Materials are able to move across a cell membrane through one of two methods: active transport or passive transport. what is the difference between active transport and passive transport?

Passive transport: When materials move across cell membranes without using cell energy (ATP). Diffusion, facilitated diffusion, and osmosis are examples Moves small molecules like water, oxygen, carbon dioxide and glucose. ... Movement of materials across the cell membrane that requires the use of cell energy (ATP).

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products