Study guide: Levels of Biological Organisation

📋 Course Outline

1. Organelles and Specialized Cells
2. Tissues and Their Functions
3. Organs and Their Functions
4. Organ Systems and Organisms

📖 1. Organelles and Specialized Cells

🔑 Key Concepts & Definitions

• Organelle: A part of a cell with a specific role.
• Specialized cell: A cell type with a particular combination and number of organelles.

★ Must-know

• Multiple organelles combine to form a single cell.

Further detail

• Examples of organelles include:

  • the nucleus
  • ribosomes
  • mitochondria

• Cells vary in shape and size and contain different combinations and numbers of organelles.

• Examples of specialized cells are:

  • epithelial cells
  • muscle cells
  • glandular cells

📖 2. Tissues and Their Functions

🔑 Key Concepts & Definitions

• Tissue: A group of similar cells that work together to carry out a particular function.

📝 Essential Points

• Epithelial tissue covers body surfaces, including the skin and the inside of the intestines.

• Muscle tissue contracts and relaxes to move different parts of the body.

• Glandular tissue makes and secretes chemicals such as enzymes and hormones.

• Similar cells work together to form tissue, such as epithelial cells forming epithelial tissue.

📖 3. Organs and Their Functions

🔑 Key Concepts & Definitions

• Organ: A group of different tissues that work together to perform a particular function.

★ Must-know

• The stomach combines epithelial, muscular, and glandular tissues and functions to kill microorganisms and break down proteins.

Further detail

• The pancreas and liver are examples of organs formed from combinations of tissues.

• Other examples of organs include:

  • the skin
  • teeth
  • lungs
  • spleen
  • bones
  • testes

📖 4. Organ Systems and Organisms

🔑 Key Concepts & Definitions

• Organ system: A group of organs that work together to perform a particular function.
• Organism: Formed when multiple organ systems work together.

★ Must-know

• The stomach, pancreas, liver, and other organs form the digestive system, which digests food and absorbs nutrients.

Further detail

• The cardiovascular system and reproductive system are examples of other organ systems.

• There are about 12 different organ systems.

• Examples of organ systems include:

  • the immune system
  • the nervous system
  • the respiratory system
  • the endocrine system
  • the urinary system