Key area 5:structure of the genome and mutation

Question 1

Define genome

Answer 1

Is the total genetic information encoded into the base sequence of its DNA.

Question 2

Define gene

Answer 2

A section of DNA which controls part of a cells chemistry

Question 3

Describe the structure of the genome

Answer 3

Contains protein coding and non protein coding regions.

Question 4

Explain the differences between coding and non coding sequences of DNA

Answer 4

Coding sequences make up less than two percent of the genome. The rest is non coding sequences. Many non coding sequences have no known function others are involved in regulating transcription or proteins

Question 5

Describe the function of non coding sequences

Answer 5

Most remains unknown but two possible functions are regulation of transcription and non translated forms of RNA

Question 6

Regulation of transcription

Answer 6

RNA polymerase can’t initiate transcription on its own, need transcription factors. Some are activators and some are depressors.activators are bound to sequences of DNA called regulator sequences and often these can be at some distance from the coding sequence. The Dana must Bend to bring the regulator and the activator bound to it in contact with other transcription close to the promoter

Question 7

Non translated forms of RNA

Answer 7

These types of RNA are transcribed but not translated into proteins : tRNA, rRNA and RNA fragments such as small nuclear RNA (snRNA) which helps with RNA splicing and micro RNA (miRNA) which helps to silence genes