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S5 Biology: DNA and Protein Synthesis (Paper 2)
S5 Biology: DNA and Protein Synthesis (Paper 2)
The second paper separates transcription from translation, keeping clear who is the template, who carries amino acids and where the chain is joined.
Direct answer Transcription copies one DNA strand into mRNA in the nucleus; translation happens on cytoplasmic ribosomes, where transfer RNA delivers amino acids by codon pairing.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 25 |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: S5 Biology: DNA and Protein Synthesis |
| Level | Four basic, three advanced, two challenge and one error-repair item |
02 Questions (10 items)
- FoundationWhere does transcription happen and what is the template?
- FoundationWhat is the direct product of transcription?
- FoundationThree consecutive bases on mRNA form a unit. What is it called?
- FoundationAn mRNA carries 300 bases. What is the maximum number of amino acids it can code for?
- IntermediateWhat is the role of transfer RNA in translation?
- IntermediateWhat role does the ribosome play in protein synthesis?
- IntermediateAn mRNA has 90 codons, one of which is a stop codon. How many amino acids are coded?
- ChallengeA template strand has 600 bases. How many amino acids can that sequence code for?
- ChallengeA protein has 150 amino acids. What is the minimum number of template bases needed?
- Error redoA student says translation happens inside the nucleus. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | In the nucleus, using one DNA strand as the template | RNA polymerase reads one DNA strand and builds a complementary messenger RNA. |
| 2 | Messenger RNA (mRNA) | The messenger carries the base sequence out of the nucleus to the ribosome. |
| 3 | A codon | Each codon specifies one amino acid and is the unit of the genetic code. |
| 4 | One hundred amino acids | Three hundred bases give one hundred codons, each coding for a single amino acid. |
| 5 | It carries amino acids to the ribosome and pairs its anticodon with the codon | Its anticodon pairs with the codon so the correct amino acid joins the growing chain. |
| 6 | It is the site of translation, joining amino acids into a polypeptide | The ribosome moves along the mRNA, adding one amino acid for every codon read. |
| 7 | Eighty-nine amino acids | A stop codon codes for no amino acid and only ends translation, so ninety minus one is eighty-nine. |
| 8 | Two hundred amino acids | The mRNA also has 600 bases, and dividing by three gives two hundred codons. |
| 9 | Four hundred and fifty bases | Three bases are needed per amino acid, so one hundred fifty times three is four hundred fifty. |
| 10 | Translation happens on ribosomes in the cytoplasm | The messenger must leave the nucleus and reach a ribosome before it is read into protein. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
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