Chapter 5 - Metabolism Flashcards
Metabolism
All chemical reactions in the body
Ability of an organism to obtain, convert, and utilize energy
Metabolism
Metabolic Pathways
A series of chemical reactions that occur in a specific order
What is the relationship between metabolism and energy?
They either release more energy than they require or require more energy than they release
What is the relationship between exergonic reactions and energy?
They release more energy than they require
What kind of reaction is an exergonic reaction?
Hydrolytic
Hydrolytic reaction
Uses water to break bonds; catabolic
What is the relationship between endergonic reactions and energy?
They require more energy than they use
What kind of reaction is an endergonic reaction?
Dehydration synthesis
Dehydration synthesis
Water is removed so new bonds are formed; anabolic
What does a catabolic reaction do with energy?
Releases it
Which kind of reaction is associated with ATP production?
Catabolic
What is the relationship of anabolic reactions and energy?
They require energy
Which reaction is associated with ATP catabolism?
Anabolic
Describe the ATP cycle
ATP is broken down, released energy is used by the cell for anabolic reactions to create more ATP
Enzymes
Critical for living organisms; needed to make chemical reactions fast enough to maintain life
What are enzymes made of?
Protein
What are the five features of enzymes?
- very efficient
- not used up nor altered
- act like catalyst
- don’t cause novel reactions
- specific to specific substrate
What do substrates bind to in enzymes?
Their active site
How are enzymes named?
According to the reactions they take part in; end in ‘ase’
What is the name of the protein portion of an enzyme?
Apoenzyme
What is the name of the non-organic portion of the enzyme?
Cofactor
When is a cofactor a coenzyme?
When the cofactor is an organic compound
What is a holoenzyme?
A complete enzyme; apoenzyme + cofactor
What is the function of the cofactor?
Receive atoms from substrate and release atoms needed by substrate
T/F - A holoenzyme is composed of an apoenzyme and a coenzyme
False
What five things can affect enzyme activity?
- Temperature
- pH
- Substrate concentration
- Concentration of enzyme
- Inhibitors
What is the ideal temperature for enzymes?
Body temperature
What happens when an enzyme gets cold?
It becomes inactive or slow
When does an enzyme denature?
When it grows too hot
What pH do enzymes prefer?
Neutral
What is the limiting factor in substrate concentrations?
The availability of the enzyme active site
T/F - To a point, the more specific substrate available, the greater rate of reaction and end product
True
What is the limiting factor in concentration of enzyme?
Availability of specific substance
What are the two kinds of enzyme inhibitor?
Competitive and Non-competitive
What is another name for non-competitive inhibition?
Allosteric inhibition
How do competitive inhibitors work?
Block active site of enzyme causing no reaction or different reaction
Why do enzymes hate when a reaction other than the one they were designed for occurs?
Energy is lost
How do allosteric inhibitors work?
Block anywhere except the active site, make active site change shape
What may be part of a feedback mechanism?
Inhibitors
Are ribozymes enzymes?
No
What are ribozymes?
A type of RNA that acts like an enzyme on RNA only
What do all cells produce?
Energy
What happens to electrons in oxidation?
They are lost