Practice Flashcards
Flip to reveal answersWhat is translation?
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 14 Flashcards — Translation: building the polypeptide
Sign up free to track progress and get spaced-repetition review schedules.
Question
What is translation?
Answer
The process where a **ribosome** reads an **mRNA** and builds the matching chain of amino acids (a **polypeptide**).
Question
Where does translation take place?
Answer
At a **ribosome** (in the cytoplasm).
Question
What is a codon?
Answer
A group of **three mRNA bases** that codes for **one amino acid** (or a stop signal).
Question
How many bases are read for each amino acid?
Answer
**Three** — the mRNA is read one **codon** (3 bases) at a time.
Question
What is the job of a tRNA?
Answer
It **brings the correct amino acid** to the ribosome; its **anticodon** base-pairs with the mRNA codon.
Question
What is an anticodon?
Answer
The **three bases on a tRNA** that base-pair with a complementary **codon** on the mRNA.
Question
How is the correct amino acid placed in the right position?
Answer
Each tRNA **anticodon** pairs with the matching **codon**, and each tRNA carries only **one specific amino acid**.
Question
What bond joins amino acids in the polypeptide?
Answer
A **peptide bond**, formed by the ribosome as each amino acid is added.
Question
What ends translation?
Answer
A **stop codon** — no tRNA matches it, so no more amino acids are added and the polypeptide is released.
Question
How do you find the number of mRNA bases from the number of amino acids?
Answer
**Bases = amino acids × 3** (three bases per codon); add 3 more for the stop codon.
Question
How many mRNA bases code for a 30-amino-acid polypeptide?
Answer
30 × 3 = **90 bases** (93 if the stop codon is counted).
Question
Why do polypeptides on the same mRNA differ in length?
Answer
They are caught **part-way through synthesis**; ribosomes further along the mRNA have added **more amino acids**, so their chains are longer.
Question
Which step is translation: transcription or making the polypeptide?
Answer
Translation is **making the polypeptide** at the ribosome. Transcription is making the **mRNA** in the nucleus.
Question
What is a polypeptide?
Answer
The **chain of amino acids** produced by translation, which folds up to form a **protein**.
Read the notes
Full study notes for Translation: building the polypeptide
Topic 4.2 hub
Protein synthesis
More from Topic 4.2
All flashcards in this topic
Biology exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free