Experiments Flashcards
When investigating the effect of temperature/pH on the rate of enzyme activity, what enzyme did you use?
Catalase in celery
When investigating the effect of temperature/pH on the rate of enzyme activity, what was the substrate?
Hydrogen peroxide
When investigating the effect of temperature/pH on the rate of enzyme activity, what was the product?
Oxygen and water
When investigating the effect of temperature/pH on the rate of enzyme activity, what was the control?
No celery or boiled celery (denatured)
When investigating the effect of temperature on the rate of enzyme activity, what pH buffer did you add and why?
pH buffer of 9
→ optimum for catalase
When investigating the effect of temperature on the rate of enzyme activity, how did you change the temperature?
Using water baths at different temperatures
When investigating the effect of pH on the rate of enzyme activity, how did you vary pH?
Using different pH buffers
→ optimum at 9
When immobilising an enzyme, what enzyme did you use?
Sucrose found in yeast
When immobilising an enzyme, what chemicals did you use?
Sodium alginate (in form of paste)
Calcium chloride (to harden)
When immobilising an enzyme, how did you form the beads?
Use a syringe, no needle
Slowly & steadily add a few drops from a height and stir to prevent clumping
Leave to harden for 15 mins
When immobilising an enzyme, why did you wash the beads?
Remove hardened yeast from outside
When immobilising an enzyme, how did you store the beads?
Can be stored in water or dried on filter paper and stared in the fridge
When immobilising an enzyme, what product did you test for? How?
Glucose
Allow to drip onto glucose test strips such as clinistix or diastrix
When immobilising an enzyme, what is the control?
Free yeast
Compare the products formed after testing an enzyme immobilisation
Free yeast → forms glucose faster but beaker is cloudy as it contains many yeast cells
Immobilised yeast → glucose is slower to form but the beaker is clear and there are no yeast cells present
When investigating the influence of light intensity on photosynthesis, what plant did you use? Why?
Elodea
So it is possible to see the bubbles of oxygen released
When investigating the influence of light intensity on photosynthesis, now did you measure the rate of photosynthesis?
The number of bubbles released in a given time
When investigating the influence of light intensity on photosynthesis, why was excess sodium bicarbonate added?
To ensure water is saturated with carbon dioxide
When investigating the influence of light intensity on photosynthesis, why is it placed in a water bath?
To keep it at optimum temperature of 25°c
When investigating the influence of light intensity on photosynthesis, why do you wait before measuring the bubbles?
Allow elodea to adapt to the conditions
When investigating the influence of light intensity on photosynthesis, how do you vary the light intensity?
Move the lamp further
When investigating the influence of light intensity on photosynthesis, what can you conclude?
As the lamp is moved closer and the rate of light intensity increases, the rate of bubble production/photosynthesis increases until it reaches saturation point at which no more light will be absorbed
Name the reagents used to test for the presence of protein in a food sample
Sodium hydroxide
&
Dilute copper sulfate
When investigating osmosis, what did you use as a semi permeable membrane?
Visiking tubing
When measuring either the pulse rate or the breathing rate, suggest any one wag of improving the accuracy of this measurement
Repeat to get an average of recovery time
When using a microscope, state one reason for using a coverslip
Prevent the sample drying out
When staining an animal / plant cell, state one precaution you took
Wear gloves
Name the part of the microscope that allows you to control the amount of light passing through the cell
Diaphragm
Name the plant used to investigate the effect of light intensity on photosynthesis, why is this plant suitable?
Elodea
Bubbles can be seen
When investigating the effect of light intensity on photosynthesis;
How did you ensure the temperature remained constant?
Water bath with a thermometer
When investigating the effect of light intensity on photosynthesis;
Why is it important to maintain a constant temperature during the investigation?
Photosynthesis controlled by enzymes which are temperature dependent
When investigating the effect of light intensity on photosynthesis;
How did you keep the concentration of carbon dioxide constant?
Add excess sodium bicarbonate to the water
Describe steps taken to view cells at 100x magnification
Select high power
Use fine focus
