Cell Biology Basics Quiz

Cell Theory

• Cells are the fundamental units of life.
• Some organisms are single-celled (unicellular), others are multicellular.
• All cells arise from pre-existing cells.

Prokaryotic vs. Eukaryotic Cells

• Prokaryotes:
  • Examples: Bacteria
  • Lack membrane-bound organelles.
  • DNA is not enclosed in a nucleus; it floats freely.
  • Smaller and simpler than eukaryotes, but capable of growth, reproduction, response to the environment, and movement.
• Eukaryotes:
  • Diverse range of organisms (animals, plants, fungi).
  • Contain membrane-bound organelles.
  • DNA is enclosed within a nucleus.
  • Larger and more complex than prokaryotic cells.

Cell Structures and Functions

• Cell Wall:
  • Function: Protection, shape maintenance, prevents excessive water uptake.
  • Structure: Composed of cellulose (and other components).
  • Found in plant and certain bacterial cells.
• Cell Membrane:
  • Function: Regulates what enters/leaves the cell, provides protection, flexible support.
  • Structure: Phospholipid bilayer with embedded proteins.
  • Found in all cells.
• Cytoplasm/Cytosol:
  • Cytoplasm: Everything within the cell membrane except the nucleus.
  • Cytosol: The jelly-like fluid surrounding organelles.
  • Found in all cells.
• Nucleus:
  • Function: Control center; contains DNA (genetic information).
  • Structure: Surrounded by double membrane (nuclear envelope) with pores for material transport.
  • Contains nucleolus (ribosome production site).
  • Found in eukaryotic cells.
• Nucleolus:
  • Function: Ribosome production.
  • Location: Inside the nucleus.
  • Found in eukaryotic cells.
• Ribosomes:
  • Function: Protein synthesis.
  • Structure: RNA and protein; two subunits.
  • Found in both prokaryotic and eukaryotic cells.
• Smooth ER:
  • Function: Lipid synthesis, detoxification.
  • Structure: Network of folded membranes.
  • Found in eukaryotic cells.
• Rough ER:
  • Function: Protein modification & transport (proteins enter for folding and processing).
  • Structure: Network of folded membranes with ribosomes attached.
  • Found in eukaryotic cells.
• Golgi Apparatus:
  • Function: Modifies, sorts, and packages proteins for secretion or intracellular use.
  • Structure: Stacked membrane sacs.
  • Found in eukaryotic cells.
• Lysosomes:
  • Function: Intracellular digestion (breakdown of molecules, damaged organelles, or cellular waste).
  • Structure: Membrane-bound sacs containing hydrolytic enzymes (pH 5).
  • Found in eukaryotic cells.
• Vacuoles & Vesicles:
  • Function: Storage of substances and transport within the cell.
  • Structure: Membrane sacs.
  • Vacuoles: Larger, for storage.
  • Vesicles: Smaller, for transport.
  • Found in eukaryotic cells.
• Chloroplasts:
  • Function: Photosynthesis (conversion of light energy to chemical energy).
  • Structure: Double-membrane-bound organelle, contains chlorophyll, stroma, and thylakoids.
  • Found in plant cells.
• Mitochondria:
  • Function: Cellular respiration (energy production from food to ATP).
  • Structure: Double-membrane-bound organelle, cristae for ATP synthesis.
  • Found in plant and animal cells.
• Central Vacuole (Plant Cells):
  • Function: Maintains cell shape and turgor pressure, stores water.
  • Structure: Large membrane-bound sac (tonoplast).
  • Found in plant cells.

Protein Synthesis and Transport

• Ribosomes synthesize proteins.
• Proteins enter the rough ER for modification.
• Proteins travel to the Golgi apparatus for sorting and packaging.
• Proteins are then shipped to their destinations within or outside the cell.

Endomembrane System

• Interchangeable membranes (e.g., ER, Golgi, lysosomes, vesicles).

Cell Membrane Structure and Function

• Structure: Phospholipid bilayer with embedded proteins and cholesterol.
• Phospholipids: Form the bilayer, regulate permeability.
• Proteins: Facilitate transport and other functions.
• Cholesterol: Maintains fluidity and stability.
• Fluid Mosaic Model: Parts of the membrane can move.
• Selectively Permeable: Membrane controls what passes through.

Cellular Transport

• Passive Transport:
  • Movement from high to low concentration, no energy required.
  • Examples: Simple diffusion, facilitated diffusion, osmosis.
• Active Transport:
  • Movement from low to high concentration, requires ATP.
• Simple Diffusion:
  • Small, nonpolar molecules pass directly through the membrane.
• Facilitated Diffusion:
  • Large, polar, or charged molecules use transport proteins to pass through.
• Osmosis:
  • Water movement across a selectively permeable membrane, often through aquaporin channels.
• Tonicity:
  • Hypertonic: High solute concentration outside the cell.
  • Hypotonic: Low solute concentration outside the cell.
  • Isotonic: Equal solute concentrations.
• Animal Cell responses to solutions
  • Hypertonic: Shrinks (crenate), may shrivel.
  • Hypotonic: Swells, may lyse (burst).
  • Isotonic: Retains normal shape.
• Plant Cell responses to solutions:
  • Hypertonic: Plasmolysis (shrinks away from cell wall).
  • Hypotonic: Turgid (normal state).
  • Isotonic: Flaccid (less firm).
• Active Transport:
  • Moves substances against a concentration gradient, requiring energy.
  • Uses specialized protein pumps across the membrane.
• Endocytosis: Taking materials into the cell.
• Exocytosis: Removing materials from the cell.
• Phagocytosis: Cellular eating (engulfing large particles).
• Pinocytosis: Cellular drinking (engulfing dissolved materials).

Scientific Method and Lab Review

• Review scientific method, experimental design, and graphing techniques.
• Review completed labs and class materials.