#3 MORE AP Bio Unit 2 EXAM

• What is the purpose of compartmentalization in cells?


  It allows for specialized functions within the cell.
• How do prokaryotes differ from eukaryotes?


  Prokaryotes have no internal compartments, while eukaryotes have organelles.
• What are organelles and their functions?

  • Nucleus: DNA storage, genetic control
  • Ribosomes: Protein synthesis
  • Smooth ER: Lipid synthesis, detoxification, calcium storage
  • Rough ER: Protein synthesis
  • Golgi Apparatus: Modifies, sorts, and ships proteins and lipids
  • Mitochondria: ATP production
  • Chloroplasts: Photosynthesis
  • Lysosomes: Digestive enzymes, waste breakdown
  • Vacuoles: Storage
  • Peroxisomes: Break down fatty acids, detoxify harmful substances
• What is the function of the nucleus in a cell?


  It stores DNA and controls genetic functions.
• What is the role of ribosomes in the cell?


  They are responsible for protein synthesis.
• What are the functions of the smooth and rough endoplasmic reticulum?


  Smooth ER is involved in lipid synthesis and detoxification, while rough ER is involved in protein synthesis.
• What is the primary function of the Golgi apparatus?


  It modifies, sorts, and ships proteins and lipids from the ER.
• What is the main function of mitochondria?


  They produce ATP through cellular respiration.
• What is the role of chloroplasts in plant cells?


  They are involved in photosynthesis.
• What do lysosomes contain and what is their function?


  They contain digestive enzymes for waste breakdown.
• What is the function of vacuoles in plant cells?


  They serve as storage, particularly for water.
• What do peroxisomes do in a cell?

  They break down fatty acids and detoxify harmful substances. Known for their role in producing hydrogen peroxide (H2O2) as a byproduct of their oxidation reactions, and also for containing the enzyme catalase which breaks down this potentially harmful H2O2 into water and oxygen, effectively neutralizing it within the cell
• What is the structure of the phospholipid bilayer?


  Hydrophobic tails face inward, and hydrophilic heads face outward.
• What does the fluid mosaic model describe?


  It describes the membrane as a fluid structure with a mosaic of proteins in or on the lipid bilayer.
• How does cholesterol affect membrane fluidity?


  It regulates membrane fluidity, making it less fluid at high temperatures and preventing freezing at low temperatures.
• What are the types of membrane proteins?

  • Integral Proteins: Penetrate the hydrophobic core
  • Peripheral Proteins: Loosely bound to the membrane’s surface
  • Glycoproteins and Glycolipids: Involved in cell recognition and signaling
• What is passive transport?


  It is the movement of substances across the membrane without energy input.
• What is simple diffusion?


  It is the movement of small nonpolar molecules across the membrane.
• What is facilitated diffusion?


  It is the movement of larger or polar molecules through channel or carrier proteins.
• What are aquaporins?


  Aquaporins are specialized channels for water movement.
• What is osmosis?


  It is the diffusion of water across a selectively permeable membrane.
• What is active transport?


  It is the movement of substances against the concentration gradient, requiring energy.
• What is the sodium-potassium pump?


  It is an example of active transport that moves Na⁺ out and K⁺ into the cell.
• What are the types of bulk transport?

  • Endocytosis: Bringing substances into the cell
  • Phagocytosis: "Cell eating"
  • Pinocytosis: "Cell drinking"
  • Receptor-mediated endocytosis: Specific molecules bind to receptors
  • Exocytosis: Exporting substances out of the cell
• What is tonicity?


  Tonicity is the ability of a surrounding solution to cause a cell to gain or lose water.
• What does isotonic mean?


  It means there is no net water movement, and the cell stays the same.
• What happens in a hypertonic solution?


  Water leaves the cell, causing it to shrink.
• What happens in a hypotonic solution?


  Water enters the cell, causing it to swell and possibly burst.
• What is water potential (Ψ)?


  It determines the direction of water movement from higher to lower water potential.
• What is the water potential equation?


  Ψ = Ψp + Ψs (pressure potential + solute potential).
• What is the solute potential equation?

  Ψs = -iCRT (where i = ionization constant, C = molar concentration, R = pressure constant, T = temperature in Kelvin).
• What are the components of the cytoskeleton?


  Microtubules, microfilaments, and intermediate filaments.
• What is the function of microtubules?


  They maintain cell shape, facilitate organelle movement, and assist in chromosome movement during cell division.
• What do microfilaments do?


  They are involved in muscle contraction, cell movement, and cytokinesis.
• What is the role of intermediate filaments?


  They provide mechanical support and are more permanent than microtubules or microfilaments.
• What are the types of cell junctions?

  • Tight Junctions: Prevent leakage of extracellular fluid
  • Desmosomes: Anchor cells together via intermediate filaments
  • Gap Junctions: Allow communication and ion transfer between cells
  • Plasmodesmata: Channels in plant cells for transport between adjacent cells
• What is the function of tight junctions?


  They prevent leakage of extracellular fluid.
• What do desmosomes do?


  They anchor cells together via intermediate filaments.
• What is the function of gap junctions?


  They allow communication and ion transfer between cells.
• What are plasmodesmata?


  They are channels in plant cells allowing transport between adjacent cells.