EXAM 3- CH 6 TRANSLATION Flashcards
in the Nuremberg experiment what was discovered
genetic code
what was used in the Nuremberg experiment
- bacteria cytoplasm
- 20 tubes with 1 radioactive amino acid
- poly- U mRNA
results of the Nuremberg experiment
uuu codon = phe
term? explains the mechanism to read codons of 3 nucleotides to produce 20 aa from only 4 diff nucleotides
genetic code
how many bases are in a codon
3
how many codons are required to stop
3
how many codons are required to start
1
what direction is a code read
5’ —> 3’
true or false: codons are almost universal in all organisms, slightly different with unicellular eukaryotes and organelles
true
what kind of bond is formed between the aa and a tRNA
- high energy
- phophodiester bond
explain the wobble effect
3 nucleotide in codon shows flexibility in complementary protein
what shape does tRNA have
clover
anticodon region in tRNA function
interact with mRNA by complementary base pairing
at what end does the aa attach
3’
where is the site of ribosomal assembly in eukaryotes
nucleolus
where are free ribosomes found
cytoplasm
function of free ribosomes
synthesize cytosol proteins
where are bound ribosomes found
ER
function of bound ribosomes
secreted/mmb protein
when do the small and large subunits assemble
translation
what is required for the small and large subunits to assemble
mRNA
where is the carboxyl terminal located
by the a site in the ribosome
where is the amino terminal located
at the end of the aa chain
what is the order of the ribosome binding sites from left to right
e, p, a
true or false: the structure and function of ribosomes are different in pro and eukaryote
false
in what kind of cell has a 70s size ribosomes
prokaryotes
in what kind of cell is the ribosome more efficient in
Prokaryotes
what structure is visible as one mRNA with multiple ribosomes
polyribosome
what is the advantage of having polyribosome
- increases speed of translation
- more proteins are produced
what terminal are aa added to
C- terminal
how long does bacteria take to add 1 aa
1/20th of a second
what kind of ribosome is RNA based, has catalytic activity, and acts like an enzyme
ribozyme
what couples each aa to its appropriate tRNA
tRNA synthetases
what drives translation forward and improves its accuracy
elongation factors
what are the 4 translation phases
- tRNA charging
- initiation
- elongation
- termination
binding of aa to the appropriate tRNAs
tRNA charging
where is the ribosome binding site on the mRNA in pro
shine-delgarno sequence
what direction is protein synthesis
n-terminus to c-terminus
true or false: there is a conformation change of the ribosome in the elongation stage
true
what 3 things are required for protein maturation
- folding (and degradation)
- modifications
- localization
when a protein folds what regions are exposed
hydrophobic regions
term? assist in the folding, ATP hydrolysis required
chaperones
if a protein can not be folded properly where is it sent to
regulated degradation
what happens during protein modification
- attachment of sugar, lipids, phosphates
- cleavage
- combine w/ different polypeptides
what triggers the protein localization
- signal sequence
where does the signal sequence need to be for the protein to go to the ER and complete translation
- n- terminus
what was probably the 1st life on the planet
pre-RNA
example of a ribozyme
spliceosome
function of antibiotics
inhibit the growth of bacteria
what is needed to activate tRNA
- a.a
- tRNA
- a.a tRNA synthetase
- ATP
what are the 2 regulatory proteins
- Activators
- repressors
what do activators bind to
enhancers
where are activators located
- far away from core promoter
what do repressors bind to
operator
true or false: differentiation in cells is irreversible
true
what is the name for genes that are always on
- constitutive or housekeeping genes
where are housekeeping genes normally found
in metabolism
true or false: low protein levels specific in some cells while absent in others
false
the cloning experiment (Gurdon) proved what
genome reprogramming
what animal was used in the cloning experiment (Gurdon)
African clawed frog
procedure of the cloning experiment (Gurdon)
- transplanted nuclei from differentiated cells into unfertilized nuclei deprived eggs
- some developed into tadpoles
what was the first mammal cloned from a cell of an adult
sheep
term? nuclei that contain a complete set of genes, and can direct formation of a new organism
totipotent
what type of cell is faster at gene expression
prokaryotes
what type of cell is based on operons
eukaryotes
operons
promoter and sequence that is going to be translated
what are the 3 specific things that make up an operon
- several genes
- core promoter
- regulatory promoter
where transcription starts with consensus sequences to bind to sigma
core promoter
regulate transcription
regulatory promoter
bind to regulatory promoter DNA sites to respond to cues
regulatory proteins
speeds up transcription
activators
slows down transcription
repressor
true or false: both activators and repressors both require ligands to bind
true
activator binding enhancer turns on expression
positive regulation
repressor binding operator turns off expression
negative regulation
inhibitory ligand (positive regulation)
inactivates activator
inducible ligand (positive regulation)
stimulates activator
inhibitory ligand (negative regulation)
activates repressor
inducible ligand (negative regulation)
inactivates repressor
how many genes does trp have
5 genes
what are the 2 ways trp regulates
- negative regulation
- attenuation
what are the 2 ways lac regulates
positive and negative regulation
how many genes does lac have
3
produces beta-galactosidase to use lactose as C when glucose is not available
lacZ
lactose permease for transport inside cell
lacY
transacetylase
lacA
