Metabolism Notes #1 -Enzymes & Metabolism
Flow of energy through life. ______
Metabolism:
- Chemical reactions of life.
- ______
- ______
- ______
- anabolic reactions
- breaking bonds between molecules
- ______
- ______
- catabolic reactions
Chemical reactions & energy
- Some chemical reactions ______
- ______
- ______
- hydrolysis = catabolism
- Some chemical reactions require ______
- ______
- building polymers
- dehydration synthesis = anabolism
Energy & life
- Organisms require energy to live
- Where does that energy come from?
- coupling ______(releasing energy) with ______(needing energy)
What drives reactions?
- If reactions are “downhill”, why don’t they just happen spontaneously?
- ______
Activation energy
- Breaking down large molecules requires an ______
- ______
- large biomolecules are stable
- ______
Too much activation energy for life
- Activation energy
- Amount of energy needed to ______
- Moves the reaction over an “energy hill”
Reducing Activation energy
- Catalysts
- ______
Catalysts
- So what’s a cell to do to reduce activation energy?
- get help! … chemical help… ______
Enzymes
- ______
- proteins (& RNA)
- facilitate chemical reactions
- ______without being consumed
- ______energy
- don’t change free energy (G) released or required
- required for ______
- ______
- thousands of different enzymes in cells
- ______
Enzyme vocabulary
- substrate
- ______
- enzyme-substrate complex: temporary association
- product
- end result of reaction
- ______
- Enzymes catalytic site; substrate fits into active site
Properties of Enzymes
- ______
- each enzyme works with a specific substrate
- chemical fit between ______
- ______
- ______
- Single enzyme molecule can catalyze thousands or more reactions per second
- Enzymes ______
- ______
- Any condition that affects protein structure
- ______
Naming Conventions
- Enzymes named for the reaction they catalyze
- ______breaks down sucrose
- ______breaks down proteins
- ______break down lipids
- ______builds DNA
- Adds nucleotides to DNA strand
- ______breaks down proteins (polypeptides)
Lock and Key model
- Simplistic model of enzyme action
- ______
- H bonds between substrate & enzyme
- Like ______
Induced fit model
- More accurate model of enzyme action
- 3-D structure of enzyme fits substrate
- Substrate
- “conformational change”
- ______
How does it work?
- Variety of mechanisms to lower activation energy & speed up reaction
- ______
- active site ______
- enzyme brings substrate closer together
- ______
- Active site binds substrate & puts ______
______