The genome size, and the number of genes it encodes varies widely between organisms. The smallest genomes occur in viruses (which can have as few as 2 protein-coding genes), and viroids (which act as a single non-coding RNA gene). Conversely, plants can have extremely large genomes, with rice containing >46,000 protein-coding genes. The total number of protein-coding genes (the Earth's proteome) is estimated to be 5 million sequences. COUNT 5
QSN1 What is one characteristic that varies widely between organisms? ANS1 genome size QSN2 In which type of organism do the smallest genomes occur? ANS2 viruses QSN3 What is the smallest number of protein coding genes that a virus can have? ANS3 2 QSN4 Which organism acts as a single non coding RNA gene? ANS4 viroids QSN5 What is the estimate for the total number of protein coding genes on Earth? ANS5 5 million