Practical skills Flashcards
How is the reliability of temperatures effect on enzyme reactions improved?
Calculating a mean and excluding any anomalies in a repeat of the experiment
What’s a control variable for measuring the effect of temperature on enzyme controlled reactions?
Concentration of enzyme/substrate and pH maintained
How can you ensure the test tubes remain at the right temperature when measuring the effect of temperature on enzyme reactions?
Warming the test tubes first ensured the temp was maintained throughout
When testing how temperature effects cell membranes what are the control variables?
Size of sample, time in water, amount of water and amount of samples used
When testing how temperature effects cell membranes, how can the results be explained?
Fluidity of membranes increases, giving pigments more opportunity for release down the concentration gradient
Why can the origin not be used for a scatter graph joining dots sometimes?
If the origin (0) was not tested as the line suggests it is
What are the limitations to biological dissections (fish)?
It can be hard to see the smaller, finer structures within an organ, the specimens do not reflect how they would look in a living organism, if only done once anomalies may not be found
What precautions are taken when performing dissections?
Disinfecting surface before and after, wearing PPE and cutting away from the body
When investigating antimicrobials, why is the neck of molten agar and cultures passed through a blue Bunsen flame?
Remove any other bacteria that may contaminate results
Why can’t agar plates be sealed down completely?
Allow oxygen in for respiration of bacterial cells
Why are the agar plates incubated upside down?
Prevent condensation dripping onto agar
What is a control experiment for investigation of antibiotic effectiveness?
Completing the same agar experiment with discs of water to show that the antibiotics were causing the deaths
