Enzymes :) Flashcards
What are enzymes
protein catalysts (speed up reactions) that get molecules into the right positions to react. These reactants are called substrates.
Why do enzymes lower activation energy?
reducing the energy needed for reactants to come together and react
ex. Enzymes bring reactants together so they don’t have to expend energy moving about until they collide at random.
How do digestive enzymes work?
stress the bonds (break bonds) between the monomers (small food molecules) of polymers (big food molecules)
these bonds break and the products are absorbed in our bloodstream
what would carbohydrates be digested into (because of enzymes)
monosaccharides
what is the most common reaction that breaks most macronutrients apart?
hydrolysis: water molecule is added to break the bond
what would lipids be digested into?
fatty acids
what is the active site
a site that fits a substrate specifically (puzzle analogy), allow for proper binding and orientation of substrates
what would proteins be digested into
amino acids
Why does temperature affect reactions
enzymes and substrates react based on collisions which temperature affects by speeding up collisions
Enzyme-Substrate Binding
The active site of an enzyme attracts the substrate when it gets close. It even changes shape slightly so it is easier for the substrate to attach and bind.
(Enzyme-Subtrate Complex)
- The enzyme then changes shape and either stresses the bonds or makes it easier for them to form in the substrates.
(Release of Products)
- The enzyme then changes shape again and releases the product molecule(s). The enzyme is then back to its original shape and ready to start again.
Order of Enzyme-Substrates
1) enzyme and substrate collide
2) enzyme and substrate bind
3) enzyme changes shape
4) substrate bonds are broken
Enzyme and homeostasis
Proteins change shape when temperature, pH, and salinity change. Enzymes have an optimum set of conditions, and organisms need to maintain these ranges. This is homeostasis.
Denaturation of enzymes
enzymes=proteins
- If the active site changes shape it makes it hard for the enzyme to catalyze the reaction. This is called denaturation
- as temp increases it breaks H-bonds and they become more unstable
where do substrates and enzymes bind
the active site
T/F Enzymes work in the digestive system by stressing bonds between monomers
True
Van Hoffs Rule
Chemical reactions happen because of collisions between reactants
➢Every 10C the rate of a chemical reaction generally DOUBLES
➢Sometimes called a Q10 coefficient
Optimal Temperature
where the reaction rate is maximized, and the denaturation is minimized.
(usually around 40 degrees)
- necessitates homeostasis
chemicals that interfere with enzyme function
inhibitors
competitive vs non-competitive inhibitor?
competitive inhibitor: blocking the active site, competes with substrate for active site
non competitive inhibitor: doesn’t compete for active site, it attaches to the allosteric site on the enzyme, changing its shape so it can’t bind to the substrate anymore
how to tell if a reaction is competitive or non-competitive inhibitor?
competitive inhibition: increased substrate molecules can out-compete the inhibitor for the active site and maximize binding
non-competitive inhibition: irregardless of the amount of substrate available, the enzyme shape has been permanently altered with the addition of the non competitive inhibitor, making it impossible for a normal reaction to play out
what factors affect enzyme function
- enzyme concentration
- substrate concentration
- temperature
- pH
- salinity
- activators
- inhibitors
enzyme concentration increases
reaction rate increases
- increased frequency of collisions with substrates, more active sites
(however, not all enzymes can find substrates)
substrate concentration increases
reaction rate increases, and then reaches a plateau
- increased substrates for enzymes to bind to
- levelling off: limited amount of active site (all active sites are already engaged and in use) and substrate can get used up (max rate of reaction+ saturated enzyme)
temperature increases
rcn rate increases
- increase amount of available energy to carry out cellular functions
- increase rate of enzyme binding
- too high, denaturation
- too low: too slow to carry out function
optimum: max reaction rate and collisions, min denaturation (around 40 degrees for human enzymes)
