Molecular Genetics

Exons are the coding regions of genes that contain the actual genetic information (protein-coding sequences). They are retained in mature mRNA after splicing and translated into proteins. The phrasing "information carrying genes" is slightly imprecise (exons are parts of genes, not genes themselves), but the core meaning is correct.

Introns are non-coding regions within genes that are removed during RNA splicing. They do NOT carry genetic information for protein synthesis - that's the job of exons. The statement correctly identifies that introns are not information-carrying sequences.

Introns are "interrupting" or non-coding sequences that break up the coding regions (exons) within a gene. They interrupt the continuous protein-coding sequence and must be removed by splicing. The term "interrupting sequences" is an accurate description of their structural role.

The Central Dogma of molecular biology states that genetic information flows from DNA to RNA to Proteins. DNA is transcribed into RNA, which is then translated into proteins. This fundamental principle correctly describes the directional flow of genetic information in cells.

mRNA (messenger RNA) carries genetic information from DNA to ribosomes for protein synthesis. This is a fundamental concept in molecular biology - the 'central dogma' flows DNA → mRNA → protein. This statement is scientifically accurate.

The first complete nucleotide sequence of a tRNA molecule was determined in 1965 by Robert W. Holley and colleagues at Cornell University, for alanine tRNA from yeast. This was a landmark achievement in molecular biology.

Plant genes are composed of DNA (deoxyribonucleic acid), which is the primary molecule storing genetic information in cells. RNA (ribonucleic acid) plays important roles in gene expression and protein synthesis, but genes themselves are DNA sequences. The claim that genes are made of RNA is false.

DNA contains the complete genetic instructions for an organism's development and functioning, earning it the 'biological blueprint' designation. RNA carries protein blueprints, cells are basic structural units, and mitochondria produce energy - none serve as the master blueprint.

The genetic code is degenerate in that most amino acids are encoded by more than one codon.

It is true that nonsense codons do not code for any amino acid.

An exon is any nucleotide sequence encoded by a gene that remains present within the final mature RNA product of that gene after introns have been removed. It helps in the synthesis of proteins.

A sigma factor (σ factor) is a protein needed only for initiation of RNA synthesis. It is associated with RNA polymerase enzyme.

It is true as these are used as stop codons and these terminate the growing amino acid chain wherever they are present.

This statement is not true as codon, which is a sequence of three nucleotides on m-RNA, is the basic unit of genetic code.