Bacterial chromosomes are often circular but sometimes linear. Some bacteria have one chromosome, while others have more than one. Bactcrial DN A also exist as plasmids which are circular pieces of DNA that can be transmitted between bacteria. Plasmids often carry the genes for antibiotic resistance and can thus spread between different bacteria. Bacterial chromosomes [...]
Most of the genes in general are discrete, non-overlapping units and do not share information with other genes. In contrast, some genes code for more than one protein or polypeptide. Such genes are called overlapping genes. Overlapping genes share some of the same sequences. These comprise of different genes whose nucleotide coding sequences overlap to some extent. The [...]
The term selfish DNA refers to a section of DNA on the genome that is not expressed phenotypically. Selfish DNA is non-transcribed and non-coding; it does not contribute anything to the benefit of the organism and is selectively neutral in most cases. Hence, it is known to have two distinct properties: (i) the DNA sequence [...]
Point mutations involve minor changes in the genetic material, often single base-pair substitution. Sickle-cell anaemia is genetically determined disorder, caused by homozygosity, producing a single amino acid substitution in the b-chain of the normal haemoglobin molecule.
Character——Double stranded DNA———- Single Stranded DNA 1.U.V. absorption ——-Constant from 10-80°C— Steady increase from ———————–and then rises rapidly——-200 to 900º 2. Action of — Resistant formaldehyde—- not resistant 3. Ratio of——– equal. A=T and———- A:T:G:C is 133:0.98:0.75 4. Shape ———-linear ———————-circular
