The enzyme that removes RNA primers and replaces them with DNA during replication is: MCQ with Answer and Explanation

The enzyme that removes RNA primers and replaces them with DNA during replication is:
A. DNA polymerase I
B. Helicase
C. DNA polymerase III
D. Ligase
Answer: Option A
Solution (By JKExamLibrary)
In prokaryotes, DNA polymerase I has 5'→3' exonuclease activity that removes the RNA primer and fills the gap with DNA. DNA polymerase III adds nucleotides to the growing strand. Ligase seals the nicks. Helicase unwinds DNA. In eukaryotes, RNase H removes primers and DNA polymerase δ fills the gap.

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Which of the following is an abiotic component of an ecosystem?
A. Consumers
B. Producers
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D. Decomposers

Correct Answer: Option C


Explanation:
Abiotic components are non-living physical and chemical factors of an ecosystem, including soil, water, temperature, light, and minerals. Biotic components include producers (plants), consumers (animals), and decomposers (bacteria, fungi). The interaction between abiotic and biotic components drives ecosystem functions. Soil provides nutrients and a medium for plant growth.

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Question #2
Consider statements about cell organelles: 1. Chloroplasts are found in all plant cells. 2. Vacuoles are larger in plant cells than animal cells. 3. Centrioles are present in higher plant cells. Which are correct?
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Correct Answer: Option B


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Chloroplasts are present only in the green, photosynthetic parts of plants, not in root cells or non-green tissues. Plant cells typically have a single, large central vacuole occupying most of the volume, whereas animal cells have small, temporary vacuoles. Centrioles are absent in higher plants (angiosperms and gymnosperms) but present in animal cells and some lower plants. Only statement 2 is correct.

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Consider statements about mitochondria: 1. They have a single membrane. 2. They contain their own circular DNA. 3. They are the site of aerobic respiration. Which are correct?
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