Exam III Study Guide Flashcards
Know the basic structure of ATP and its role as the energy currency of ALL cells
Adenosine TriPhosphate (ATP) Consists of three phosphate groups, ribose, and adenine
- ATP contains energy in its chemical bonds, and it is the energy currency for all cells!
Know and compare Chemotrophs (auto traps vs heterotrophs) and Phototrophs (autotrophs vs heterotrophs).
Chemotrophs: Get their energy from Chemical Compounds
Phototrophs: Get their Energy from Sunlight
Autotroph: Get their Carbon from CO2
Heterotrophs: Get their Carbon from organic compounds
Describe and compare the metabolic processes of catabolism an anabolism.
Catabolism: Breakdown of molecules into smaller units to Produce ATP
Anabolism: Building of molecules from smaller units; Requires ATP Energy
Know the types of work that cells need to carry out.
Work of a Cell:
1) Synthesizing DNA/RNA/Proteins
2) Moving Vesicles
3) Pumping Substances across Membranes
Know and compare kinetic and potential energy
Kinetic Energy: Energy of Motion
Potential Energy: Stored energy, which can potentially be used to do work
* (Chemical Energy is a form of Potential Energy
Describe chemical energy
Chemical Energy: Energy stored within the bonds of a molecule. When an energy is broken, it releases energy
- The inverse is also true — it takes energy to form bonds!
Know where chemical energy is stored within ATP
Within ATP, the Majority of ATP is stored in the Phosphate Groups!
- The rest of the molecule is just Carbons, Nitrogen’s, and Hydrogens… Which aren’t very electronegative in comparison.
Define an open system in the context of thermodynamics
Open System: Energy and Matter can be transferred between the system and its surroundings
Example: Organisms are open systems: I can eat food, and absorb chemical energy — and my body can release thermal energy back into the atmosphere
Describe and compare the first and second laws of thermodynamics
First Law of Thermodynamics: Energy is neither creates nor destroyed — it transforms from one form to another
Second Law of Thermodynamics: There is a loss of energy available to do work when energy is transformed
- Less Energy will be available after transforming
Define Gibbs Free Energy and describe its relationship to endergonic and exergonic reactions
Gibbs Free Energy: The amount of energy available in a system to “do work”
- Endergonic Reaction: Products have more free energy than reactants; So Gibbs Free Energy is Positive
- Exergonic Reaction: Products have less free energy than reactants; So Gibbs Free Energy is Negative!
Describe and compare endergonic and exergonic reactions
Endergonic: Starting Reactants have less energy than the Products (Energy is usually added to a reaction like this)
Exergonic: Starting Reactants have more energy than the products (Energy is lost in this reaction as products are formed, like the production of heat).
Know the definition of Gibbs free energy and the equation for calculating ΔG
ΔG= ΔH-T*ΔS
(G): Gibbs Free Energy
(H): Enthalpy, total energy available
(S): Entropy: Degree of Disorder
(T): Temperature: Absolute temperature in Kelvin, influences the movement of molecules and adds to the degree of disorder
Describe the relationship between Gibbs free energy and catabolism/anabolism.
Catabolic Reactions (Break one thing into many small parts): Products have less chemical energy than reactants, more disordered, yielding a negative ΔG
Anabolic Reactions (Building a large thing from small parts): The Products have more chemical energy than the reactants (Yielding a Positive ΔG).
Know the process of ATP hydrolysis
Adenosine TriPhosphate + Water —> Adenosine Diphosphate + Phosphate
-ΔG= -ΔH - T*ΔS -ΔG: Exergonic Reaction
Describe the coupling of endergonic and exergonic reactions
Coupling of Endergonic and Exergonic Reactions allow for the Energy Lost in one reaction (Exergonic Reactions) to fuel the Activation Energy required for an Endergonic Reaction (Products have Greater Energy than Reactants).
Define the activation energy of a reaction and describe the role of enzymes
Activation Energy: The minimum input of energy required for a reaction to proceed
Role of Enzymes in Reactions: Reduces the Activation Energy Requirements (making it easier/faster to proceed).
Describe the active site of an enzyme (including its formation and interaction with substrate molecules)
Active Site: Region of an enzyme that binds the substrate and converts it to the product.
- Interactions (between Substrate and Active Site) are typically Non-covalent, and help to stabilize the transition state; resulting in a decrease of activation energy.
Describe and compare competitive inhibition, non-competitive inhibition, and allosteric activation
Inhibitors: Decreases the activity of enzymes
Competitive Inhibition: The Enzyme binds either its substrate or its inhibitor
Non-Competitive Inhibition: The binding sites of the substrate and inhibitor are different, allowing for the Enzyme to bind to both.
Allosteric Activation: Positive effector binds to an enzyme, shaping its active site to one that is complementary to the substrate.
Describe positive and negative feedback
Positive Feedback: A positive feedback loop occurs in nature when the product of a reaction leads to an increase in that reaction. If we look at a system in homeostasis, a positive feedback loop moves a system further away from the target of equilibrium. It does this by amplifying the effects of a product or event and occurs when something needs to happen quickly.
Negative Feedback: A negative feedback loop occurs in biology when the product of a reaction leads to a decrease in that reaction. In this way, a negative feedback loop brings a system closer to a target of stability or homeostasis. Negative feedback loops are responsible for the stabilization of a system, and ensure the maintenance of a steady, stable state. The response of the regulating mechanism is opposite to the output of the event.
Know the definition and objective of cellular respiration
Cellular Respiration: The Process in which sugars (glucose) are converted into usable energy (ATP)
Know and describe the four stages of cellular respiration, including the order in which they occur relative to one another
The Four Stages of Respiration (in order) Are:
1) Glycolysis (Cytoplasm): Glucose is partially broken down, energy is released (Proteins and Lipids may also be broken down by different pathways.
2) Acetyl-CoA synthesis (Mitochondria): Pyruvate, produced in Glycolysis, is converted into Acetyl-CoA and CO2
3) Citric Acid Cycle (Mitochondria): Acetyl-CoA is broken down releasing CO2 energy, and electron carriers
4) Oxidative Phosphorylation (Mitochondria): Electron carriers from stages 1-3 release high-energy electrons to the electron transport chain, producing ATP
Describe oxidation-reduction reactions (including oxidizing agent, reducing agent, oxidized product, reduced product)
Oxidaition: Loss of Electrons (What is getting Oxidized, Making it the Reducing agent of the reaction).
Reduction: Gain of Electrons (What is getting Reduced, Making it the Oxidizing agent of the reaction).
Describe the breakdown of glucose relative to an oxidation-reduction reaction
Glucose —-> CO2 and H20
Glucose is broken down into Co2 and H20.
In this reaction, Glucose is the Electron donor (getting oxidized) —> Thus, it is considered to be the Reducing Agent.
Describe the process of carbohydrate catabolism
Chemical Energy is stored in bonds. The Chemical Energy of Glucose is transferred to the chemical bonds of ATP and Electron carriers as Glucose goes through Catabolism (broken down into smaller parts).
Define, describe, and compare the electron carriers NAD+ and FAD
Electron Carriers: Can accept electrons to become Reduced. Once it is Reduced, it can be used to Synthesize ATP
NAD+: Has Nitrogen and 3 rings
FAD: Has Fluorine and 3 rings.
Describe the process of substrate-level phosphorylation
Phosphorylation: Organic Molecule transfers one of their phosphate groups to ADP, Producing ATP
- Substrate-Level Phosphorylation is used to generate all of the ATP during the stages of Glycolysis and the Citric Acid Cycle.