Transcript Translation Notes

DNA & Translation
methionine proline
glycine
serine
valine
Ribosome
RibosomeRibosome
Ribosome
Ribosome
Ribosome
AUG CCA GGA UCG GUU UAA
START
STOP!
DNA and Translation
• Gene: section of DNA that
creates a specific protein
– Approx 25,000 human genes
• Proteins are used to build cells
and tissue
• Protein synthesis involves two
processes:
1) Transcription
2) Translation
Transcription Review
UA A GG C U A G C A C U G C A A C G UU GU C A
ATTCCGATCGTGACGTTGCAACAGT
U
GG
CA
AA
CG
T AA A
AG
GC
C UT A
AG
GC
CA
A CC U
TG
GC
AC
GU
TU
TG
G UT C
CA
A
• Transcription takes place in the nucleus
– 1) DNA double helix is broken apart
– 2) mRNA nucleotides match up
– 3) Finished mRNA detaches, and moves to a ribosome
Nucleus
Cytoplasm
UAAUAGCACCGUUGUCA
This mRNA will exit the nucleus
and enter into the cytoplasm
Cytoplasm
Ribosome
UAAUAGCACCGUUGUCA
Once mRNA arrives at the ribosome,
“translation” will begin.
• Codon: Combination of 3 mRNA
• AUG codon: Activates
nucleotides
the ribosome
• Each mRNA codon matches with 1
• UAA or UAG or UGA
of 20 amino acids
codon: deactivates the
ribosome
• Ribosome reads one codon at a time
Translation (overview)
methionine proline
glycine
serine
valine
Ribosome
RibosomeRibosome
Ribosome
Ribosome
Ribosome
tRNA
tRNA
tRNA
protein
tRNA
tRNA
AUG CCA GGA UCG GUU UAA
START
STOP!
• Defined: Process of making proteins
– Step 1: mRNA enters ribosome
– Step 2: Ribosome reads one mRNA codon at a time
– Step 3: tRNA delivers amino acids until a protein is created
Translation (in detail)
methioninehistidine
proline glycine
serine
lysine
valine
Ribosome
RibosomeRibosome
Ribosome
Ribosome
Ribosome
Ribosome
protein
UAC GGU
GUA CCU UUU
AGC CAA
CCU AUG CCA GGA UCG GUU UAA CAC
ignore
STOP!
IMPROPER
IMPROPER
MATCH
MATCHMATCH
MATCH
MATCH
MATCH
MATCH
• Translation begins
when the mRNA
codon “AUG” is read
by a ribosome
• Ribosome reads one
codon at a time
AUG = methionine
GCU = alanine
• tRNA carries over the proper amino acid
– tRNA anticodon matches with the mRNA
codon
– Prevents delivery of wrong amino acid
• One by one, amino acids are linked together
• Translation ends when a “stop” codon is
reached
• End Result?: A ribosome made a protein
1 minute: Discuss with your neighbor
DNA
mRNA
codon
tRNA
anticodon
TGA
ACU
UGA
Always use
mRNA to find
the amino
acid
Amino Acid
30 seconds: Discuss with your neighbor
DNA
TTC
mRNA
codon
AAG
Always use
mRNA to find
the amino acid
tRNA
anticodon
Amino Acid
UUC
Phenylalanine
30 seconds: Discuss with your neighbor
DNA
mRNA
codon
tRNA
anticodon
Amino Acid
CCA
GGU
CCA
Proline
Always use
mRNA to find
the amino acid
Questions to answer:
1) In order, list the amino acids that will be delivered to this ribosome.
Methionine, Proline, Serine, Proline, Glycine, Serine
2) What is the anticodon of each codon?
tRNA
tRNA
tRNA
tRNA
tRNA
tRNA
UAC
GGC
UCA
GGU
CCU
AGA
3) When finished, how many amino acids in size is this protein?
Methionine Proline
(MET)
(PRO)
ignore
Serine
(SER)
Proline
(PRO)
Glycine
(GLY)
Serine
(SER)
tRNA
tRNA
tRNA
tRNA
tRNA
tRNA
UAC
GGC
UCA
GGU
CCU
AGA
GAU AUG CCG AGU CCA GGA UCU UGA
start
Ribosome
stop
Practice Quiz
1)
2)
3)
4)
5)
6)
7)
Define transcription? Translation?
What are genes and how are they different from
chromosomes?
How many nucleotides make a codon?
The anticodon can be found on which object?
The anticodon must match the ______.
Place the following steps in order from start to finish:
a. Proteins are assembled
b. Ribosome reads a codon one at a time
c. mRNA arrives at the ribosome
d. tRNA delivers amino acids to the ribosome
Be able to solve practice problems similar to those just
completed.