Cells

Question 1

In required practical 2 (garlic root tips) explain why a student would:

1. Use the first 5mm from the garlic root tip
2. Press down on the cover slip firmly
3. Add acid to the root

Answer 1

1. This is where mitosis occurs
2. To create a single layer of cells so that light can pass through the specimen
3. To break down links between cell walls (so that cells can be separated and squashed)

Question 2

The cells lining the ileum are specialised for absorbing the products of digestion, such as amino acids. One specialisation is they contain embedded proteins to transport molecules across the surface.
One of these proteins is the membrane bound enzyme ATP hydrolase
Suggest and explain the function of this enzyme in absorbing amino acids

Answer 2

1. (State function) Hydrolysing ATP into ADP + Pi releasing energy
2. (Explain) this energy actively transports sodium ions out of the epithelial cells into the blood
3. This creates a sodium Jon concentration gradient from the ileum into the epithelial cells
4. Sodium ions are cotransported into the epithelial cells with amino acids