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Cellular and Molecular Biology

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Genomes and the Complexity of Organisms

CELLS-EOXDX2

Genomes are the sum total of DNA in an organism and represent very complex molecular templates that serve as design plans for organisms. DNA is transcribed into RNA and RNA into protein.

However, not all DNA is specifically translated into protein. Most genes include exons and introns; following transcription into RNA the intron sequences are usually removed. In addition, large blocks of DNA, known as non-coding DNA, exist between specific genes.

It is surprising that widely diverse organisms have a similar number of protein-coding genes. Genes, their composition and their evolution have an interesting relationship to the organism's complexity.

Which ONE of the following statements is FALSE?

A

The total number of protein encoding genes in a species correlates with organism complexity.

B

Humans and the worm, C. elegans, have roughly the same number of protein encoding genes.

C

Organism complexity is correlated with the proportion of non-coding DNA.

D

Many pseudogenes have lost their introns.

E

Introns are transcribed into RNA only to be lost later via RNA splicing.