Zoology

• What are the two types of prokaryotic cells mentioned?

  Archaea and bacteria
• What is a key characteristic of prokaryotic cells regarding their nucleus?


  They have no nucleus
• Where is DNA located in prokaryotic cells?


  In an unbound region called the nucleoid
• What is a defining feature of prokaryotic cells regarding organelles?


  They have no membrane-bound organelles
• What bounds the cytoplasm in prokaryotic cells?


  The plasma membrane
• Which type of white blood cells are best for studying lysosomes?


  Phagocytic white blood cells
• How does a greater proportion of unsaturated phospholipids affect membrane fluidity?


  It tends to increase membrane fluidity
• What is true about membranes rich in unsaturated fatty acids?


  They are more fluid than those rich in saturated fatty acids
• What are the main types of carbohydrates?

  • Monosaccharides
  • Disaccharides
  • Polysaccharides
  • Starch
• What is the function of the nuclear lamina?


  It is responsible for maintaining the shape of the nucleus
• What is the structure and function of microtubules?


  • Thickest cytoskeletal component
  • Involved in organelle movement
  • Transport secretory vesicles to plasma membrane
  • Play a role in mitosis
• What is diffusion?


  It is the tendency for molecules to spread out evenly into the available space
• What is osmosis?


  It is the passive diffusion of water molecules across a selectively permeable membrane
• What are peroxisomes responsible for?


  Oxidative metabolism and detoxification of harmful substances
• How are food vacuoles formed?


  During phagocytosis
• What is the role of the phosphate group in the plasma membrane?


  It is responsible for the hydrophilic nature of the plasma membrane
• What is the primary use of Transmission Electron Microscopy (TEM)?


  To view the internal structures of cells
• What does the Sodium-Potassium Pump do?


  It exchanges Na+ for K+ across the plasma membrane of animal cells
• What is the simplest collection of matter that can be alive?

  The cell
• How do ribosomes use DNA?


  They use the information from DNA to make proteins
• How is DNA organized in the nucleus?


  Into discrete units called chromosomes
• What is the relationship between the endoplasmic reticulum (ER) and the nuclear envelope?


  The ER is continuous with the nuclear envelope
• What role do microtubules play in cilia and flagella?


  They control the beating of cilia and flagella
• What is the most abundant lipid in the plasma membrane?


  Phospholipids
• How does cholesterol affect membrane fluidity?


  It has different effects on membrane fluidity at different temperatures
• How does water diffuse across a membrane?


  From the region of lower solute concentration to the region of higher solute concentration
• What problems do hypertonic or hypotonic environments create for organisms?


  They create osmotic problems
• What is true about facilitated diffusion?


  It does not require expenditure of energy
• What does the Endosymbiont Theory explain about mitochondria?


  • Mitochondria originated from free-living prokaryotic organisms (proteobacteria)
  • An ancestral eukaryotic cell engulfed a bacterium through endocytosis
  • Developed a symbiotic relationship providing energy (ATP) and protection
  • Mitochondria have their own circular DNA and reproduce independently
• How do microtubules and motor proteins function in transporting cargo vesicles?


  • Microtubules act as tracks for motor proteins
  • Kinesin moves toward the plus end (outward transport)
  • Dynein moves toward the minus end (inward transport)
  • Cargo vesicles are attached to motor proteins that walk along microtubules
• What are the differences between passive and active transport?


  • Passive transport: no energy required, moves from high to low concentration (e.g., diffusion, osmosis)
  • Active transport: requires energy, moves from low to high concentration (e.g., sodium-potassium pump, endocytosis)
  • Passive transport maintains equilibrium; active transport is crucial for nutrient uptake and waste removal
• What is the structure of the plasma membrane and its role in transport?


  • Selectively permeable barrier
  • Composed of phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates
  • Hydrophilic heads face outward; hydrophobic tails face inward
  • Allows small nonpolar molecules to pass via simple diffusion; larger molecules require facilitated diffusion or active transport