LIFE SCIENCE

Detailed explanation-1: -Thus, bacterial genomes are only about 0.1% as big as the human genome, and have about 10% as many genes as we do. A comparison of those two percentages shows immediately that in bacteria the “gene density” (how many genes there are per unit length along the genome) is much higher than in humans.

Detailed explanation-2: -The human genome is comprised of 23 pairs of linear chromosomes, and approximately 3000 megabases (Mb) of DNA, while the genome of the bacterium Escherichia coli consists of a single 4.6 Mb circular chromosome.

Detailed explanation-3: -Like other organisms, bacteria use double-stranded DNA as their genetic material. However, bacteria organise their DNA differently to more complex organisms. Bacteria have a single circular chromosome that is located in the cytoplasm in a structure called the nucleoid.

Detailed explanation-4: -Bacterial DNA contains uracil instead of thymine. The four bases contained in all organisms’ DNA are adenine, thymine, cytosine, and guanine. Uracil is a base that replaces thymine in RNA. Uracil is not present in the DNA of bacteria.

Detailed explanation-5: -As eukaryotes, mammalian cells have DNA housed in a nucleus and transcription occurs there. Translation occurs in the cytoplasm, separating it spatially and temporally from transcription. Bacterial cells have a single type of RNA polymerase that catalyzes transcription of all forms of RNA.