Practicing Transcription & Translation worksheet - Free Printable

Absolutely! Let’s solve Worksheet 2: Practicing DNA Transcription and Translation step by step. This worksheet tests your understanding of how genetic information flows from DNA → mRNA → tRNA → Amino Acids (polypeptide), following the central dogma of molecular biology.

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## 🔬 Key Concepts Recap:

- Transcription: DNA → mRNA
- Base pairing:
- DNA `A` → mRNA `U`
- DNA `T` → mRNA `A`
- DNA `C` → mRNA `G`
- DNA `G` → mRNA `C`

- Translation: mRNA → Amino Acid (via tRNA anticodons)
- tRNA anticodon is complementary to mRNA codon:
- mRNA `A` → tRNA `U`
- mRNA `U` → tRNA `A`
- mRNA `C` → tRNA `G`
- mRNA `G` → tRNA `C`

- Use the genetic code chart (codon table) to translate mRNA codons into amino acids.

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# ✔ EXAMPLE 1

DNA: TAC GCG CCT AGG GGG TGG

Step 1: Transcribe DNA → mRNA

Use complementary base pairing (remember: in RNA, T becomes U):

- TAC → AUG
- GCG → CGC
- CCT → GGA
- AGG → UCC
- GGG → CCC
- TGG → ACC

✔ mRNA: AUG CGC GGA UCC CCC ACC

Step 2: Translate mRNA → Amino Acids (AA)

Break mRNA into codons (groups of 3):

- AUG → Methionine (Met) — Start codon
- CGC → Arginine (Arg)
- GGA → Glycine (Gly)
- UCC → Serine (Ser)
- CCC → Proline (Pro)
- ACC → Threonine (Thr)

✔ AA: Met Arg Gly Ser Pro Thr

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# ✔ EXAMPLE 2

DNA: TTC GAT TAG ATG CCG AAG

Step 1: Transcribe DNA → mRNA

- TTC → AAG
- GAT → CUA
- TAG → AUC
- ATG → UAC
- CCG → GGC
- AAG → UUC

✔ mRNA: AAG CUA AUC UAC GGC UUC

Step 2: Translate mRNA → AA

Codons:

- AAG → Lysine (Lys)
- CUA → Leucine (Leu)
- AUC → Isoleucine (Ile)
- UAC → Tyrosine (Tyr)
- GGC → Glycine (Gly)
- UUC → Phenylalanine (Phe)

✔ AA: Lys Leu Ile Tyr Gly Phe

Step 3: Find tRNA anticodons

tRNA anticodon = complement of mRNA codon:

- mRNA AAG → tRNA UUC
- mRNA CUA → tRNA GAU
- mRNA AUC → tRNA UAG
- mRNA UAC → tRNA AUG
- mRNA GGC → tRNA CCG
- mRNA UUC → tRNA AAG

✔ tRNA: UUC GAU UAG AUG CCG AAG

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# ✔ EXAMPLE 3

This one gives partial sequences — we need to fill in missing bases using complementary rules.

Given:

DNA: C _ _ _ G _ A _ _ _ A _ _ C _ _ T _

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

tRNA: _ A U G _ U _ U G G _ U C C _ G _ A

AA: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Let’s solve column by column.

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Column 1:

DNA: C _ _
mRNA: _ U _
tRNA: _ A U
AA: ?

→ tRNA anticodon ends in U, so mRNA codon ends in A → mRNA: ? U A
→ DNA template strand must be complementary to mRNA:
mRNA: ? U A → DNA: ? A T
But given DNA starts with C, so DNA: C A T
→ mRNA: G U A (complement of CAT)
→ tRNA: C A U (complement of GUA) — matches given “_ A U” → first base = C
→ AA: GUA → Valine (Val)

✔ Col 1:
DNA: CAT
mRNA: GUA
tRNA: CAU
AA: Val

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Column 2:

DNA: _ G _
mRNA: _ A _
tRNA: G _ U
AA: ?

→ tRNA: G _ U → mRNA: C _ A
→ DNA: G _ T (complement of C_A)
Given DNA has G in middle → DNA: G G T
→ mRNA: C C A
→ tRNA: G G U — matches given “G _ U” → middle = G
→ AA: CCA → Proline (Pro)

✔ Col 2:
DNA: GGT
mRNA: CCA
tRNA: GGU
AA: Pro

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Column 3:

DNA: A _ _
mRNA: _ C _
tRNA: _ U G
AA: ?

→ tRNA: _ U G → mRNA: _ A C
→ DNA: T _ G (complement of _AC)
Given DNA starts with A → DNA: A T G
→ mRNA: U A C
→ tRNA: A U G — matches “_ U G” → first = A
→ AA: UAC → Tyrosine (Tyr)

✔ Col 3:
DNA: ATG
mRNA: UAC
tRNA: AUG
AA: Tyr

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Column 4:

DNA: _ A _
mRNA: _ A _
tRNA: G _ U
AA: ?

→ tRNA: G _ U → mRNA: C _ A
→ DNA: G _ T
Given DNA has A in middle → DNA: G A T
→ mRNA: C U A
→ tRNA: G A U — matches “G _ U” → middle = A
→ AA: CUA → Leucine (Leu)

✔ Col 4:
DNA: GAT
mRNA: CUA
tRNA: GAU
AA: Leu

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Column 5:

DNA: _ C _
mRNA: _ G _
tRNA: C C _
AA: ?

→ tRNA: C C _ → mRNA: G G _
→ DNA: C C _ (complement of GG_)
Given DNA has C in middle → DNA: C C G
→ mRNA: G G C
→ tRNA: C C G — matches “C C _” → last = G
→ AA: GGC → Glycine (Gly)

✔ Col 5:
DNA: CCG
mRNA: GGC
tRNA: CCG
AA: Gly

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Column 6:

DNA: _ T _
mRNA: _ A _
tRNA: G _ A
AA: ?

→ tRNA: G _ A → mRNA: C _ U
→ DNA: G _ A
Given DNA has T in middle → DNA: G T A
→ mRNA: C A U
→ tRNA: G U A — matches “G _ A” → middle = U
→ AA: CAU → Histidine (His)

✔ Col 6:
DNA: GTA
mRNA: CAU
tRNA: GUA
AA: His

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Final Answer for Example 3:

DNA: CAT GGT ATG GAT CCG GTA
mRNA: GUA CCA UAC CUA GGC CAU
tRNA: CAU GGU AUG GAU CCG GUA
AA: Val Pro Tyr Leu Gly His

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# 🧬 DIAGRAM LABELING (Bottom of Worksheet)

The diagram shows the process of transcription and translation.

Here’s how to label it correctly:

From top to bottom:

1. Top double helix DNA → Label: DNA (template strand) or just DNA

2. Arrow pointing down to partially unwound DNA → Label: Transcription

3. mRNA strand being synthesized → Label: mRNA

4. mRNA moving out of nucleus (if shown) or to ribosome → Label: mRNA transcript

5. Ribosome assembling on mRNA → Label: Ribosome

6. tRNA molecules bringing amino acids → Label: tRNA

7. Amino acids being linked → Label: Polypeptide chain or Growing protein

8. Completed polypeptide → Label: Protein

9. Arrow from DNA to mRNA → Label: Transcription

10. Arrow from mRNA to ribosome/tRNA/AA → Label: Translation

*(Note: Some diagrams may show nucleus, cytoplasm, etc. — label based on position.)*

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## ✍️ FINAL ANSWERS SUMMARY

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Example 1:

mRNA: AUG CGC GGA UCC CCC ACC
AA: Met Arg Gly Ser Pro Thr

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Example 2:

mRNA: AAG CUA AUC UAC GGC UUC
tRNA: UUC GAU UAG AUG CCG AAG
AA: Lys Leu Ile Tyr Gly Phe

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Example 3:

DNA: CAT GGT ATG GAT CCG GTA
mRNA: GUA CCA UAC CUA GGC CAU
tRNA: CAU GGU AUG GAU CCG GUA
AA: Val Pro Tyr Leu Gly His

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Diagram Labels (suggested):

- Top DNA: DNA
- Arrow 1 (unwinding): Transcription
- mRNA strand: mRNA
- Ribosome: Ribosome
- tRNA: tRNA
- Growing chain: Polypeptide
- Final product: Protein
- Process 1: Transcription
- Process 2: Translation

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✔ You’ve now completed the entire worksheet! Great job practicing the central dogma!

Let me know if you’d like a printable version or a codon chart reference! 🧬📚