Temperature on cell membranes

Question 1

What’s the independent variable?

Answer 1

temperature of water

Question 2

What is the dependent variable?

Answer 2

% transmission of light through the resulting solution

Question 3

What are other variables to be controlled?

Answer 3

• volume of distilled water
• time left in water
• size of beetroot pieces

Question 4

Equipment

Answer 4

• raw beetroot
• cork borer
• tile
• knife
• ruler
• beaker
• forceps
• water baths
• boiling tubes
• thermometer
• colourimiter
• stop clock
• distilled water

Question 5

Describe the method.

Answer 5

1. using a cork borer and knife cut beetroot into 1cm length
2. place in distilled water overnight to remove any dye released on preparation by cutting and breaking cells innit)
3. wash and blot dry
4. place 8 boiling tubes of distilled water into 8 water baths of different temparatures
5. one at tempatarure add a piece of beetroot to each test tube and leave for 30 mins
6. remove beetroot and shake test tube to disperse dye
7. set colourimeter to % absorbance on blue/green filer
8. calibrate using distilled water
9. add 2cm3 of each distilled water and dye solution to a cuvette and read absorbance value of colorimeter.

Question 6

Possible evaluation issues.

Answer 6

• some beetroot may have skin on, affecting surface area
• dificulty in maintaining temperature
• accurate reading of colourimeter
• accurate size of beetroot
• ensuring same amount of time at different temparatures

Question 7

What is another way this can be experimented?

Answer 7

the effect of alcohol n membrane permeability. Add different concentrations of alcohol and keep temperature the same