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Protein Synthesis Worksheet with Answers (Grade 11 Biology)

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📄 Protein Synthesis Worksheet with Answers (Grade 11 Biology)

A free printable protein synthesis worksheet for Grade 11–12 biology.

This free protein synthesis worksheet follows a gene all the way from DNA to a finished protein. Students compare DNA and RNA, transcribe template strands into mRNA, and translate mRNA into amino acids using the codon chart printed on the sheet.

They then go from DNA to protein in one step and analyse four mutations of the same gene: silent, missense (the sickle-cell change), nonsense and frameshift. Every sequence in the answer key was transcribed and translated by computer using the standard genetic code.

Grade 11–12 Biology
21 marks
40–50 minutes
Codon chart included

What's in This Protein Synthesis Worksheet

Part	Skill practised	Marks
A	DNA vs RNA	2
B	Transcription	3
C	Translation, codons and anticodons	4
D	From DNA to protein	2
E	Silent, missense, nonsense and frameshift mutations	5
F	Steps of protein synthesis and the role of tRNA	3
G	Spot the mistake	2

It works as an introduction in Grade 11 biology and as core practice for the Ontario Grade 12 Molecular Genetics unit.

DNA vs RNA

Feature	DNA	RNA
Sugar	Deoxyribose	Ribose
Bases	A, T, G, C	A, U, G, C
Number of strands	Two (double helix)	One
Where it works	Stays in the nucleus	Leaves the nucleus (mRNA)

Students complete this table from memory in Part A of the protein synthesis worksheet. The key swap to remember: RNA uses uracil where DNA uses thymine.

Transcription: DNA to mRNA

In the nucleus, RNA polymerase reads the DNA template strand from 3′ to 5′ and builds a matching mRNA from 5′ to 3′. Each base is paired with its complement, except that A pairs with U. For example, the template 3′-TACGGATTCACT-5′ is transcribed as 5′-AUGCCUAAGUGA-3′. Base pairing within DNA itself is covered in the DNA replication worksheet.

Translation and the Codon Chart

At the ribosome, the mRNA is read three bases at a time. Each codon matches a tRNA with a complementary anticodon, which delivers one amino acid. Translation always starts at AUG (methionine) and ends at a stop codon (UAA, UAG or UGA).

Codon chart (mRNA): first base on the left, second base on top, third base on the right
	U	C	A	G
U	UUU Phe UUC Phe UUA Leu UUG Leu	UCU Ser UCC Ser UCA Ser UCG Ser	UAU Tyr UAC Tyr UAA Stop UAG Stop	UGU Cys UGC Cys UGA Stop UGG Trp	U C A G
C	CUU Leu CUC Leu CUA Leu CUG Leu	CCU Pro CCC Pro CCA Pro CCG Pro	CAU His CAC His CAA Gln CAG Gln	CGU Arg CGC Arg CGA Arg CGG Arg	U C A G
A	AUU Ile AUC Ile AUA Ile AUG Met	ACU Thr ACC Thr ACA Thr ACG Thr	AAU Asn AAC Asn AAA Lys AAG Lys	AGU Ser AGC Ser AGA Arg AGG Arg	U C A G
G	GUU Val GUC Val GUA Val GUG Val	GCU Ala GCC Ala GCA Ala GCG Ala	GAU Asp GAC Asp GAA Glu GAG Glu	GGU Gly GGC Gly GGA Gly GGG Gly	U C A G

Using the chart, 5′-AUG GCA UGG CAU UAA-3′ translates to Met–Ala–Trp–His, then stop. Every question on this protein synthesis worksheet uses this same chart. For background, see protein biosynthesis on Wikipedia.

How Mutations Change Proteins

Part E starts from the normal mRNA 5′-AUG GAG CCU UGG AAA UAA-3′ (Met–Glu–Pro–Trp–Lys) and changes it four ways:

Mutated mRNA	Protein	Type
AUG GAA CCU UGG AAA UAA	Met–Glu–Pro–Trp–Lys	Silent
AUG GUG CCU UGG AAA UAA	Met–Val–Pro–Trp–Lys	Missense
AUG GAG CCU UGA AAA UAA	Met–Glu–Pro	Nonsense
AUG AGC CUU GGA AAU AA	Met–Ser–Leu–Gly–Asn	Frameshift

The missense change from GAG to GUG is the real mutation behind sickle cell anemia, where one amino acid change alters the shape of haemoglobin. Frameshifts are usually the most damaging because every codon after the change is misread.

Protein Synthesis Worksheet Practice Questions

These questions match the protein synthesis worksheet PDF, which has the codon chart, sequence lines and ruled answer space.

Part A – DNA vs RNA

Questions 1–4: compare the sugar, bases, number of strands and location of DNA and RNA.

Part B – Transcription

Transcribe the DNA template strand 3′-TACGGATTCACT-5′ into mRNA.
Transcribe 3′-TACCGTTGGATC-5′.
Where in the cell does transcription happen, and which enzyme carries it out?

Part C – Translation

Translate 5′-AUG CCU AAG UGA-3′.
Translate 5′-AUG GCA UGG CAU UAA-3′.
A codon on the mRNA is 5′-CCU-3′. What is the anticodon on the tRNA that reads it?
Why is AUG called the start codon?

Part D – From DNA to Protein

A DNA template reads 3′-TAC AAA CCG ATT-5′. Write the mRNA and the amino acid sequence.

Part E – Mutations

Questions 13–16: translate each mutated mRNA in the table above and name the mutation type.

Why is a frameshift mutation usually more harmful than a single-base substitution?

Part F – The Steps of Protein Synthesis

Put the steps in order: P mrna leaves the nucleus through a nuclear pore; Q rna polymerase transcribes the dna template into mrna; R trnas bring amino acids that match each codon; S the ribosome reaches a stop codon and releases the polypeptide; T a ribosome attaches to the mrna at the start codon aug.
What is the job of tRNA in translation?

Part G – Spot the Mistake

A student writes: “During transcription, adenine on the DNA pairs with thymine on the mRNA.” Explain the error and correct it.
A student writes: “Each amino acid is coded for by one base on the mRNA.” Explain the error and correct it.

Protein Synthesis Worksheet Answer Key

Open each part of the protein synthesis worksheet answers to check your work. The printable key is at the end of the PDF.

Part A answers (Q1–4)

Sugar: DNA – Deoxyribose; RNA – Ribose
Bases: DNA – A, T, G, C; RNA – A, U, G, C
Number of strands: DNA – Two (double helix); RNA – One
Where it works: DNA – Stays in the nucleus; RNA – Leaves the nucleus (mRNA)

Part B answers (Q5–7)

5′-AUGCCUAAGUGA-3′
5′-AUGGCAACCUAG-3′
In the nucleus, by RNA polymerase

Part C answers (Q8–11)

Met–Pro–Lys, then stop (UGA)
Met–Ala–Trp–His, then stop (UAA)
3′-GGA-5′ (complementary and antiparallel)
It signals the ribosome where to begin translation, and codes for methionine (Met).

Part D answer (Q12)

mRNA 5′-AUG UUU GGC UAA-3′ → Met–Phe–Gly, then stop

Part E answers (Q13–17)

Silent: Met–Glu–Pro–Trp–Lys. GAG → GAA still codes for Glu, so the protein is unchanged.
Missense: Met–Val–Pro–Trp–Lys. GAG → GUG changes Glu to Val; this is the sickle-cell mutation.
Nonsense: Met–Glu–Pro. UGG (Trp) → UGA, a stop codon, so the protein is cut short.
Frameshift: Met–Ser–Leu–Gly–Asn. One base deleted, so every codon after it is read differently.
It shifts the reading frame, so every codon after the mutation changes, often adding an early stop codon.

Part F answers (Q18–19)

Q → P → T → R → S
tRNA carries a specific amino acid to the ribosome and matches it to the mRNA codon using its anticodon.

Part G answers (Q20–21)

RNA has no thymine. Adenine on the DNA pairs with uracil on the mRNA.
Each amino acid is coded for by a codon of three bases. That gives 64 codons for 20 amino acids.

5 Common Protein Synthesis Mistakes

Writing T in mRNA. Every T becomes U in RNA.
Reading the codon chart from the DNA. The chart uses mRNA codons, so transcribe first.
Starting translation at the first base. Translation starts at the first AUG.
Translating past the stop codon. UAA, UAG and UGA end the protein; they code for no amino acid.
Mixing up codons and anticodons. Codons are on mRNA; anticodons are on tRNA.

How to Use This Protein Synthesis Worksheet in Class

Lesson 1: Parts A–D of the protein synthesis worksheet, modelling one full DNA → mRNA → protein example first.
Lesson 2: Parts E–G on mutations, linking the sickle-cell example to real patients.
Extension: Students write a secret message as a DNA sequence for a partner to decode with the codon chart.

For quick review, assign the protein synthesis quiz, then explore applications with the biotechnology quiz.

Frequently Asked Questions

Is this protein synthesis worksheet free?

Yes. The worksheet and its answer key are free to download and print as a PDF, with no account needed.

What are the two stages of protein synthesis?

Transcription copies a gene from DNA into mRNA in the nucleus. Translation reads the mRNA at a ribosome in the cytoplasm and joins amino acids into a polypeptide.

How do you use a codon chart?

Find the first base of the mRNA codon on the left, the second base along the top, and the third base on the right. The box where they meet gives the amino acid.

What is the difference between a codon and an anticodon?

A codon is a three-base sequence on mRNA. An anticodon is the complementary three-base sequence on tRNA that pairs with it.

What type of mutation causes sickle cell anemia?

A missense mutation. One base change turns the codon GAG (glutamic acid) into GUG (valine) in the haemoglobin gene.

More Free Grade 11 Biology Resources

Ready to start? Download the free protein synthesis worksheet PDF (use the Download button above), print it double-sided, and keep the answer key pages for marking.