University:
Western Oregon University
Course:
BI 102 | General Biology
Academic year:

2022
Views:

5

Pages:

1
Author:

LauraParks11

Cell membrane: is the boundary that separates the living cell from its surrounding; it has selective permeability which allows some substances to cross it more easily than others The plasma membrane is primarily composed of phospholipids and proteins in a form of a fluid mosaic (bilayer); carbohydrate are an important component of structure; phospholipids are amphipathic molecules: hydrophobic tails and hydrophilic heads Molecule movement: Types of passive transport: 1- passive transport: - no energy required - movement due to a gradient (difference in concentration pressure or charge) - movement from high to low concentration to equalize gradient 1- diffusion: Movement of particles from area of high concentrations area of low concentration 2- active transport: - needs energy - movement from low to high concentration against their concentration gradient 3- facillated diffusion: Transport proteins speed the positive movement of molecules across the path membrane (channel proteins carrier proteins) Protein properties: Hemolysis: The breakage of RBCs membrane causing the release of the hemoglobin and other internal components into surrounding fluid; visually detected by showing a pink to red color in serum or plasma - have a 3-D shape that determines the function and the structure is affected by environmental conditions like temperature and pH - if proteins or phospholipids are distorted, this can affect the permability of the membrane 2- osmosis: Diffusion of water across a selectively permeable membrane Solvent + solute= solution The effect of temperature on cell membrane: 1-hypotonic: solute concentration inside the cell is higher than outside - extremely high or low temperatures cause hemolysis - at very high temperature, the proteins become denatured - at very low temperature, the lipid bilayer structure changes from semi-fluid to gel-like and semi-crystalline 2-isotonic: solute concentration is equal inside and outside the cell 3- hypertonic: solute concentration is higher outside the cell The effect of PH on cell membrane: The effect of detergents on cell membrane: - acidic or basic PH disrupts the interactions and causes hemolysis - changing the pH of cells affects membrane proteins structure, causing proteins denaturation - detergents are molecules that manipulate and disrupt the form of hydrophobic hydrophilic interactions among the molecules (permeabilize cell membrane and leaves holes in the membrane) - cause hemolysis