Podcast
Questions and Answers
What principle does the First Law of Thermodynamics emphasize?
What principle does the First Law of Thermodynamics emphasize?
What does an endothermic reaction imply about energy?
What does an endothermic reaction imply about energy?
Which of the following statements is consistent with the Second Law of Thermodynamics?
Which of the following statements is consistent with the Second Law of Thermodynamics?
How is chemical energy from ATP typically utilized by cells?
How is chemical energy from ATP typically utilized by cells?
Signup and view all the answers
What relationship does entropy have with living systems and the universe?
What relationship does entropy have with living systems and the universe?
Signup and view all the answers
What is the effect of phosphorylation by Pyruvate Dehydrogenase Kinase (PDK) on enzymes?
What is the effect of phosphorylation by Pyruvate Dehydrogenase Kinase (PDK) on enzymes?
Signup and view all the answers
How does an enzyme affect the activation energy (EA) of a reaction?
How does an enzyme affect the activation energy (EA) of a reaction?
Signup and view all the answers
What occurs at the active site of an enzyme?
What occurs at the active site of an enzyme?
Signup and view all the answers
What is represented by the transition state during a reaction?
What is represented by the transition state during a reaction?
Signup and view all the answers
In the reaction glucose + ATP -> glucose 6-phosphate, how is the reaction's free energy characterized?
In the reaction glucose + ATP -> glucose 6-phosphate, how is the reaction's free energy characterized?
Signup and view all the answers
What happens to the proportion of substrate molecules reaching the transition state when an enzyme is present?
What happens to the proportion of substrate molecules reaching the transition state when an enzyme is present?
Signup and view all the answers
Which component does NOT influence the rate of a reaction according to the activation energy concept?
Which component does NOT influence the rate of a reaction according to the activation energy concept?
Signup and view all the answers
What is the significance of lowering activation energy for a chemical reaction?
What is the significance of lowering activation energy for a chemical reaction?
Signup and view all the answers
Which macromolecule contains a sugar backbone?
Which macromolecule contains a sugar backbone?
Signup and view all the answers
Which feature is not unique to DNA when compared to RNA?
Which feature is not unique to DNA when compared to RNA?
Signup and view all the answers
What type of amino acids can form ionic bonds?
What type of amino acids can form ionic bonds?
Signup and view all the answers
Which amino acid has only a hydrogen in its side chain and can fit in either a hydrophilic or hydrophobic environment?
Which amino acid has only a hydrogen in its side chain and can fit in either a hydrophilic or hydrophobic environment?
Signup and view all the answers
How do amino acids like hydroxylysine and thyroxine integrate into proteins?
How do amino acids like hydroxylysine and thyroxine integrate into proteins?
Signup and view all the answers
What is the focus of bioenergetics in the context of living organisms?
What is the focus of bioenergetics in the context of living organisms?
Signup and view all the answers
Which of the following accurately describes energy in biological terms?
Which of the following accurately describes energy in biological terms?
Signup and view all the answers
Which statement correctly defines thermodynamics in the context of bioenergetics?
Which statement correctly defines thermodynamics in the context of bioenergetics?
Signup and view all the answers
What does a negative Gibbs Free Energy change (ΔG) indicate about a chemical reaction?
What does a negative Gibbs Free Energy change (ΔG) indicate about a chemical reaction?
Signup and view all the answers
Which variable in the Gibbs Free Energy equation represents the entropy of the system?
Which variable in the Gibbs Free Energy equation represents the entropy of the system?
Signup and view all the answers
If a reaction has a positive ΔG, what does it require to proceed?
If a reaction has a positive ΔG, what does it require to proceed?
Signup and view all the answers
Which factor does NOT affect the rate of a chemical reaction?
Which factor does NOT affect the rate of a chemical reaction?
Signup and view all the answers
In the reaction 2H2(g) + O2(g) → 2H2O(g), which condition affects the Gibbs Free Energy change?
In the reaction 2H2(g) + O2(g) → 2H2O(g), which condition affects the Gibbs Free Energy change?
Signup and view all the answers
What does the equilibrium constant (Keq) represent?
What does the equilibrium constant (Keq) represent?
Signup and view all the answers
What effect does a higher activation energy (EA) have on a chemical reaction?
What effect does a higher activation energy (EA) have on a chemical reaction?
Signup and view all the answers
Which of the following processes is likely to have a ΔS (Entropy) > 0?
Which of the following processes is likely to have a ΔS (Entropy) > 0?
Signup and view all the answers
What effect does pH have on enzymatic activity?
What effect does pH have on enzymatic activity?
Signup and view all the answers
How do competitive inhibitors affect enzyme kinetics?
How do competitive inhibitors affect enzyme kinetics?
Signup and view all the answers
What is a characteristic of noncompetitive inhibitors?
What is a characteristic of noncompetitive inhibitors?
Signup and view all the answers
What might occur when an enzyme is exposed to a pH significantly outside its optimal range?
What might occur when an enzyme is exposed to a pH significantly outside its optimal range?
Signup and view all the answers
Which statement is true regarding enzyme inhibitors?
Which statement is true regarding enzyme inhibitors?
Signup and view all the answers
What is the role of end product inhibition in metabolic pathways?
What is the role of end product inhibition in metabolic pathways?
Signup and view all the answers
How does temperature generally affect enzymatic reactions?
How does temperature generally affect enzymatic reactions?
Signup and view all the answers
What is the effect of covalent modification on enzymes?
What is the effect of covalent modification on enzymes?
Signup and view all the answers
Study Notes
Bioenergetics and Enzymes
- Bioenergetics is the study of energy transformation in a living organism.
- Energy is the capacity to do work; change or move things.
- Thermodynamics is the study of changes of energy.
First Law of Thermodynamics
- Energy can neither be created nor destroyed but can be converted into different forms.
- For example, Chemical energy in ATP → mechanical energy for organelles to move about the cell.
- This law is represented by the equation: ∆E = Q - W
- ∆E = change in internal energy
- Q = heat (energy in/out)
- W = work (energy in/out)
Second Law of Thermodynamics
- In any natural process, the total entropy (measure of randomness or disorder) of a closed system will increase or remain constant, but never decrease.
- Energy tends to spread out and systems naturally evolve towards a state of greater randomness or disorder.
Entropy
- It is a measure of randomness or disorder.
- It also reflects the tendency of energy to spread out over time in isolated systems.
- Every event is accompanied by an increase in the entropy of the universe.
- Living systems maintain a state of ‘system’ order (low entropy) at the expense of higher ‘universe’ disorder (high entropy) - through metabolism.
Gibbs Free Energy
- ΔG represents the maximum amount of work that can be performed by a system at constant temperature and pressure.
- This allows us to predict whether a chemical reaction or process will occur spontaneously.
- This is represented by the equation: ∆G = ∆H – (T x ∆S)
- ∆H = is the change in enthalpy
- T = Temperature in Kelvin
- ∆S = Entropy
- If ΔG is negative, the reaction is exergonic and spontaneous - towards a state of lower energy.
- If ΔG is positive, the reaction is endergonic and requires energy input or coupling.
Enzymes
- Enzymes are biological catalysts that speed up chemical reactions in living organisms.
- They bind to specific substrates at the active site.
- They lower the activation energy required for a reaction to occur.
- Temperature and pH can affect enzymatic reaction rates.
- Each enzyme is most active under specific conditions.
Enzyme Inhibitors
- Enzyme inhibitors slow the rates of enzymatic reactions.
- Irreversible inhibitors bind tightly to the enzyme.
- Reversible inhibitors bind loosely to the enzyme.
-
Competitive inhibitors compete with the substrate for the active site.
- They resemble the substrate structure.
- They can be overcome with high substrate/inhibitor ratios.
- They increase Km, but do not alter Vmax.
-
Noncompetitive inhibitors bind to sites other than the active site.
- They reduce Vmax, but do not alter Km.
- They are usually reversible.
Metabolic Regulation
- Cellular activity is highly regulated.
- Enzymes are controlled by alterations in their active or allosteric sites.
- Covalent modification of enzymes with the addition of a phosphate group (P) → protein kinases.
- Allosteric modulation of enzymes by compounds binding to allosteric sites.
- End-product inhibition - the product of a pathway inhibits enzymes of the pathway.
Pyruvate Dehydrogenase Kinase (PDK)
- PDK is an enzyme that inactivates pyruvate dehydrogenase by phosphorylation at specific sites.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on bioenergetics and the laws of thermodynamics. This quiz covers essential concepts such as energy transformations, the first and second laws of thermodynamics, and the nature of entropy. Dive into the fascinating world of energy in living organisms!
