Biology 9700 · AS & A Level · The immune system

The immune system — practice question

Stem cells become neutrophils through several distinct stages. A number of these stages can carry out cell division. Fig. 6.2 provides a summary of neutrophil development, and some features of cell structure are shown.
(b(i))[1]

State the place in the body where the neutrophil develops and matures.

(b(ii))[1]

Describe the shape of the nucleus in a mature neutrophil.

(b(iii))[1]

State the alternative name for the cell structures labelled as “granules” in Fig. 6.2.

(c(i))[2]

Primary granules contain proteins called defensins. These attach to bacterial cell-surface membranes and make very small pores in the membrane. Suggest how defensins help the neutrophil kill bacteria.

(c(ii))[2]

Secondary granules contain lysozyme. This enzyme breaks bonds in peptidoglycan molecules. Explain how lysozyme activity will cause the bacterial cell to be destroyed.

Worked solution & mark scheme

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