Practice Questions

Having fewer hydrogen bonds makes A-T rich regions easier to unzip, which is why replication origins and promoters are rich in A-T pairs.

B-DNA is the standard, stable conformation adopted by native DNA molecules inside the aqueous environment of living cells.

A cistron is a genetic unit defined by the cis-trans position test, matching the DNA sequence needed to build one polypeptide.

The wider, deeper gap on the outside of the helix is the major groove, which provides easy access for sequence-specific DNA-binding proteins.

DNA methyltransferases add a methyl group to the carbon-5 position of cytosine rings, a key modification for silencing gene expression.

Without a functional promoter sequence, RNA polymerase cannot locate or bind the gene, shutting down transcription entirely.

Enclosing the genetic bases within the hydrophobic core protects the fragile hereditary codes from reactive molecules in the cytoplasm.

By showing that viral DNA (32P) enters the host cell while viral protein (35S) stays outside, they proved DNA is the hereditary material.

The template strand runs anti-parallel and complementary to the coding strand, making the matching sequence 3'-TACGTT-5'.

The spliceosome is a large ribonucleoprotein complex that removes introns and splices exons together to form mature mRNA.