Biology 9700 · AS & A Level · Protein synthesis

Protein synthesis — practice question

Bees are insects that use venom as a defence against attack. Melittin is a polypeptide found in bee venom.
(a(i))[1]

State how many carbon atoms are present in the R group of lysine.

(a(ii))[2]

Finish the diagram showing the structure of lysine in Fig. 2.1.

(b)[3]

Complete Table 2.1 by entering the level of protein structure that matches each description.

(a)

Lysine is one of the amino acids found in melittin. Fig. 2.1 presents an incomplete diagram of lysine’s structure.

(c)[2]

When a bee stings a person, venom is introduced into the body. Melittin in the venom interacts with the cell surface membranes of body cells, as shown in Fig. 2.2. Outline how melittin affects the structure of a cell surface membrane, as shown in Fig. 2.2.

(d)[4]

Cells affected by melittin break down into cell fragments. These cell fragments are then taken up by phagocytes for further breakdown. Describe the process by which phagocytes take in and break down these cell fragments.

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