The enzyme that adds nucleotides to the growing DNA strand during replication is:
A. Primase
B. Helicase
C. DNA polymerase
D. Ligase
Answer: Option C
Solution (By JKSSB Mock Tests)
DNA polymerase catalyzes the formation of phosphodiester bonds between adjacent nucleotides, extending the new strand complementary to the template. Helicase unwinds DNA, ligase joins fragments, primase synthesizes RNA primer. In prokaryotes, DNA polymerase III is the main replicative enzyme.
Explanation:
Mitochondria and chloroplasts contain their own DNA and ribosomes (70S) and can replicate by binary fission, a feature supporting their endosymbiotic origin. Golgi apparatus, lysosomes, and rough ER cannot self-replicate; they are part of the endomembrane system and arise from pre-existing membranes. Mitochondria are thus semi-autonomous organelles.
Consider the following statements about ecosystem:
1. Producers are autotrophs.
2. Consumers are heterotrophs.
3. Decomposers recycle nutrients.
Which of the above is/are correct?
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