End of Year Exam Revision 2026 Core Sciences

Smoking and Breathing

  • Respiration vs. Breathing:

    • Respiration: The cellular process of releasing energy from glucose.

    • Breathing: The physical mechanism of ventilation (inhaling and exhaling).

  • Air Composition:

    • Inhaled Air: Contains approximately 21% oxygen, 0.04% carbon dioxide, 78% nitrogen.

    • Exhaled Air: Contains approximately 16% oxygen, 4% carbon dioxide, 78% nitrogen.

  • Thorax and Ventilation:

    • The chest cavity's mechanics facilitate air movement in and out of lungs through muscle contractions.

  • Alveoli:

    • Specialized structures for gas exchange.

    • Adaptations:

      • Large surface area to maximize gas exchange.

      • Thin walls to reduce diffusion distance.

      • Close proximity to blood vessels for efficient transport of gases.

  • Smoking Impact:

    • Nicotine:

    • Highly addictive stimulant affecting the nervous system.

    • Tar:

    • Carcinogenic substance leading to increased cancer risks and chronic bronchitis.

    • Carbon Monoxide:

    • Reduces blood's oxygen-carrying capacity, leading to fatigue and poor health.

    • Emphysema:

    • Damage to alveoli structure reduces the efficiency of gas exchange.

Atoms and Elements

  • Foundations:

    • Elements are pure substances made up of atoms, represented by unique symbols.

  • Atomic Structure:

    • Atoms consist of three subatomic particles:

    • Protons: Positively charged particles in the nucleus.

    • Neutrons: Neutral particles also in the nucleus.

    • Electrons: Negatively charged particles orbiting the nucleus.

  • The Periodic Table:

    • A systematic arrangement of all known elements by increasing atomic number.

  • Metals vs. Non-metals:

    • Metals: Good conductors of heat and electricity, malleable, and lustrous.

    • Non-metals: Poor conductors, brittle in solid state, and dull appearance.

Electricity

  • Safety and Components:

    • Understanding and identifying electrical symbols is crucial for safety.

  • Materials:

    • Conductors: Materials that allow electrical flow (e.g., copper).

    • Insulators: Materials that do not allow electrical flow (e.g., rubber).

  • Circuits:

    • Series Circuits: One continuous path; current is the same throughout.

    • Parallel Circuits: Multiple paths; current divides among branches.

  • Switches:

    • Used to control the completion of a circuit, turning devices on or off.

Food and Digestion

  • Balanced Diet:

    • Essential nutrients include:

    • Carbohydrates (sugars and starch)

    • Proteins

    • Lipids (fats)

    • Water

    • Vitamins and minerals

    • Fibre

  • Deficiencies:

    • Specific diseases can arise when nutrients are lacking (e.g., scurvy from vitamin C deficiency).

  • Food Tests:

    • Benedict's test: Identifies sugars.

    • Iodine test: Identifies starch.

    • Biuret test: Identifies proteins.

    • Emulsion test: Identifies lipids.

  • Digestive Process:

    • Includes mechanical breakdown (teeth/saliva) and chemical breakdown (enzymes).

    • Peristalsis: Wave-like muscle contractions that move food through the digestive tract, aided by dietary fibre.

    • Key Organs:

    • Stomach: Breaks down food using digestive acids.

    • Pancreas: Produces enzymes for digestion.

    • Intestines: Absorb nutrients into the bloodstream.

Forming Compounds

  • Changes:

    • Chemical changes result in new substances; physical changes do not alter composition.

  • Conservation of Mass:

    • Total mass remains unchanged in chemical reactions.

  • Compounds:

    • Formed when atoms bond chemically, represented by chemical formulas (e.g., H<em>2OH<em>2O for water, CO</em>2CO</em>2 for carbon dioxide).

  • Reactions:

    • Involves writing word equations and predicting products like oxides, sulphides, and chlorides.

  • Mixtures:

    • Combinations of substances where no chemical bonding occurs.

Space

  • Hierarchy:

    • Structure of the cosmos includes:

    • Solar System: Comprises planets and the sun.

    • Milky Way Galaxy: Contains our solar system.

    • Universe: Encompasses all galaxies and space.

  • Orbits:

    • Gravitational forces keep planets in motion around the sun.

  • Earth Mechanics:

    • Day and Night: Result of Earth's rotation on its axis.

    • Seasons: Caused by Earth’s axial tilt and orbit around the sun.

    • Phenomena: Includes phases of the moon and solar/lunar eclipses.

    • Satellites: Distinction between polar and geostationary orbits based on their functions.

Scientific Skills

  • Units and Conversions:

    • Every measurement requires appropriate units (e.g., 10extcm=0.1extm10 ext{ cm} = 0.1 ext{ m}).

  • Experimental Variables:

    • Identification of variables is essential for conducting a "fair test" to minimize errors.

  • Data Presentation:

    • Tables: Must include clear headings and units.

    • Graphing:

    • Independent variable is plotted on the xx-axis; dependent variable on the yy-axis.

    • Requires a continuous scale with accurate plotting and a line of best fit.