Gene Expression: From Gene to Protein (Translation, etc.) Flashcards
Polypeptides
Long chains of amino acids (polymers)
As many as how many different amino acids are commonly found in polypeptides
20
The specific amino acid in a polypeptide chain And the order in which they are joined determines the
Shape and functions of different proteins
Genetic code
The language of genes which is made of A C G T (for dna) these letters are read in sets of three
Is there only one genetic code
No there are multiple genetic codes for codons and anticodons etc.
In DNA one word is called a
Triplet
In mRNA one word is called a
Codon
In tRNA one word is called an
Anti codon
All three types of words (Triplets codons and anticodons)
Complement each other
For every DNA triplet mRNA codon and tRNA anticodon you have one amino acid because of
Translation
How many possible three base codons are there
64 (4x4x4)
Wobble effect
Hypothesis at the third base is not very important because the third base in the anticodon faces the wrong way and therefore ppl think that only the first 2 anticodons rly matter bc the orientation is wrong on the other one
Synonyms
Amino acids that can be the outcome of more than one codon
What do you use to decode codons
Genetic code table
How many stop codons are there
3
What is the start codon
AUG methionine
Do ribosomes always look like ribosomes
No the large and small subunits do not join and appear as ribosomes until they are translating
How do ribosomes translate
They use the sequence of codons in the mRNA to assemble amino acids into polypeptide chains
Translation
The decoding of MRNA message into a protein
What is translation also known as
Protein synthesis
Where does protein synthesis take place
Occurs in ribosomes after the transcribe mRNA enters the cells cytoplasm
When does translation begin
Begins on a ribosome connect to a MRNA molecule in the cytoplasm
What happens after the mRNA connects to the Small subunit of the ribosome in the cytoplasm
The large subunit connects to the small subunit with mRNA
what happens in translation after the ribosome is asembled
Methionine the start codon bonds to the P site
what happens in translation after methionine starts the making of the polypetide chain
Another tRNA that carries an anti-codon which matches with the next codon of the mRNA bonds to the P site and the previous trna moves to the left into the a site
what happens in translation after methionine starts the making of the polypetide chain and there is smth else in the a site now bc it moved
At the same time as the fourth step of translation the bond between tRNA and it’s amino acid is broken in the ribosome helps form a peptide bond between the first and second amino acids
What is the sixth step of translation
The first tRNA moves into the e site and exits the ribosome
What happens in the seventh step of translation
The cycle continues until a stop codon moves into the a site
What is the last step of translation
The ribosome releases a polypeptide chain,mRNA, and tRNA and breaks into two subunits again
Gene expression
The way in which DNA, RNA and proteins are involved in putting genetic information into action in living cells
E Site
Exit site on ribosome far left
A site
Attachment site far right
P site
 The one in the middle where are the amino acids join on top of each other to form the polypeptide chain
How many sides are there on a ribosome
3
where are bound ribosomes
on the rough er
polyribosomes
string of ribosomes that read one piece of mRNA
describe the movement of polyribosomes
they all move at the same rate and this is done so that alot of proteins can be made from one mRNA
ribosome made of
small and large subunits that are made of proteins and rRNA
frameshift mutation
the insertion or deletion of nucleotide bases in numbers that are not multiples of three
main types of frameshift mutations
insertions and deletions
spotaneous mutation
a type of frameshift mutation with no known cause
mutagen
a number of physical and chemical agents interact with DNA in ways that cause mutations (type of frameshift mutations)
gene
A gene is a region of DNA that can be expressed to produce a final functional product that is either a polypeptide or an RNA molecule (frameshift mutation)
which type of base pair substitutions is the most rare
improved protein
imporved protein
proteins that become better adaptive
detrimental protein
Negative effect, ability to repoduce/surive is lower
missense mutation
nucleotide pair substitution that results in a codon that codes for a different amino acid
nonsense mutation
causes translation to be terminated prematurely, the resulting polypeptide will be shorter and lead to nonfunctional proteins
what are frameshift mutations
when one change causes all the changes after that
