second page

• Cell Transport

  • Passive Transport
  • Active Transport
• Passive Transport


  Movement of substances across the plasma membrane without the use of the cell's energy (with the concentration gradient), includes diffusion, osmosis, and facilitated transport
• Active Transport


  Movement of substances across the plasma membrane that requires the use of the cell's energy and carrier molecules, substances are moving from an area of low concentration to an area of higher concentration (against the concentration gradient), includes endocytosis and exocytosis
• Homeostasis


  Internal equilibrium, the plasma membrane regulates what enters and leaves the cell, a selectively permeable membrane only allows certain substances to pass through
• Effect of Concentration on a Cell

  • Hypotonic - water moves in, cell bursts
  • Hypertonic - water moves out, cell shrivels
  • Isotonic - no net movement, cell maintains equilibrium
• Homeostasis: Self-regulating mechanism that maintains internal conditions (with individual cells and within organs, systems), example: body temperature, respiration, nutritional balance, etc., cells communicate their needs to each other mainly through their cell membranes by releasing chemical messengers that, ultimately, tell the hypothalamus gland in the brain that a change needs to be made in the interstitial fluid, since it is the ruler of homeostasis, the hypothalamus sends neural and chemical signals to other glands, tissues, organs, and organ systems to adjust the internal environment, the interstitial fluid, so that it is more suitable for all the cells at that particular time, and since we are always changing what we are doing, homeostasis needs to change along with our activities, both day and night, this constantly changing internal environment is the process of homeostasis
• Negative Feedback


  Glucose / Insulin levels in cells
• Positive Feedback


  Blood platelets / Blood clotting
• Cellular Respiration


  1. Glycolysis (anaerobic)

  2. Citric acid cycle (aerobic)

  3. Electron transport chain (aerobic)
• Photosynthesis


  Carbon dioxide + water + energy from sunlight -> glucose + oxygen
• ATP


  A molecule that stores and releases the energy in its bonds when the cell needs it, removing a phosphate group (P) releases energy for chemical reactions to occur in the cell and ATP becomes ADP, when the cell has energy, the energy is stored in the bond when the phosphate group is added to the ADP
• Fermentation


  1. Lactic Acid Fermentation (muscle cells): glucose -> lactic acid + 2ATP

  2. Alcoholic Fermentation (plant cells): glucose -> carbon dioxide + alcohol + 2ATP