gene expression

Question 1

what is a transcription factor?

Answer 1

transcription factors are proteins that control the transcription of genes

Question 2

what are promoters?

Answer 2

specific DNA sites that transcription factors bind to which are found near the start of their target cell

Question 3

what are activators?

Answer 3

they are transcription factors that increase the rate of transcription (they help RNA polymerase bind to the start of the target gene)

Question 4

what are repressors?

Answer 4

they are transcription factors that inhibit transcription by binding to the start of the gene, preventing RNA polymerase from binding to the start of the target gene

Question 5

benign tumour traits

Answer 5

grow large and slow
cell nucleus has a relatively normal appearance
produce adhesive molecules which stick together
tumour surrounded by capsule of dense fibrous tissue
localised effects on the body
removed via surgery
rarely occur after treatment

Question 6

what does an increase in methylation of DNA mean?

Answer 6

a methyl group joins to CpG site

increase methylation means transcriptional machinery can’t interact with the genes

Question 7

what does a decrease in acetylation of histones mean?

Answer 7

when histones are acetylated, it means the chromatin is less condensed
this means the transcriptional machinery can access DNA more easily allowing more genes to be transcribed

Question 8

what does a primer do?

Answer 8

locate a DNA sequence on either side of the target gene