Studied by 169 people• Biochemical Reactions • Cells • Organisms • Ecosystems
What can systems be? (4)
• No exchange of energy or matter with surroundings.
Isolated System
• Exchanges energy with surroundings.
Closed System
• Exchanges energy and matter with surroundings.
Open System
C) Open
Biological systems are...
A) Isolated B) Closed C) Open
• Must absorb needed and remove unneeded molecules.
Why are biological systems open systems?
• The ability to cause change.
Energy
• Change that requires energy.
Work
Any of these answers are correct: • DNA Replication • Protein Synthesis • Metabolism • Mobility • Reproduction • Transport • Cell Division
List three types of work that cells/organisms perform.
• Stored energy of an object due to its position or chemical structure.
Potential Energy
• Energy of motion or change.
Kinetic Energy
B) High Potential Energy
A molecule with lots of non-polar covalent bonds has...
A) Low Potential Energy B) High Potential Energy
• The arrangement of electrons in its bonds.
What changes the potential energy within a molecule?
• Energy is neither created nor destroyed.
The First Law of Thermodynamics
• Changes location or changes forms.
What happens to the energy within a system according to the first law of thermodynamics? (2)
• Sum of potential energy and kinetic energy of a system.
Enthalpy
Yes, due to the energy change in the system.
Does the enthalpy change when work occurs?
• Delta H (∆H)
What is the symbol for change in enthalpy?
• Exothermic
If heat is released, the ∆H is...
• Endothermic
If heat is absorbed, the ∆H is...
• Products have less enthalpy than reactants. • Heat released to surroundings.
What are the two characteristics of an exothermic reaction?
• Products have more enthalpy than the reactants. • System absorbs heat from surroundings.
What are the two characteristics of an endothermic reaction?
• A reaction that is able to occur under current conditions.
Spontaneous
Yes.
Is an ice cube to liquid water a spontaneous reaction?
No, since it requires sunlight to begin the process.
Is photosynthesis a spontaneous reaction?
• Instantaneous
Spontaneous reactions are not...
• Nonspontaneous
If a reaction is spontaneous, then it is ___________________ in the reversed direction.
• A reaction that cannot occur under the current conditions.
Nonspontaneous
No.
Is liquid water to an ice cube a spontaneous reaction?
Yes.
Can exothermic and endothermic reactions both be spontaneous?
• How dispersed the energy of the system and surroundings is.
Entropy
• Delta S (∆S)
What is the symbol for change in entropy?
• Positive
If energy has higher dispersion, then ∆S is...
• Negative
If energy has a lower dispersion, then ∆S is...
• The total entropy of the universe if always increasing.
The Second Law of Thermodynamics
• Spontaneous
Entropy determines if a reaction is...
• ∆Stotal = ∆Ssystem + ∆Ssurroundings
What is the equation for total entropy?
• Measure of energy in a system that is free to do work.
Free Energy
• The amount of energy that was used to make the change.
The change in free energy in a reaction is measured as...
• More
For work to occur, energy must be available to carry out the change and reactants must have ______ free energy than the products.
• Delta G (∆G)
What is the symbol for free energy?
• Positive
If energy is available, the change in free energy is...
• Negative
If energy is not available, the change in free energy is...
• Negative free energy. • Spontaneous.
What are the characteristics of exergonic reactions? (2)
• ∆G = -T∆Stotal
What is the equation that relates free energy to the total entropy of a system and its surroundings?
• Positive free energy change. • Nonspontaneous.
What are the characteristics of an endergonic reaction? (2)
• Enough energy available to change the system and the total entropy of the universe increases.
What causes exergonic reactions?
• Not enough energy to change the system, total entropy of the universe decreases.
What causes endergonic reactions?
∆G = ∆H - T∆Ssystem
What is the equation that relates free energy, entropy, and enthalpy?
• Exergonic
Are biological reactions exergonic or endergonic?
• The rate of the forward reaction = the rate of the reverse reaction.
Chemical Equilibrium
• The reverse reaction is spontaneous.
What does a positive tabulated standard free energy mean?
∆G = ∆G° + RT(ln(product/reactant))
What is the equation that involves standard free energy?
• Chemical reactions in the cells that change food into energy.
Metabolism
• Breaking down of complex molecules.
Catabolism
• Amino acids
If a protein undergoes catabolism, what is the product?
• Building up of complex molecules.
Anabolism
• Protein
If an amino acid undergoes anabolism, what is the product?
• A series of connected reactions.
Biochemical Pathways
• Biochemical Pathways
In cells, metabolic reactions are linked to...
• Endergonic
Is anabolism endergonic or exergonic?
• False, it is exergonic.
Catabolism is endergonic, true or false?
• When the second reaction contains the first reactions product as a substrate.
Connected Reactions
• Nitrogenous Base (Adenine) • Ribose (Sugar)
What is adenosine made up of?
• Potential Energy
What type of energy does ATP store?
• Negative compressed charges.
Where does the potential energy in ATP come from?
• Reaction of the interaction of chemicals with water, leading to their decomposition.
Hydrolysis
• A single reaction with two things happening, which occur at the same time and same place.
Coupled Reactions
• Coupled
What is the first reaction of glycolysis considered?
• No, since it only has one thing occurring.
Is the second reaction of glycolysis considered coupled?
• Yes.
Is the third reaction of glycolysis a coupled reaction?
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