Using the Correct Vocabulary (AQA GCSE Biology): Revision Note
Exam code: 8461
Using precise scientific terms
Biology has its own scientific vocabulary, and many marks depend on using the right term
Everyday words are often not precise enough to score marks, e.g.:
Use pathogen, or name the type of pathogen, e.g. bacteria, instead of "germ"
Name the specific cell type, e.g. palisade mesophyll cells instead of "leaf cells"
Use air spaces, not "empty spaces" when describing leaf structure
Use nutrients or a named example, e.g. glucose, rather than "food"
Use anomalous result, not "mistake", when describing a result that does not fit a pattern
Using an imprecise term, even if its meaning is correct, is likely to result in marks being lost
AQA publishes a list of practical terms with set meanings
Use these terms correctly in practical questions
Accuracy
A measurement result is considered accurate if it is judged to be close to the true value
Precision
Precise measurements are ones in which there is very little spread about the mean value
Precision depends only on the extent of random errors – it gives no indication of how close results are to the true value
Repeatable
A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results
Reproducible
A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained
Resolution
This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading
Validity
Suitability of the investigative procedure to answer the question being asked
Worked Example
A student heated a solution of amylase to 80 °C. After it had cooled, the amylase could no longer digest starch.
Give the term for what happened to the amylase when it was heated to 80 °C.
[1]
Zero-mark answer:
The heat killed the enzyme
Full-mark answer:
The amylase was denatured [1 mark]
Examiner Tips and Tricks
The zero-mark answer does not use the correct scientific term. The correct term for what happens to an enzyme at high temperature is denatured, and words such as "killed" or "died" are not accepted. This is also a scientific error, because enzymes are protein molecules rather than living organisms, so they cannot be killed.
The full-mark answer uses the precise term, denatured. In a question that asks you to explain what happened, a description of the active site changing shape would also gain credit.
Avoid vague statements
Using biological terms in your answer will prevent vagueness and show that you understand the underlying biology
Student answers often lose marks because they do not express what they intend to say using clear enough language
Examples include:
explaining the impact of thick mucus in cystic fibrosis as "difficulty in breathing" or "affecting the airway", rather than stating clearly that the blocked airway reduces oxygen delivery for aerobic respiration
stating that enzymes break down "food", but not specifying what food is broken down into, i.e. small, soluble molecules
describing how information reaches the brain as "messages" or "signals" in "nerves", rather than impulses along neurones
Commonly confused terms in biology
Some biology terms sound alike or are easily mixed up, for example:
Chlorophyll is the green pigment that absorbs light
Chloroplasts are the structures in plant cells that contain chlorophyll
Excretion is the removal of the waste products of metabolism, such as urea and carbon dioxide
Egestion is the removal of undigested food from the body as faeces
Mitosis leads to genetically identical cells being formed
Meiosis leads to genetically different cells being formed, and is how gametes are made
Antibiotic resistance arises in bacteria by random mutation; resistant bacteria survive and reproduce, so resistance spreads by natural selection
Examiner reports show that students often mix up these pairs of terms
Worked Example
A gardener grows a plant with leaves that have green areas and white areas. One leaf was kept in the light for two days, then tested for starch with iodine solution. Only the green areas turned blue-black.
Explain why starch was found only in the green areas of the leaf.
[2]
Zero-mark answer:
The green areas have chloroplasts, so they can make food
Full-mark answer:
The green areas contain chlorophyll, but the white areas do not [1 mark]
Chlorophyll absorbs light, so photosynthesis happens in the green areas, and the glucose made is stored as starch [1 mark]
Examiner Tips and Tricks
The zero-mark answer names chloroplasts, not chlorophyll. Chloroplasts are the structures, and chlorophyll is the green pigment that absorbs light, so it is chlorophyll that the mark scheme asks for. "Make food" is also too vague. Instead, say that light is absorbed for photosynthesis, so starch can be formed.
The full-mark answer names chlorophyll, links it to absorbing light, and follows this through to photosynthesis and starch.
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