Practicals

Question 1

How does amylase break down starch?

Answer 1

Starch/ substrate binds to the active site of an enzyme
Shape of enzyme and active site are complementary
A chemical reaction occurs to produce smaller molecules

Question 2

Microscopy practical …

Answer 2

Use a stain to make organelles visible ( cell wall, nucleus )
Get the specimen as flat and thin as possible
Start on the smallest lens, focus , then move up a lens
A ruler or eyepiece scale can be used to measure size

Question 3

Investigating the effect of antiseptics / antibiotics practical

Answer 3

Prepare a plate of agar with a culture of bacteria
Divide the plate into 3 sections
Put different antibiotics/antiseptics on paper discs and place in each section
Incubate the plate at 25 degrees for 48 hours
Measure the area of the clear zone

Question 4

Osmosis practical

Answer 4

Bore 5 equal size potatoes
Measure the length and mass of each size of potatoe
Place the potatoes in 5 different concentrations of solution ranging from 1 m in concentration all the way to distilled water
leave over night
Dry the potatoes and measure the lengths and masses of them

Question 5

How to do food test practicals

Answer 5

For each food test the sample must be grinded up with a pestle and mortar
Waters then added and it’s filtered
Protein - biuret solution is added
Fats - Sudan solution is added
Carbohydrates - iodine is added
Sugars - Benedict solution is added