Tag: biology
Questions Related to biology
Deoxyribonucleoside triphosphates serve dual purposes in DNA replication. In addition to acting as substrate, the other function is similar to?
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DNA polymerase
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rRNA
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Topoisomerase
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ATP
DNA replication includes which of the following enzymes?
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DNA ligase
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DNA polymerase and ligase
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RNA polymerase and ligase
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All of the above
DNA polymerase and ligase as well as RNA polymerase and ligase have an important role in DNA replication. DNA replication, like all biological polymerization processes, proceeds in three enzymatically catalyzed and coordinated steps : initiation, elongation and termination. All enzymes mentioned play important roles in these steps of replication.
Which of the following is true about DNA polymerase?
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It can synthesize DNA in the 5' to 3' direction
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It can synthesize DNA in the 3' to 5' direction
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It can synthesize DNA in both directions
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Depend upon the condition
Select the correct statement:
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DNA polymerase has high degree of accuracy
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During DNA replication, only one strand of DNA act as template for synthesis of new strand.
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Taylor has proved by his experiment that DNA is the genetic material
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E. coli has $4.6 \times 10^9$ bp in its genetic material
Which of the following enzyme is used in DNA multiplication?
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RNA polymerase
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DNA endonuclease
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Exonuclease
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DNA polymerase
The DNA polymerases are enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA. These enzymes are essential to DNA replication and usually work in pairs to create two identical DNA strands from a single original DNA molecule. During this process, DNA polymerase reads the existing DNA strands to create two new strands that match the existing ones. Every time a cell divides, DNA polymerase is required to help duplicate the cells DNA, so that a copy of the original DNA molecule can be passed to each of the daughter cells. In this way, genetic information is transmitted from generation to generation.
DNA polymerase is needed for
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Replication of DNA
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Synthesis of DNA
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Elongation of DNA
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All of the above
Enzyme responsible for DNA chain elongation is
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DNA polymerase II
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DNA ligase
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RNA poymerase III
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DNA polymerase III
DNA helicase helps in
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Opening supercoils of DNA
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Making DNA helix
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Opening two chains of DNA helix
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Making hydrogen bonds of nitrogenous bases
Helicases move along the double-stranded DNA and separate the strands by breaking hydrogen bonds at the expense of energy from ATP. DNA unwinding by helicases creates topological stress/supercoils in the helical DNA structure which is relieved by the action of topoisomerases. These enzymes transiently break both DNA strands of one chromosome thereby making the other chromosome to pass through the break and relieve the stress. DNA polymerase enzyme synthesizes DNA strands by adding deoxyribonucleotides to 3' end of the primer via phosphodiester bonds; it uses parental DNA as template. Hydrogen bonding between base pairs is facilitated by the presence of hydrogen bond donor (primary and secondary amine groups or hydroxyl groups) and complementary hydrogen bond acceptor (carbonyls and tertiary amines) in bases; it is not enzymatic process. The correct option is C.
Which of the following help in repairing of DNA?
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Ligase
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DNA polymerase I
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RNA primer
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DNA polymerase III
DNA polymerase I serve clean-up functions during replication, recombination, and repair. It has 3' --> 5' proofreading exonuclease activity and 5' --> 3' exonuclease activity. The 5' --> 3' exonuclease activity of DNA polymerase I can replace an error containing the segment of DNA/RNA, paired to the template strand which is then simultaneously replaced by polymerase activity of the same enzyme. The process is called as nick translation. DNA polymerase III with its ten types of subunits has 5' --> 3' polymerization and 3' --> 5' proofreading activities in its $\alpha$ and $\epsilon$ subunits, respectively.
During splicing, the exons are joined and the enzyme which catalyzes this reaction is
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RNA ligase
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RNA catalase
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RNA polymerase
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RNA primase