Ch.3 Energy, Enzymes, & Metabolism Flashcards
Define Metabolism
The set of all chemical reactions in a cell that keep it alive, including both building up and breaking down substances
Define Catabolism
The process of breaking down larger molecules into smaller ones, releasing energy
Define anabolism
The process of building larger molecules from smaller ones, using energy
Relating to chemical reactions, define reactants
Substances that start a chemical reaction and are changed during the reaction
Relating to chemical reactions, define products
Substances formed as a result of the chemical reaction
Relating to chemical reactions, define bidirectional
A reaction that can go in both directions, meaning reactants can turn into products, and products can turn back into reactants
Define equilibrium
When a chemical reaction balances out, so the amounts of reactants and products stay the same over time
Describe the rates of forward and backwards reactions when a system is at equilibrium
At equilibrium, the rate of the forward reaction (reactants to products) is equal to the rate of the backward reaction (products to reactants)
State the essential properties of enzymes
Speed Up Reactions: They act as catalysts, making chemical reactions happen faster
Are Specific: Each enzyme works on a specific substrate (reactant) or type of reaction
Are Not Used Up: Enzymes are not consumed in the reaction; they can be used repeatedly
Lower Activation Energy: They reduce the amount of energy needed to start a reaction
Define substrate as it relate to enzymes
The molecule that an enzyme acts on to start a chemical reaction
Define active site as it relate to enzymes
The specific part of the enzyme where the substrate binds and the reaction occurs
Define conformational change as it relate to enzymes
The change in the enzyme’s shape when the substrate binds, which helps the enzyme work more effectively
Define product as it relate to enzymes
The new molecule(s) formed as a result of the enzyme-catalyzed reaction
Describe the effect enzymes have on biochemical reactions
Enzymes help reactions happen faster by reducing the energy needed to start them
Define oxidation type chemical reactions
A chemical reaction where a molecule LOSES electrons, often releasing energy
Define reduction type chemical reactions
A chemical reaction where a molecule GAINS electrons, usually requiring energy
Describe the relative energy level of the electrons carried in a reduced electron carrier (high or low)
Electrons carried in a reduced electron carrier (like NADH or FADH2) have high energy
State the primary function of ATP in human cells
ATP provides energy for various cellular processes, like muscle contraction and active transport
Describe the higher- and lower-energy states of ATP in human cells
Higher-Energy State: ATP (adenosine triphosphate) has three phosphate groups and is rich in energy
Lower-Energy State: ADP (adenosine diphosphate) and a free phosphate group result from ATP losing one phosphate group, releasing energy
Describe the efficiency of glucose oxidation reactions in human cells
Is highly efficient, converting most of the glucose’s energy into usable ATP
State the three major steps in glucose oxidation and the average number of ATPs generated during these processes
Glycolysis: Breaks down glucose into pyruvate, generating about 2 ATPs
Krebs Cycle (Citric Acid Cycle): Processes pyruvate to produce energy carriers, generating about 2 ATPs
Electron Transport Chain: Uses energy carriers to produce ATP, generating about 28-34 ATPs
Overall, glucose oxidation generates about 32-38 ATPs in total.
State where in the cell the Kreb’s cycle and electron transport system take place
Krebs Cycle (Citric Acid Cycle): Takes place in the mitochondria, specifically in the mitochondrial matrix
Electron Transport Chain: Takes place in the mitochondria, specifically in the inner mitochondrial membrane
Describe the role of oxygen in aerobic respiration
Oxygen helps to remove used electrons by turning them into water, which keeps the process going and allows for more ATP to be made
In your own words, state the first law of thermodynamics
Energy can’t be made or lost; it just changes form. The total energy stays the same.
