Biology 9700 · AS & A Level · Protein synthesis

Protein synthesis — practice question

Fibroblasts are a type of cell found in connective tissue. They synthesise and secrete collagen, which is part of the supportive material outside cells, called the extracellular matrix.
(a)[3]

Fig. 5.1 depicts the primary structure of part of a collagen polypeptide chain. Explain how the primary structure shown in Fig. 5.1 shows that the polypeptide is suitable for acting as a component of a collagen molecule.

(b)[3]

Once final processing has taken place in the Golgi body, collagen is expelled to the cell’s outer surface by exocytosis. Complete the passage to describe the process of exocytosis. Once final processing has taken place in the Golgi body, ...

(c(i))[2]

Hydrolytic enzymes called collagenases are secreted by cells in an inactive form. Cells also secrete collagenase inhibitors. The activities of the enzymes and inhibitors are controlled so that development and maintenance of the extracellular matrix are regulated. State and explain what the result will be for the composition of the extracellular matrix if collagenase inhibitor activity is needed.

(c(ii))[2]

Synthetic inhibitors have been tested as possible treatments for diseases caused by failure to regulate collagenase activity. The research requires investigation of an inhibitor’s mechanism of action. State the effect that a non-competitive inhibitor will have on the maximum rate of reaction, $V_{\max}$, and the Michaelis-Menten constant, $K_m$, of collagenase.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: glycine is found at every third amino acid

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