3.2.3 controls / 3.2.4 in vivo and in vitro

Question 1

what are control groups

Answer 1

these are groups used for comparison with the results of treatment groups

Question 2

what is a negative control group

Answer 2

these provide results in the absence of treatment

Question 3

what is a positive control group

Answer 3

this is when a treatment is included to check that the system can detect when a positive result occurs

Question 4

when can placebos be used

Answer 4

they can be included as a treatment without the presence of the independent variable being measured

Question 5

what is the placebo effect

Answer 5

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

Question 6

what does in vitro refer to

Answer 6

the technique of performing a given procedure in a controlled environment outside of a living organism

Question 7

what does in vivo refer to

Answer 7

experimentation using a whole living organism

Question 8

whar are the advantages of using in vitro studies

Answer 8

• model systems are relatively cheap, simple to procure
• efficient
• results are rapid
• cell cultures studied in the lab

Question 9

what are the disadvantages of using in vitro studies

Answer 9

• findings need to be confirmed on live volunteers by in vivo methods anyway

Question 10

what are the advantages of using in vivo studies

Answer 10

more specific and detailed result

Question 11

what are the disadvantages of using in vivo studies

Answer 11

• expensive since it involves using animals or human volunteers
• ethical dilemmas when recruiting subjects
• takes longer to arrive at the result
• strict because it involves working with live subjects