Protein Synthesis Review
Amino
11.
Acids
2. DNA
3.mRNA
tRNA
10.
Ribosome
9.
Codon
1
5.
1. DNA
4.mRNA
Codon
2
6.
Codon
3 Codon
4
7.
8.
DNA Review
1.
2.
3.
4.
What does DNA stand for? Deoxyribonucleic Acid
Where is it found? Nucleus
What is its function? Genetic code for protein synthesis
What is the sequence of DNA structures from
Interphase to Prophase DNA is referred to as?
• _________(uncoiled)_________(condensed)
Chromatin
Chromatid
Chromosome (X-shaped)
 ___________
THE CENTRAL DOGMA
DNA
transcription
RNA
translation
proteins
**Remember that the Central Dogma of Molecular Genetics
explains the __________
molecules and _________
processes which occur during
the production of proteins within a cell.**
How do changes in DNA
affect the protein?
• Changes in the DNA sequence are
called mutations
_________; because the
information is changed, a different
mRNA will be produced resulting in
different amino
the possibility of a ________
acid being incorporated into the
protein chain.
• Different sequence = possible
shape = possible different
different ______
function
________
• Because the genetic code is
redundant, a change in an mRNA
sequence does not
___ always mean the
amino acid sequence will be
different...it depends on the change.
2 Main Types of Mutations
I.
Gene Mutation (aka: _____
point mutation) –
Single _____
changes in nucleotide sequence (one gene)
II. Chromosomal
____________ Mutation – change or rearrangement
detrimental if
of many or “chunk” of genes. These are __________
lethal
not _____.
• https://www.youtube.com/watch?v=kp0esidDr-c
• TRIAL: http://study.com/academy/lesson/effects-of-mutations-on-protein-function-frameshift-silent-nonsense-missensemutations.html
Types of Point Mutations
A. Substitution
___________ mutations replace one nucleotide with
another; these ____
CAN result in a different amino acid in the
Sickle-cell _______
anemia
chain (depends on the codon) ex: _________
Frame Shift
B. ______
_____ mutations (aka:________
deletion OR ________)
insertion
occur when nucleotides are added or removed; these
result in codons shifting and will ________
ALWAYS produce a
different length and amino acid sequence.
3 Types of Substitution Mutations:
Silent Mutations:
1. _____
NOT
Involve substitution that does ____
affect the amino acid coded for. An
example would be a change from
TAC to TAT, both codons are for the
amino acid tyrosine.
Nonsense Mutation
2. ________
Involve a nucleotide substitution that
results in the replacement of the
STOP
original amino acid with a “_____”
codon (TAG).
Missense Mutations:
3. _________
Involve a substitution that results in the
replacement of the original amino acid
with a ________
different amino acid.
PRACTICE: For the original DNA strands below,
decide which mutation is the point mutation, the
insertion and the deletion.
Point Mutation
Insertion
Deletion
More Practice:
Compare each of the following mutations to the original strand,
then identify the type of mutation that took place.
GCGUUGUAU
Ala – Leu - Tyr
GCGUUGUAA
Ala – Leu - STOP
Nonsense mutation
GCGUUAUAU
Ala – Leu - Tyr
Silent mutation
GUGUUGUAU
Val – Leu - Tyr
Missense mutation
How Do Mutations Occur?
Naturally (aka: Spontaneous) – randomly occurs
• ________
when an organism reproduces
_________ or ______
repairs DNA
incorrectly, but these occurrences are very rare.
mutagens which are any
• _______
Induced - Involves _________
agent (physical or chemical) that can induce a
genetic mutation or can increase the rate of
mutation deliberately or accidentally. Examples of
radiation etc.
UV-rays ________,
X-rays _______,
mutagens: ______,
positive or
• The change in trait(s) can exert a _______
negative influence on survival and reproduction
_______
depending mainly by the environment. Examples:
• + bird fur color in specific landscape leads to
increased or decreased survival
• + giraffe's long neck and legs increases ability
for getting more food
• - cancer
• Some mutations can be detrimental
to the cell causing ______
death or
disruption of the ___
_____
cell cycle
• Others result in inappropriate
functioning proteins resulting in
diseases or decreased/increased
________
_____ to do something.
ability
• From an evolutionary standpoint,
mutations are extremely important
variation and
as they generate ________
explain why diversity
_______ exists; without
mutations, there would be no
diversity!
•
Trial: http://study.com/academy/lesson/mutagens-how-theenvironment-affects-mutation-rates.html