NEET Practice Questions (MCQs) with Answers & Solutions

ATP (Adenosine Triphosphate) is the common instant source of energy for cellular activities. It acts as an energy currency in cells, providing the energy needed for many biochemical reactions. The energy is released when ATP is hydrolyzed to ADP (Adenosine Diphosphate) and an inorganic phosphate.

t-RNA, or transfer RNA, is known as the adapter molecule. It functions during translation by carrying amino acids to the ribosome and matching them to the coded mRNA message using its anticodon. This 'adapts' the genetic code into a sequence of amino acids to form proteins.

The RNA responsible for transporting amino acids to the protein synthesis site is known as transfer RNA (t-RNA). t-RNA has a crucial role in translating the genetic code from m-RNA into a sequence of amino acids during protein synthesis. It carries specific amino acids to the ribosome, where they are added to the growing polypeptide chain.

The special function of t-RNA is to act as an adapter molecule in protein synthesis. It attaches specific amino acids to the m-RNA template during translation. Each t-RNA molecule has an anticodon that pairs with a corresponding codon on the m-RNA, ensuring that the correct amino acid is added to the growing polypeptide chain.

Ribosomal RNA (r-RNA) is proportionally more abundant in cells than other types of RNA. r-RNA is a major component of ribosomes, which are the cellular machinery responsible for protein synthesis. It makes up about 80% of the RNA in a cell, whereas m-RNA and t-RNA are present in smaller quantities.

In DNA molecules, the part that varies among different DNA molecules is the nitrogen base. The nitrogen bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G). These bases pair in a specific manner (A with T, and C with G) and the sequence of these bases determines the genetic information carried by the DNA.

The two polynucleotide chains in DNA are arranged in an antiparallel and complementary manner. This means that one strand runs in the 5' to 3' direction, while the other runs in the 3' to 5' direction. The bases on one strand pair with the complementary bases on the opposite strand (A pairs with T, and C pairs with G), forming a double helix structure.

The base sequence of the opposite chain of DNA can be determined using the complementary base pairing rules. Adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Therefore, if one strand has the sequence ACGTTGG, the complementary sequence on the opposite strand will be TGCAACC.

ATP (Adenosine Triphosphate) is composed of a pentose sugar (ribose), adenine (a nitrogenous base), and three phosphate groups. ATP is the primary energy carrier in cells. The structure is crucial for its role in energy transfer.

Ribozymes are RNA molecules that have the ability to catalyze specific biochemical reactions, similar to the action of protein enzymes. They are essentially nucleic acids that behave like enzymes, playing important roles in various cellular functions.