UNIT 3: METABOLISM AND HOMEOSTASIS
Introduction to Metabolism (Ch. 6)
General structure of ATP
The functions of enzymes
- Enzymes are proteins: provide a
space(active site) for
reactants(substrates) to me
- Tool for reactions, can speed up or slow
down reactions
How/why enzymes lower the activation
energy
- The enzymes allows the substrates to meet and create a product easier so there is
less of a need for activation energy.
The catalytic cycle of an enzyme involving its active site
- Catalyst: the leftover
- The enzyme binds two substrates together to make a product and goes on to the next
one, so more products are created from one enzyme
Difference between exergonic and endergonic reaction
- Exergonic reactions: spontaneous, releases energy
- Endergonic reactions: not spontaneous, requires energy
Difference between anabolic and catabolic pathways
- Anabolism: endergonic reaction (requires energy)
- Catabolism: exergonic reaction (releases energy)
Different forms of energy and descriptions
- Light energy: used for photosynthesis
- Glucose: sugar energy used in cellular energy production
- ATP: chemical energy created from cellular respiration
The laws of thermodynamics
1. Energy can not be created nor destroyed, only converted
2. Energy transfers in the universe increase entropy
How the hydrolysis of ATP provides energy for work, and the regeneration provides
storage
- Hydrolysis of ATP ⇒ ATP + H2O ⇒ ADP + Pi
- Hydrolysis of ATP and ADP is reversible ⇒ regenerates ATP from ADP and P
- ATP provides storage for potential energy since it will be broken again and it will
release energy.
- Why does it release energy? ATP breaks bonds: breaks ADP and a phosphate group, ATP
also forms bonds: forms bonds between broken phosphate group and OH, forms bond
between H and ADP.
, The relationship between an enzyme and its substrate (ex: charges must be
complementary)
- Enzymes are proteins that provide an active site for substrates to meet and form a
product
- Enzymes can help speed up chemical reactions ⇒ lowers activation energy
Effects of local conditions on enzyme activity - including temp, pH, cofactors, and
enzyme inhibitors, esp. the graphs of them
- Competitive enzyme inhibitors: compete with the substrate for the active site +
prohibit products from forming
- Noncompetitive enzyme inhibitors: binds at an area away from the active site but
changes its shape to prevent substrate from fitting
- Cofactors: help the substrate fit into the enzyme’s
active site
Temperature:
- → activity reaches a peak at a certain temperature,
before reaching the peak, temperature increases ⇒
activity increase ⇒ substrates move faster into the
enzymes ⇒ increasing rate of activity
→ after activity reaches the peak, enzymes denature ⇒
slower rate of activity
pH:
- Each enzyme has an ideal range of pH range; changing the
pH out of the range ⇒ slows enzyme activity
- Extreme pH ⇒ enzyme will denature
Substrate concentration:
- Increasing substrate concentration increases the rate of
reaction to a certain point. After all the enzymes are
bound ⇒ increase in substrate concentration won’t have
an effect on enzyme activity b/c enzymes are working at
max rate = saturation
Enzyme concentration:
- Increase enzyme concentration ⇒ more enzymes substrates
can bind to; once all enzymes are bound ⇒ reaction will
plateau because not enough enzymes for substrates to
bound to
Regulation (activation and inhibition) of enzymes
- Inhibitor: prevent the substrate from working in the enzyme
- Allosteric regulation: particle binds at one site and enables a change in
configuration at a separate site allosteric inhibition: inhibitor fits into
allosteric site and changes the shape of the active site
Introduction to Metabolism (Ch. 6)
General structure of ATP
The functions of enzymes
- Enzymes are proteins: provide a
space(active site) for
reactants(substrates) to me
- Tool for reactions, can speed up or slow
down reactions
How/why enzymes lower the activation
energy
- The enzymes allows the substrates to meet and create a product easier so there is
less of a need for activation energy.
The catalytic cycle of an enzyme involving its active site
- Catalyst: the leftover
- The enzyme binds two substrates together to make a product and goes on to the next
one, so more products are created from one enzyme
Difference between exergonic and endergonic reaction
- Exergonic reactions: spontaneous, releases energy
- Endergonic reactions: not spontaneous, requires energy
Difference between anabolic and catabolic pathways
- Anabolism: endergonic reaction (requires energy)
- Catabolism: exergonic reaction (releases energy)
Different forms of energy and descriptions
- Light energy: used for photosynthesis
- Glucose: sugar energy used in cellular energy production
- ATP: chemical energy created from cellular respiration
The laws of thermodynamics
1. Energy can not be created nor destroyed, only converted
2. Energy transfers in the universe increase entropy
How the hydrolysis of ATP provides energy for work, and the regeneration provides
storage
- Hydrolysis of ATP ⇒ ATP + H2O ⇒ ADP + Pi
- Hydrolysis of ATP and ADP is reversible ⇒ regenerates ATP from ADP and P
- ATP provides storage for potential energy since it will be broken again and it will
release energy.
- Why does it release energy? ATP breaks bonds: breaks ADP and a phosphate group, ATP
also forms bonds: forms bonds between broken phosphate group and OH, forms bond
between H and ADP.
, The relationship between an enzyme and its substrate (ex: charges must be
complementary)
- Enzymes are proteins that provide an active site for substrates to meet and form a
product
- Enzymes can help speed up chemical reactions ⇒ lowers activation energy
Effects of local conditions on enzyme activity - including temp, pH, cofactors, and
enzyme inhibitors, esp. the graphs of them
- Competitive enzyme inhibitors: compete with the substrate for the active site +
prohibit products from forming
- Noncompetitive enzyme inhibitors: binds at an area away from the active site but
changes its shape to prevent substrate from fitting
- Cofactors: help the substrate fit into the enzyme’s
active site
Temperature:
- → activity reaches a peak at a certain temperature,
before reaching the peak, temperature increases ⇒
activity increase ⇒ substrates move faster into the
enzymes ⇒ increasing rate of activity
→ after activity reaches the peak, enzymes denature ⇒
slower rate of activity
pH:
- Each enzyme has an ideal range of pH range; changing the
pH out of the range ⇒ slows enzyme activity
- Extreme pH ⇒ enzyme will denature
Substrate concentration:
- Increasing substrate concentration increases the rate of
reaction to a certain point. After all the enzymes are
bound ⇒ increase in substrate concentration won’t have
an effect on enzyme activity b/c enzymes are working at
max rate = saturation
Enzyme concentration:
- Increase enzyme concentration ⇒ more enzymes substrates
can bind to; once all enzymes are bound ⇒ reaction will
plateau because not enough enzymes for substrates to
bound to
Regulation (activation and inhibition) of enzymes
- Inhibitor: prevent the substrate from working in the enzyme
- Allosteric regulation: particle binds at one site and enables a change in
configuration at a separate site allosteric inhibition: inhibitor fits into
allosteric site and changes the shape of the active site
