Biology Topics 1-10

Topic 1: Life Processes

The Seven Life Processes

• Move: All living things show movement. Even plants move, such as turning towards the sun.
• Respire: Releasing energy from food.
• Sense: Responding to environmental changes.
• Grow: Increasing in size or developing.
• Reproduce: Producing new organisms.
• Excrete: Eliminating waste.
• Nutrition: Intake of food and nutrients.

Breathing vs Respiration

• Breathing: Involves air movement in and out of lungs.
• Respiration: Chemical reaction in cells releasing energy.

Types of Respiration

• Aerobic respiration: Uses oxygen.
  • Word Equation: Glucose + Oxygen → Carbon dioxide + Water + Energy
  • Symbol Equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy
• Anaerobic respiration: Occurs without oxygen.
  • Word Equation: Glucose → Lactic Acid
  • Symbol Equation: C₆H₁₂O₆ → 2C₃H₆O₃

Viruses

• Tiny particles that reproduce by infecting living cells.
• Called obligate parasites because they need host cells.
• Not considered living as they don’t carry out all life processes independently.

Topic 2: Cells and Organisation

Structure of Cells

• Animal Cells: Include cell membrane, cytoplasm, mitochondria, nucleus.
• Plant Cells: Include cell wall, chloroplasts, permanent vacuole in addition to animal cell components.

Identifying Cell Parts

• Recognize and label parts such as cell wall, membrane, cytoplasm, nucleus, vacuole, mitochondria, chloroplasts.

Functions of Cell Parts

• Cell Wall: Supports/protects plant cells.
• Cell Membrane: Regulates entry/exit.
• Cytoplasm: Site of cell activities.
• Nucleus: Holds genetic material; controls cell.
• Vacuole: Stores cell sap, maintains firmness.
• Mitochondria: Energy release through respiration.
• Chloroplasts: Photosynthesis site.

Levels of Organisation

• Cells → Tissues → Organs → Organ Systems → Organism

Major Human Organs and Systems

• Understand the function of lungs, kidneys, skin, brain, heart, liver, digestive organs, nervous system, skeleton, and muscles.

Plant, Animal, and Bacterial Cells

• Similarities: All have cell membrane, cytoplasm.
• Bacteria lack nucleus, mitochondria, are smaller.

Topic 3: Pathogens

Pathogens and Parasites

• Pathogen: Microorganism causing disease (viruses, bacteria, fungi, protoctists).
• Parasite: Lives in/on another organism, deriving nutrients at the host’s expense.

Types of Pathogens

• Viruses: Smaller than bacteria; reproduce inside cells.
• Bacteria: Single-celled, lack nucleus.
• Fungi: Can be single-celled or multicellular.
• Protoctists: Usually single-celled with various structures.

Antibiotics and Problems

• Antibiotics work on bacterial infections but not viruses.
• Overuse can lead to antibiotic resistance.

Vaccination

• Vaccines train the immune system to fight specific pathogens, helping prevent disease.

Topic 4: Movement of Molecules

Diffusion

• Movement from high to low concentration.
• Faster with higher temperature and larger concentration difference.

Surface Area to Volume Ratio

• Larger surface area relative to volume enhances absorption and release speed.

Topic 5: The Digestive System

Digestive System Parts

• Includes teeth, salivary glands, esophagus, stomach, pancreas, intestines.

Balanced Diet

• Includes carbs, proteins, fats, vitamins, minerals, fiber, water.

Starvation and Malnutrition

• Starvation: Insufficient food.
• Malnutrition: Lack of specific nutrients.

Energy Needs

• Varies by age and activity level.
• Different foods provide varying energy levels.

Topic 6: The Circulatory System

Circulatory Systems

• Single: One loop (e.g., fish).
• Double: Two loops (e.g., humans).

Main Parts and Functions

• Heart, Arteries, Veins, Capillaries: Blood circulation and substance exchange.

Exercise and Heart Rate

• Increases during exercise to supply muscles with oxygen and nutrients.

Lifestyle and Heart Health

• Factors like smoking, diet, exercise, and stress impact heart health.

Topic 7: Plants

Plant Structure and Function

• Roots absorb water/minerals; stems support/transport; leaves photosynthesize.

Leaf Adaptations

• Large area, waxy surface, stomata, chloroplasts for photosynthesis.

Photosynthesis

• Word Equation: Carbon dioxide + Water → Glucose + Oxygen
• Symbol Equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
• Factors: Light, CO₂ levels, temperature.

Topic 8: Organisms and Environment

Adaptations and Factors

• Features aiding survival (e.g., fur for warmth, spines for protection).
• Abiotic (non-living) and biotic (living) factors affect organisms.

Topic 9: Interactions Between Organisms

Feeding Roles

• Producers, consumers (primary, secondary, tertiary), decomposers.

Energy Flow

• Energy transfer through food chains/webs; energy lost as heat, etc.

Topic 10: Further Interactions with the Environment

Role of Decomposers

• Recycle carbon by breaking down dead organic matter.

Human Activities and Carbon Dioxide

• Activities like burning fossil fuels, deforestation increase CO₂ levels, contributing to global warming.