FREE NEET Biology Practice MCQ Test: Molecular Basis Of Inheritance Exercise 4 Questions Answers With Detailed Explanations [PDF]

Answer: (a)

Answer: (d)

The relationship between the sequence of amino acids in a polypeptide and nucleotide sequence of DNA or mRNA is called genetic code. The genetic code is continuous and does not possess pause after the triplets. So, a codon in mRNA is present in contiguous fashion. If a nucleotide is deleted or added, the whole genetic code will read differently.

Answer: (c)

Answer: (a)

Sigma factor is associated with the initiation of transcription. Sigma factor confers the specificity of RNA synthesis at the promoter region. Capping involves the addition of unusual nucleotide at the 5' end of hn RNA. Tailing involves the addition of adenylate residues at 3' end in a template independently. Coding strand (also called leading strand) is a strand synthesized by an enzyme in continuous piece in 5' - 3' direction.

Answer: (a)

Answer: (c)

Answer: (a)

In a DNA strand the nucleotides are linked together by3’–5’ phosphor diester linkage (bonds) to form adinucleotide. To form a polynucleotide chain, more nucleotides can be joined.

Answer: (c)

AUG is initiating codon. UCG codes for serine, UUU codes for phenylalanine, UGU codes for cysteine.

Answer: (b)

Answer: (a)

If deletion happen at 901st position than the remaining 98 bases specifying for 33 codons of amino acids will be altered.

Answer: (d)

Answer: (c)

A gene is a hereditary unit consisting of a sequence of DNA and occupying a specific position or locus within the genome. Gene activity ultimately affects the phenotype of the organism possessing the gene. Thus gene is a physical and functional unit of genetic information. A cistron is a unit of genetic function. In prokaryotes, there is one gene one enzyme correspondence. It means that in these organisms genes and cistrons are equivalent.

Answer: (d)

Answer: (d)

Answer: (a)

Crossing over occurs between non–sister chromatids of two homologous chromosomes. Homologous chromosomes form bivalen t. Crossing over occurs between chromosomes in a nucleus.

Answer: (a)

Answer: (c)

Answer: (b)

Answer: (c)

Answer: (b)

Anticodon is the sequence of three nucleotides in a transfer RNA molecule that pairs with a complementary sequence of three nucleotides (codon) on a molecule of messenger RNA. tRNA has clove like shape or L shape (three dimensional). It has G at 5′ end CCA at 3′ end. CCA at 3′ end is meant for attaching to a specific amino acid (AA-binding site). On the opposite side lies an anticodon that is complementary to a specific codon of mRNA. The two are called recognition sites.