GCSE Biology Syllabus

Biology syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Biology in GCSE, not a summary of it.

1. 1

   Cell Biology

   3 topics

   • Cell Structure
   • Cell Division
   • Transport in Cells
2. 2

   Organisation

   3 topics

   • Digestive System
   • Circulatory System
   • Plant Tissues
3. 3

   Infection and Response

   3 topics

   • Pathogens
   • Immune System
   • Vaccination
4. 4

   Bioenergetics

   2 topics

   • Photosynthesis
   • Respiration

Biology flashcards for GCSE

22 of 50 cards from the Biology deck — real questions with worked answers.

1. What are the main sub-cellular structures found in ALL eukaryotic cells (animal and plant)?

   Nucleus (contains DNA/controls activities), cytoplasm (site of chemical reactions), cell membrane (controls what enters and leaves), mitochondria (site of aerobic respiration), and ribosomes (site of protein synthesis).

2. Which sub-cellular structures do plant cells have that animal cells do NOT?

   Cell wall (made of cellulose, for strength/support), permanent vacuole (filled with cell sap, maintains turgor), and chloroplasts (contain chlorophyll, site of photosynthesis).

3. List the key differences between prokaryotic and eukaryotic cells.

   Prokaryotic cells are much smaller, have no true nucleus (DNA is a single loop free in the cytoplasm plus small rings called plasmids), and have no membrane-bound organelles. Eukaryotic cells are larger, have a nucleus enclosing their DNA, and contain membrane-bound organelles like mitochondria.

4. What is the equation for calculating magnification, and how do you rearrange it?

   $$\text{magnification} = \frac{\text{image size}}{\text{real (actual) size}}$$ Rearranged: $\text{real size} = \frac{\text{image size}}{\text{magnification}}$.

5. How many micrometres ($\mu m$) and nanometres ($nm$) are in one millimetre?

   $1\ \text{mm} = 1000\ \mu m$ and $1\ \mu m = 1000\ nm$, so $1\ \text{mm} = 1\times10^{6}\ nm$.

6. Why do electron microscopes allow us to see more detail than light microscopes?

   Electron microscopes have much higher magnification AND much higher resolution (resolving power), so they can distinguish two points that are very close together, revealing sub-cellular structures (e.g. ribosomes, internal mitochondrial structure) that light microscopes cannot resolve.

7. What are the stages of the cell cycle in order, including mitosis?

   1) Interphase — cell grows, DNA replicates (each chromosome makes a copy), and organelles/ribosomes/mitochondria increase in number. 2) Mitosis — chromosomes line up, are pulled to opposite poles, and the nucleus divides. 3) Cytokinesis — cytoplasm and cell membrane divide to form two identical daughter cells.

8. What is mitosis and why is it important for organisms?

   Mitosis is cell division producing two genetically identical diploid daughter cells. It is important for growth, development, tissue repair, and replacement of damaged/worn-out cells, and for asexual reproduction.

9. What is a stem cell, and what are the two main types in animals?

   A stem cell is an undifferentiated cell that can divide to produce more cells of the same type and can differentiate into specialised cells. Embryonic stem cells can differentiate into ANY cell type; adult stem cells (e.g. in bone marrow) can only form a limited range, such as blood cells.

10. How can meristem stem cells in plants be used, and give one advantage.

    Meristem tissue (found in root and shoot tips) can differentiate into any plant cell throughout life. It can be used to produce clones of plants quickly and cheaply, e.g. to grow crops with desirable features or preserve rare species from extinction.

11. Define diffusion and give three factors that increase its rate.

    Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration (down a concentration gradient). Rate increases with a steeper concentration gradient, higher temperature, and a larger surface area of the membrane.

12. Define osmosis.

    Osmosis is the net movement of water molecules from a dilute solution (high water concentration) to a more concentrated solution (low water concentration) across a partially permeable membrane.

13. What is active transport and how does it differ from diffusion?

    Active transport is the movement of substances AGAINST a concentration gradient (from low to high concentration) using energy from respiration. Unlike diffusion, it requires energy (ATP); diffusion is passive and moves down the gradient.

14. Give two examples of active transport in living organisms.

    Root hair cells absorbing mineral ions from dilute soil solution into more concentrated cell sap; and the small intestine absorbing glucose into the blood when glucose is at a lower concentration in the gut.

15. State the surface-area-to-volume ratio principle and why large organisms need exchange surfaces.

    As an object gets larger, its surface-area-to-volume ratio decreases. Large/multicellular organisms have a small SA:V ratio so diffusion across the outer surface is too slow to meet needs; they need specialised exchange surfaces (e.g. lungs, gills, villi) and transport systems.

16. List the adaptations that make an effective exchange surface.

    Large surface area, thin membrane (short diffusion distance), a good blood supply (in animals) to maintain a steep concentration gradient, and for gases, ventilation (a supply of the substance and removal at the other side).

17. Name the enzymes that digest carbohydrates, proteins, and lipids, and their products.

    Carbohydrase (e.g. amylase) breaks down starch into glucose/sugars; protease breaks down proteins into amino acids; lipase breaks down lipids into fatty acids and glycerol.

18. Where is amylase produced in the digestive system?

    Amylase is produced in the salivary glands, the pancreas, and the small intestine.

19. What are the roles of bile in digestion?

    Bile is made in the liver, stored in the gall bladder, and released into the small intestine. It neutralises stomach acid (making conditions alkaline for enzymes to work) and emulsifies fats into small droplets, increasing surface area for lipase to work faster.

20. Describe the lock-and-key model of enzyme action.

    Each enzyme has an active site with a specific shape that is complementary to its substrate. The substrate fits into the active site like a key in a lock, forming an enzyme-substrate complex, allowing the reaction to occur. Only the correct substrate fits, which is why enzymes are specific.

21. What happens to an enzyme at temperatures above its optimum or at extreme pH?

    The active site changes shape (the enzyme denatures) so the substrate can no longer fit, and the enzyme stops working. Rate of reaction rapidly falls to zero.

22. How are villi adapted for the absorption of digested food?

    Villi provide a large surface area, have a thin wall (one cell thick) for a short diffusion distance, a rich blood supply to maintain a concentration gradient, and contain a lacteal for absorbing lipid products.

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