Chapter 6 Flashcards
What is energy?
The ability to do work or bring about change
What is life dependent on?
Solar energy
What are the 2 forms of energy?
Kinetic energy: energy of motion
Potential energy: stored energy
What are the different types of energy
Chemical energy: stored in chemical bonds
Mechanical energy: energy of motion
What are the 2 laws of thermodynamics?
- Energy cannot be created or destroyed, but it can be changed from one form to another
- Energy cannot be changed from one form to another without a loss of usable energy
What form of energy is always lost?
Heat
Is energy conversion always 100% efficient?
No
What is entropy
Refers to the relative amount of disorganization
What do cellular processes require?
An input of energy from an outside source.
What do living organisms depend on?
A constant supply of solar energy
What is metabolism?
The sum of all the chemical reactions that occur in a cell. The breaking down and building up of molecules is a large part of cellular metabolism.
What is Catabolism?
Breaking down of molecules.
What is Anabolism?
Building of molecules.
What are reactants?
Substances that participate in a reaction.
What are products?
Substances that form as a result of a reaction.
What is free energy?
The amount of energy available to do work.
How do you calculate the charge of free energy?
Subtract the free energy of the reactions from that of the products.
Where is there less free energy: in products or reactants.
Products.
What do you need a lot of for anabolism?
Energy
What is a big factor of anabolism?
Smaller components coming together to make larger things. You need an influx of energy to do it and the product will have more free energy than the reactants.
Explain Catabolism
Breakdown of larger molecules into smaller components, won’t see an influx of energy and there is less free energy in products than reactants.
What is an exergonic reaction?
Energy is released and free energy is negative. The products will have less free energy than the reactants.
What is an endergonic reaction?
They require an input of energy and free energy is positive. The products have more free energy than the reactants because of the input of energy.
What is the common energy currency for cells?
ATP.
What is ATP generated from?
ADP and an inorganic phosphate molecule.
What is the structure of ATP?
ATP is a nucleotide composed of: Adenine, Ribose, and 3 phosphate groups. Energy is stored in their chemical bonds.
What is the function of ATP?
Chemical work: energy to synthesize macromolecules
Transport work: energy to pump substances across membranes
Mechanical work: energy to make muscles contract
What are coupled reactions?
When the energy released by an exergonic reaction is used to drive an endergonic reaction.
What is a metabolic pathway?
A series of linked reactions.
Describe an enzyme
Typically proteins that function as catalysts to speed up chemical reactions. They don’t get used up and can be used multiple times.
What is energy of activation?
Energy that must be adde to cause reactants to react with each other. (Such as you need a match to start wood burning)
Do enzymes raise or lower the energy of activation?
Lower, and they do not change the end result of the reaction they just increase the reaction rate.
How do enzymes function?
An enzyme binds to a substance to form a complex. The active site is a small part of the enzyme that complexes with the substrate. The active site typically undergoes a slight change in shape to accommodate substrate binding (induced fit). After a reaction is completed, products are released.
What is degradation?
When the substate is broken down to smaller products.
What is synthesis?
When the substrates are combined to produce a larger product.
What are some factors that effect enzyme speed.
Substrate concentration, temperature and pH, enzyme activation, enzyme inhibition, and enzyme cofactors.
Describe substrate concentration
Enzyme activity increases as substrate concentration increases as there are more collisions between substrate and enzyme. As more active sites are filled with substrate, more product will form.
Describe temperature and pH
Enzyme activity increases as the temperature rises. Higher temperature causes more effective collisions between enzymes and substrates. As temperature rises beyond a certain point, enzyme activity levels out but at high temperatures there is a loss of structure and function and the enzyme will become denatured. Each enzyme has an optimal pH at which its activity is at the highest, enzyme structure is also pH dependant and extremes of pH can denature an enzyme by altering its structure
Describe enzyme activation
Enzyme can be modified by adding or removing phosphates which temporarily changes the shape which can make them active or inactive.
Describe enzyme inhibition
Inhibition occurs when substrate cannot bind to active site of enzyme. The activity of almost every enzyme in a cell is regulated by feedback inhibition. Poisons are a common enzyme inhibitor.
What is the simplest type of enzyme inhibition
When product is so abundant it binds to enzymes active site and blocks further production.
What is a more complex enzyme inhibition
Product binds to a site other than the active site, which changes the shape of the active site.
Describe enzyme cofactors
Enzymes require an inorganic ion or non-protein organic molecule to assist in reaction.
What is oxidation
The loss of electrons and hydrogen atoms. The term is used when oxygen is not involved
What is reduction
The gain of electrons and hydrogen atoms.
