Structure of genome

Question 1

Genome definition

Answer 1

An organisms genome is the genetic information encoded in the DNA of a complete set of chromosomes, it is the entire hereditary information encoded in DNA

Question 2

Genome composition

Answer 2

A genome is made up of genes and other DNA sequence that do not code for proteins.
Most of the eukaryotic genome consists of non-coding sequences.

Question 3

Purpose of non-coding regions of DNA

Answer 3

The three functions are:
Protection,
Regulation of transcription,
Transcription of non translated RNA.

Question 4

Non coding regions of DNA function 1: protection

Answer 4

Telomeres are protective end caps to chromosomes which stop them unraveling.
These are made of repetitive DNA sequences.

Question 5

Non coding regions of DNA function 2: Regulation of transcription.

Answer 5

Transcription occurs when RNA polymerase binds to specific transcription factors. Sequence which act as transcription factors (activators) attach to non-coding regulator sequences of DNA.
Some sequences can also prevent transcription.
(Repressors)

Question 6

Non coding regions of DNA function 2: Transcription of non translated RNA

Answer 6

Some sequences of non-protein coding DNA code for other forms of RNA such tRNA & rRNA.
RNA fragments are another form of non-translated RNA. These are involved in splicing (small nuclear/snRNA) and help to silence genes (micro/miRNA).