As Biology (7401/1) Paper 1 Specimen 2014 39 Correctly Answered Questions Latest Update

01 . 4) Name two structures in a eukaryotic cell that cannot be identified using an optical microscope. [1 mark] {Ans: Mitochondrion/ribosome/endoplasmic reticulum/lysosome/cell-surface membrane}07 . 2) The part of the phospholipid in Figure 8 labelled A is formed from a particular molecule. Name this molecule. [1 mark] {Ans: Glycerol;}07 . 6) Cholesterol increases the stability of plasma membranes. Cholesterol does this by making membranes less flexible. Suggest one advantage of the different percentage of cholesterol in red blood cells compared with cells lining the ileum. [1 mark] {Ans: Red blood cells free in blood/not supported by other cells so cholesterol helps to maintain shape;}04 . 04) The arrows in Figure 5 show the directions in which each new DNA strand is being produced. Use Figure 4, Figure 5 and your knowledge of enzyme action to explain why the arrows point in opposite directions. [4 marks] {Ans: 1. (Figure 4 shows) DNA has antiparallel strands/described; 2. (Figure 4 shows) shape of the nucleotides is different/nucleotides aligned differently; 3. Enzymes have active sites with specific shape; 4. Only substrates with complementary shape/only the phosphate end (of the developing strand) can bind with active site of enzyme/active site of