DNA, RNA - Gene Transcription Flashcards
Describe flow of information
DNA -> m-RNA -> proteins
DNA to m-RNA by transcription
m-RNA to proteins by translation
What are housekeeping genes?
Genes that encode proteins which are common to all cells
Describe the process of gene expression?
The expression of genes can be altered by diet/exercise/hormones
Genes express proteins and hence processes within the cell can change
What does a nucleotide consist of?
A base, a sugar and one or more phosphate molecules
Describe the 4 bases in DNA?
Adenine is paired with thymine
Cytosine is paired with guanine
A + G are purines
C + T are pyrimidines
How does RNA differ from DNA?
Is single stranded as opposed to duplex
Instead of thymine, there is U which is identical and pairs to A
What is the half life of m-RNA?
20 mins to several hours
What specifies the start and end of a gene?
A series of base pairs signifies the start and end of a gene
What is a gene promoter?
A stretch of DNA that acts as a initiator for a starting off a particular region of DNA to be sequenced.
What are the important regions of gene promoters and how many are necessary?
Important regions are TATA box, CAAT box and GC box
All genes require at least one element
What are enhancer regions and what do they do?
They contain the same elements as promoter regions but are further down on the DNA sequence typically
They help increase the amount of m-RNA produced (requires a stimulus)
What are transcription factors?
Proteins that interact with the DNA promoters and enhancers by either directly binding or not (co-activators)
Where are transcription factors located?
They can sit in the cell inactive where activation comes from different stimuli (signals)
How are genes ‘turned off’?
They must be turned off when transcription is no longer needed, the signal is removed and the transcription factor is altered (de-phosphorylated)
Also induction of hormones will result in inactivation of transcription factor meaning m-RNA no longer produced
What happens to the lengths of DNA with no apparent function?
They are first transcribed into RNA and then the m-RNA is spliced to remove the redundant sections (introns) then the exons come together
