I need help with my bio quiz. please, If possible to answer the questions I prov

Question

I need help with my bio quiz. please, If possible to answer the questions I provided it's what I have left, it is all mutiple choice. Thank you!!

4. A-T base pairs in a DNA double helix are more heat-stable than G-C base pairs. O are chemically distinct from G-C base pairs. O form three hydrogen bonds with each other. O are of a substantially different length than G-C base pairs. are not accessible to DNA binding proteins. 5. If 23 percent of the bases in a sample of double-stranded DNA are adenine, what percentage of the bases are uracil? O 50 O 23 6. The uniform diameter of the DNA structure provides evidence for o 3 end phosphorylation. antiparallel DNA strands. O purine-pyrimidine pairing. O a right-handed helix. O a double-stranded helix

Explanation / Answer

4. Answer is AT base pair is chemically distinct from GC base pair. These bases have different structure thats why AT forms two hydrogen bonds whereas GC forms three hydrogen bonds. The other options are ruled out because GC base pair are more heat stable than AT. GC form 3 hydrogen bond not AT. DNA binding proteins are accessible to AT. The length of AT and GC pairing have nearly same length.

5. The answer is 0 because in double stranded DNA thymin is present not uracil. Uracil is present in RNA. In DNA adenin is make pair with thymin. Adenin is present in equal to thymin and guanin is equal to cytosine according to chargaff rule.

6. DNA is a polynucleotide that made up of nuciotide monomer. The monomer is made up of sugar, phosphate and nitogenous bases (purine and pyrimidine). DNA double helix form ladder like structure and bases form rungs of this ladder. There is a pairing of one large purine with one small pyrimidine because purine has one six ring and one five ring structure whereas pyrimidine has only one six ring. So, AT and GC pairing have nearly the exact same length means the length of rungs of ladder is exactly same that is why diameter of DNA double helix is uniform.

7. Answer is 3' ACTGATAG 5'. A always pair with T and G always pair with C in DNA double helix.

8. Ans is hydrogen bonding between the paired bases. Hydrogen bonds are noncovalent bond that easily break by helicase enzyme and two strands of DNA are separated from each other during DNA replication.3' end phosphorylation not responsible for DNA strand separation . Purine pyrimidin pairing with hydrogen bond is responsible for separation. Covalent bond between sugar and phosphate form backbone of each strand, that are not involve in dissociation.

9. Answer is semiconservative DNA replication. These scientists prove that DNA replication is semiconservative means one strand is conserved in generations. Each DNA strand act as template for syntheis of new strand. DNA molecule synthesized in replication contain one strand old and one new strand.

10. Acyclovir is a antiviral medication. If acyclovir is introduce into elongated DNA then polymerase will not be able to link successive nucleotide because 3' OH end is require for made a phosphodiester bond with successive nuceiotide phosphate group.

11 Single stranded binding protein require to keep strands apart. This will not represent stability of DNA . It is require to maintain each strand individually during replication. It prevent complementry base pairing. All other options demonstrate stability of DNA.

12 In DNA replication, primase provide primer for DNA polymerase. First primer make complementry base pairing with template strand then DNA polymerase add nucleotide because primer provide 3' OH end for the nucleotide addition.Addition of primase inhibitor means no primer availabilty. So, the answer is primase would not be able to provide primer for DNA polymerase.

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