Molecular Biology MCQ on DNA Replication (Molecular Biology MCQ-07)
(Biology / Life Sciences MCQ: Multiple Choice Questions in Molecular Biology)
(Sample/Model/Practice Questions for CSIR JRF/NET Life Science Examination, ICMR JRF Exam, DBT BET JRF Exam, GATE BT and XL Exam, ICAR JRF NE Exam, PG Entrance Exam, JAM Exam, GS Biology Exam and Medical Entrance Exam)
Prokaryotic Chromosome vs Eukaryotic Chromosome (Similarities and Differences between the Chromosomes of Prokaryotes and Eukaryotes)
Prokaryotes and Eukaryotes are the two major domains of living organisms. This classification is on the basis of the features of their cellular features primarily the nature of membrane bounded organelles and organization of the genetic materials. Both prokaryotes and eukaryotes contain the genetic materials which are organized into specialized structures called Chromosomes. Even though the term chromosome is accurate only for eukaryotes, the genetic materials of prokaryotes are also described as prokaryotic chromosome. The prokaryotic chromosome is considerably different from that of eukaryotes. The present post describes the Similarities and Differences between the Prokaryotic Chromosome and Eukaryotic Chromosome with the help of a Comparison Table.
Similarities between Prokaryotic and Eukaryotic Chromosomes
Ø The chromosome of both prokaryotes and eukaryotes contains the genetic material DNA.
Ø The chemical composition and structural organization of DNA is similar in both prokaryotes and eukaryotes.
Ø In both prokaryotes and eukaryotes, the expression of genetic material is facilitated by transcription and translation.
Ø In both groups, the negatively charged DNA interacts with some positively charged proteins to nullify their charges.
Ø The genetic material contains both coding and noncoding sequences.
The DNA molecules are not always double stranded helical structures, sometimes they occur in single stranded form called ssDNA. In 1959 Robert Sinsheimer discovered a unique bacteriophage called φX 174 (which infect Escherichia coli) with single stranded DNA as its genetic material. Even though the chemical composition of single stranded and double stranded DNA are the same, they also show some characteristic differences.
The present post describes the similarities and differences between dsDNA and ssDNA.s
Similarities between dsDNA and ssDNA
Ø Both dsDNA and ssDNA can acts as genetic material
Ø Both are polymers of nucleic acids
Ø The sugar molecule in both the case is deoxyribose
Ø Both contain purines and pyramidines
Ø Both ssDNA and dsDNA contain the nitrogen bases A, G, T and C
Similarities & Differences between DNA and RNA – A Comparison Table
We wish to suggest a structure for the salt of deoxyribose nucleic acid (DNA).
This structure has novel features which are of considerable biological interest. Watson & Crick, 1953
DNA and RNA are the two types of nucleic acids (a class of macromolecules in the cells) present in all prokaryotic and eukaryotic organisms. Both are essentially the polymers of nucleotides and have immense role in the storage and expression of genetic information in an organism. DNA and RNA allow the storage of genetic information for long period of time without any changes in the genetic constitution of the organism. The presence of two categories of nucleotides also allows the decoding of genetic information during protein synthesis by the process of transcription and translation. The current post describes the similarities and differences between DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
Similarities between DNA and RNA
Ø Both DNA and RNA can acts as genetic material.
Ø Both are polymers of nucleotides.
Ø Both DNA and RNA are linear structures with secondary and super-secondary arrangements.
Ø Both contain purines and pyrimidines.
Ø Both DNA and RNA contain pentose sugar.
Ø In DNA and RNA the adjacent nucleotides are connected by 3’-5’ phosphodiester bonds.