Unit 3 Flashcards
*Metabolism
-All of the chemical reactions within each cell of an organism.
*Chemical reactions
-The breaking and forming of bonds between different substances during chemical changes.
*Catabolic
-Reactions that break down larger molecules into simpler compounds.
*Anabolic
-Reactions that build larger molecules from smaller ones.
*Activation energy
-The amount of energy needed to make a chemical reaction start.
*Reactant (substrate)
-Substance that is changed during a chemical reaction.
*Product
Substance that is made during a chemical reaction.
*Endothermic
-A reaction that overall absorbs more energy (in the form of heat or light) than it releases.
*Exothermic
-A reaction that overall releases more energy (in the form of heat or light) than it absorbs.
*Enzyme
-(Usually a protein) that speeds up a biochemical reaction by lowering its activation energy.
*Catalyst
-Substances that speed up reactions without being permanently altered.
*Active site
-Location on an enzyme where the substrate binds.
*Denaturation
When an enzyme’s active site loses its specific shape, causing a loss in biological activity
Summarize how energy changes during a chemical reaction as bonds are broken and formed.
*Energy is released when bonds are formed.
*Energy is absorbed when bonds are broken.
*No energy in the system gets lost, but can seem lost due to a change in form.
Explain the overall function of enzymes in biochemical reactions like photosynthesis and cellular respiration.
*Enzymes control all metabolic reactions. They speed up reactions (that can occur on their own, just slowly) by lowering the activation energy needed to get the reaction started.
Draw and label energy diagrams of biochemical reactions (endothermic AND exothermic), including products, reactants, and activation energy.
check doc
Describe five factors that affect the rate of chemical reactions.
As temperature increases, the rate increases (to a degree) due to molecules moving faster and colliding more.
Enzymes work in specific pH ranges. They can lose function outside of that range and not be able to speed up the reaction.
As substrate concentration increases, the rate increases, due to more particle collisions.
Catalysts (like enzymes) speed up reactions by lowering the activation energy needed.
Competitive inhibitors lower the rate by competing with substrate for the enzyme’s active site.
*ATP
-An energy-carrying molecule that carries/stores energy for cell functions; the main energy currency for the cell
*Chemiosmosis
-Movement of ions down a concentration gradient
Explain the purpose of ATP.
*ATP carries energy in a usable form for the cell wherever it is needed.
2.Draw the structure and label the parts of a molecule of ATP.
check doc
Describe the ATP-ADP cycle. Include what is and is not recycled, and the role of ATP synthase.
*ATP is really unstable, so it doesn’t take a lot of energy to break the bond between the 2nd and 3rd phosphates.
*When this happens and the P goes off to bond elsewhere, energy is released for the cell to use.
*When consumed food gets broken down during cellular respiration, the energy gets stored in ATP by adding a 3rd phosphate back on to ADP.
*ADP is recycled, nothing else necessarily is.
*ATP Synthase is the enzyme that catalyzes the addition of the 3rd phosphate to make ADP à ATP.
Explain what the energy is used for when a phosphate is removed, and where that energy initially comes from.
*Energy can be used for active transport, cell division, or other cellular processes.
*That energy initially comes from glucose (a carb) and other macromolecules.
Summarize why the overall process of breaking down ATP is considered an exothermic process, while the overall process of forming ATP is considered an endothermic process.
*It doesn’t take a big input of energy to break the 3rd phosphate off (since ATP is so unstable).
Overall, more energy is released than absorbed by this process, and thus it is considered exothermic.
*It takes a lot of energy to attach the 3rd phosphate, so very little is released when ATP is formed.
Overall, because more energy is absorbed than released, it is considered an endothermic process.
