🧬 Biochemistry Solved MCQs with Answers

Practice 1490 approved 🧬 Biochemistry questions with verified answers from the 🧬 Medical Science subject for Pakistan exams.

1490 solved MCQs

A cesium chloride will separate DNA molecules byAnswer: Density If one cell has AT contents 40%, what will be the percentage of Guanine residue?Answer: 30% Which of the following enzyme adds complementary bases during replication?Answer: Polymerase Which DNA polymerase removes RNA primers in DNA synthesis?Answer: Polymerase I Enzymes, responsible for unraveling short segments of DNA isAnswer: Helicase Enzyme, responsible for proofreading base pairing isAnswer: DNA polymerase Which of the following would not contain DNA?Answer: Glass crystals The nucleosome consists of histoneAnswer: Octamer and 146 bp of DNA What bands will be observed in a cesium chloride gradient after two rounds of replication?Answer: One light and one medium band Proteins involved in opening a replication bubble areAnswer: DNA topoisomerase What is the main damaging effect of UV radiation on DNA?Answer: Formation of thymine dimers The higher order structure of DNA shows symmetry, whereas the higher order structures of most proteins do not. Why isn't protein shape more regular like DNA?Answer: All of the above DNA helicase is used toAnswer: Unwind the double helix Klenow fragment without free nucleotides exhibitsAnswer: Exonuclease activity E.coli DNA polymerases II and III lackAnswer: 5' → 3' exonuclease activity In sperm heads, DNA is particularly highly condensed and the histones are replaced with small basic protein calledAnswer: Protamines Okazaki fragments occur duringAnswer: Replication DNA can be sequenced by theAnswer: Both (a) and (b) Which histone(s) are associated with the linker DNA of a nucleosome?Answer: Histone H1 Because DNA is a highly charged polyanion, its stability to heat denaturationAnswer: Increases with increasing salt The sugar in RNA is __________ , the sugar in DNA is __________Answer: Ribose, deoxyribose Nucleoside is a pyrimidine or purine baseAnswer: Covalently bonded to a sugar In gel electrophoresis, what fragments will move most quickly through a gel?Answer: Small fragments Which pyrimidine base contains an amino group at carbon 4?Answer: Cytosine Nucleotide bases and aromatic amino acids absorb light respectively atAnswer: 260 and 280 nm The glycosidic bonds in DNA and RNAAnswer: Connect the sugar to the base Nucleic acids can be analyzed experimentally by theirAnswer: absorption of uv light ThymidineAnswer: All of the above A nucleotide consists ofAnswer: A sugar, a base and a phosphate A five carbon sugar lacking a hydrogen at the number 2 carbon is found inAnswer: DNA