Transcript Translation Details

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 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
• Codon: Combination of 3
mRNA nucleotides
• Each mRNA codon matches
with 1 of 20 amino acids
• Ribosome reads codons 1 at
a time
• Codon AUG = Methionine
(Start)
• Codon GUU = Valine
• Codons UAA or UAG or UGA
= 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 Details
• Translation begins
when the mRNA
codon “AUG” is read
by the ribosome
• Each mRNA codon
matches with a
specific amino acid
AUG = methionine
GCU = alanine
• tRNA carries over the
proper amino acid
– tRNA anticodon
matches with the
mRNA codon
– Ensures proper match
• One by one, amino acids
are linked together
• Translation ends when a
“stop” codon is read by
the ribosome
• End result: Protein
Now the codon and
anticodon match. This
ensures
proper
Thisthe
is why
the
amino
acid (serine)
anticodon
is is
delivered.
important!
Because the codon and anticodon don’t match, the
wrong amino acid will not be delivered.
Methi
onine
Proline
Serine
Proline
Glycine
Serine
tRNA
tRNA
tRNA
tRNA
tRNA
tRNA
UAC
GGC
UCA
GGU
CCU
AGA
GAU AUG CCG AGU CCA GGA UCU UGA
Ribosome
Practice Problem
Always use mRNA to find
the amino acid
DNA
mRNA
codon
tRNA
anticodon
Amino Acid
Practice Problem
Always use mRNA to find
the amino acid
DNA
mRNA
codon
tRNA
anticodon
Amino Acid
Practice Problem
Always use mRNA to find
the amino acid
DNA
mRNA
codon
tRNA
anticodon
C
C
A
G
G
U
C
C
A
Amino Acid
Kobe Kuiz
1) Define transcription? Translation?
2) What are genes and how are they different from
chromosomes?
3) How many nucleotides make a codon?
4) The anticodon can be found on which object?
5) The anticodon must match the ______.
6) 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
7) Be able to solve practice problems similar to the three
examples on slides #9-11.
mRNA codes
mRNA codes