Gene Expression
What are the three parts of Cell Theory?
All cells come from existing cells
Cells are the basic units of structure and function
All living things are composed of cells
What is the location of transcription in prokaryotic cells?
Where does transcription take place in eukaryotic cells?
in the nucleus
What is the job of the promoter?
tells the RNA polymerase where to bind
What is a gene?
A segment of DNA that codes for a specific protein.
Why do prokaryotic cells not transcribe all of their genes at the same time?
They can conserve energy and resources by regulating their activities and only producing the genes necessary for the cell to function.
What happens during RNA processing?
introns are spliced out, exons are joined together, a methyl cap is added to the 5' end and a poly-A tail is added to the 3' end
What is the job of the operator?
Turn on or off the gene
What is the flow of information according to the central dogma?
DNA --> RNA --> Proteins
What are the three parts of an operon?
Promoter, operator, structural genes
What is alternative splicing?
Different combinations of exons are joined together to create different proteins
Why is a cap added to the mRNA after transcription?
the cap helps the mRNA bind to a ribosome and prevents the strand from being broken down too fast
Why is gene expression regulated?
to ensure the correct proteins are made in the cells in which they are needed
What sugar is needed for gene expression in prokaryotic bacterial cells?
Lactose
What is a transcription factor?
an enzyme that is needed to begin and/or continue genetic transcription and may bind to a promoter, enhance, or other sections of DNA
Why is a tail added to an mRNA molecule after transcription?
helps the mRNA molecule exit the nucleus
If all cells share the same DNA how are they all different?
Different genes are turned on and off (cell differentiation)
When there is enough tryptophan available the trp binds to the trp repressor which undergoes a conformational change and binds to the complementary operator. This blocks RNA polymerase from transcribing the structural genes and regulates the production of trp.
What is the TATA box?
7 nucleotide promoter in eukaryotic cells that indicates where a genetic sequence can be read and decoded
What are introns and exons?
Introns - segment of DNA that does not code for an amino acid
Exons - sequence of DNA that codes information for protein synthesis