(3 points) Simple diffusion moves molecules from an area of higher concentration to an area of lower concentration without an input of energy. Facilitated diffusion follows the same rules as regular diffusion (higher to lower concentration and no energy input), but uses protein carrier molecules to allow substances that are fat soluble to diffuse through the cell membrane. 5. List three examples of passive transport mechanisms. (3 points) • Movement of O2 through membrane • Movement of glucose into cells • Movement of H2O in & out of cells • Formation of kidney filtrate 6.
4. What is the main difference between simple diffusion and facilitated diffusion? (3 points) Simple diffusion moves substances from an area of higher concentration to an area of lower concentration; it does not require energy. Facilitated diffusion moves substances from an area of higher concentration to an area of lower concentration; it does not require energy but the transported substance either binds to protein carriers in the membrane and is ferried across or moves through water-filled protein channels. 5.
Distinguish between oxidation/reduction, activation energy/catalysis, substrate/product, and hydrogen peroxide/peroxidase. Describe how temperature, pH, enzyme concentration, and substrate concentration affect the reaction rate. Explain why peroxidase is a necessary enzyme for all aerobic or oxygen-using cells. Background Information The thousands of chemical reactions that occur in a cell at any given time do not occur randomly, but are highly under the control of biological catalysts called enzymes. A catalyst is a substance that speeds up a chemical reaction without being consumed by the reaction.
Cell Membrane The cell membrane is a thin semi-permeable membrane that surrounds the cytoplasm of a cell. The membranes function is to protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out. It is a fluid phospholipid bilayer embedded with proteins and glycoproteins. The phospholipid bilayer is arranged so that the polar ends of the molecules (the portion of the phospholipid that is soluble in water) form the outermost and innermost surface of the membrane while the non-polar ends (the fatty acid portions of the phospholipids that are insoluble in water) form the centre of the membrane Nuclear Membrane It is a double-layered membrane enclosing the nucleus of a cell that controls what enters and leaves the nucleus. It can also be called nuclear envelope.
Final Lab Catalase Formal Lab: Introduction: An enzyme is a biological catalyst that alters the rate of reaction without being consumed or changing the reaction itself. Enzymes are also proteins; they take on a three- dimensional shape which forms a specific active site. An active site is a location where a substrate binds with an enzyme. Usually they are a pocket or groove in the three- dimensional shape of the protein. Next to the active site, but still a great distance away is the Allosteric site, sites containing receptors.
D) The active transport of a substance out of a cell to maintain equilibrium. E) The movement of solute molecules from a lower to a higher concentration across a semipermeable membrane. Answer: B, osmosis is specifically the movement of solvent, not a solute or a general substance described in
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea: Sodium chloride < urea < glucose < albumin. Activity 2: Simulated Facilitated Diffusion 1. Explain one way in which facilitated diffusion is the same as simple diffusion and one way in which it differs: One way in which facilitated diffusion and simple diffusion are similar is that both transport molecules from high concentration to low concentration (down the concentration gradient). This process (in both cases) does not require energy from the cell.
The intracellular loop between domains I and II is the site for PKC and cAMP-dependent protein kinases which reduce the channel activation. Inactivation can be slowed by the phosphorylation of the intracellular loop between domains III IV (near IFM motif). Voltage-gated channels can exist in three functional states: resting (closed during normal resting potential), activated (open state briefly during initial depolarisation) and inactivated (blocked state). Various drugs can have their actions by either
In all forms of digestion (whether of proteins, carbohydrates, or fats), larger molecules are broken down into smaller molecules by a reaction with water in which a water molecule is split in two, with each part joining a different product molecule. This type of reaction is called hydrolysis. Remember that proteins are long chains of amino acids linked together by amide functional groups called peptide bonds. When protein molecules are digested, a series of hydrolysis reactions convert them into separate amino acids. RCONR2 + H2O RCO2H + HNR2 In the laboratory, the reaction above is very slow unless a strong acid catalyst is added to mixture, yet in the small intestines, where the conditions are essentially neutral rather than acidic, most of the hydrolysis of proteins takes place rather quickly.
For this reason glucose is broken down in a process known as respiration; this causes glucose to release its energy which is then used to produce adenosine triphosphate (ATP). ATP is now the immediate source of energy for the cell and allows it to carry out processes which are essential to life. ATP is found in both plant and animal cells. Adenosine triphosphate is composed of the nucleotide base adenine, combined with a ribose sugar and three phosphate groups. The bonds between the phosphate groups are unstable and therefore have a low activation energy, meaning that they can easily be broken.