Exam Techniques

Question 1

Two variables in the question

Answer 1

• Make comparative statements

Question 2

Biotic and abiotic factors

Answer 2

• Always be specific e.g
  food, water, O2 concentration, soil concentration, sunlight,temperature e.t.c

Question 3

How to describe comparisons

Answer 3

Valid comparison

Question 4

Application question on quantity e.g. sample, volume (water, blood)

Answer 4

Number in sample varies

Question 5

Explain

Answer 5

• Identify if its a knowledge/ application question
• Underline key words
• Write the definition of the keyword
• Write down words associated with keyword topic e.g.
• Plan your answer
• Red blood cells: Oxygen transport
• White blood cells: Immunity

Question 6

Data

Answer 6

• Positive/ negative correlation e.g. for species
• State what you see
• Use variables in the question e.g. temperature
• General trend: specific, range

Question 7

Conclusion

Answer 7

• Fewer/ more (variable)
• Comparison e.g higher% / lower % (variable)

Question 8

keyword

Answer 8

Variation

Question 9

concentration/diffusion/water potential gradient

Answer 9

maintains

Question 10

Evaluate

Answer 10

• Other factor/ named variable might cause harm
• Only one sample
• No stats taken
• Quote figures variables in the data

Question 11

Safe

Answer 11

Harmful

Question 12

Suggest one practical advantage of measuring the masses of frog eggs, tadpoles and adults, compared with measuring their volumes (4)

Answer 12

• More accurate/ less error in measuring mass
• Causes less distress/ damage to animal to measure mass
• Easier/ quicker to find mass because irregular shapes
• Fewer measurements/ calculations

Question 13

Trust your…

Answer 13

Gut

Question 14

Key words to use when data would be similar

Answer 14

• Similar trends
• Similar pattern
• Similar peaks
• Similar curve

Question 15

Name two other variables the student should have kept constant during this
investigation.

Answer 15

1. Temperature;
2. Agitation/mixing/stirring;
3. Source/age/type of blueberries;
4. Crushing of the blueberries;
5. Rinsing of the blueberries prior to mixing;
6. Concentration of ethanol/acid;

Question 16

How is standard deviation used to answer question?

Answer 16

• If the standard deviation does not overlap then the difference is statistically significant and the difference has not been due to chance
• If the standard deviation does overlap then the difference is not statistically significant and the difference has been due to chance

Question 17

• Large sample size so….
  Long period of time (be specific and use the question in your answer) so…
• Control used so….
• Chosen at random to…

Answer 17

• Large sample size so representative
• Long period of time to allow… e.g. growth
• Control used for comparison
• Chosen at random to eliminate bias

Question 18

Explain why a log scale is used to record the number of cells

Answer 18

• Large range/difference/increase in numbers;
• Accept reference to exponential (increase)

Question 19

Keywords for describing trends

Answer 19

• Less
• Reduced
• Slows

Question 20

Some students investigated the effect of temperature on the rate of anaerobic respiration in yeast. The apparatus they used is shown in the diagram. The yeast suspension was mixed with glucose solution and the volume of gas collected in five minutes was recorded.
Each student repeated the experiment and the results were pooled. Explain the advantages of collecting a large number of results (3)

Answer 20

• reduces the effect of anomalies on the mean
• Increases reliability
• More representative MEAN
• Allows use of statistical test