5.2) Phagocytosis

Question 1

What is the body’s first line of defence?

Answer 1

A physical or chemical barrier to entry

Question 2

What is the second line of defence if the first line of defence fails?

Answer 2

White blood cells

Question 3

What are the two types of white blood cell?

Answer 3

• Phagocyte
• Lymphocyte

Question 4

What is the function of a phagocyte?

Answer 4

To ingest and destroy the pathogen by the process of phagocytosis before it can cause harm

Question 5

What is the function of a lymphocyte?

Answer 5

It is involved in immune responses

Question 6

What is involved in the process of phagocytosis:

1.
2.
3.
4.
5.

Answer 6

1. The phagocyte is attracted to the chemical products of the pathogen. It moves towards the pathogen along a concentration gradient
2. The phagocyte has receptors on its cell-surface membrane that can attach to chemicals on the surface of the pathogen
3. Lysosomes in the phagocyte move towards the phagosome formed by engulfing the bacterium
4. The lysosomes release lysozymes into the phagosome where they hydrolyse (break down) the bacterium
5. The hydrolysis products of the bacterium are absorbed by the phagocyte

Question 7

What are some examples of attractants that phagocytes are attracted to?

Answer 7

• Dead cells
• Damaged cells
• Abnormal cells
• Chemical products of pathogens