30 Questions
What is the main result of DNA mutation?
Change in the mRNA codon nucleotide sequence
Which type of mutation arises when a base pair with an inappropriate partner during DNA replication?
Point Mutation
What is the result of a nonsense mutation?
Change in the protein being translated into
In a transition type of point mutation, what occurs?
One base pair is changed to its kind
What is the clinical significance of a nonsense mutation?
Factor XI deficiency: a blood clotting disorder
What does a missense mutation change?
The protein being translated into
What are the two general classes of DNA repair discussed in the text?
Direct Reversal and Replacement of damaged bases
Which type of DNA damage can be repaired by photoreactivation?
Formation of pyrimidine dimers
What is the name of the enzyme involved in photoreactivation?
Photolyase
Which DNA repair mechanism requires light for its function?
Direct reversal through photoreactivation
What is the function of the protein MGMT in DNA repair?
Helps restore original guanine structure
Which type of DNA damage can be reversed by O6methylguanine methyltransferase?
Methylation of guanine
What is the consequence of a point mutation in the B-globin chain of Hemoglobin causing codon GAG to change into GUG?
Change in the amino acid coded from Glutamic Acid to Valine
Which type of mutation refers to the loss of a single base either spontaneously or due to damage?
Deletion mutation
When can frameshift mutations likely occur?
When any number of bases are added or deleted, except for multiples of three
What causes DNA damage leading to mutation and genomic instability?
Incorrect nucleotide bases during DNA replication
Which process can identify the correct damage in DNA molecules for repair?
DNA repair
What does DNA encode, making it a permanent copy necessary for cell functioning?
Cell genome
What is the term used to describe an enzyme that becomes inactivated after accepting an alkyl group through its sulfur atom of a cysteine residue?
Suicide enzyme
Which type of repair involves the removal of a single damaged base and requires glycosylases enzymes?
Base Excision Repair
What is the general mechanism by which repairs are made when one of the double helix strands is damaged?
Excision Repair
What occurs after the damaged DNA on one strand is removed in the excision repair process?
The intact DNA strand is replaced by DNA polymerase
Which repair mechanism involves recognizing damage and cleaving it on both sides by endonucleases before resynthesis by DNA polymerase?
Nucleotide Excision Repair
What kind of damage does Nucleotide Excision Repair specifically recognize for repairs?
Formation of pyrimidine dimers from UV light
What is the main function of mismatch repair in DNA replication?
Remove mismatched bases missed by proofreading DNA polymerase
Which repair mechanism is particularly important in maintaining genomic integrity by fixing damage to both DNA strands?
Homologous recombination
What is one of the risks associated with single-stranded annealing and alternative joining as repair mechanisms?
Leading to a loss in genetic information
Which repair mechanism connects double strand break ends without using a homologous template?
Nonhomologous end joining
What is the undefined mechanism used in repairing double strand breaks that risks genomic integrity?
Alternative joining
How does homologous recombination repair damaged bases on both strands of DNA?
By exchanging nucleotide sequences with a sister chromatid
Explore the two main classes of DNA repair mechanisms: Direct Reversal and Replacement of damaged nucleotide bases. Learn about how direct reversal repairs DNA damage without requiring a template, and how replacement repairs damaged nucleotide bases. Test your knowledge on these fundamental DNA repair processes.
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