REQUIRED PRACTICAL'S

Question 1

Microscopes to look at cells

Answer 1

1. Place a tissue on the microscope slide.
2. Add a few drops of a suitable stain.
3. Lower the coverslip onto the tissue.
4. Place the slide on the microscope stage and focus on the cells using LOW power.
5. Change to HIGH power and refocus.
6. Draw any types of cells that you see.
7. Add a scale line to the diagram.

Question 2

Potato Cylinders

Answer 2

1. Cut some cylinders of potato and measure there mass.
2. Place them in different sugar solutions.
3. After 30 minutes remove the potato and measure their mass again.

Independent Variable - What you change
Dependent Variable - That is measured
Control Variable - Kept the same throughout

Question 3

Test for Sugars, Starch & Proteins

Answer 3

• Sugars - add BENEDICTS Reagent and heat in a water bath for 2 minutes. If the sugar is there it will turn RED.
• Starch - add IODINE solution. If the starch is there it will turn BLUE/BLACK.
• Protein - add BIURET Reagent. If protein is there it will turn PURPLE.

Question 4

pH reaction of amylase enzyme

Answer 4

1. Test tube containing starch solution and a test tube containing amylase get out in a water bath at 37•
2. After 5 minutes add the amylase to the starch.
3. Every 30 seconds take a drop from the mixture and test it for starch using iodine.
4. Record how long it takes and repeat.

Question 5

Investigate the effect of light intensity - Photosynthesis

Answer 5

1. Place a piece of pondweed in a beaker and shine a light at it using a lamp.
2. Record the number of bubbles of gas coming out in one part of the pond weed for one minute.
3. Repeat this with the lamp at different distances from the pondweed.