Cell Biology Basics

What is a cell?

• The smallest structural and functional unit of an organism.
• Typically microscopic.

Characteristics of living things

• Grow in size
• Reproduce
• Repair themselves
• Require energy
• Respond to their environment
• Have a lifespan
• Made of one or more cells
• Produce waste

Cell Theory

• All living things are made up of one or more cells.
• The cell is the basic unit of life.
• All cells come from pre-existing cells.

Who discovered cells?

• Robert Hooke, around 1665.

Organelles

• Mitochondria: Powerhouse of the cell.
• Nucleus: The "brain" of the cell, helps with cell growth.
• Cytoplasm: A goopy substance that holds the cell's parts together.
• Vacuole: Works like a vacuum, stores water and nutrients.
• Cell Wall: Protects the outer layer of plant cells.
• Chloroplasts: Found in plants, help with photosynthesis.
• Cell Membrane: Keeps the cell separate from its environment.

Plant vs. Animal Cells:

• Plant cells: Have cell walls, chloroplasts, and larger vacuoles.
• Animal cells: Do not have cell walls or chloroplasts, but contain lysosomes.

Diffusion

• The movement of particles from an area of high concentration to an area of low concentration.
• Essential for cells to obtain nutrients and remove waste.

Osmosis

• A special type of diffusion involving water molecules.
• Water moves from an area of high concentration to an area of low concentration across a semi-permeable membrane.
• Key for maintaining proper water levels within cells.

Unicellular vs. Multicellular Organisms

• Unicellular: Made up of a single cell, move with structures like cilia, flagella, or pseudopods, absorb nutrients directly from the environment, exchange gases through the cell membrane.
• Multicellular: Made up of many cells, use muscles/skeletons for movement, have specialized systems for digestion and gas exchange.

Examples of Unicellular Organisms

• Amoeba
• Paramecium
• Bacteria
• Diatoms

Organ Levels in Multicellular Organisms

• Tissues: Cells with similar functions group together, e.g., muscle tissue.
• Organs: Different tissues work together, e.g., the heart.
• Organ Systems: Organs work together, e.g., the circulatory system.

Multicellular Organism Organization

• Cells are organized into tissues, organs, and organ systems.

Levels of Permeability

• Not provided in the text, this question needs further clarification.

Test your knowledge on the fundamental concepts of cell biology. This quiz covers the definition of a cell, characteristics of living organisms, the cell theory, and the functions of various organelles. Ideal for students studying biology or life sciences.