D2.2 Gene Expression Flashcards
(43 cards)
How does gene expression relate to phenotypes
it is the mechanism through which info in genes has effects on the phenotype
What are transcription factors
they are proteins that bind to specific sequences of DNA to control transcription
Each has a DNA binding site that allows it to bind to enhancer or promoter sequences
What are enhancer sequences
regulatory sequences that enhance the transcription of an associated gene when bound by transcription factors
Where are regulatory sequences found
usually upstream of the gene being transcribed but can sometimes be downstream
what is the most common form of gene control
regulation of transcription
How is the control of the degradation of mRNA a means of regulation translation
for mRNA to be broken down, the 3’ poly A tail must be degraded before the mRNA is broken down.
Ensures proteins are only synthesized when needed and mRNA is removed afterwards
what is epigenesis
the development of an organism by differentiation from an undifferentiated zygote
Essentially, the development of patterns of differentiation in the cells of a multicellular organism
What is epigenetics
the study of heritable changes in gene activity that are not caused by changes in DNA base sequences
what are the mechanisms through which gene activity is changed
DNA methylation and histone modifications
what is altered in epigenetic changes
the phenotype
what is the proteome
refers to all the proteins expressed within a cell, tissue or organism at a certain time
What is the genome
the whole of the genetic info of an organism
It is unique
how does the uniqueness of the genome affect the proteome
because its unique, the proteome it expresses is also unique
how can genome stay the same and proteome change
genome is the same in all cells of the same organism but diff tissues have different proteins
This means proteomes vary with the function, location or environmental conditions of the cell
what is the transcriptome
the range of mRNA transcripts produced in a specific cell/tissue at a particular time
how are genome, transcriptome and proteome related
transcriptome will determine which proteins are synthesized within a cell, which means it is dependent on which parts of the genome are activated
what is methylation
the addition of a methyl group within the chromatin , to the DNA molecule itself at the promoter
what are epigenetic tags and where are they found
the methyl group which is attached to the cytosine
occurs while DNA is wrapped around the histone proteins
what does methylation do
methylation of amino acids in histones either enables or disables the recruitment of regulatory proteins to the chromatin, causing transcription to be repressed or activated
what can be the reason for methylation
external conditions which lead to the switching off of certain genes
what happens once methylation has occurred
it can remain like that from cell division to cell division
what is epigenetic inheritance
the acquisition of characteristics gained by a parent in their lifetime and passed onto their offspring.
this happens through modification of chromatin via epigenetic tags
what is the result of epigenetic inheritance
phenotypic changes in a cell or organism can be passed on to daughter cells or offspring without changes
what can modify DNA and histone methylation patterns
air pollution , chemicals
can lead to CV diseases, asthma
