Tiêu đề Feb-Mar_2025_9700_12_QP - Crack A Level.pdf ✅

2 © UCLES 2025 9700/12/F/M/25 1 In an electron micrograph, the length of a mitochondrion is measured as 17.1 cm. The magnification of the electron micrograph is 38 000. What is the actual length of the mitochondrion? A 0.22 m B 0.45 m C 2.22 m D 4.50 m 2 There is a theory that mitochondria and chloroplasts were originally free-living prokaryotes. It is thought that millions of years ago these free-living prokaryotes were taken into larger cells by endocytosis where, instead of being digested, they became functional organelles. Which features of mitochondria and chloroplasts support this theory? 1 Mitochondria and chloroplasts are surrounded by double membranes. 2 Mitochondria and chloroplasts have small, circular DNA. 3 Mitochondria and chloroplasts synthesise proteins. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 3 Which row correctly describes a function of each cell structure? lysosome mitochondrion smooth endoplasmic reticulum A digestion of unwanted structures abundant in sites of active transport processing of proteins B digestion of unwanted structures ATP synthesis lipid production C spherical sacs containing hydrolytic enzymes abundant in sites of active transport lipid production D spherical sacs containing hydrolytic enzymes ATP synthesis processing of proteins 4 Which cell components are present in typical prokaryotic cells? cell wall 80S ribosomes A key B = present C = not present D