FIGURE 19.16 Direct repair of dam- aged bases in DNA. (a) The repair of thymine dimers by photolyase. (b) The repair of methylguanine by the transfer of the methyl group to Thymine dimer CH3 SH 06-Methylguanine CH2 ONLINE ANIMATION Н. CH3 Нас. N- н- Н Н N. `NH2 Alkyltransferase alkyltransferase. CONCEPT CHECK: Which of these DNA backbone Alkyltransferase catalyzes the removal of the methyl group onto itself. repair systems is particularly valuable to plants? DNA DNA photolyase cleaves the 2 backbone bonds between the thymine dimer. CH3 Guanine На 'N' CHз Нас. -- н CH2 н Н `NH2 The normal structure of the 2 thymines is restored. The normal structure of guanine is restored. (a) Direct repair of a thymine dimer (b) Direct repair of a methylated base O=

FIGURE 19.16 Direct repair of dam- aged bases in DNA. (a) The repair of thymine dimers by photolyase. (b) The repair of methylguanine by the transfer of the methyl group to Thymine dimer CH3 SH 06-Methylguanine CH2 ONLINE ANIMATION Н. CH3 Нас. N- н- Н Н N. `NH2 Alkyltransferase alkyltransferase. CONCEPT CHECK: Which of these DNA backbone Alkyltransferase catalyzes the removal of the methyl group onto itself. repair systems is particularly valuable to plants? DNA DNA photolyase cleaves the 2 backbone bonds between the thymine dimer. CH3 Guanine На 'N' CHз Нас. -- н CH2 н Н `NH2 The normal structure of the 2 thymines is restored. The normal structure of guanine is restored. (a) Direct repair of a thymine dimer (b) Direct repair of a methylated base O=

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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In the following sequence, a cytosine was deaminated and is now a uracil (underlined). 5’-GGTAUTAAGC-3’ a. Which repair pathway(s) could restore this uracil to cytosine? b. If the uracil is not removed before a DNA replication fork passes through, what will be the sequences of the two resulting double helices? Provide the sequences of both strands of both helices. Label the old and new strands and underline the mutation(s). c. Could the mismatch repair pathway fix the mutations you’ve indicated in part b? d. If the cell undergoes mitosis, and the replicated DNAs are distributed into the two daughter cells. Will 0, 1, or 2 daughter cells have a mutation in this sequence?
All of the following proteins function during nucleotide excision repair, EXCEPT: A. DNA pol B. Uvr A C. Uvr C D. Ligase E. Gyrase
If DNA polymerase requires a perfectly pairedprimer in order to add the next nucleotide, how is it thatany mismatched nucleotides “escape” this requirementand become substrates for mismatch repair enzymes?
What is the function of DNA methyl transferases (DNMTs)?
Cytosine can be deaminated to form Uracil What type of mutation is this classified as? Discuss what happens to the base-pairing properties from switching from C to U? When U is replicated in two rounds of synthesis, what substitution does this result in? Before Uracil alters the DNA during replication, what repair system can be used to correct this error? Describe how this type of DNA repair works?
The base analog 5-bromouracil undergoes tautomerization. One tautomer behaves like thymine, and the other behaves like cytosine. If 5-bromouracil is incorporated in the DNA, what is the minimum number of cycle(s) of DNA replication that must occur to mutate the codon for proline (CCC) into the codon for serine (TCC)? A) one cycle B) two cycles C) three cycles D) 5-bromouracil cannot induce this mutation
Given 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?
Given this sequence (of course the DNA is double stranded, but I’m only showing one strand), will it tend to cause a deletion to form, or an inversion? Diagram how it (either the deletion or inversion) will happen. xxxxxxxcatatgctttcag (another five hundred or so letters) catatgctttcagxxxxxxxxx Ditto, using this sequence xxxxxxxxcatatgctttcag (another five hundred or so letters) gactttcgtatacxxxxxxxxxxx
Insulin is synthesized as preproinsulin, which has 81 amino acids. How many heterocyclic bases must be present in the informational DNA strand to code for preproinsulin (assuming no introns are present)?
What would happen to DNA repair in bacteria if MutH is mutated such that is cannot recognize the hemi- methylated strand of DNA?
How would the uniform 2 nm diameter of DNA be affected iftwo purines or two pyrimidines could pair with each other?
How would nucleotide excision repair be affected if one of the followingproteins was missing? Describe the condition of the DNAif the repair was attempted in the absence of the protein.A. UvrAB. UvrCC. UvrDD. DNA polymerase