Principles of Biomedical Technology (Principles of Biomedical Science)

Unit 2: Unit 2.2 Decoding a DiagnosisPBS 2.2Biotechnology Research and Experiments

Model DNA to Protein

Build a protein from DNA: copy the template strand into mRNA (T to U), then read codons to name the amino acids.

Builds on (2 levels back)inferred · high confidence

DNA/RNA base pairing: Building mRNA means pairing each DNA base to its partner (A-U, T-A, C-G, G-C).
Use a codon chart: Naming the amino acid means looking up each three-base codon on a chart.

Prerequisites are inferred: pending teacher review.

Re-learn the skill with worked practice and clear examples.

Model DNA to protein in two steps: transcribe the template strand into mRNA (T to U), then translate the mRNA codon into its amino acid using the chart.

Step 1: Transcribe

Go base by base across the DNA template, writing each mRNA partner from the table: A->U, T->A, C->G, G->C.

Step 2: Group into codons

Split the mRNA into groups of three bases. Each group of three is one codon.

Step 3: Translate

Look up each codon on the chart to name its amino acid. That string of amino acids is the protein.

Practice

A DNA template strand reads TAC. Build the mRNA (pair each base, T becomes U) and use the chart to name the amino acid.

Approved

DNA base on template	mRNA base to write
A	U
T	A
C	G
G	C
mRNA codon	Amino acid
AUG	Methionine (Met) - start
UUU	Phenylalanine (Phe)
UAC	Tyrosine (Tyr)
GGU	Glycine (Gly)

A.mRNA AUG = Methionine (Met)
B.mRNA TAC = Tyrosine (Tyr)
C.mRNA UUU = Phenylalanine (Phe)
D.mRNA GGU = Glycine (Gly)

Show the worked solution ▾

Answer: A. mRNA AUG = Methionine (Met)

Step 1: Pair each base: T->A, A->U, C->G using the pairing table, so DNA TAC gives mRNA AUG.
Step 2: Look up the codon: The chart shows AUG codes for Methionine (Met), the start amino acid.

Why it's right: DNA template TAC pairs to mRNA AUG (T->A, A->U, C->G), and the chart shows AUG = Methionine.

Why the others miss:

B: mRNA uses U, not T, so the mRNA is AUG, not TAC.
C: UUU comes from DNA AAA, not from TAC.
D: GGU comes from DNA CCA, not from TAC.

Aligned to BRE: transcribe and translate · reading level ~grade 9

Where you'd see this

In Unit 2.2 Decoding a Diagnosis, this skill turns class evidence into a result another person can check.

Careers that use this

Genetic Counselor: Works out the protein a gene sequence makes so they can explain how a change affects it.

Video library

Watch: Model DNA to Protein

Protein Synthesis: Transcription and Translation (Updated)

Amoeba Sisters · 8:47

Guided notes

Fill these in as you work through the lesson.

Big idea: You can model how a cell makes protein in two steps: transcription copies the DNA template strand into mRNA (T becomes U), and translation reads the mRNA codons to name the amino acids.

Key terms: write the meaning

Template strand (the DNA side that is copied):
Transcription (DNA -> mRNA):
mRNA (the message copy of the gene):
Codon (three mRNA bases = one amino acid):
Translation (mRNA codons -> amino acids):
Amino acid (a protein building block):

The rule

To copy DNA into mRNA, pair A with , T with , C with , and G with . Then read the mRNA in groups of bases to name each amino acid.

Check yourself

When you build mRNA from DNA, which base replaces T?
How many mRNA bases make one codon?
What two steps take you from a DNA template strand to a finished chain of amino acids?

Work one example

DNA template = TAC. Build the mRNA (pair each base, T->U) and then name the amino acid. (Answer: mRNA = AUG, which the chart shows is Methionine, the start.)