Unit 3: Investigative Biology

Question 1

The Scientific Cycle

Answer 1

• observation
• construction of a testable hypothesis
• experimental design
• gathering, recording, and analysis of data
• evaluation of results and conclusions
• the formation of a revised hypothesis where necessary.

Question 2

What is a null hypothesis

Answer 2

The null hypothesis proposes that there will be no statistically significant effect as a result of the experiment treatment. If there is evidence for an effect, unlikely due to chance, then the null hypothesis is rejected.

Question 3

Failure to find an effect (a negative result) is a valid finding, as long as…

Answer 3

an experiment is well designed

Question 4

When can scientific ideas become accepted

Answer 4

once they have been checked independently.

Question 5

one-off results are treated…

Answer 5

with caution

Question 6

The importance of publication of methods, data, analysis, and conclusions in scientific reports

Answer 6

so that others are able to repeat an experiment.

Question 7

Common methods of sharing original scientific findings include

Answer 7

seminars, talks and posters at conferences, and publishing in academic journals.

Question 8

What is peer review for scientific publication

Answer 8

• Specialists with expertise in the relevant field
• assess the scientific quality of a submitted manuscript and
• make recommendations regarding its suitability for publication.

Question 9

Why is honesty and integrity important

Answer 9

The replication of experiments by others reduces the opportunity for dishonesty or the deliberate misuse of science.

Question 10

3Rs

Answer 10

reduce, replace, refine

Question 11

What risks must be taken into account

Answer 11

The risk to and safety of subject species, individuals, investigators and the environment must be taken into account.

Question 12

As a result of the risks involved, many areas of scientific research are…

Answer 12

highly regulated and licensed by governments.

Question 13

Why is legislation important

Answer 13

limits the potential for misuse of studies and data.

Question 14

When are results reliable

Answer 14

consistent values in repeats and independent replicates.

Question 15

conditions for validity

Answer 15

variables controlled so that any measured effect is likely to be due to the independent variable.

Question 16

what is accuracy

Answer 16

data, or means of data sets, are close to the true value.

Question 17

What is precision

Answer 17

measured values are close to each other.

Question 18

Pilot studies (4)

Answer 18

• a pilot study is used to help plan procedures, assess validity and check techniques.
• This allows evaluation and modification of experimental design.
• The use of a pilot study can ensure an appropriate range of values for the independent variable
• allows the investigator to establish the number of repeat measurements required to give a representative value for each independent datum point.

Question 19

What is a multifactoral experiment

Answer 19

A multifactorial experiment involves a combination of more than one independent variable or combination of treatments.

Question 20

Advantage of experiments in a laboratory

Answer 20

The control of laboratory conditions allows simple experiments to be conducted more easily than in the field.

Question 21

Disadvantage of experiments in a laboratory

Answer 21

its findings may not be applicable to a wider setting.

Question 22

Observational studies are good for detecting correlation, but why are they less useful for determining correlation?

Answer 22

Observational studies are good at detecting correlation, but since they do not directly test a hypothesis, they are less useful for determining causation.

Question 23

What is an observational study

Answer 23

In observational studies the independent variable is not directly controlled by the investigator, for ethical or logistical reasons

Question 24

What is a confounding variable

Answer 24

other variables besides the independent variable may affect the dependent variable.

Question 25

Why must confounding variables be kept constant (or at least monitored)

Answer 25

so that their effect on the results can be accounted for in the analysis.

Question 26

Experimental design to help prevent effects of confounding variables

Answer 26

randomised bloc design

Question 27

What is a positive control

Answer 27

A positive control is a treatment that is included to check that the system can detect a positive result when it occurs.

Question 28

What is placebo effect

Answer 28

Placebo effect is a measurable change in the dependent variable as a result of a patient’s expectations, rather than changes in the independent variable.

Question 29

what is in vitro

Answer 29

In vitro refers to the technique of performing a given procedure in a controlled environment outside of a living organism.

Question 30

examples of in vitro

Answer 30

cells growing in culture medium, proteins in solution, purified organelles.

Question 31

What is in vivo

Answer 31

refers to experimentation using a whole, living organism

Question 32

disadvantages of in vivo

Answer 32

- more time consuming - expensive

Question 33

Advantages of in vitro

Answer 33

- less expensive - less time consuming

Question 34

disadvantages of in vitro

Answer 34

- less precise -incomplete representation of being able to see effect in whole organism

Question 35

advantages of in vivo

Answer 35

- more precise - accurately represents the entire organism as a whole

Question 36

Where it is impractical to measure every individual, a __________ of the population is selected.

Answer 36

representative sample

Question 37

What determines the appropriate sample size

Answer 37

The extent of the natural variation within a population. More variable populations require a larger sample size

Question 38

A representative sample should share the same...

Answer 38

- mean - degree of variation as the population as a whole

Question 39

What is random sampling

Answer 39

members of the population have an equal chance of being selected.

Question 40

What is systematic sampling

Answer 40

members of a population are selected at regular intervals.

Question 41

What is stratified sampling

Answer 41

the population is divided into categories that are then sampled proportionally.

Question 42

Variation in experimental results may be due to...

Answer 42

-the reliability of measurement methods and/or - inherent variation in the specimens.

Question 43

The reliability of measuring instruments or procedures can be determined by...

Answer 43

repeated measurements or readings of an individual datum point.

Question 44

The variation observed indicates the...

Answer 44

precision of the measurement instrument or procedure but not necessarily its accuracy.

Question 45

Overall results can only be considered reliable if they can be...

Answer 45

achieved consistantly

Question 46

Overall results can only be considered reliable if they can be...

Answer 46

the data transformation in which numerical values are replaced by their rank when the data are sorted from lowest to highest.

Question 47

Causation exists if...

Answer 47

the changes in the values of the independent variable are known to cause changes to the value of the dependent variable.

Question 48

What is selection bias

Answer 48

is the selection of a sample in a non-random way, so that the sample is not representative of the whole population. Selection bias may have prevented a representative sample being selected.

Question 49

Ethical requirements of human studies

Answer 49

- confidentiality - right to withdraw - informed consent