Honors Biology Chapter 05B Metabolism — Concise Review
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/47
Earn XP
Description and Tags
48 short question-and-answer cards covering energy, thermodynamics, metabolism, ATP, enzymes, inhibition, redox reactions, and electron transport.
48 Terms
What is energy?
The ability to do work or cause change.
What is kinetic energy?
Energy of motion.
What is potential energy?
Stored energy.
What is chemical energy?
Potential energy stored in chemical bonds.
What is the first law of thermodynamics?
Energy cannot be created or destroyed, only transferred or transformed.
What is the second law of thermodynamics?
Every energy transfer releases some unusable energy as heat.
What is entropy?
A measure of disorder or energy dispersal.
Why do cells need a constant energy input?
To maintain organization and homeostasis.
What is metabolism?
All enzyme-controlled reactions in a cell.
What is an anabolic pathway?
A pathway that builds molecules and requires energy.
What is a catabolic pathway?
A pathway that breaks molecules down and releases energy.
What are reactants?
Starting molecules in a reaction.
What are products?
Molecules made by a reaction.
What does delta G describe?
The change in free energy during a reaction.
What is an exergonic reaction?
A reaction that releases energy and has negative delta G.
What is an endergonic reaction?
A reaction that requires energy and has positive delta G.
Why is ATP called the cell's energy currency?
It transfers usable energy to power cell work.
What happens when ATP loses its third phosphate?
Energy is released, producing ADP and phosphate.
What is energy coupling?
Using energy from an exergonic reaction to power an endergonic one.
What three types of work does ATP power?
Chemical, transport, and mechanical work.
What is a metabolic pathway?
A sequence of enzyme-controlled reactions.
What is a catalyst?
A substance that speeds a reaction without being used up.
What is an enzyme?
A biological catalyst, usually a protein.
What is a substrate?
The reactant an enzyme acts on.
What is an active site?
The part of an enzyme where the substrate binds.
What is an enzyme-substrate complex?
The temporary structure formed when a substrate binds an enzyme.
Are enzymes used up in reactions?
No; they can be reused.
What is activation energy?
The energy needed to start a reaction.
How do enzymes speed reactions?
They lower activation energy.
Do enzymes change delta G?
No; they only lower activation energy.
What is denaturation?
Loss of an enzyme's functional shape.
How can temperature affect enzymes?
Activity rises to an optimum, then drops if heat denatures the enzyme.
How can pH affect enzymes?
Extreme pH can change the active site and reduce activity.
What is enzyme inhibition?
A decrease in enzyme activity caused by an inhibitor.
What is competitive inhibition?
An inhibitor competes with the substrate for the active site.
What is noncompetitive inhibition?
An inhibitor binds elsewhere and changes enzyme function.
What is feedback inhibition?
A pathway's end product shuts down an earlier enzyme.
What is a redox reaction?
A reaction in which electrons are transferred.
What is oxidation?
Loss of electrons.
What is reduction?
Gain of electrons.
What mnemonic helps remember redox?
OIL RIG: Oxidation Is Loss; Reduction Is Gain.
What is an electron transport chain?
A series of carriers that pass electrons and pump hydrogen ions.
What happens as electrons move through an ETC?
They lose energy, which is used to pump H+ across a membrane.
What is an electrochemical gradient?
A difference in ion concentration and charge across a membrane.
What is chemiosmosis?
H+ flowing down its gradient through ATP synthase.
What is ATP synthase?
An enzyme that uses H+ flow to make ATP.
Where are ETCs used?
In cellular respiration and photosynthesis.
What is the final electron acceptor in aerobic respiration?
Oxygen, which forms water.