Study Notes
Cells are the basic building blocks of all living things, providing structure, taking in nutrients, converting them into energy, and carrying out specialized functions. Specialized cells in animals and plants have unique features that allow them to perform specific roles.
- Cell — the basic unit of life in all living organisms. Example: Human body is composed of trillions of cells.
- Nucleus — serves as the cell's command center and houses DNA. Example: Directs cell growth and division.
- Plasma membrane — the outer lining of the cell that controls entry and exit of materials. Example: Separates the cell from its environment.
- Cytoplasm — jelly-like fluid inside the cell surrounding the nucleus. Example: Contains organelles and supports cellular functions.
- Mitochondria — organelles that convert energy from food into usable cell energy. Example: Known as the powerhouse of the cell.
- Sap vacuole — stores materials and maintains water pressure in plant cells. Example: Provides mechanical support.
- Cell wall — rigid layer providing structural support and protection in plant cells. Example: Filters molecules passing in and out.
- Chloroplast — organelle where photosynthesis occurs in plant cells. Example: Contains chlorophyll to absorb sunlight.
- Red blood cells — specialized cells that carry oxygen around the body. Example: Biconcave shape increases surface area for oxygen absorption.
- Ciliated cells — cells with tiny hairs that move mucus and particles out of airways. Example: Found in the respiratory tract.
- Nerve cells — long cells that transmit nerve impulses. Example: Covered with a fatty sheath for insulation.
- Root hair cells — increase surface area for water and mineral absorption in plants. Example: Tiny hairs poke into the soil.
- Palisade cells — major site of photosynthesis in plants. Example: Contain many chloroplasts for maximum light absorption.
Exam Tips
Key Definitions to Remember
- Cell: Basic unit of life
- Nucleus: Command center of the cell
- Plasma membrane: Outer lining controlling material entry and exit
- Mitochondria: Energy converters of the cell
- Chloroplast: Site of photosynthesis in plant cells
Common Confusions
- Difference between plant and animal cells
- Function of mitochondria vs chloroplasts
Typical Exam Questions
- What is the function of the nucleus? It directs cell activities and contains DNA.
- How do red blood cells carry oxygen? They contain hemoglobin and have a biconcave shape.
- What is the role of chloroplasts in plant cells? They conduct photosynthesis using chlorophyll.
What Examiners Usually Test
- Differences between plant and animal cells
- Functions of specialized cells
- Structure and function of cell organelles