Controlling strength of promoter in prokaryotes to regulate transcription

Strength of promoter is determined by how similar the -10 and -35 sequences are to the consensus sequences which are:

-10: 5' - TATAAT - 3'

-35: 5' - TTGACA - 3'

Stronger promoters have higher frequency of transcription.

In what way does the alpha helix (of some protein) and RNA differ?

 Helical structures in RNA is a result of it folding back on itself. The helical structures in the protein is a result of the regular coiling of the alpha helix;

 The helical structures in RNA are due to complementary base pairing between different segments of the same strand. The helical structures in protein are due to presence of hydrogen bonds within a single segment of polypeptide.

 The sections in RNA are made up of a double helix. The sections in protein are made of a single helix.

Explain the role of telomeres.

1) Ensure genes are not lost/eroded due to end replication problem, preventing loss of vital genetic information

2) Protect and stabilise the terminal ends of chromosomes - prevent chromosomes from fusing with other chromosomes and prevent DNA repair machinery from recognising 3' overhangs as DNA breaks, preventing apoptosis.

3) Allow their own extension - attachment point for telomerase (germ cells, embryonic stem cells, cancer cells)

How mutations result in differences in [protein]

1. Single base substitution → change in one codon → different amino acid incorporated in the polypeptide chain. Protein → different conformation that can no longer bind to [protein]
2. Deletion → frameshift mutation → viable [protein] not produced, could result in premature termination due to a new STOP codon /newly synthesized mutant protein quickly targeted for breakdown