Topic 7 DNA

Question 1

Transcription

Answer 1

Transcription factors- are proteins that bind to the DNA in the nucleus and affect the process of transcribing the genetic material.

transcription factors bind to the DNA’s promotor region, which is found upstream of the gene.
Enhancer sequence: When transcription binds here, it changes the structure of chromatin (the wound-up DNA), making it more or less available to RNA polymerase and, therefore, controlling gene expression.

Question 2

Epigenetics

Answer 2

genetic control by factors other than DNA sequence.

the environment can influence cell bio chemistry altering these epigenetic factors and therefore the development of specialised cells.

Question 3

DNA methylation

Answer 3

DNA methylation silences a gene or
sequence of genes

it works by the addition of a methyl group (-ch3) by a DNA methyltransferase enzyme at a cpG site.

prevent transcription from taking place.

very important in embryonic development. DNA demthylation is also important, when you remove the methyl group you activate the DNA again so it can be transcribed.

Question 4

Cell differentiation

Answer 4

As an organism grows the cells differentiate to become specialised cells.
the change in epigenetic factors can be in response to internal stimuli within the cell or external factors in the environment for the cell.