Test 4 Flashcards
(30 cards)
What is the Ribosome made up of?
The ribosome is made of protein and RNA, and has the LSU (large subunit) and the SSU (small subunit)
Define Polypeptide
a multi protein chain
Name the three (relevant) types of RNA and their roles
tRNA - transfer RNA, nucleotide code -> AA code
rRNA - Ribosomal RNA
mRNA - Messenger RNA
What is aminoacyl tRNA synthetase?
Takes uncharged tRNA (tRNA without an amino acid) and uses ATP to bind with it
What is “wobble” base pairing?
where the last codon is “less important” and can change without changing the amino acid it codes for
What are the four sites on a ribosome?
“E” site (exit)
“P” site (peptidyl tRNA binding site)
“A” Site (Acceptor/aminoacytl tRNA binding site)
Outline the process of translation
1-SSU binds to mRNA
2- AUG initiator tRNA binds and initiates ribosome assembly
3- GTP -> GDP
4- Ribosome assembles
Where does Translation (most often) occur?
in the cytoplasm
Describe termination
Stop codon binds with a release factor, which cuts the polypeptide off and releases the tRNA before using energy to break the ribosome into recyclable parts
Define Gene expression
when a gene is being transcribed and is yielding a result
Define regulation
The change in what and how much of something cells make as a response to signals
Define transcription factor
A factor that either initiates or inhibits transcription
what is a factor?
something that influences or contributes to an outcome
What tells cells what to do?
Signals such as growth factors, energy/food, and density dependent inhibition
what do transcription factors do?
when active, they bind to the control elements on a DNA strand
What is the difference between a positive and negative transcription factor?
Positive: Activates the protein/enzyme when bound
negative: Deactivates the protein/enzyme when bound
What is an Operon?
Sets of co-transcribes genes that usually have similar purposes
Define allosteric regulation
the changing of a proteins shape or activity at one site though the binding of another site on the protein
What is the relationship between glucose levels and cAMP levels?
Inverse. when glucose is high, cAMP is low, and vice versa
How is gene expression in eukaryotes altered?
by changing the density of the chromatin
What is euchromatin?
acetylated, or far apart, chromatin that is available for coding
what is Heterochromatin?
unacetylated, or closely wound chromatin that is unavailable for coding
What are the two kinds of promoters and what are their jobs
Enhancers- distal control elements
proximal - nearby control elements
What is splicing?
splicing is the process of cutting the non-coding intron sequences out of the pre-mRNA, leaving only the exons in the mature mRNA
