Gene Expression Flashcards
What is a genome?
Complete genetic information of an organism
Includes coding and non coding dna
What does haploid mean?
One copy of something
What is a gene?
Sequence of nucleotides on a chromosome that codes for one or more biological product
What do protein vs non-protein coding genes code for?
Polypeptides, tRNA and rRNA
What is gene expression?
Synthesizing product encoded by the gene
When a product is synthesized the gene is?
Expressed
What is a nucleosome?
Histone octamer that dna wraps around
What is a histone octamer?
Two molecules of histones (H2A, H2B, H3, H4)
What does Linker DNA do?
Connect adjacent nucleosomes
What does the binding of histone H1 cause?
nucleosomes to package into a coiled structure called a solenoid
What is a solenoid also called?
30 nm chromatin fibre
What happens after solenoid is made?
fold and packs tighter to form chromosomes during division
What is the information flow pathway?
DNA turns into RNA, RNA is turned into protein, and this protein is expressed through the phentype
What is genotype vs phenotype?
genotype is our genes and phenotype is what you can see
(genotype is heterozygous brown/blue eyes, phenotype is brown eyes)
At what stage in the information pathway is gene expression regulated?
every stage
What does transcriptional control? Example?
controls which genes are translated, chromatin remodelling and transcription initiation
What does posttranscriptional control? Example?
controls the availability of mRNAs to ribosomes, pre-mRNA processing and miRNA
What does translational control? Example?
controls rate of protein synthesis, regulating translation initiation
What does posttranslational control?
controls availability of newly synthesized proteins, removing masking segments, glycosylation, phosphorylation, controlling protein breakdown, folding
What is transcription?
when the information of a gene is turned into a complementary mRNA strand
In transcription what direction is DNA read and what direction is mRNA created?
DNA is read in the 3’-5’ direction and mRNA is created in the 5’-3’ direction
Is DNA turned directly into mRNA?
No its first turned into premRNA which is then modified and turned into mature mRNA
What are the 3 phases of transcription?
initiation, elongation, termination
What are some regions that are upstream of the gene that are important? Why are they important?
Enhancer: activators also bind here, activators need to interact with each other
Promoter Proximal Element: contains regulatory sequences, site where protein binds, activators bind here
Promoter site: contains TATA box
What is chromatin remodelling?
DNa associated with histones are loosened in order to expose the promoter sequence
What needs to happen before transcription can occur in terms of tightness of dna?
needs to be loosened in order to make genes, promoter, enhancer, and promoter proximal site availble
What happens after activators bind to the DNA?
Recruit chromatin remodelling complexes which include molecules called histone acetyltransferase, other activators will bind to other regions which recruits general transcription afctors and rna polymerase
What do histone acetyltransferases do?
add acetyl groups to histones which removes the positive charge of the histones, this makes the attraction of the DNA to the histone less
If you find an activator on a gene it is probably in which format?
euchromatin