Unit 3 - Investigative Biology Flashcards

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1
Q

What is a discrete variable?

A

Can have a finite range of values.

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2
Q

What is a continuous variable?

A

Can have an infinite, uncountable range of values.

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3
Q

What is accuracy?

A

Data is close to the true value.

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4
Q

What is reliability?

A

Consistent values are achieved in repeats and independent replicates.

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5
Q

What is validity?

A

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

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6
Q

What is precision?

A

Measured values are close to each other.

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7
Q

What 3 ethical considerations must be adhered to in human studies?

A

Informed consent
The right to withdraw
Confidentiality

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8
Q

What 3 ethical considerations must be adhered to in animal studies?

A

Replacement - animals are replaced with alternatives such as tissue cultures or less sentient species.
Reduction - minimal number of animals are used to achieve robust results.
Refinement - using methods that minimise potential pain, suffering or distress on the animals.

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9
Q

What process ensures that published data is scientifically correct?

A

Peer review.

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10
Q

What 4 things must be published in scientific reports so that others are able to repeat an experiment?

A

Methods, data, analysis, conclusions.

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11
Q

What is a null hypothesis?

A

Statement which proposes that there will be no statistically significant effect as a result of the experimental treatment.

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12
Q

What is the process of the scientific cycle?

A
Observation
Hypothesis
Experimental design
Gathering, recording and analysis of data
Evaluation of results
Conclusion
If necessary, revise the hypothesis
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13
Q

What is it called when a biological investigation fails to find an effect?

A

Negative result.

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14
Q

What is a pilot study?

A

Small-scale, preliminary study used to plan procedures, assess validity and check techniques.

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15
Q

What are the advantages of carrying out a pilot study?

A
  • plan procedures, assess validity and check techniques
  • allows evaluation/modification of experimental design
  • ensure appropriate range of values for independent variable
  • establish number of repeats required for representative values
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16
Q

What is a negative control?

A

Provides results in the absence of treatments.

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17
Q

What is a positive control?

A

Ensures that the system can detect a positive result when it occurs.

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18
Q

What is a placebo?

A

Treatment without the presence of the independent variable being investigated.

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19
Q

What is the placebo effect?

A

Measurable change in the dependent variable as a result of the patient’s expectations rather than a change in the independent variable.

20
Q

What is random sampling?

A

Members of a population have an equal chance of being selected.

21
Q

What is systematic sampling?

A

Members of a population are selected at regular intervals.

22
Q

What is stratified sampling?

A

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

23
Q

What is qualitative data?

A

Data which is subjective and descriptive.

24
Q

What is quantitative data?

A

Data which can be measured objectively, usually with a numerical value.

25
Q

What is ranked data?

A

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

26
Q

What is a correlation?

A

Relationship between two values where they both follow the same pattern.

27
Q

What can be used when confounding variables cannot easily be controlled?

A

Randomised block design.

28
Q

What is a confounding variable?

A

Variable, other than the independent or dependent variables, which may affect the results so must be considered during the investigation.

29
Q

What is an experiment with more than one independent variable called?

A

Multifactorial.

30
Q

What is a dependent variable?

A

Variable that is measured.

31
Q

What is an independent variable?

A

Variable that is controlled.

32
Q

What is in vivo experimentation?

A

Experimentation using a whole, living organism.

33
Q

What is in vitro experimentation?

A

Experimentation in a controlled environment outside of a living organism. (eg test tubes)

34
Q

What is an advantage and a disadvantage of in vitro experiments?

A

Advantage - Better control of experiment and any confounding variables
Disadvantage - Not possible for many biological studies

35
Q

What is an advantage and a disadvantage of in vivo experiments?

A

Advantage - Get a better idea of what is going on inside the cell or organism
Disadvantage - Living organisms show great variability which cannot really be controlled.

36
Q

What is a representative sample?

A

Sample which shares the same mean and degree of variation around the mean as the population as a whole.

37
Q

What is the median?

A

Middle value for the data.

38
Q

What is the mode?

A

Most common value for the data.

39
Q

What indicates high variability on a graph?

A

Large error bars.

40
Q

What is a statistically significant result?

A

Result that is unlikely to be due to chance alone.

41
Q

State the 6 ways in which data can be processed for analysis.

A

Graph, mean, median, mode, standard deviation and range.

42
Q

What indicates that results are statistically significant?

A

Their error bars do not overlap.

43
Q

What is selection bias?

A

The selection of a sample in a non-random way, so that the sample is not representative of the whole population.

44
Q

When may the validity of an experiment be compromised?

A

When confounding factors influence the value of the dependent variable.

45
Q

What 3 things should scientific reports contain?

A

Explanatory title,
Abstract including aims and findings,
Introduction explaining the purpose and context of the study including the use of several sources, supporting statements, citations and references.