Science Examination Notes
Chapter 1.1-1.2: Photosynthesis & Transport in Plants
Photosynthesis:
- Process by which green plants make food using sunlight, CO2, and water.
- Occurs in the chloroplasts (contain chlorophyll).
- Equation: 6CO2 + 6H2O -> C6H12O6 + 6O2
- Factors affecting photosynthesis: Light, Carbon dioxide, Temperature
Transport of Water and Mineral Salts:
- Water enters roots via osmosis.
- Minerals enter through active transport.
- Xylem transports water and minerals from roots to leaves.
- Transpiration helps pull water upwards.
Chapter 2: Producing Urine
- The kidneys filter blood to produce urine.
- Urine contains water, urea, and excess salts.
- Nephron is the functional unit of the kidney.
- Process: Filtration (glomerulus) -> Reabsorption (tubule) -> Secretion -> Excretion (collecting duct to ureter).
Chapter 3.1-3.5: Genetics and Evolution
Variation:
- Differences between individuals of the same species.
- Can be inherited or caused by environment.
Chromosomes, Genes, and DNA:
Science Examination Notes
- DNA stores genetic information.
- Genes are segments of DNA coding for proteins.
- Chromosomes are structures made of DNA.
Fertilisation and Inheritance:
- Sperm and egg combine to form a zygote.
- Offspring inherit genes from parents.
Fetal Development:
- Embryo develops in the uterus.
- Grows into a fetus with all organs.
Natural Selection:
- Organisms with favorable traits survive and reproduce.
- Leads to evolution over time.
Chapter 4: Population and Extinction
- Population: Group of the same species living in an area.
- Factors affecting population size: food, predators, disease.
- Extinction: When no members of a species remain.
- Causes: Habitat loss, pollution, overhunting, climate change.
Chapter 5.1-5.2: Atomic Structure and the Periodic Table
- Atoms: Made of protons, neutrons, electrons.
- Atomic number = number of protons.
- Periodic Table: Arranges elements by increasing atomic number.
Science Examination Notes
Trends:
- Groups = columns (same valence electrons).
- Periods = rows (same number of shells).
- Trends: Atomic size, reactivity, metallic character.
Chapter 6.1-6.3: Bonding and Structures
Chemical Bonds:
- Ionic: transfer of electrons.
- Covalent: sharing of electrons.
- Metallic: sea of electrons.
Structures:
- Simple molecular: low melting points.
- Giant covalent: high melting points (e.g., diamond).
- Giant ionic: solid lattice, high melting points.
Density:
- Mass per unit volume.
- Density = mass/volume.
Chapter 7.1-7.5: Chemical Reactions
Changes in Reactions:
- Physical vs. Chemical changes.
- Energy changes: Exothermic (release), Endothermic (absorb).
Equations:
- Word: magnesium + oxygen -> magnesium oxide
Science Examination Notes
- Symbol: 2Mg + O2 -> 2MgO
Making Salts:
- Methods: neutralisation, precipitation, metal + acid.
Displacement Reactions:
- More reactive element displaces less reactive from compound.
Rates of Reaction:
- Affected by temperature, concentration, surface area, catalysts.