What is the significance of the START codon AUG in the genetic code?
AUG is the most common start codon, which always codes for the amino acid Methionine and signals the ribosome to begin protein synthesis.
Question 182 of 519
📘 CLASS XII
The three-nucleotide sequence on the tRNA that recognizes the codon on the mRNA is the:
The anticodon on the tRNA is complementary to the codon on the mRNA, ensuring that the correct amino acid is incorporated into the growing polypeptide chain.
Question 183 of 519
📘 CLASS XII
Which scientist, listed in the unit introduction, is known for co-discovering the double helix structure of DNA?
James Watson and Francis Crick are famously credited with elucidating the double helix structure of DNA in 1953.
Question 184 of 519
📘 CLASS XII
Which molecular process is essential for providing genetic stability and transmitting genetic information accurately to the next generation?
DNA replication, the process of making identical copies of the DNA, is essential for ensuring that each daughter cell or offspring receives a complete and stable set of genetic instructions.
Question 185 of 519
📘 CLASS XII
What was the major contribution of T.H. Morgan in the field of genetics?
T.H. Morgan's experiments on the fruit fly (Drosophila melanogaster), particularly with sex-linked traits like eye color, provided concrete evidence that genes are located on chromosomes, confirming the Chromosomal Theory of Inheritance.
Question 186 of 519
📘 CLASS XII
The organism T.H. Morgan primarily worked with to establish the chromosomal theory of inheritance was:
Drosophila melanogaster (fruit fly) was Morgan's model organism due to its short life cycle, high number of progeny, and clearly distinguishable inherited traits.
Question 187 of 519
📘 CLASS XII
Which scientist worked alongside James Watson to propose the model of the DNA double helix?
James Watson and Francis Crick co-authored the 1953 paper describing the structure of DNA.
Question 188 of 519
📘 CLASS XII
The 'entire body of molecular biology' was a consequent development following the understanding of the nature of Mendel’s factors, with major contributions from which group of scientists?
The text specifically lists "Watson, Crick, Nirenberg, Khorana, Kornbergs (father and son), Benzer, Monod, Brenner" as major contributors to the development of molecular biology.
Question 189 of 519
📘 CLASS XII
Which scientist is known for his work in chemically synthesizing genetic code words, contributing significantly to cracking the genetic code?
H. G. Khorana developed chemical methods to synthesize long nucleotide sequences, which was crucial in determining the codons for specific amino acids.
Question 190 of 519
📘 CLASS XII
Which of the following is NOT considered a fundamental mechanism of evolution?
The inheritance of acquired characteristics (Lamarckism) is a discredited theory. Mutation, Genetic Drift, and Natural Selection are the modern accepted mechanisms of evolution.
