Ch. 6 Flashcards
State the first law of thermodynamics.
- Energy can not be created or destroyed
2. But energy can be changed from one form to another
State the second law of thermodynamics.
- The law of entropy
- Energy can not be changed from one form to another without the loss of usable energy
- Entropy is the name for calculating how much unusable energy is present in a system
- The more usable energy there is left in a system after chemical reactions, the more efficient the system.
Define potential energy.
- Stored energy
Give examples of potential energy stored in biological important molecules.
Glucose and ATP
Define kinetic energy.
- The energy of motion
What is entropy?
- The measure of the disorganization of a system.
2. Entropy is the name for calculating how much unusable energy is present in a system
Does the universe move towards less entropy or more entropy?
The universe is moving towards more entropy.
When molecules move from being less complex and less organized to being more complex and more molecules, what happens to entropy? Is this associated with exergonic or endergonic reactions? Is this a positive of negative (triangle)G?
- More organized= less entropy = not going to happen without the use of energy to fight the law of increasing disorder(increasing entropy)
- Endergonic reaction: cells capture some of the energy released
- Positive (triangle)G
What are the three parts of ATP?
- The nucleotide base adenine
- The 5 carbon sugar ribose
- 3 phosphate groups
What happens at the active site of an enzyme?
- The part of the enzyme where the substrate binds
2. The active site will be a pocket in the enzymes surface,and it’s often just a small part of the overall molecule.
What is a reactant? (Substrate)
Substances that participated in a reaction
A+B -> C+D it is (A+B)
What are products?
- The substances that form as a result of a reaction.
A+B -> C+D its the (C+D)
Define the energy of activation.
The energy that must be added to a system in order for the reaction to occur.
What does an enzyme do to the energy of activation of a reaction?
- Enzymes lower the energy of activation
2. Enzymes, therefore reduce the energy need for a reaction to begin.
What happens when an enzyme is denatured?
It’s when extreme temp. And the wrong levels of pH happen, enzymes are no longer active and cannot function.
What happens to a reaction rate when an enzyme is denatured?
Since amino acid “R” group interaction determines 3D structure, anything changes this enough will keep the enzyme from functioning correctly.
Can low pH (acidic) or high pH (basic) solution cause denaturation?
Yes, to acidic or to basic will cause enzyme denaturation.
Can a high temperature denature an enzyme?
Yes because high heat ruptures bonds in protein structure.
What is the basic difference between a cofactor and a coenzyme?
Cofactor- an inorganic or a non-protein organic molecule necessary at the activation site for correct function of the enzyme.
Coenzyme- a non-protein compound that is necessary for the functioning of an enzyme.
Which cofactor and coenzyme include metal ions and which include vitamins?
Vitamins
1. The vitamin niacin is part of the structure of NAD+ (nicotinamide adenine dinucleotide)
2. The vitamin riboflavin (B2) is part of the structure of FAD (Flavin adenine dinucleotide)
Metal Ions
Copper
Zinc
Iron
Describe non-competitive enzyme inhibition.
The enzyme has two sites that bind other molecules
1. One site is the active site
2. A different site binds the inhibitor
Without the inhibitor, the active site is the correct shape to accept and bind the substrate
When the inhibitor is bound to its site, the active site changes shape and the substrate won’t fit= no reaction/ no product
Describe competitive enzyme inhibition.
- The enzyme has one site, the active site
- The inhibitor is not the substrate, but can fit in the active site
- When the inhibitor is present, it fills the active site and the substrate won’t fit.
- No substrate in active site= no product
What is oxidation?
When a metal loses electrons
The loss of the whole hydrogen atom
What is reduction?
When oxygen gains electrons
The gain of the whole hydrogen atom
