AQA A-Level Biology Paper 1: Practice Questions and Answers, Exams of Advanced Education

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AQA A-Level Biology Paper 1

No large lipid droplets are visible with the optical microscope in the samples from suspension A. Explain why. [2 marks]

1. Emulsification;
2. (Cannot be seen) due to resolution (of optical microscope); Modern farming techniques have led to larger fields and the removal of hedges between fields. Use Figure 4 to suggest why biodiversity decreases when farmers use larger fields. [1 mark] More centre 3 multiple choice options Describe the structure of the human immunodeficiency virus (HIV). [4 marks]
3. RNA (as genetic material);
4. Reverse transcriptase;
5. (Protein) capsomeres/capsid;
6. (Phospho)lipid (viral) envelope
7. Attachment proteins; 1 multiple choice option Use the data in Table 3 and your knowledge of the immune response to suggest why HIV controllers do not develop symptoms of AIDS. [3 marks]
8. (All) have more T helper/CD4 cells;
9. Lower viral load to infect/destroy helper T/CD4 cells;
10. (So more/continued) activation of B cells/cytotoxic T cells/phagocytes; 2 multiple choice options Describe how BrdU would be incorporated into new DNA during semi-conservative replication. [5 marks]
11. DNA helicase;
12. Breaks hydrogen bonds (between 2 DNA strands);
13. BrdU complementary to adenine (on template strand)

4. DNA polymerase joins (adjacent) nucleotides (to incorporate BrdU into the new DNA strand);
5. Phosphodiester bonds form (between nucleotides); 1 multiple choice option Suggest how Ulva lactuca is able to survive without xylem tissue. [1 mark] Short diffusion pathway (to cells) 1 multiple choice option Use your knowledge of gas exchange in leaves to explain why plants grown in soil with very little water grow only slowly. [2 marks]
6. Stomata close;
7. Less carbon dioxide (uptake) for less photosynthesis/glucose production; We have an expert-written solution to this problem! Explain five properties that make water important for organisms. [5 marks]
8. A metabolite in condensation/hydrolysis/ photosynthesis/respiration;
9. A solvent so (metabolic) reactions can occur
10. High heat capacity so buffers changes in temperature;
11. Large latent heat of vaporisation so provides a cooling effect (through evaporation);
12. Cohesion (between water molecules) so supports columns of water (in plants);
13. Cohesion (between water molecules) so produces surface tension supporting (small) organisms;