Life Processes and Chemical Reactions

Definition: Life processes are essential functions that living organisms perform to maintain life.
Key Processes:
1. Nutrition:
  - Involves intake of food and its utilization.
  - Types: Autotrophic (self-synthesis; e.g., plants) and Heterotrophic (obtaining food from others; e.g., animals).
2. Respiration:
  - Process of breaking down food to release energy.
  - Types: Aerobic (with oxygen) and Anaerobic (without oxygen).
3. Transportation:
  - Movement of substances (nutrients, gases) within the organism.
  - In humans, involves the circulatory system (heart, blood vessels).
4. Excretion:
  - Removal of waste products from the body.
  - Involves kidneys in humans, which filter blood to form urine.
5. Reproduction:
  - Process of producing offspring.
  - Can be sexual (involving gametes) or asexual (without gametes).

Definition: A chemical reaction involves the transformation of reactants into products through the breaking and forming of bonds.
Types of Reactions:
1. Combination: Two or more substances combine to form a single product (e.g., A + B → AB).
2. Decomposition: A single compound breaks down into two or more products (e.g., AB → A + B).
3. Displacement: An element displaces another in a compound (e.g., A + BC → AC + B).
4. Redox Reactions: Involves oxidation (loss of electrons) and reduction (gain of electrons).
Indicators of Chemical Reactions:
- Color change
- Temperature change
- Formation of gas (bubbles)
- Formation of precipitate (solid)

Definition: Electricity is the flow of electric charge, typically through conductors like metals.
Key Concepts:
1. Current:
  - Flow of electric charge (measured in Amperes).
  - Types: Direct Current (DC) flows in one direction; Alternating Current (AC) changes direction periodically.
2. Voltage:
  - Electric potential difference between two points (measured in Volts).
3. Resistance:
  - Opposition to the flow of current (measured in Ohms).
  - Factors affecting resistance: Material, length, cross-sectional area, temperature.
4. Ohm's Law:
  - Relationship between voltage (V), current (I), and resistance (R): V = I × R.
5. Series and Parallel Circuits:
  - Series: Components connected end-to-end; total resistance increases.
  - Parallel: Components connected across the same voltage source; total resistance decreases.

Life Processes: Essential functions enabling organisms to sustain life.
Nutrition:
- Intake and utilization of food.
- Autotrophic organisms synthesize their own food (e.g., plants).
- Heterotrophic organisms obtain food from external sources (e.g., animals).
Respiration:
- Breakdown of food for energy release.
- Aerobic respiration requires oxygen, while anaerobic occurs without it.
Transportation:
- Movement of nutrients and gases within an organism.
- In humans, the circulatory system (heart and blood vessels) facilitates this process.
Excretion:
- Removal of waste products.
- In humans, kidneys filter blood to produce urine.
Reproduction:
- Offspring production through sexual (involving gametes) or asexual (without gametes) methods.

Chemical Reaction: Transformation of reactants into products through bond changes.
Types:
- Combination: Multiple substances combine to form one product (e.g., A + B → AB).
- Decomposition: A single compound separates into two or more products (e.g., AB → A + B).
- Displacement: An element replaces another in a compound (e.g., A + BC → AC + B).
- Redox Reactions: Processes involving oxidation (loss of electrons) and reduction (gain of electrons).
Indicators of Reactions:
- Observable changes such as color alteration, temperature variation, gas formation (bubbles), or solid formation (precipitate).

Electricity: Flow of electric charge through conductors, primarily metals.
Key Concepts:
- Current: Movement of electric charge, measured in Amperes.
  - Types: Direct Current (DC) flows unidirectionally; Alternating Current (AC) reverses direction periodically.
- Voltage: Electrical potential difference between two points, measured in Volts.
- Resistance: Opposition to current flow, measured in Ohms.
  - Influenced by material, length, cross-sectional area, and temperature.
- Ohm's Law: Describes the relationship between voltage (V), current (I), and resistance (R) with the formula V = I × R.
- Circuits:
  - Series Circuits: Components connected sequentially; total resistance increases.
  - Parallel Circuits: Components connect across the same voltage source; total resistance decreases.