practicals Flashcards
(21 cards)
What is the aim of the Microscopy practical?
To use a light microscope to observe, draw, and label a plant or animal cell.
What stain is used to see plant cells more clearly under the microscope?
Iodine.
What is the aim of the Osmosis practical?
To investigate the effect of different sugar or salt solutions on potato mass.
What is the independent variable in the osmosis practical?
The concentration of the sugar or salt solution.
What is the dependent variable in the osmosis practical?
The change in mass of the potato cylinders.
What is the aim of the Enzymes practical?
To investigate how pH affects the rate of reaction of amylase on starch.
What indicator is used in the enzyme/amylase practical?
Iodine – to test if starch is present.
What is the aim of the Food tests practical?
To identify the presence of starch, sugar, protein, and lipids in different foods.
What is the aim of the Photosynthesis practical?
To investigate the effect of light intensity on the rate of photosynthesis (using pondweed).
What is measured to show the rate of photosynthesis?
The number of bubbles or volume of oxygen produced.
What test is used to detect starch?and what colour
Iodine test.
What is a positive result for starch?
The iodine solution turns blue-black.
What test is used to detect sugar (glucose)?
Benedict’s test.
What is a positive result for sugar?
The solution turns from blue to green, yellow, or brick red after heating.
What test is used to detect protein?
Biuret test.
What is a positive result for protein?
The solution turns from blue to purple.
What test is used to detect lipids (fats)?
Sudan III test or ethanol test.
What is a positive result for lipids?
A red layer forms on top (Sudan III), or a cloudy white layer appears (ethanol test).
What enzyme breaks down starch?
Amylase.
What enzyme breaks down proteins?
Protease.
What enzyme breaks down lipids?
Lipase.
