Point 21 of 28 — Lesson 2: DNA Structure, Replication and DNA Repair EnzymesQuestion bank: 3 questions (0 with pictures)
22Repetitive DNA
Most genes occur in one or a few copies. But a eukaryotic cell holds many (often hundreds) of copiesof the genes forrRNA and histones, since the cell needs these in large amounts. Many copies speed up the production of new ribosomes and histones.
Eukaryotic genomes also contain a great deal of other non-coding DNA (including satellite DNA). The amount of DNA in a species bears little relation to the complexity of the organism or the number of proteins it makes. Example: the largest known genome belongs to a salamander, with about30 times the DNA of a human cell, though it makes fewer proteins.
Some non-coding DNA may maintain the structure of chromosomes; some regions mark where RNA synthesis should start. These are promoters, at the beginning of each gene, and are important in protein synthesis.
📝 Question bank for this point
3 questions linked to this point only, 0 of them with pictures.
