Download Translation (Protein Synthesis)

Translation
(Protein Synthesis)
Using the Cell’s Machinery
to Make a protein
The Central Dogma
Characteristics of Proteins
• Proteins are made by joining _______
_____ into long ___________ chains.
– Polypeptides contain a combination of ____
different amino acids.
– __________ of proteins: determined by
______ of amino acids.
• What determines the order of amino acids
in a protein?
Genetic Code
• The ________ of _____.
– Uses the __ different bases (__, __, __, & __).
– How can a code of four bases be used to make
20 different amino acids?
• Genetic code read ______ letters at a time.
– Each _______-letter combination in mRNA
create a ______.
•
3 consecutive nucleotides that specify an amino
acid.
• ___________ = _______:: _______ = ______
Examples
UCGCGACCU
This would be broken down to
____ ____ ____
This means it makes
_______ ________ _______
Genetic Code
• How many possible
codons are there?
– (____ Bases)3 = ___
• __ x __ x __ = ___
• Amino acids can be
specified by ____ _____
____ codon.
– Only ___ codon =
“____”
• ___ = Methionine
– Three codons = “_____”
* Found on page 303 in your text book
• ___ ____ code for aa.
• Signal ___ of
polypeptide.
Translation
• The decoding of an ____ into a
___________ chain (also known as a
_________)
• This takes place on which organelle??
– ________ (Protein factory)
How Does Translation Occur in Your Cells?
• Transcription of ___ to ____ in the _______.
– mRNA transported ____ of the _______ to the
_________.
• Translation ______ when an _____ molecule
reaches a ________.
– _______ of mRNA move through, “coding” for
_______ AAs to be attached to the ___________.
– Ribosome ______ _____ know which amino acid
to ______ each codon.
• Who matches correct AA to correct codon?
How Does Translation Occur in Your Cells?
!
• Job of ________ RNA
(__RNA).
– Has ______ _____ attached to
one end.
– Region of _____ _________
_____ to the other.
• Called __________.
• _____________ to one of the
mRNA _______.
How Does Translation Occur in Your Cells?
!
• Ribosome forms _______
bond between ___ & ___ AA.
• Also, breaks ____ that held
____ to its ______ ____.
– Releases tRNA.
• Polypeptide chain grows
until ribosome reaches
_____ codon.
– __________ & _____
released.
Translation has 3 steps
• __________
• __________
• __________
Terminology
• _____: single stranded RNA takes message from
nucleus to cytoplasm
• ______: 3 letter base code that codes for an
amino acid
• _____: transfers amino acid to the ribosome to
make the protein
• __________: 3 letter code on the tRNA that
allows it to match up with the corresponding
mRNA codon
• ______ _____: monomer of a protein
• ____________: chain of amino acids that makes
up a protein
How Does Translation Occur in Your Cells?
• Use vocab to label and
describe what is
happening mRNA
Codon
tRNA
Anticodon
Amino acid
Polypeptide (Protein)
Be tRNA and Put Together a Polypeptide!
• Use your mRNA sequence and determine the
amino acid sequence:
!
CAG ACC AUG AUC CGC CAU CGU GUA UAC UAA AUC
UUG
!
* Remember to start translating at the first start
codon and stop at the stop codon!
Put these steps in order
____mRNA attaches to the ribosome
____Amino acids are connected together to form a
polypeptide or protein
____ tRNA molecules line up by matching their
anticodons to the mRNA codon sequence
____ tRNA pick up amino acids and bring them to the
ribosome
____ mRNA detaches from ribosomes, proteins are
modified and folded for use
!
The above process is called ___________________
What Happens When There are Mistakes
in Translation?
• Cells make mistakes!!!
– Anything from copying DNA to inserting an
incorrect base to skipping a base
• Mistakes are called _________.
– Changes in the ____ sequence that affect
________ information.
– Come in many shapes and sizes.
• Can be ____ or ____________.
• Not necessarily _____ or ____…just different!
Changes in DNA = Mutations
• _____ mutations
affect only
___nucleotide.
– _______: Results in a
______ that codes for
the _____ amino acid.
• Does not cause a _____
in the amino acid
_________.
• No ___________
_______ in protein.
• Evolutionarily ________.
➢ Nucleotide cytosine is replaced by
uracil, resulting in no change.
Changes in DNA = Mutations
• Point mutations
affect only ONE
nucleotide.
– __________: Results
in a ______ that
codes for a
__________ amino
acid.
• May lead to a
______________
protein.
➢ Nucleotide adenine is replaced by
cytosine, introducing an incorrect
amino acid.
Changes in DNA = Mutations
• Point mutations
affect only ONE
nucleotide.
– _________: Results
in a ______ that
_____ ____ code for
an amino acid.
• Leads to protein
product that is
____________ early.
➢ Nucleotide cytosine is replaced by
thymine, introducing a STOP codon.
Changes in DNA = Mutations
• _________ mutations
disrupt the “_______
______” of the genetic
message.
– Affects _____ amino
acid that _______ the
point of the mutation.
• Usually involves the
_________ or ________
of a nucleotide in which
the number of deleted
base pairs is not divisible
by ______.
Point vs Frameshift Mutation
THE FAT CAT ATE THE RAT (normal)
!
THE FAT HAT ATE THE RAT
What happened?
!
!
TEF ATC ATA TET HER AT
What happened?
Effects of Mutations
________ Mutation: occur in ___ of the cells of the body except the germ cells
(_____ and ___). These are ___ ______ on to children.
!
________ Mutation: gene change in the body's _____________ cells (egg or
sperm) that becomes incorporated in the ___ of ______ cell in the body. These
___ __ ______ on to further ____________.
Effects of Mutations
Somatic Mutation: occur in any of the cells of the body except the germ cells
(sperm and egg). These are not passed on to children.
!
Germline Mutation: gene change in the body's reproductive cells (egg or
sperm) that becomes incorporated in the DNA of every cell in the body. These
can be passed on to further generations.
_____ Mutations in DNA of skin cells of sunbathing senior citizen
!
_____ Mutation in DNA of brain cells in developing embryo
!
_____ Mutations in DNA of sperm cells of X-ray recipient
!
_____ Mutations in RNA made during transcription of lactase gene