Cell Exam Questions

Question 1

Describe how HIV replicates? [4 marks]

Answer 1

1. RNA is converted into DNA using the enzyme reverse transcriptase.
2. The DNA is inserted into the DNA of the helper T cell.
3. The DNA is transcribe into mRNA.

Question 2

Describe how HIV replicates? [4 marks]

Answer 2

1. RNA is converted into DNA using the enzyme reverse transcriptase.
2. The DNA is inserted into the DNA of the helper T cell.
3. The DNA is transcribe into mRNA.

Question 3

To observe the behaviour of chromosomes during mitosis using an optical microscope, a student prepared a microscope slide of stained, squashed cells from the tip of an onion root.

To create the slide she:
-cut the first 5mm from the top of an onion root and placed it on a glass slide.
-added stain and acid to the root tip on the slide and placed a cover slip on top.
-warmed the glass slide
-pressed down firmly on the cover slip

Explain why the student:
1. Used the first 5 mm from the onion root tip.
2. Pressed down on the cover slip firmly.
3. Added acid to the root [3 marks]

Answer 3

1. This is where mitosis occurs.
2. To created a single layer of cells so that light can pass through the specimen.
3. To break down links between cells/cell walls.

Question 4

The cells lining the ileum are specialised for absorbing the products of digestion, such as amino acids. One specialisation is that the container embedded proteins to transport molecules across the surface.

One of these proteins is the membrane-bound enzyme ATP-hydrolyse.

Suggest and explain the function of this enzyme in absorbing amino acids. [4 marks]

Answer 4

1. Hydrolyses ATP into ADP + Pi releases energy.
2. This energy actively transport sodium ions of the epithelial cells into the blood.
3. This creates a sodium ion concentration radiant from the ileum into the epithelial cells.
4. Sodium ions are cotransported into the epithelial cells with amino acids.