class lecture mod 4 Flashcards
DNA and RNA are both
-are both polymers of nucleotides
-directional polymer of nucleotides from 5’ to 3’
the sugars in DNA and RNA
DNA: deoxyribose
RNA: ribose
Bases in DNA
A, G, C, T
Bases in RNA
A, G, C, U
base parings in DNA vs RNA
DNA: A-T and G-C
RNA: A-U and G-C
structure of DNA vs RNA
DNA: double stranded, in double helix
RNA: single stranded
Stability in DNA vs RNA
DNA: stable, for long term information holding
RNA: unstable, use for information transfer since it is short lived
base pairs form between
-anti-parallel strands w/in the DNA double helix
during transcription, RNA binds in
an ani-parallel manner like the DNA template strand
each gene has a ____ that ____
-promoter
-indicates where the RNA polymerase will attach to the DNA to start transcription
binding of the RNA polymerase depends on
-transcription factors
-they are DNA binding proteins that affect the rates of transcription
some transcription factors bind to the
-promoter and direct the RNA polymerase to bind to the promoter to indicate transcription
some transcription factors bind to regulatory regions of the DNA…
-specifies when and where genes are to be transcribed
promoter
where the RNA polymerase binds and directs the start of transcription
enhancer
-a sequence of DNA that enhances the action of a promoter by increasing the probability of transcription occurring
-enhancers can be far from the gene
changes to the DNA sequence of the promoter or enhancer regions of a gene can…
can change the transcriptional activity of the gene
why is genetic variations among individuals?
-single nucleotide polymorphisms (SNPs), which are genetic differences at a single bases
what is epigenetic mechanisms and give examples
-they are processes that regulate how genes are expressed
ex) histone modifications and DNA methylation
DNA methylation
when cytosine residue in a DNA sequence is modified to have a methyl group added (H3C)
-happens at the C and G sequences in the DNA in both strands
transcription factors can bind to both
the promoter and the regulatory sequences (controlling gene expressions) outside the gene
relaxed chromatin allows for the RNA polymerase to
bind to the core promoter and transcription can begin
5’ cap protects the
growing mRNA from degradation and assists in ribosome binding during translation
3’ poly-A tail protects the
mRNA from degradation and aids in the export of the mature mRNA to the cytoplasm
splicing
-small nuclear ribonucleoproteins combine with the pre-RNA to from a spliceosome where the intron is excised
-the spliceosome knows where to cut the intron based n the info in the intron
