Enzymes :)

Question 1

What are enzymes

Answer 1

protein catalysts (speed up reactions) that get molecules into the right positions to react. These reactants are called substrates.

Question 2

Why do enzymes lower activation energy?

Answer 2

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.

Question 3

How do digestive enzymes work?

Answer 3

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

Question 4

what would carbohydrates be digested into (because of enzymes)

Answer 4

monosaccharides

Question 5

what is the most common reaction that breaks most macronutrients apart?

Answer 5

hydrolysis: water molecule is added to break the bond

Question 6

what would lipids be digested into?

Answer 6

fatty acids

Question 7

what is the active site

Answer 7

a site that fits a substrate specifically (puzzle analogy), allow for proper binding and orientation of substrates

Question 8

what would proteins be digested into

Answer 8

amino acids

Question 9

Why does temperature affect reactions

Answer 9

enzymes and substrates react based on collisions which temperature affects by speeding up collisions

Question 10

Enzyme-Substrate Binding

Answer 10

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.

Question 11

Order of Enzyme-Substrates

Answer 11

1) enzyme and substrate collide
2) enzyme and substrate bind
3) enzyme changes shape
4) substrate bonds are broken

Question 12

Enzyme and homeostasis

Answer 12

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.

Question 13

Denaturation of enzymes

Answer 13

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

Question 14

where do substrates and enzymes bind

Answer 14

the active site

Question 15

T/F Enzymes work in the digestive system by stressing bonds between monomers

Answer 15

True

Question 16

Van Hoffs Rule

Answer 16

Chemical reactions happen because of collisions between reactants
➢Every 10C the rate of a chemical reaction generally DOUBLES
➢Sometimes called a Q10 coefficient

Question 17

Optimal Temperature

Answer 17

where the reaction rate is maximized, and the denaturation is minimized.

(usually around 40 degrees)

• necessitates homeostasis

Question 18

chemicals that interfere with enzyme function

Answer 18

inhibitors

Question 19

competitive vs non-competitive inhibitor?

Answer 19

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

Question 20

how to tell if a reaction is competitive or non-competitive inhibitor?

Answer 20

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

Question 21

what factors affect enzyme function

Answer 21

• enzyme concentration
• substrate concentration
• temperature
• pH
• salinity
• activators
• inhibitors

Question 22

enzyme concentration increases

Answer 22

reaction rate increases
- increased frequency of collisions with substrates, more active sites
(however, not all enzymes can find substrates)

Question 23

substrate concentration increases

Answer 23

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)

Question 24

temperature increases

Answer 24

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)

Question 25

as pH increases

Answer 25

increase or decrease of pH can cause the denaturation of proteins
- optimum pH=7

• acidic and basic pH are damaging the hydrogen bonds because they get attracted to eachother instead of the R group
• this process causes fermentation: ex. yogurt: bacteria get in the milk and produce lactic acid as a byproduct of metabolism, proteins denature via hydrogen bonds breaking, and the clumps that form=yogurt

Question 26

as salinity increases

Answer 26

reaction rate increases

• changes in salinity: add/remove cation and disrupts hydrogen bonding, therefore disrupting shape and can cause denaturation
• cytoplasm not 100% water–dissolved ions
• electrolytes (metal ions)
• enzymes are intolerant of extreme salinity (hence the Dead Sea and pickling), it denatures them and reduces their solubility

Question 27

when would you need exocytosis?
when would you need endocytosis?

Answer 27

exocytosis: cell produces something meant for exportation, such as waste where it may need to leave against concentration gradient

endocytosis: taking in products necessary for biochemical function where it may need to leave against concentration gradient