One of the 4 nucleic acids that make up dna. It is purine derived & pairs with thymine.
Answer:
True
(I am not 100% sure because the question is very short with no context, but I believe it to be true)
<span>D) Vaccines allow for building immunity without harmful exposure because not all viruses are safe to be exposed to.</span>
Answer:
Restriction enzymes (endonucleases) are used to cut the DNA into fragements.
Explanation
Restriction enzymes are obatained from bacteria where they are utilized by bacteria for protection against viruses. Restriction enzymes are used in biotechnology research. There are several restriction enzymes and each cut the DNA at specific site known as recognition site which is usually 4-8 neucleotide long. They produce sticky ends (cutting the both DNA strand on different site) and blunt ends (cutting the both DNA strand on same site) on DNA fragments.
Answer:
a. True, b. False, c.True, d. True
Explanation:
a. Base excision repair is started by a DNA glycosylase that recognizes the changes and removes the altered base by cleavage of the glycosidic bond binding the base and the deoxyribose sugar together.
b. Nucleotide excision repair works by a cut-and patch mechanism that removes their heavy lesions, including pyrimidine dimers and nucleotides . Endonucleases are responsible for the lesion of the damaged strand.
c. Nucleotide excision repair is initiated by the proteins namely UvrA, UvrC, and UvrB in Escherichia coli.
-UvrD (helicase II) later removes the damaged strand
-DNA polymerase I (PolI) fills in the resulting gap.
d. DNA glycolases removes the damaged nitrogenous base.
-It leaves the sugar-phosphate backbone intact and thus creating an apurinic/apyrimidinic site, which is commonly referred to as an AP site.
e. Xeroderma pigmentosum complementation group A(XPA)
-This is an essential protein in the nucleotide excision repair pathway.
- It helps to make a pre-incision complex along with other proteins.
