Ch. 15 Translation Flashcards
Translation
RNA –> proteins
amino acids
building blocks for proteins
what are the components that every amino acid has in common?
- amino group
- carboxyl group
- hydrogen
- R group
- carbon (center)
what are the different types of R groups?
- nonpolar
- polar
- aromatic (ring structure)
- positively charged
- negatively charged
how many different amino acids are there?
20
what type of bonds join amino acids?
peptide bonds
define “polypeptide”
a string of amino acids (a protein)
will mutation be greater when swapping one type of R group for a DIFFERENT type of R group? or will it be greater when swapping same R group for same type of R group?
swapping different TYPES of R groups will cause greater mutations in secondary protein structure
- swapping same TYPE of R group will not cause as great of a mutation
(ex. swapping polar for non-polar)
where do peptide bonds form between amino acids?
dehydration reactions from N terminus –> C terminus
primary structure of amino acids
polypeptide chain
secondary structure of amino acids
areas of folding or coiling within a protein; examples include alpha helices and pleated sheets, which are stabilized by hydrogen bonding
tertiary structure of amino acids
the final three-dimensional structure of a protein, which results from a large number of non-covalent interactions between amino acids.
quaternary structure of amino acids
several different polypeptide strands together, all folding together into complex structure, gain of function
genetic code consists of _____.
triplets of bases
(one triplet = one amino acid)
each triplet is a CODON
define “degeneracy” of amino acid codes
more than one triplet encodes for the same aa
synonymous codons
codons that specify for the same amino acid
where are codons found?
mRNA
where are anticodons found?
tRNA
- complementary to codons
- responsible for “reading” the mRNA
what is the wobble position?
the third base pair of a triplet is usually not detrimental because it will still code for the same protein as long as the first 2 base pairs are the same
-allows for degeneration of the code
the genetic code is ______.
non overlapping
each triplet of 3 is read separately
for any stretch of DNA, there are ____ possible reading frames.
3
this depends on where you begin to read the DNA
how do we know which reading frame to start reading on?
start codons!
what is the start codon?
AUG
what are the stop codons? (or non-sense codons)
UAA
UAG
UGA
stop codons have NO AMINO ACIDS and no tRNAs associated with them
what is an “open reading frame”? (ORF)
goes from the start codon to the stop codon
which 3 types of RNA are involved with translation?
mRNA
tRNA
ribosomes (rRNA and proteins)
what is the structure of tRNA?
- cloverleaf secondary structure
- presence of rare bases
- amino acid attachment site (CCA)
- anticodon arm (pairs with corresponding mRNA sequence, reads the mRNA by complementary base pairing)
what is tRNA charging?
the process of attaching an amino acid to the appropriate tRNA
- so that tRNA can “read” mRNA in a complementary and antiparallel fashion
- requires ATP*
what enzyme carries out tRNA charging?
aminoacyl-tRNA synthetases
mature ribosomes are made of many proteins associated with ____.
4 RNA subunits
ribosomes are _______.
translators
_____% of the total cellular RNA is ribosomes
80%
ribosomes consist of a ___ subunit and a ____ subunit
small
large
ribosomes have ___ distinct sites
3
what are the 3 main sites on a ribosome?
- E exit site (tRNA dissociates)
- P peptidyl site (peptide bonds forms)
- A aminoacyl site (charged tRNA attaches)
what is a release factor?
comes in to stop elongation once a stop codon is reached
separate strands
multiple ribosomes translate the same mRNA in a structure called a ____.
polyribosome
how can we tell that translation is occurring in a bacteria or an animal?
translation happens in cytoplasm in animals
transcription and translation happen together in bacteria (also no RNA processing)
