Test: Molecular Basis of Inheritance- 1 - NEET MCQ

Genetic information is carried out by DNA and RNA. Both DNA and RNA are called genetic material, made up of long chain of nucleotide having-nitrogenous base, sugar and phosphate ions.

Nucleoproteins are the chromosome made up of DNA, some RNA and histone proteins. They act as genetic material in living cells.

In complementary strands of DNA, purines and pyrimidine are held together by Hydrogen bond (H-bond). Adenine and Thymine have double hydrogen bond and cytosine and guanine are held by triple hydrogen bond.

In mature RBCs nucleus is absent and there is no DNA. Mature DNA do not divide to form new cells.

The strand of DNA that forms mRNA is called the template strand or the antisense strand. During transcription, the DNA molecule unwinds, and one of the strands (the template strand) is used as a template to synthesize a complementary RNA molecule, which is called messenger RNA (mRNA). The other strand of DNA, which is not used as a template during transcription, is called the coding strand or the sense strand because it has the same sequence as the mRNA molecule (except for the presence of thymine instead of uracil).

Codon is triplet means made up three nucleotides. Each codon codes for one amino acid to form proteins during protein synthesis.

Code AUG code for Methionine. In all organism first amino acid coded is methionine by codon AUG.

Protein synthesis occurs over ribosomes which are also called protein factories of cell. Each ribosomes have two parts 40S and 60S in eukaryotes and 30S and 50S in prokaryotes.

Okazaki discovered the way in which the lagging strand of DNA is replicated via fragments by conducting an experiment using E. coli named the strand Okazaki fragment. Okazaki fragments are the fragmented piece of newly synthesized DNA strand called as lagging strand during DNA replication. They are complementary to the lagging template strand, together forming short double-stranded DNA sections.

Griffith carried out experiment on mice using pneumonia causing bacteria to show that DNA is the genetic material by transforming non-virulent strain into virulent strain which is called bacterial transformation.

Enzymes DNA polymerase adds complementary nucleotides. This enzyme is present floating inside the nucleus.

Regulator genes codes for repressor proteins during translation of DNA into protein via mRNA.

In the process of transcription RNA polymerase is only capable of elongation.

Initiation factor sigma helps in the process of initiation while termination factor Rho is helping in termination of the process.

So the correct option is 'Elongation'.

• The distance between 2 consecutive bp is 0.34 nm. The formula to calculate the length of the DNA double helix:
• The length of the DNA double helix = The total number of bp x distance between two consecutive bp.
• As a result, we get 2.2 m as the length of the DNA double helix.

The main purpose of human genome project launched in 1990 was to identify the sequence of human DNA.

Human genome project was associated with the rapid development of new area of biology called as bioinformatics. This branch of biological science is used to known the sequence of gene on Chromosome of living organisms.

Human genome contains 3164.7 million nucleotide bases.

Gel electrophoresis technique is used for separation of DNA fragments according to their size. This is an important tool to study the genome of an individual. 

There are 23 pairs of chromosome in human cells. The chromosome Y is the smallest and contain least number of gene (231) and chromosome 1 contain highest number of gene (2968).

About 3% or so of the human genome has highly repetitive sequences or simple-sequence DNA or simple sequence repeats or satellite DNA. It does not encode proteins or RNAs but have identifiable functional importance owing to their presence in centromeres and telomeres; which makes option B wrong as genetic engineering mainly aims at transfer of genes producing desired products. Satellite DNA show relative uniformity within species and great variability between closely related species. This DNA polymorphism is revealed during DNA finger printing in identification of suspect. For the purpose, restriction enzyme digested DNA samples are sorted by gel electrophoresis followed by southern blotting. Finally, radioactive probes are washed over the nylon surface to allow their joining to any DNA fragments of same composition. Correct option is A. Sex determination in human is governed by presence or absence of Y-chromosome, not by satellite DNA which makes option D wrong. Organ transplantation mainly aims at immune system; option C is wrong.

So, the correct answer is 'Forensic science'

• Histones are rich in basic amino acid (AA) residues such as lysine and arginine.
• These two amino acids carry a positive charge at their side chains.
• Due to this reason, histones are called as the set of positively charged basic proteins.

The DNA required for finger printing can be obtained from WBCs, root hair cells and body secretion as all the cells contain same type of genetic makeup.

• Nucleosomes are the bead-like structures which are present on a chromatin.
• These nucleosomes contain the DNA, which is the genetic material.
• Such a typical nucleosome contains nearly 200 bp.

In prokaryotes the 23srRNA of the larger subunit of ribsome is a ribozyme that catalyzes peptide bond formation.

The two chains are coiled in a right handed fashion.