OCR 2023 Biology B H422/03: Practical skills in biology A Level Question Paper & Mark Scheme (Merged)

Apoptosis is the programmed cell death of damaged or unwanted cells. (a) Fig. 1.1 shows a transmission electron micrograph (TEM) of apoptosis of a leucocyte. Fig. 1.1 A B C (i) Name the following structures and processes shown in Fig. 1.1: • the structure labelled A forming in the cell surface membrane • the process occurring to the organelle labelled B • the structure labelled C. Structure A ........................................................................................................................ Process B .......................................................................................................................... Structure C ........................................................................................................................ [3] D 3 OCR 2023 Turn over 4 OCR 2023 M G2 G1 S (ii) The magnification used to produce the TEM in Fig. 1.1 was ×20000. Calculate the actual diameter of the structure labelled D in Fig. 1.1. Give your answer in standard form. Diameter of structure D = ...................................................... m [2] (b) A diagram of the cell cycle is shown in Fig. 1.2. The diagram shows a cell entering apoptosis from the G2 phase. Fig. 1.2 Apoptosis