Cell Theory and Cell Types Quiz

Cell Theory

• All living organisms are made up of cells
• All life functions occur within cells
• All cells come from pre-existing cells

Prokaryotic Cells

• Unicellular organisms belonging to Bacteria or Archaea domains
• Smallest and oldest form of life
• High diversity and adaptability.
• Cell membrane creates a barrier between inside and outside environments of the cell, controls what enters and exits
• Cytoplasm is a fluid-like substance filling the cell, containing biomolecules and inorganic substances
• Nucleoid region contains DNA in a dense form, without a membrane
• Ribosomes are small particles responsible for protein synthesis, essential for cell functions
• Cell wall provides protection, and mechanical structure (present in many bacteria)

Eukaryotic Cells

• Larger than prokaryotic cells
• Organisms include protists, plants, fungi, and animals
• Presence of internal compartments (organelles) each with its own membrane
• Organelles are specialized in their form and function
• Animal cells do not contain a cell wall or chloroplasts
• Plant cells contain a cell wall and chloroplasts; have large central vacuoles

Cell Organelles

• Organelles: Structures within a cell with specific functions
• Membrane-bound organelles: Enclosed structures within a membrane
• Nucleus: Control center of the cell, contains DNA
• Endoplasmic Reticulum (ER): Network of tubes, smooth ER and rough ER
• Golgi bodies: Packages substances for transport within or out of the cell
• Ribosomes: Synthesize proteins
• Mitochondria: Powerhouse of the cell, responsible for energy production (aerobic respiration)
• Lysosomes: Contain digestive enzymes to break down waste materials (mostly in animal cells)
• Vacuoles: Membrane-bound sacs, used to store water, food, or waste (larger in plant cells)

Cell Membrane

• Protective layer made up of phospholipids and proteins
• Phospholipids form a double layer (hydrophilic heads, hydrophobic tails)
• Cholesterol affects membrane fluidity and flexibility (mostly in animal cells)
• Proteins have various functions including determining cell identity, communicating with other cells, and transporting molecules across the membrane
• Different types of proteins (e.g., signal, enzyme, channel, transporter, recognition).

Membrane Transport

• Passive transport: Spontaneous movement of molecules across a membrane, does not require energy (e.g., simple diffusion, facilitated diffusion)
• Active transport: Requires energy to move molecules against their concentration gradient; essential for maintaining specific concentrations of molecules within or outside the cell

Osmosis and Tonicity

• Osmosis: The movement of water across a selectively permeable membrane from a region of high water concentration to a region of low water concentration
• Tonicity: Comparative measurement of osmotic pressure between two solutions separated by a membrane
• Isotonic: Concentration of solutes is equal on both sides of the membrane
• Hypertonic: Higher concentration of solutes outside the cell relative to the inside; causes water to flow out of the cell
• Hypotonic: Lower concentration of solutes outside the cell relative to the inside; causes water to flow into the cell

Test your knowledge on the fundamentals of cell theory and the differences between prokaryotic and eukaryotic cells. This quiz covers the characteristics, structure, and functions of both cell types. Perfect for biology students studying cell biology.