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 ______

______