Ch 5

• Membrane function: cell must regulate the flow of materials to and from the environment, plasma membrane is selectively permeable
• Passive Transport: is the spontaneous movement of substances across a membrane - molecules are naturally in constant motion, they continue to more further until they are evenly spread out
• Diffusion: net movement of molecules from an area of high concentration to lower concentration, no energy input
• Passive transport: three types across the plasma membrane - diffusion, facilitated diffusion, and osmosis
• Facilitated Diffusion: some substances dont cross the membranes so they transport via facilitated diffsuion, requires the help of transport proteins embedded within the plasma membrane
• Osmosis: dissuion of water across a selectively permeable mebrane, down the concetration gradient (high to low)
• Solvent: dissolving agent (water)
• solute: dissolved in the solvent (salts/sugars)
• Hypertonic solution: more solute outside the cell than inside the cell
• isotonic solution: same amount of solute outside the cell and inside the cell
• hypotonic solution: less solute outside than inside the cell
• Active Transport: requires the input of energy to move molecules across a membrane, is against the concentration gradient(low to high), and also utilizes a membrane transport proteins.
• Energy: the capacity to do work/ cause change
• Energy is considered to exist in two states: Kinetic Energy - the energy of motion, Potential energy - stored energy that can be used for motion, location, structure
• 1st law of thermodynamics: energy can be formed to another but it cannot create or destroy
• 2nd law of thermodynamics: every time energy is converted entropy (amount of disorder/ randomness) increases
• Potential Energy: chemical energy - stored in chemical bonds of molecules that can be released by chemical reaction
• Photosynthesis: convert light energy from the sun into chemical energy stored in organic molecules(food)
• Cellular respiration: breaks down organic molecules - releases chemical energy - uses to generate ATP
• ATP(adenosine triphosphate): energy of the cell, acts like a shuttle of energy
• ATP functions: three negatively charged phosphate groups contain high energy bonds, bond between 2nd and 3rd phosphate group is broken off to power cellular processes
• Metabolism: Anabolism - forms bond, photosynthesis, Catabolism - breaks bond, cellular respiration
• Chemical reaction include: Reactants - the starting materials, Products - the end materials
• Enzyme: is very selective in the reaction it catalyzes, each enzyme recognizes a specific substrate