Cell Membrane and Cell Transport

• The cell membrane separates the components of a cell from its environment and regulates the flow of materials into and out of the cell.
• Homeostasis is a stable, internal environment.
• The cell membrane helps cells maintain homeostasis by balancing pH, temperature, glucose intake, and water balance.
• Active Transport is like going UPHILL
• The cell membrane is a double layer (bilayer) of phosphates and fats (lipids).
• The cell membrane is made up of phospholipids with hydrophilic phosphate heads and hydrophobic fatty acid tails.
• All cells have a cell membrane made of phosphate, proteins, and lipids, known as the phospholipid bilayer.
• Prokaryotes have a cell wall and cell membrane, while eukaryotes have either a cell membrane (animal cells) or a cell membrane and cell wall (plant cells).
• Passive transport is a process that does not require energy and includes simple diffusion, osmosis, and facilitated diffusion.
• Simple diffusion is the random movement of particles or solutes in an area, both inside and outside of the cell.
• Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
• Osmosis is the movement of water through a selectively permeable membrane, such as the cell membrane.
• A semi-permeable membrane is permeable to water, but not to sugar.
• Hypertonic solutions contain a high concentration of solute relative to another solution, causing a cell to shrink when placed in it.
• Hypotonic solutions contain a low concentration of solute relative to another solution, causing a cell to swell and possibly explode when placed in it.
• Isotonic solutions contain the same concentration of solute as another solution, resulting in no net movement of water into or out of the cell.
• In hypertonic solutions, the water or solution outside of the cell is saltier than the inside of the cell, causing the cell to shrink.
• Hyper refers to "more" or "above" and is associated with the shrinking of cells in hypertonic solutions.
• Hypotonic solution: A solution with a lower concentration than the cell, causing the cell to take in water and swell.
• Isotonic solution: A solution with an equal amount of salt as the cell, resulting in no change in cell size.
• Facilitated diffusion: Requires carrier and channel proteins to move particles from an area of high concentration to an area of low concentration.
• Active transport: Movement of molecules from low to high concentration, requiring energy as molecules are pumped against the concentration gradient.
• Three types of membrane proteins involved in active transport: Uniport (transports a molecule in one direction), Symport (transports two different molecules in the same direction), and Antiport (transports different molecules in opposite directions).
• Active transport uses ENERGY (ATP)
• EXOcytosis is how materials EXIT the cell
• ENDOcytosis is how materials ENTER the cell (cell eating/engulfing)
• PINOcytosis is how small materials ENTER the cell
• PHAGOcytosis is how larger materials ENTER the cell
• NO ENERGY NEEDED: Diffusion, Osmosis, Facilitated Diffusion
• ENERGY NEEDED: Active Transport
• Cell membrane helps cells maintain homeostasis —stable internal balance
• The cell membrane maintains homeostasis through balancing the pH, temperature, glucose (sugar intake), water balance
• •ALL cells have a cell membrane made of Phosphate, proteins, and lipids. That’s why it’s called the Phospholipid Bilayer
• A single phospholipid has hydrophilic (water loving) phosphate heads AND hydrophobic (water hating) fatty acid tails