Question

Match the damage type or repair step at the left with a related enzyme at right. Only one answer will be the most direct for each. (4%)

cytosine deamination (a) hypoxanthine-N-glycosylase
base loss (b) AP endonuclease
adenine deamination (c) mutH protein
binds to GATC sequences (d) DNA polymerase I
binds to mismatch in DNA (e) uracil N-glycosylase
DNA synthesis in gaps (f) mutS-mutL complex
seals nicks (g) ABC excinuclease
06-methylguanine (h) DNA photolyase
direct chemical reversal of pyrimidine dimer formation (i) O6-methylguanine methyltransferase
double-strand break (j) DNA ligase
excision of a lesion-containing oligonucleotide (k) a integrase
(i) RecA protein
(m) restriction endonuclease

Answer 1

The most direct matches for the given types of DNA damage and repair steps include uracil N-glycosylase for cytosine deamination, AP endonuclease for base loss, and hypoxanthine-N-glycosylase for adenine deamination. Additional matches are DNA polymerase I for gap filling, DNA photolyase for reversal of pyrimidine dimers, DNA ligase for double-strand breaks, and ABC excinuclease for lesion excision.

Step-by-step explanation:

DNA Damage Types and Repair Enzymes Matching

Here are the most direct matches for each item:

Cytosine deamination - uracil N-glycosylase

Base loss - AP endonuclease

Adenine deamination - hypoxanthine-N-glycosylase

DNA synthesis in gaps - DNA polymerase I

Direct chemical reversal of pyrimidine dimer formation - DNA photolyase

Double-strand break - DNA ligase

Excision of a lesion-containing oligonucleotide - ABC excinuclease

These enzymes are essential in maintaining the integrity of the DNA by recognizing and repairing specific types of damage, such as deamination, nicks, and dimers, following various DNA repair mechanisms like base excision, nucleotide excision, or direct reversal.