Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

89 Cards in this Set

  • Front
  • Back
What produces energy from the sun?
Plants and other phytosynthetic organisms
Sum of all chemical reactions that occur in an organism
Metabolic Pathway
A series of steps that converts a molecule into a product
What catalyzes each step in a metabolic reaction?
A specific enzyme catalyzes each specific step
Anabolic Pathways
Metabolic pathways that breakdown complex molecules into simpler ones

Releases Energy
Anabolic Pathways
metabolic pathways that build complex molecules from simpler ones.

consumes energy
What is an example of a catabolic pathway?
Cellular Respiration. Releases energy by breaking down glucose and other organic fuels
What is an example of an anabolic pathway?
Photosynthesis. Consumes energy (light) to produce glucose and oxygen
The capacity to do work
What is kinetic energy?
The energy of motion
What is potential energy?
stored energy
What are the three types of energy?
Chemical Energy, Radiation Energy, and Thermal Energy
Chemical Energy
The energy stored in molecular bonds
What kind of energy is released by catabolic pathways?
Chemical Energy
What kind of energy is used during photosynthesis?
Radiation Energy
Radiation Energy
Thermal Energy
Kinetic energy of atomic motion. Heat.
The First Law of Thermodynamics
Any form of energy can be converted to any other form of energy BUT is never created or destroyed.
The Second Law of Thermodynamics
All transfers and transformations increase the entropy of the universe.
a quantity that measures disorder or randomness
What is lost in all energy transformations?
useful energy in the form of heat
As heat increases atomic motion _____ increases
Free Energy
The energy in a system that is available to do work. Useful energy.
Gibb's Free Energy Equation

Δfree energy = Δtotal energy - (Kelvin temp X Δsystem's entropy)
What happens to a system as the free energy increases?
The system becomes less stable -> can do more work
What happens to a system as the free energy decreases?
The system becomes more stable -> can do less work
How can all energy transformations be described?
by the change in free energy
What must happen in order for a process to occur spontaneously?
There must be a decrease in free energy. (-ΔG)
Characteristics of an Exergonic Reaction
-reactions that release energy
- -ΔG
- spontaneous
Characteristics of Endergonic Reactions
- reactions that absorb energy
- +ΔG
- not spontaneous
What are the equations for cellular respiration and photosynthesis?
C₆H₁₂O₆ + O₂ ⇔ CO₂ + H₂O
What can the released free energy do in a spontaneous metabolic reaction?
The released free energy can be harnessed to do work.
How does a cell keep its metabolic pathways from reaching equilibrium?
By using catabolic pathways in which a series of exergonic reactions release energy. The products of one reaction are the reactants to the next.
How do cells drive endergonic reactions?
By using the energy released from exergonic reactions.
Why does a phosphate molecule break off from the triphosphate group of ATP sponateously?
Because the negative charges on the phosphate groups repel one another.
Energy coupling
the use of exergonic reactions to drive endergonic reactions. The overall ΔG is negative, so together the reaction is sponateous.
a substance that speeds up a reaction without being consumed or changed by the reaction
A catalytic protein
Activation Energy
The initial energy required to place reactant molecules in an unstable state.
What types of molecules are most likely to undergo energy transformations?
Unstable molecules
What often provides activation energy?
heat. It causes the molecules to be less stable.
What lowers activation energy?
reactant molecule that enzymes bind to
Active Site
Region of enzyme that binds substrate
Enzyme-Substrate Complex
combination of enzyme and substrate molecules
Induced Fit
When substrate binds, enzyme changes shape to hold substrate tightly
Where does enzyme specificity arise from?
The shape of the active site.
How do enzymes lower activation energy?
1. Position two substrates so that bonds can form
2. Contort substrate, creating an instability of bonds
3. Create a favorable microenvironment
4. Active site amino acids participate in reaction.
What factors effect enzyme specificity?
pH and Temperature
How does temperature effect enzyme specificity?
Low temps decrease molecular motion, making substrate-enzyme collisions less likely. High temps denature the enzyme
How does pH effect enzyme specificity?
enzyme denatures at too high or too low of pH.
competetive inhibition
Inhibitor molecule binds to active site, preventing binding of substrate.

Can be overcome by adding more substrate
Noncompetitive inhibition
inhibitor molecule binds to site other than active site, changing the shape of the active site, therefore not allowing binding of substate.

Cannot be overcome by adding more substrate
Allosteric Regulation
binding of a molecule at one site of an enzyme affects function at another site.
Allosteric activator:
molecule that stabilizes the active form of an enzyme
Allosteric Inhibitor
molecule that stabilizes the inactive form of an inhibitor
What does allosteric regulation control?
metabolic pathways
feedback inhibition
allosteric inhibition of a metabolic pathway by the product of that pathway. The end product binds inhibitorily to an enzyme that acts early in the pathway.
What are the three stages of cellular respiration?
1. Glycolysis
2. Citric Acid Cycle
3. Oxidative Phosphorylation
What happens between glycolysis and the citric acid cycle?
Pyruvate from glycolysis enter mitochondria and is converted to acetyl CoA
What does glycolysis produce?
1 glucose produces 2 pyruvate, 2 ATP and NADH
What does the glycolysis/citric acid junction produce?
2 pyruvate produce 2 acetyl CoA, 2 NADH and 2 CO2
Where does he citric acid cycle occur and what does it require?
The krebs cycle occurs in the mitochondrial matrix and requires oxygen
What is the finction of the krebs cycle?
oxidation of organic compounds derived from acetyl CoA
How many steps are in the citric acid cycle?
How many turns of the citric acid cycle are there for every glucose?
2 turns
For every acetyl CoA, what does the citric acid cycle produce?
3 NADH, 1 FADH2, 1 ATP, 2 CO2
For every glucose, what does the citric acid cycle produce?
6 NADH, 2 FADH2, 1 ATP, 2 CO2
Oxidatitive Phosphorylation
The production of ATP using energy derived from the redox reactions of an electron transport chain.
Where does the tranformation of chemical energy come from?
The transfer of electrons from one atom to another
Oxidation Reduction Reaction
the transfer of electrons from one reactant to another
Loss of electrons.
addition of electrons
Reducing Agent
atom that loses electrons
Oxidizing agent
atom that gains electrons
Describe the potential energy of polar vs nonpolar molecules
Nonpolar- high potential energy
polar- low potential energy
What makes oxygen a strong oxidizer?
its high electronegativity
Cellular Respiration
extracting chemical energy from complex organic molecules
How much energy does cellular respiration produce?
686 kcal/mole
What is the energy from cellular respiration used to produce?
What is the oxidizing agent of cellular respiration?
Nicotinamide adenine dinucleotide (NAD+)
During respiration, electrons are transferred from _____ to _____ throught the electron transport chain.
NADH to oxygen
How does respiration harvest chemical energy?
Through transfer of electrons from organmic compounds to oxygen.
Where does glycolysis occur?
In the cytosol
What is the only stage of respiration that does not require oxygen?
What is the function if glycolysis?
Glycolysis breaks down glucose into two pyruvate molecules
Glycolysis is a catabolic pathway that involves how many steps?
10 steps
For every glucose molecule, how many ATP are invested during glycolysis?
What is the energy payoff of every glucose molecule?
4 ATP and 2 NADH