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Bioenergetics and Enzymes
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Bioenergetics and Enzymes
Bioenergetics and Enzymes
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1
Question
What is metabolism defined as?
Answer
Sum of all chemical reactions in an organism
2
Question
What is a metabolic pathway?
Answer
Series of steps converting starting molecule to product, catalyzed by enzymes
3
Question
What are catabolic pathways?
Answer
Breakdown pathways that release energy, like cellular respiration
4
Question
What are anabolic pathways?
Answer
Build-up pathways that consume energy, like photosynthesis
5
Question
What is energy in biological terms?
Answer
Capacity to cause change
6
Question
What is kinetic energy?
Answer
Energy of motion, like a falling leaf
7
Question
What is potential energy?
Answer
Stored energy due to position or structure, like chemical bonds
8
Question
What is thermal energy?
Answer
Kinetic energy of molecular motion, also known as heat
9
Question
What is chemical energy?
Answer
Potential energy stored in molecules
10
Question
What is thermodynamics?
Answer
Study of energy transformations
11
Question
What does the First Law of Thermodynamics state?
Answer
Energy cannot be created or destroyed, only transformed
12
Question
What does the Second Law of Thermodynamics state?
Answer
Every energy transfer increases entropy, some becomes unusable heat
13
Question
How do organisms handle entropy biologically?
Answer
Create local order but increase global entropy
14
Question
What is free energy (G)?
Answer
Energy available to do work in a system
15
Question
What does ΔG < 0 indicate?
Answer
Exergonic reaction, spontaneous, releases energy
16
Question
What does ΔG > 0 indicate?
Answer
Endergonic reaction, nonspontaneous, requires energy
17
Question
What is equilibrium in terms of free energy?
Answer
Maximum stability, but cells avoid it to stay dynamic
18
Question
What is ATP?
Answer
Adenosine triphosphate: ribose + adenine + three phosphates
19
Question
How does ATP hydrolysis release energy?
Answer
By breaking the terminal phosphate bond
20
Question
What is energy coupling?
Answer
Exergonic ATP hydrolysis driving endergonic reactions
21
Question
What is phosphorylation in ATP context?
Answer
Transferring a phosphate group to create intermediates
22
Question
What is the ATP cycle?
Answer
ATP ⇌ ADP + Pi, regenerated by catabolism
23
Question
What is a catalyst?
Answer
Substance that speeds up reaction without being consumed
24
Question
What are enzymes?
Answer
Catalytic proteins, like sucrase breaking sucrose
25
Question
What is activation energy (Ea)?
Answer
Energy barrier that enzymes lower to speed reactions
26
Question
Do enzymes change ΔG?
Answer
No, they only change reaction rate
27
Question
What is the substrate?
Answer
Reactant that an enzyme acts on
28
Question
What is the active site?
Answer
Region where substrate binds on enzyme
29
Question
What is induced fit?
Answer
Enzyme molds around substrate for better catalysis
30
Question
How do enzymes lower Ea by orienting substrates?
Answer
Positioning them for optimal reaction