Cambridge A-Level · Biology

Cells, Biological Molecules and Genes

19 practice questions, each with the answer and an explanation.

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Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 19 questions

  1. Which organelle is the main site of aerobic respiration in a eukaryotic cell?
  2. What type of bond joins amino acids together in a polypeptide?
  3. A competitive inhibitor reduces the rate of an enzyme-controlled reaction. Which statement explains this?
  4. In the fluid mosaic model of the cell surface membrane, what is the function of cholesterol?
  5. A cell placed in a solution has a water potential lower than the cell contents. What happens?
  6. Which statement about DNA replication is correct?
  7. What is the role of mRNA in protein synthesis?
  8. A section of DNA has the base sequence TACGGT. What is the sequence of the mRNA transcribed from it?
  9. A gene has 600 nucleotides in its coding region, including the stop codon, and no introns. How many amino acids are in the polypeptide?
  10. What is the function of the enzyme helicase during DNA replication?
  11. Which cell type contains a cell wall made of cellulose?
  12. Why does the surface area to volume ratio matter for a single-celled organism?
  13. In which stage of mitosis do sister chromatids separate and move to opposite poles?
  14. A cell has a mitotic index of 0.15. A sample of 400 cells is counted. How many are in mitosis?
  15. What is the difference between a stem cell that is totipotent and one that is multipotent?
  16. What is the name of the process by which a gene is copied into mRNA?
  17. Which feature of the genetic code is described as degenerate?
  18. A point mutation changes a codon from GAA to GAG, and both code for glutamic acid. What is the effect on the polypeptide?
  19. What is the role of the SA node in the heart?

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