VCAA Biology How is scientific inquiry used to investigate cellular processes and/or biological change?
15 sample questions with marking guides and sample answers
Most vinegar flies have wild type (reddish-brown) eyes. However, some mutants have white eyes and cannot see. Biologists conducted a laboratory experiment to compare the fitness of flies with wild type and white eyes.
The dependent variable in the experiment is the
laboratory conditions.
eye colour of the flies.
vision of the flies.
fitness of the flies.
Reveal Answer
laboratory conditions.
Laboratory conditions are typically controlled variables that are kept constant throughout the experiment to ensure a fair test, rather than the variable being measured.
eye colour of the flies.
Eye colour is likely the independent variable, which is the specific trait or condition being manipulated or categorized to observe its effects.
vision of the flies.
While vision might be related to eye colour, the dependent variable is the specific overall outcome being measured, which in this context is fitness.
fitness of the flies.
The dependent variable is the outcome that is measured or observed in an experiment. In this case, the fitness of the flies is the measured response to the independent variable.
A student completed an experiment to investigate how light is reflected from different leaves. The results were recorded qualitatively.
Which one of the following could be a correct statement about the qualitative data obtained by the student?
An average result for the data could be obtained.
The same number would be recorded for each result.
The data was obtained by measuring the wavelength of light.
The data could be the names of the different colours of the reflected light.
Reveal Answer
An average result for the data could be obtained.
Qualitative data is descriptive and non-numerical, meaning it is not possible to calculate a mathematical average from it.
The same number would be recorded for each result.
Qualitative data consists of descriptions, characteristics, or categories, rather than numerical values.
The data was obtained by measuring the wavelength of light.
Measuring the wavelength of light produces numerical values with units, which is an example of quantitative data, not qualitative.
The data could be the names of the different colours of the reflected light.
Qualitative data describes qualities or characteristics. Recording the names of the colors of reflected light is a perfect example of qualitative data.
A camel can obtain 1.12 mL of water from each gram of fat stored in its hump. On this basis, how many millilitres of water would a camel obtain from 36 kg of stored fat?
32.142
40.320
32 142
40 320
Reveal Answer
32.142
This incorrect answer results from dividing the mass by the conversion factor and failing to convert kilograms to grams ().
40.320
This incorrect answer results from multiplying the mass by the conversion factor without converting kilograms to grams ().
32 142
This incorrect answer results from correctly converting kilograms to grams but dividing by the conversion factor instead of multiplying ().
40 320
To find the total volume, convert the mass of fat to grams () and multiply by the water yield per gram ().
The purpose of a 'control' in an experiment is to
determine the reliability of the experiment.
provide a comparison for the experimental treatment.
reduce the sample sizes needed for the experiment to be valid.
minimise the number of variables to be tested.
Reveal Answer
determine the reliability of the experiment.
Reliability is determined by repeating the experiment multiple times to check for consistent results, rather than by using a control group.
provide a comparison for the experimental treatment.
A control group provides a baseline where the independent variable is not applied, allowing researchers to see the actual effect of the experimental treatment by comparison.
reduce the sample sizes needed for the experiment to be valid.
Using a control group does not reduce the required sample size; in fact, larger sample sizes generally increase the statistical power and validity of an experiment.
minimise the number of variables to be tested.
While researchers keep certain variables constant to isolate the independent variable, the control group itself serves as a baseline for comparison, not a tool to reduce the number of variables.
Use the following information to answer the question.
Students investigated the proteins found in several different types of human cells.
Students completed their investigation and analysed their results. They suggested their results were affected by systematic errors.
Systematic errors
result in a spread of readings.
affect the precision of a measurement.
are easy to identify and eliminate.
cause readings to differ from the true value by a consistent amount each time.
Reveal Answer
result in a spread of readings.
Incorrect. Random errors cause a spread or scatter of readings, whereas systematic errors shift all measurements in the same direction.
affect the precision of a measurement.
Incorrect. Systematic errors affect the accuracy of a measurement, while random errors affect its precision.
are easy to identify and eliminate.
Incorrect. Systematic errors are often difficult to identify because the measurements may still appear highly precise despite being consistently inaccurate.
cause readings to differ from the true value by a consistent amount each time.
Correct. By definition, a systematic error consistently shifts all measurements by the same amount and in the same direction from the true value.
Eloise wanted to investigate the effect of temperature changes on the basal metabolic rate of rats. According to the Australian code of practice for care and use of animals for scientific purposes, eighth edition 2013, she must follow the principles of the 3Rs for the ethical and humane care of the animals. Which of the following is not one of the 3Rs?
Replacement – that wherever possible one should use alternative approaches that do not use animals.
Reduction – one should use the smallest number of animals possible to achieve the aims and statistical design requirements.
Refinement – one should modify methodology to minimise harm to the animals.
Repetition – one should repeat the investigative approach to ensure consistent results.
Reveal Answer
Replacement – that wherever possible one should use alternative approaches that do not use animals.
Replacement is one of the 3Rs of animal ethics, which advocates for using non-animal alternatives (like computer models or cell cultures) whenever possible.
Reduction – one should use the smallest number of animals possible to achieve the aims and statistical design requirements.
Reduction is one of the 3Rs, focusing on minimizing the number of animals used in research while still obtaining statistically valid results.
Refinement – one should modify methodology to minimise harm to the animals.
Refinement is one of the 3Rs, which involves modifying experimental procedures and animal care to minimize pain, suffering, and distress.
Repetition – one should repeat the investigative approach to ensure consistent results.
Repetition is not one of the 3Rs of animal ethics. The internationally accepted 3Rs for the ethical use of animals in research are Replacement, Reduction, and Refinement.
Prior to modern human pregnancy test kits, Xenopus frogs were used. Urine samples from women were injected into the legs of female frogs. The frogs were then placed back into water tanks and, the following day, the tanks were checked for eggs. If a female frog had laid eggs, the woman who had provided the urine sample was diagnosed to be pregnant.
Which one of the following factors may result in a false diagnosis of pregnancy?
using male frogs instead of female frogs
maintaining an optimum tank temperature
replacing the water in the tanks with fresh water each day
female frogs laying eggs naturally around the time of the injection
Reveal Answer
using male frogs instead of female frogs
Male frogs cannot lay eggs, so using them would result in a false negative (no eggs laid), rather than a false positive diagnosis of pregnancy.
maintaining an optimum tank temperature
Maintaining an optimum temperature is a standard procedure to keep the frogs healthy and capable of responding to the hormone; it does not spontaneously induce egg-laying.
replacing the water in the tanks with fresh water each day
Replacing the water is a standard husbandry practice to maintain a clean environment and would not trigger spontaneous egg-laying.
female frogs laying eggs naturally around the time of the injection
If a frog lays eggs naturally, it would appear as a positive test result even if the woman's urine did not contain pregnancy hormones, leading to a false positive diagnosis.
Use the following information to answer the question.
Dengue is a disease primarily transported by mosquitoes. A group of students wish to investigate whether mosquitoes can be effectively controlled by spraying insecticide. The students will investigate the effect of spraying five different insecticides on mosquitoes.
Which one of the following techniques could the students use to generate quantitative primary data?
obtaining data from other students’ investigations
recording the smell of the five different insecticides
reading newspaper articles on the effect of insecticides on mosquitoes
measuring the mass of dead mosquitoes after spraying each insecticide
Reveal Answer
obtaining data from other students’ investigations
Obtaining data from other students' investigations is an example of collecting secondary data, not primary data.
recording the smell of the five different insecticides
Recording the smell of insecticides generates qualitative data (descriptive), not quantitative data (numerical).
reading newspaper articles on the effect of insecticides on mosquitoes
Reading newspaper articles is a method of gathering secondary data, as the information was collected and published by someone else.
measuring the mass of dead mosquitoes after spraying each insecticide
Measuring the mass of dead mosquitoes generates numerical (quantitative) data and is collected directly by the students conducting the experiment (primary data).
Ocean temperatures are rising, threatening coral reefs like the Great Barrier Reef. A selective breeding program is being trialled to develop heat-tolerant corals for reef recovery.
The program involves:
- identifying heat-tolerant parent corals
- collecting spawn (eggs and sperm) from parent corals
- mixing parent coral spawn, fertilisation occurring producing some heat-tolerant offspring
- exposing coral offspring to high temperatures in the lab and eliminating those that are not heat-tolerant
- testing survivors in the ocean to determine their suitability for reef recovery.
It is important to test the coral offspring under ocean conditions in order to
accelerate the adaptation of corals to warmer ocean temperatures.
ensure that offspring can survive natural environmental conditions.
determine whether laboratory testing can be replaced by ocean testing.
optimise breeding methods by identifying heat-sensitive coral strains early in the process.
Reveal Answer
accelerate the adaptation of corals to warmer ocean temperatures.
Testing offspring in the ocean evaluates their current fitness but does not actively accelerate the evolutionary process of adaptation to warmer temperatures.
ensure that offspring can survive natural environmental conditions.
The ultimate goal of breeding corals is to restore reefs, making it crucial to verify that lab-reared offspring can actually survive the complex, natural conditions of the ocean.
determine whether laboratory testing can be replaced by ocean testing.
Ocean testing is meant to complement laboratory testing by providing real-world validation, not to replace the controlled environments needed for initial breeding and research.
optimise breeding methods by identifying heat-sensitive coral strains early in the process.
Identifying specific traits like heat sensitivity early in the process is best achieved through controlled laboratory experiments rather than unpredictable ocean testing.
Use the following information to answer the question.
Dengue is a disease primarily transported by mosquitoes. A group of students wish to investigate whether mosquitoes can be effectively controlled by spraying insecticide. The students will investigate the effect of spraying five different insecticides on mosquitoes.
The students want to check the reproducibility of their results.
To do this, they should ensure that the investigation
uses only recently calibrated equipment.
has both a positive and a negative control.
is conducted by only one student, in the same laboratory.
is conducted on different days by different students.
Reveal Answer
uses only recently calibrated equipment.
Using recently calibrated equipment improves the accuracy of the measurements, but it does not test whether the experimental results can be reproduced.
has both a positive and a negative control.
Controls are essential for the validity of an experiment to ensure the independent variable is causing the observed effect, but they do not check reproducibility.
is conducted by only one student, in the same laboratory.
Having the same student perform the experiment in the same lab tests repeatability (consistency under identical conditions), not reproducibility.
is conducted on different days by different students.
Reproducibility is the ability of an experiment to be duplicated by different researchers under different conditions (such as on different days) and still yield the same results.
Most vinegar flies have wild type (reddish-brown) eyes. However, some mutants have white eyes and cannot see. Biologists conducted a laboratory experiment to compare the fitness of flies with wild type and white eyes.
Which of the following is the best hypothesis for the experiment?
Is there a difference in the fitness of flies with wild type and white eyes?
There is a difference in the fitness of flies with wild type and white eyes.
If flies cannot see, then they will have reduced fitness.
Do flies that cannot see have reduced fitness?
Reveal Answer
Is there a difference in the fitness of flies with wild type and white eyes?
A hypothesis must be a testable statement, not a question. This option represents a research question rather than a hypothesis.
There is a difference in the fitness of flies with wild type and white eyes.
This is the best hypothesis because it is a clear, testable statement that proposes a relationship between the variables being investigated (eye type and fitness).
If flies cannot see, then they will have reduced fitness.
While related to the experiment, this is formatted as a prediction (an "if-then" statement) rather than a formal hypothesis comparing the two specific phenotypes.
Do flies that cannot see have reduced fitness?
Like option A, this is phrased as a question. A scientific hypothesis must be a declarative statement that can be tested.
Yeast is used to help make bread. When yeast cells respire anaerobically, they produce a gas that helps make bread rise. Tha Dah Say and Amal wanted to test how the different amounts of yeast used in dough impact the height of a loaf of bread. Each carried out their own experiment. They each used the same bread maker to bake loaves of bread with varying amounts of yeast. They then measured the height of each loaf of bread. All other variables were kept the same. All the baking was completed over the course of one day.
The following table shows the height of each loaf of bread.
| Amount of yeast (teaspoon) | Bread height (cm) | ||
|---|---|---|---|
| Tha Dah Say | Amal | ||
| Trial 1 | 0.5 | 13.8 | 4.2 |
| 1.0 | 15.9 | 7.5 | |
| Trial 2 | 0.5 | 13.6 | 3.9 |
| 1.0 | 15.7 | 7.4 | |
| Trial 3 | 0.5 | 13.7 | 4.1 |
| 1.0 | 16.1 | 7.4 |
Which one of the following statements is correct?
The amount of yeast is the dependent variable as it is a form of quantitative data.
The height of the bread is the independent variable as Tha Dah Say and Amal chose to measure it in centimetres.
The amount of yeast is the controlled variable as Tha Dah Say and Amal accurately measured the amount used.
The height of the bread is the dependent variable because it changes due to the different amounts of yeast present.
Reveal Answer
The amount of yeast is the dependent variable as it is a form of quantitative data.
The amount of yeast is the independent variable, not the dependent variable, because it is the factor that the experimenters intentionally changed.
The height of the bread is the independent variable as Tha Dah Say and Amal chose to measure it in centimetres.
The height of the bread is the dependent variable, not the independent variable, because it is the outcome being measured in response to changes in the yeast.
The amount of yeast is the controlled variable as Tha Dah Say and Amal accurately measured the amount used.
The amount of yeast is the independent variable, not a controlled variable, because it was deliberately varied between 0.5 and 1.0 teaspoons.
The height of the bread is the dependent variable because it changes due to the different amounts of yeast present.
The dependent variable is the outcome that is measured in an experiment. In this case, the height of the bread depends on the amount of yeast used.
Use the following information to answer the question.
A Year 12 student conducts an investigation into the effects of different amounts of water on the growth of lettuce plants. The following table outlines some aspects of the investigation.
| Lettuce plant | Amount of water (mL/day) | Temperature (°C) | Light wavelength (nm) | Percentage increase in mass of lettuce (%) |
|---|---|---|---|---|
| 1 | 150 | 10 | 660 | 5 |
| 2 | 200 | 15 | 660 | 10 |
| 3 | 250 | 20 | 660 | 15 |
| 4 | 300 | 25 | 660 | 13 |
Which one of the following would be the most likely qualitative data for this investigation?
the concentration of carbon dioxide in the air surrounding each plant
the number of chlorophyll molecules in each lettuce leaf
the shape of the lettuce leaves
the mass of minerals in the water
Reveal Answer
the concentration of carbon dioxide in the air surrounding each plant
The concentration of carbon dioxide is a measurable, numerical value, making it quantitative data rather than qualitative.
the number of chlorophyll molecules in each lettuce leaf
The number of chlorophyll molecules is a countable, numerical value, which represents quantitative data.
the shape of the lettuce leaves
The shape of the lettuce leaves is a descriptive, non-numerical observation, which fits the definition of qualitative data.
the mass of minerals in the water
The mass of minerals is a measurable, numerical value, making it quantitative data.
Use the following information to answer the question.
A Year 12 student conducts an investigation into the effects of different amounts of water on the growth of lettuce plants. The following table outlines some aspects of the investigation.
| Lettuce plant | Amount of water (mL/day) | Temperature (°C) | Light wavelength (nm) | Percentage increase in mass of lettuce (%) |
|---|---|---|---|---|
| 1 | 150 | 10 | 660 | 5 |
| 2 | 200 | 15 | 660 | 10 |
| 3 | 250 | 20 | 660 | 15 |
| 4 | 300 | 25 | 660 | 13 |
The investigation is not considered valid because
it contains more than one dependent variable.
only lettuce is used in the investigation.
the light wavelength is set at 660 nm.
the temperature is different for each plant.
Reveal Answer
it contains more than one dependent variable.
The investigation only has one dependent variable, which is the percentage increase in mass of the lettuce.
only lettuce is used in the investigation.
Using only one type of plant is necessary to control variables and ensure a fair test, so this does not invalidate the experiment.
the light wavelength is set at 660 nm.
Keeping the light wavelength constant at 660 nm is a controlled variable, which actually supports the validity of the experiment rather than undermining it.
the temperature is different for each plant.
For an experiment to be valid, only the independent variable (amount of water) should change. Because the temperature also changes, it acts as a confounding variable, making it impossible to know whether the water or the temperature caused the difference in growth.
A study assessed the effectiveness and safety of a drug called doxycycline. One hundred and fifty adults hospitalised with malaria were involved. These adults were randomly placed into two groups of equal size. One group received doxycycline in addition to standard care. The other group received standard care only.
The group receiving standard care only was the
control group.
variable group.
unsupported group.
experimental group.
Reveal Answer
control group.
The control group serves as a baseline for comparison by receiving the standard treatment without the new experimental drug.
variable group.
'Variable group' is not a standard scientific term; while variables are tested in an experiment, the groups are typically designated as control or experimental.
unsupported group.
'Unsupported group' is not a scientific term, and this group is still receiving standard medical care for their condition.
experimental group.
The experimental group is the one receiving the new intervention being tested, which in this study is the group receiving doxycycline.