Living Environment Regents Practice Test

Which organic compounds are used by scientists to manipulate DNA?

1. Nucleotides

2. Proteins

3. Enzymes

4. Carbohydrates

The correct answer is: Enzymes

Scientists use enzymes to manipulate DNA because these proteins catalyze biochemical reactions, making them essential tools in various molecular biology techniques. Enzymes such as restriction endonucleases cut DNA at specific sequences, allowing researchers to splice genes, clone DNA, or create recombinant DNA. Other enzymes, like DNA polymerases, are critical for synthesizing new strands of DNA during the processes of DNA replication and polymerase chain reaction (PCR). This capability to cut, modify, and replicate DNA forms the backbone of many genetic engineering and biotechnology applications. Nucleotides are the building blocks of DNA and RNA but do not function to manipulate DNA directly. Proteins perform various functions within cells but are not primarily used as tools for DNA manipulation in the same way that enzymes are. Carbohydrates, although vital for energy storage and structural components in organisms, do not play a direct role in the manipulation of DNA.