Physiology of Plant Cells

• Diffusion refers to the net movement of particles (atoms, molecules, or ions) from a region of higher concentration to a region of lower concentration as a result of random motion.
• Diffusion is important to cellular function because it is responsible for the movement of many materials throughout the cytoplasm and into and out of cells.
• Passive diffusion is the movement of molecules across a semi-permeable membrane without the help of protein channels, thus, does not require energy.
• Facilitated diffusion is the flow of molecules down a concentration gradient across a membrane through special passageways or membrane proteins called carrier proteins.
• Passive transport is the movement of ions and other atomic or molecular substances across cell membranes without the need for energy input.
• Active transport requires the expenditure of the cell’s energy to move specific substances against their concentration gradients.
• Osmosis refers to the diffusion of water through a semipermeable membrane.
• The concentration of water is inversely related to the concentration of the solution, meaning more solute present in the solution corresponds to lesser concentration of water.
• Photosynthesis is the chemical process that transforms light energy into chemical energy by green plants and other producer organisms.
• The light-dependent reaction in the thylakoid generates energy as ATP and NADPH, which power the carbon fixation reactions in the stroma.
• Carbon fixation reaction utilizes carbon dioxide and is fixed into three-carbon molecules and subsequently synthesized into glucose.