Central Dogma:
Translation
Science 10
Objectives:
• Make a model of the translation
process
• Describe a codon and the role of
tRNA in the formation of protein.
Science 10
Translation is the process
of converting information in
mRNA into a sequence of
amino acids in a protein.
Science 10
1. How do cells use DNA to make proteins?
Most genes contain the information
needed to make functional molecules
called proteins. Through the processes
of transcription and translation,
information from DNA is used to make
proteins.
Science 10
2. What are cell structures
made of?
Proteins and other types of
biomolecules including lipid,
carbohydrates, and other
metabolites. Science 10
Science 10
https://www.youtube.com/watch?v=gG7uCskUOrA&t=1s Science 10
Activity 4
Relay the Message?
Science 10
Guide Questions
Science 10
Q1. What are the four nucleotide
bases present in tRNA? Do these
bases differ from those found in
mRNA?
Q2. What base in mRNA can only join
with the adenine base of RNA? Uracil
base of tRNA?
Science 10
Q3. What is a codon? What does it
represent?
Q4. What is the role of tRNA in protein
synthesis?
Q5. How does a tRNA molecule
carrying its amino acid recognize
which codon to attach?
Science 10
Q6. You have learned that there is a
stop codon that signals the end of an
amino acid chain. Why is it important
that a stop codon be part of protein
synthesis?
Science 10
Q1. What are the four nucleotide bases present in
tRNA? Do these bases differ from those found in
mRNA?
In tRNA , the nucleotides are adenine,
uracil, guanine and cytosine. The same
nitrogenous bases are found in mRNA. The
tRNA contains other nitrogenous bases that
are derivatives of the same nucleotides.
Science 10
Q2. What base in mRNA can only
join with the adenine base of RNA?
Uracil base of tRNA?
Adenine pairs with uracil
and vice-versa.
Science 10
3. What is a codon? What does it
represent?
A codon is a set of three
nitrogenous bases in mRNA
which codes for a specific amino
acid.
Science 10
Q4. What is the role of tRNA in protein
synthesis?
Transfer RNA brings an amino
acid in the cytoplasm to the
ribosomes. Each tRNA molecule
attaches to only one type of
amino acid. Science 10
Q5. How does a tRNA molecule carrying its amino
acid recognize which codon to attach?
In tRNA there is a sequence of three
nucleotides that are complementary to the
nucleotides in the mRNA codon. These three
nucleotides are called an anticodon because
they bond to the codon of the messenger
RNA. The tRNA carries only the amino acid
that the anticodon specifies.
Science 10
Q6. You have learned that there is a stop
codon that signals the end of an amino acid
chain. Why is it important that a stop codon
be part of protein synthesis?
When a stop codon is reached,
translation ends and amino acid
strand is released from the
ribosome. Science 10
STEPS:
1. As translation begins, mRNA binds to a
ribosome in which the ribosomal RNA is found.
Then, tRNA molecules, each carrying a specific
amino acid, attract the ribosome. The tRNA
anticodon pairs with the first mRNA (start)
codon AUG, to form the initiation complex. The
two molecules temporarily join together.
Science 10
STEPS:
2. Usually, the first codon on mRNA is AUG,
which codes for the
amino acid methionine. AUG signals the start of
protein synthesis. Then,
the ribosome slides along the mRNA to the next
codon.
Science 10
STEPS:
3. A new tRNA molecule carrying an amino
acid pairs with the second
mRNA codon.
4. When the first and second amino acids
are in place, an enzyme
joins them by forming a peptide bond
between them.
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STEPS:
5. As the process continues, a chain of
amino acids is formed until the ribosome
reaches a stop codon (e.g., UAA, UGA,
UAG) on the mRNA strand. The polypeptide
chain is released and protein synthesis is
complete.
Science 10
Science 10
Key Concepts:
✓ The process of converting the information in
a sequence of nitrogenous bases in mRNA
into a sequence of amino acids that make a
protein is known as translation.
✓ The role of transfer RNA (tRNA) is to bring the
amino acids in the cytoplasm to the
ribosomes to form polypeptides.
Science 10
