Transcription and translation process worksheet with fill-in-the-blank exercises for DNA, mRNA, tRNA, and amino acids.

Let’s solve both examples step by step.

We’re working with DNA → mRNA → tRNA → Amino Acids.

Remember the base pairing rules:

- In DNA:
A pairs with T
G pairs with C

- When transcribing DNA to mRNA:
DNA A → mRNA U
DNA T → mRNA A
DNA G → mRNA C
DNA C → mRNA G

- tRNA is complementary to mRNA (so it matches the original DNA strand, but with U instead of T)

- Then we use the mRNA codons (groups of 3 bases) to find amino acids using a genetic code chart. Since no chart is given, I’ll use standard codon table values that are commonly taught.

---

Example #1

Given DNA strand (top):
A T G G T A G C T A A C C T T

Step a: Fill in complementary DNA strand (bottom).

Complementary DNA means:
A ↔ T
T ↔ A
G ↔ C
C ↔ G

So for each base in top DNA:

A → T
T → A
G → C
G → C
T → A
A → T
G → C
C → G
T → A
A → T
A → T
C → G
C → G
T → A
T → A

Bottom DNA strand:
T A C C A T C G A T T G G A A

Step b: Transcribe bottom DNA to mRNA.

mRNA uses U instead of T, and pairs as:

DNA A → mRNA U
DNA T → mRNA A
DNA G → mRNA C
DNA C → mRNA G

Bottom DNA: T A C C A T C G A T T G G A A

mRNA:
T → A
A → U
C → G
C → G
A → U
T → A
C → G
G → C
A → U
T → A
T → A
G → C
G → C
A → U
A → U

Wait — let me double-check this transcription.

Actually, when transcribing from DNA to mRNA, you read the template strand (which is the bottom one here), and build mRNA complementary to it.

Standard rule:
Template DNA base → mRNA base
A → U
T → A
G → C
C → G

So bottom DNA: T A C C A T C G A T T G G A A

mRNA:
T → A
A → U
C → G
C → G
A → U
T → A
C → G
G → C
A → U
T → A
T → A
G → C
G → C
A → U
A → U

So mRNA = A U G G U A G C U A A C C U U

That makes sense — because the top DNA was A T G G T A G C T A A C C T T, and mRNA should be same as top DNA except T→U. Yes! So mRNA = AUG GUA GCU AAC CUU

Good.

Step c: tRNA bases — these are anticodons, complementary to mRNA.

mRNA: A U G G U A G C U A A C C U U

tRNA:
A → U
U → A
G → C
G → C
U → A
A → U
G → C
C → G
U → A
A → U
A → U
C → G
C → G
U → A
U → A

So tRNA = U A C C A U C G A U U G G A A

Step d: Translate mRNA codons to amino acids.

Break mRNA into codons (groups of 3):

AUG | GUA | GCU | AAC | CUU

Now use standard genetic code:

AUG → Methionine (Met) — start codon
GUA → Valine (Val)
GCU → Alanine (Ala)
AAC → Asparagine (Asn)
CUU → Leucine (Leu)

So amino acids: Met - Val - Ala - Asn - Leu

---

Example #2

Given DNA strand (top):
C A G G A A T T G C T C G A T

Step a: Complementary DNA strand (bottom)

C → G
A → T
G → C
G → C
A → T
A → T
T → A
T → A
G → C
C → G
T → A
C → G
G → C
A → T
T → A

Bottom DNA: G T C C T T A A C G A G C T A

Step b: Transcribe bottom DNA to mRNA

Bottom DNA: G T C C T T A A C G A G C T A

mRNA:
G → C
T → A
C → G
C → G
T → A
T → A
A → U
A → U
C → G
G → C
A → U
G → C
C → G
T → A
A → U

So mRNA = C A G G A A U U G C U C G A U

Check: Top DNA was CAG GAA TTG CTC GAT → replace T with U → CAG GAA UUG CUC GAU → wait, that’s not matching.

Hold on — if top DNA is coding strand, then mRNA should match top DNA with T→U.

Top DNA: C A G G A A T T G C T C G A T

Replace T with U: C A G G A A U U G C U C G A U → yes, that’s what we got.

So mRNA = CAG GAA UUG CUC GAU

Step c: tRNA bases — complementary to mRNA

mRNA: C A G G A A U U G C U C G A U

tRNA:
C → G
A → U
G → C
G → C
A → U
A → U
U → A
U → A
G → C
C → G
U → A
C → G
G → C
A → U
U → A

tRNA = G U C C U U A A C G A G C U A

Step d: Translate mRNA codons to amino acids

mRNA codons: CAG | GAA | UUG | CUC | GAU

Use genetic code:

CAG → Glutamine (Gln)
GAA → Glutamic acid (Glu)
UUG → Leucine (Leu)
CUC → Leucine (Leu)
GAU → Aspartic acid (Asp)

So amino acids: Gln - Glu - Leu - Leu - Asp

---

Final Answer:

Example #1

Complementary DNA: T A C C A T C G A T T G G A A
mRNA: A U G G U A G C U A A C C U U
tRNA: U A C C A U C G A U U G G A A
Amino Acids: Methionine - Valine - Alanine - Asparagine - Leucine

Example #2

Complementary DNA: G T C C T T A A C G A G C T A
mRNA: C A G G A A U U G C U C G A U
tRNA: G U C C U U A A C G A G C U A
Amino Acids: Glutamine - Glutamic Acid - Leucine - Leucine - Aspartic Acid