Chapter 8 Flashcards
Metabolism definition
Sum total of all chemical reactions occurring in a biological system at a given time
What do cells use energy to do?
To grow, reproduce, maintain their structure, respond to environmental changes
Major theme is biology
Life requires energy transfer and transformation
Two distinct divisions of metabolism
Catabolic reactions (catabolism) and anabolic reactions (anabolism)
Catabolism definition
Release energy by breaking down complex molecules into smaller compounds ; downhill reaction
Anabolism definition
Consume energy to build complex molecules from simpler ones ; uphill reaction
What are metabolic pathways?
Series of chemical reactions occurring within a cell
Metabolic pathway reactions are ____________ , where the product _____
Catalyzed by enzymes ; the product of one enzyme acts as the substrate for the next
Feedback Inhibition definition
When the product of a pathway acts as an inhibitor of the pathway to prevent too much build up of a product
Spontaneous Reactions
Occurs without any requirement for outside energy, but it may occur so slowly that it is imperceptible
What kind of reaction is hydrolysis of sucrose
Exergonic and spontaneous reaction ; very very slow reaction
Free-Energy Change (∆G) Definition
Tells us whether the reaction occurs spontaneously
Free-Energy Change Equation
∆g= ∆H-T ∆S
∆=change
G=Gibb’s Free Energy
H= Total Energy
T= Absolute Temperature (k)
S= Entropy
When is ∆G spontaneous and when is energy required?
∆G < 0 = Spontaneous
∆G > 0 = Energy Required
What does more free energy equal (higher G)?
More energy, less stable, greater work capacity
What does less free energy equal (lower G)?
Less energy, more stable, less work capacity
What can catalyst reactions?
Enzymes can catalyst a reaction but are not used up in the reaction ; only connect to certain substrates
What impacts enzymatic activity? (5)
Temperature, pH, Cofactors, Competitive Inhibitors, Noncompetitive Inhibitors
How does temperature impact enzymatic activity?
As temp, increases, reaction rate will increase ; Enzymes have a peak performance at a temp, optimum ; Beyond that they denature
How does pH impact enzymatic activity?
Most enzymes have a pH at which they perform at peak efficiency - the pH optimum
How do cofactors impact enzymatic activity?
Non-protein enzyme helpers ; Cofactor may be inorganic but can also be organic
How do competitive inhibitors impact enzymatic activity?
Bind to active site of enzyme, competing with substrate for binding to the exact same site (decreases productivity)
How do noncompetitive Inhibitors impact enzymatic activity?
Bind to another part of the enzyme, causing the enzyme to change shape, making the active site less effective
What do allosteric sites do?
They bind ATP and AMP
Which is an inhibitor and which is an enhancer, ATP and AMP?
ATP is an inhibitor and AMP is an enhancer
What happens when ATP production is greater than use?
The ATP will accumulate and then slow of shut off pathway
What happens when ATP production is behind?
ATP will accumulate and enhance the pathway
What is a coupled reaction?
Couple a spontaneous reaction to a non-spontaneous reaction ; Uses exergonic reaction to drive endergonic reactions
What happens in an oxidation reaction?
Cells release (catabolism) the energy in their food molecules through a series of oxidation reactions (cellular respiration)
What happens to electrons in an oxidation reaction?
Electrons are transferred from one molecule to another changing in composition and energy content of both the donor and acceptor molecules ; energy generated is stored at ATP and NADH
What kinds of things does ATP do?
Powers cellular work by coupling reactions ; Drives endergonic reactions by phosphorylation (transferring a phosphate group to some other molecule)
Three types of cellular work
Chemical, transport, mechanical
What is chemical cellular work?
ATP phosphates key reactants
What is transport cellular work?
ATP phosphates transport proteins
What is mechanical cellular work?
ATP phosphates motor proteins
