Transcript Mutations - Hicksville Public Schools

H
W: page306#1-5
1. Types ofR
N
A: mR
N
A, tR
N
A
2. Transcription: mR
N
A makes a copy ofD
N
A in the
nucleus
3. Translation: tR
N
A reads mR
N
A codons (3bases) and
brings the correct amino acid to the ribosome
4. Sugar: D
N
A= deoxribose,R
N
A= ribose
Bases: D
N
A has T andR
N
A has U
D
N
A: double stranded,R
N
A: single stranded
5.UGG CAG UGC
Try
Glu
Cys
What do enzymes, antibodies, hormones,
hemoglobin and membrane proteins have
in common?
Enzymes
H
emoglobin
All are proteins
with a specific
shape that
determines
their function.
H
ormone
Antibodies
What determines a protein’s
Shape?
A protein’s shape is determined by its
sequence of amino acids.
What happens after translation
of the genetic code?
Proteins do not remain as single strands
of amino acids, rather the amino acids
chain gets folded into a specific shape.
This shape is determined by the OR
D
ERof
the amino acids in the chain.
Protein Shape:
1) The DNA base sequence (order) determines
the sequence of amino acids.
2) The sequence (order) of amino acids in a
protein determine its shape.
3) The shape of a protein determines its activity.
Transcription & Translation:
The processes of
transcription and
translation, lead to
the final shape of a
protein. Therefore it
is the genetic code:
D
N
A base sequence
that ultimately
determine a protein’s
sequence of amino
acids.
A–T
U
C–G
G
C–G
G
Tryptophan
Mutations
Mutations (changes in the genetic code) that
can lead to changes in the amino acid
sequence and ultimately to the overall shape
of the protein. Why?
What causes mutations errors
inD
N
A replication?
• Chemicals
• UVRadiation
• X-R
ay radiation
Mutated Proteins
It changes the amino acids sequence
which determines protein shape
How does a mutated protein
affect a cell?
•The mutated
protein may have a
different shape and
disrupt its normal
activity.
Types of Mutation
• Substitution
Original
DNA Strand
• Deletion
• Insertion
• Inversion
Copy theNormalD
N
A Strand:
D
N
A
CCT CAA GAT GCG
R
N
A
AA Sequence
GGA GUU CUA CGC
Gly – Val – Leu -Arg
Substitution
• Substitution – One nitrogenous base is
substituted for another.
D
N
A CCT CAA GAT GCG
D
N
A CCC CAA GAT GCG
R
N
AGGG GUU CUA CGC
Amino Gly - Val - Leu - Arg
acid
D
eletion
• One nitrogenous base is deleted
(removed).
D
N
A
CCT CAA GAT GCG
D
N
A CTC AAG ATG CG
mR
N
A GAG UUC UAC GC
Amino Glu - Ala - Tyracid
Insertion (Addition)
• Insertion – Extra nitrogenous bases are
added to the genetic code.
D
N
A
D
N
A
CCT CAA GAT GCG
CCT CTA AGA TGC G
mR
N
A GGA GAU UCU ACG C
Amino
acid
Gly - Asp - Ser - Thr -
Inversion
• Inversion – The genetic code is
inverted or reversed.
D
N
A CCT CAA GAT GCG
D
N
A CCT CAA TAG GCG
mR
N
A GGA GUU AUC CGC
Amino Gly - Val – Iso - Arg
acid
Sickle Cell Anemia
Point mutation
A change in ONE nitrogenous base, the
overall number of bases stays the same
(Substitution or Inversion)
Frame shift mutation
A change in the number of overall
nitrogenous bases in the genetic code
(Addition orDeletion)
What type of mutation is it?