lab exam 2

• In all chemical reactions, the reactants are molecules that undergo a change.
• Reactants can also be called substratses, which are changed during the course of the reaction and are turned into the products.
• A single reactant breaks down to two products.
• All the reactions that occur in a cell have an enzyme.
• Enzymes are organic catalysts that speed metabolic reactions.
• The reactants in an enzymatic chemical reaction are called substrates.
• During a degradation reaction, the substrate is broken down to the products.
• During a sythesis reaction, substrates are joined to form a product.
• The location where the enzyme and substrate form an enzyme-substrate complex is called the active site.
• Catalase speeds the breaking down of hydrogen peroxide in nearly all organisms including bacteria, plants, and animals.
• Enzymes lower the energy of activiation.
• Increasing the temperature increases the likelihood that active sites will be occupied because molecules move about more rapidly as the temperature rises.
• A warm temperature increases enzyme activity
• A very high temperature causes the enzyme to denature - lose its original shape.
• Catalase is an enzyme found in cells where the pH is near 7.
• The cell theory states that all organisms are composed of cells and that cells come only from other cells.
• The content of the cell, called the cytoplasm, is enclosed by the plasma membrane.
• The plasma membrane regulates the movement of molecules into and out of the cytoplasm.
• Prokaryotic cells do not have a nucleus or organelles.
• Eukaryotic cells contain a nucleus and organelles
• Organelles are small, membraneous bodies, each with a specific structure and function.
• The nucleus in a eukaryotic cell is enclosed by a nuclear envelope and contains nucleoplasm.
• Cytology is the study of cellular structure and function.
• Pili is used to attach some types of bacteria to surfaces or to exchange genetic material with other bacteria.
• Nucleoid regions are concentrations of DNA.
• Cyanobacteria are the largest prokaryotes.
• Cyanobacteria are often surrounded by a mucilaginous sheath.
• All of the material and organelles contained by the plasma membrane are collectively called the protoplast.
• Movement of the chloroplast is called cytoplasmic streaming or cyclosis.
• The pH scale ranges from 0-14
• A buffer is a system of chemicals that takes up excess hydrogen ions or hydroxide ions as needed.
• Heat causes random motion of molecules that passively moves molecules in biological systems.
• The Brownian Movement is the uncontrolled movement of particles in a liquid and visible under high magnification.
• Diffusion is the movement from a region of high concentration to a region of low concentration.
• Polar molecules have positively charged areas and negatively charged areas.
• Dialysis is the seperation of dissolved substances by means of their unequal diffusion through a differentially permeable membrane.
• Phenolepthalein is a pH indicator that turns red in basic solutions
• Iodine is a starch indicator that changes from yellow to dark blue in the presence of starch.
• Osmosis is the diffusion of water across a differentially permeable membrane.
• A solution is a liquid mixuture of two or more kinds of molecules.