How do genes make cells? Flashcards
What is transcriptional control?
Transcription control determines when and in what cells a gene is transcribed to produce mRNA. It is therefore the first step in determining how many individual proteins are produced in a cell
How are cells different?
Every cell has the same DNA and same ~21,000 protein coding genes, about 11,000-17,000 genes are expressed (making mRNA)
- 10,000 expressed in all cells, 1,000-2,000 unique to specific cell type (make heart cells different to brain cells)
- Rest are expressed in some but not all cell types
What is transcription?
Controlling transcript to determine which cell type will be made is key in DNA. A gene can be turned on/expressed when it is transcribed. If a gene is transcribed it is used to make a protein (expressed) or if it is not transcribed it will not make a protein in that cell
What are transcription factors?
Transcription factors are protein that bind to a specific DNA sequence and control the rate of transcription (DNA to RNA). Amino acids within protein are able to specifically interact so that the protein will only bind to a specific sequence (decode information in our DNA that determines life)
What is the promoter?
The DNA sequence at which transcription factors bind and recruit RNA polymerase. Determines if and how much a gene is transcribed. Contains short sequences that transcription factors bind to
What is the transcribed region?
Sequences of DNA that are copied into RNA (transcribed). The transcribed RNA (pre-mRNA) is processed so that it can be translated (intron sequences removed)
How do transcription factors control transcription?
The gene is only expressed when both activator transcription factors are present and repressor is absent to stabilise RNA polymerase, if you only have one there will be little/no transcription. Transcription factors bind and recruit RNA polymerase - factors control and determine how quickly RNA polymerase found, how much is being made, where its being made and how quickly it is being made
