 14N-DNA A mix of DNA molecules corresponding to A and B. Correct Chapter 7 Question 14 Multiple Choice Part A Based on the following replication bubble, which of these statements is true? ANSWER: W and Y are leading strands, X and Z are lagging strands W and Z are leading strands, X and Y are lagging strands X and Y are leading strands, W and Z are lagging strands X and Z are leading strands, W and Y are lagging strands X and W are leading strands, Y and Z are lagging strands Correct Chapter 7 Question 21 Multiple Choice Part A If Single-Stranded Binding protein (SSB) is NOT present during DNA replication, what would you expect to see? ANSWER: The replisome complex would not assemble on the oriC region. Helicase activity is inhibited, so DNA strands cannot be separated. SSB prevents reannealing of the separated strands, so strands would quickly reanneal and DNA replication cannot proceed. The DNA cannot bend, so hydrogen bonds in the 13-mer region of oriC remain intact. SSB carries the helicase protein to the open region of DNA, so hydrolysis and strand separation will not occur. Correct Chapter 7 Question 24 Multiple Choice Part A Why are leading and lagging strand primers removed rather than joined with Okazaki fragments? ANSWER: They have to be removed for leading and lagging strand synthesis to begin. The primers do not hydrogen bond to the template strand correctly. Primers are too short to efficiently bind to Okazaki fragments. They lack the 3' OH that would permit them to be covalently linked to the Okazaki fragments. Correct Chapter 7 Question 37 Part A What is removed from dNTPs to provide the energy required for DNA polymerase to catalyze DNA strand elongation? ANSWER: two phosphates one hydroxyl group one ribose two hydrogens Correct Chapter 7 Question 30 Multiple Choice Part A Which of the following would you find in a Sanger sequencing reaction but not in a polymerase chain reaction? ANSWER: DNA template ddNTPs DNA primer dNTPs DNA polymerase Correct Chapter 7 Question 31 Multiple Choice Part A Which functional groups have been altered in a ddNTP compared to a dNTP? ANSWER: The ddNTPs have a 2' OH and a 3' OH, while dNTPs have a 2' H and a 3' H. The ddNTPs have a 2' H and a 3' H, while dNTPs have a 2' H and a 3' OH. The ddNTPs have a 2' OH and a 3' H, while dNTPs have a 2' H and a 3' OH. The ddNTPs have a 2' H and a 3' H, while dNTPs have a 2' OH and a 3' OH. The ddNTPs have a 2' H and a 3' OH, while dNTPs have a 2' H and a 3' H. Correct Chapter 7 Question 46 Part A What characteristic of the polymerase isolated from Thermus aquaticus makes it unique and highly useful for maintaining the enzyme effic ANSWER: small molecular-weight high electrophoretic mobility proofreading capability heat stability Correct Score Summary: Your score on this assignment is 100%. You received 20 out of a possible total of 20 points.