What is a genome? How is the genome of prokaryotes different from eukaryotes?
A genome is the complete genetic information or complete DNA content present in the cell of an organism. It represents the total hereditary material encoded in the DNA.
The genome of prokaryotes differs from eukaryotes based on the location of the DNA. In prokaryotes, the genome includes the DNA present in the nucleoid region and the plasmid. In contrast, the eukaryotic genome includes the DNA present in the chromosomes of the nucleus as well as the DNA present in organelles like mitochondria and plastids.
Explanation
The answer is derived directly from the textbook definitions provided in the context. The first section defines a genome based on the statement that it is the 'complete genetic information present in the cell' and the 'complete DNA content'. The second section contrasts prokaryotes and eukaryotes using Fig. 5.1 and the accompanying text, specifically noting that prokaryotic DNA is found in the nucleoid and plasmids, whereas eukaryotic DNA is found in the nuclear chromosomes and organelles (mitochondria and plastids).
Solution Steps
Step 1: Define 'genome' using the context phrases 'complete genetic information' and 'complete DNA content'.
Step 2: Identify prokaryotic genome components from the text: DNA in the 'nucleoid' and 'plasmid'.
Step 3: Identify eukaryotic genome components from the text: DNA in 'chromosomes of the nucleus' and organelles ('mitochondria' and 'plastids').
Step 4: Synthesize these points into a comparative answer format suitable for a 3-mark question.