How to answer QCE Biology short response questions

Calculations need every step and a unit; written answers follow the cognitive verb: describe gives features, explain adds cause and effect, and evaluate ends with a judgement.

Answers	Single words, sentences or paragraphs, and calculations
Often on	Unseen graphs, tables or diagrams
Calculations	Population estimates, diversity, efficiency, frequencies

Write to the question

For a calculation, write each step with its formula, carry the units and give the answer to sensible significant figures.
For explain, give the point, tie it to the organism, ecosystem or data in the question, then say what it causes.
For evaluate, weigh a strength and a limitation, then give a judgement and its reason.

Use the stimulus

Quote the numbers, the organisms or the result in the question. An answer that could be written without reading the stimulus is rarely a full-marks answer.

Try 2 questions

Question 1

Number of snails of each species counted in one rock pool
Species	Number of snails
Periwinkle	10
Nerite	6
Limpet	4

A student counted the snails in a rock pool on a reef flat near Townsville and recorded three species, shown in the table. Simpson's diversity index is SDI = 1 − Σn(n − 1) ÷ N(N − 1). What is the SDI for the rock pool?

Question 2

Part of the genetic code: mRNA codons and the amino acids they code for
mRNA codon (5' to 3')	Amino acid
AUG	Met
GCU	Ala
UGG	Trp
AAA	Lys
UAG	stop

From the table, which polypeptide is made by translating the mRNA 5' AUGGCUUGGAAAUAG 3'?

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Questions people ask

How long should a longer answer be?

Long enough to make each point, tie it to the question and develop it. Plan two or three linked points rather than a list.