FBISE Examinations Biology (HSSC) Syllabus

Biology (HSSC) syllabus — full chapter and topic list

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

1. 1

   Bioenergetics

   2 topics

   • Photosynthesis
   • Respiration
2. 2

   Enzymes

   3 topics

   • Mechanism of Enzyme Action
   • Factors Affecting Enzyme Activity
   • Enzyme Inhibition
3. 3

   Nutrition

   3 topics

   • Autotrophic and Heterotrophic Nutrition
   • Human Digestive System
   • Disorders of Nutrition
4. 4

   Gaseous Exchange

   3 topics

   • Gaseous Exchange in Plants
   • Respiratory System in Humans
   • Respiratory Disorders
5. 5

   Transport

   3 topics

   • Transport in Plants
   • Human Circulatory System
   • Blood and Lymphatic System
6. 6

   Coordination and Control

   3 topics

   • Nervous Coordination
   • Chemical Coordination
   • Coordination in Plants
7. 7

   Support and Movement

   3 topics

   • Human Skeleton
   • Joints and Muscles
   • Locomotion Disorders
8. 8

   Reproduction

   3 topics

   • Reproduction in Plants
   • Human Reproductive System
   • Sexually Transmitted Diseases
9. 9

   Inheritance

   3 topics

   • Mendelian Genetics
   • Gene Linkage and Crossing Over
   • Genetic Disorders
10. 10

    Biotechnology

    2 topics

    • Genetic Engineering
    • Applications of Biotechnology

Biology (HSSC) flashcards for FBISE Examinations

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

1. What is the overall balanced chemical equation for photosynthesis?

   6CO2 + 12H2O --(light, chlorophyll)--> C6H12O6 + 6O2 + 6H2O

2. In which two stages does photosynthesis occur, and where in the chloroplast does each take place?

   The light-dependent reactions occur in the thylakoid membranes (grana); the light-independent reactions (Calvin cycle) occur in the stroma.

3. What is the source of the oxygen released during photosynthesis?

   The oxygen comes from the photolysis (splitting) of water molecules, not from carbon dioxide.

4. What two energy-carrying products of the light reactions are used to drive the Calvin cycle?

   ATP and NADPH.

5. Which wavelengths of visible light does chlorophyll absorb most strongly, and which does it reflect?

   It absorbs mostly red and blue light and reflects green light (which is why plants appear green).

6. State the overall equation for aerobic cellular respiration.

   C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy (ATP, ~38 ATP)

7. Name the three main stages of aerobic respiration and where each occurs in the cell.

   Glycolysis (in the cytoplasm), Krebs cycle (in the mitochondrial matrix), and the electron transport chain / oxidative phosphorylation (on the inner mitochondrial membrane).

8. What are the products of alcoholic fermentation in yeast?

   Ethanol (ethyl alcohol) and carbon dioxide, plus a small amount of ATP.

9. What is produced during lactic acid fermentation in human muscle cells?

   Lactic acid (lactate), produced when oxygen is insufficient, with a small yield of ATP.

10. Compare the ATP yield of aerobic respiration versus anaerobic respiration of one glucose molecule.

    Aerobic respiration yields about 38 ATP, whereas anaerobic respiration yields only 2 ATP per glucose molecule.

11. What is an enzyme?

    An enzyme is a biological catalyst, usually a protein, that speeds up the rate of a biochemical reaction by lowering the activation energy without being consumed.

12. Explain the 'lock and key' model of enzyme action.

    The active site of an enzyme has a rigid, specific shape that exactly fits a particular substrate, like a key fitting a lock, allowing the enzyme to act only on that substrate.

13. Explain the 'induced fit' model of enzyme action.

    The active site is flexible and slightly changes its shape to fit closely around the substrate when the substrate binds, improving the fit for catalysis.

14. What is the 'active site' of an enzyme?

    The specific region of an enzyme where the substrate binds and the catalytic reaction takes place.

15. What is an enzyme-substrate complex?

    The temporary structure formed when a substrate binds to the active site of an enzyme before products are formed and released.

16. How does temperature affect enzyme activity?

    Activity increases with temperature up to an optimum (about 37C in humans); above this, the enzyme denatures and activity falls sharply; very low temperatures slow or inactivate enzymes.

17. How does pH affect enzyme activity?

    Each enzyme has an optimum pH at which it works best; deviation from this pH alters the active site's shape and reduces activity, and extreme pH denatures the enzyme.

18. What is the optimum pH for the enzyme pepsin, and where does it act?

    Pepsin works best at a strongly acidic pH of about 2 and acts in the stomach.

19. How does substrate concentration affect the rate of an enzyme-catalysed reaction?

    Rate increases with substrate concentration until all active sites are saturated, after which the rate levels off and becomes constant.

20. What does it mean for an enzyme to be 'denatured'?

    Denaturation is the permanent change in the enzyme's three-dimensional shape (especially the active site) caused by heat or extreme pH, so it can no longer bind substrate or function.

21. Distinguish between competitive and non-competitive enzyme inhibition.

    A competitive inhibitor resembles the substrate and binds to the active site, blocking the substrate; a non-competitive inhibitor binds elsewhere (allosteric site), changing the active site's shape so substrate cannot react.

22. How can the effect of a competitive inhibitor be reduced?

    By increasing the substrate concentration, since substrate and inhibitor compete for the active site.

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