Enzymes PPT Flashcards
the capacity to do work
energy
How do cells obtain energy?
- sun
2. organic/ inorganic compounds
List the 2 types of energy.
- kinetic energy
2. potential energy
chemical energy stored in bonds; concentration gradient across a membrane
potential energy
light; sound; movement of atoms and molecules; muscle contraction
kinetic energy
List 4 forms of energy.
- chemical
- electrical
- mechanical
- radiant or electromagnetic
form of energy stored in bonds of chemical substances
chemical energy
form of energy which results from movement of charged particles
electrical energy
form of energy directly involved in moving matter
mechanical energy
form of energy which travels in waves (e.g. visible light, ultraviolet light, and x-rays)
radiant or electromagnetic energy
Explain the flow of energy.
one way:
- starts with the sun (lost)
- transferred to environment
- transferred to organisms (gain)
- transferred back to environment (loss)
reaction that occurs whenever chemical bonds are formed, rearranged, or broken
chemical reaction
reaction pathway term:
substances that enter a reaction
substrates
What are substrates also called?
reactants/ precursors
reaction pathway term:
any substance that forms between the start and conclusion of the pathway
intermediate
reaction pathway term:
substances left at the end of the reaction
end products
reaction pathway term:
proteins that speed up specific reactions
enzymes
reaction pathway term:
assist enzymes
cofactors
chemical reaction in which small molecules are used to build bigger ones
anabolic
chemical reaction in which large molecules are broken down into smaller products
catabolic
the total of reactions taking place inside the cell
metabolism
chemical reaction in which smaller particles are bonded together to form larger, more complex molecules molecules
synthesis reaction
Give an example of a synthesis reaction.
Amino acids are joined together to form a protein molecule.
Synthesis reactions are also called ___ or ___ reactions when water is produced.
condensation/ dehydration synthesis
chemical reaction in which bonds are broken in larger molecules, resulting in smaller, less complex molecules
decomposition reaction
Give an example of a decomposition reaction.
Glycogen is broken down to release glucose units.
Decomposition reactions are also called ___ reactions when water is split.
hydrolysis
The patterns of chemical reactions can be either ___ or ___.
constructive,
degradative
reactions where electrons are exchanged
oxidation-reduction (“redox”) reactions
part of a redox reaction:
gain of electrons; electron acceptor
reduction
part of a redox reaction:
loss of electrons; electron donor
oxidation
Where can oxidation-reduction reactions be observed?
in cellular reactions such as cellular respiration
energy flow in chemical reactions:
energy input required; product has more energy than starting substances
endergonic
energy flow in chemical reactions:
energy released; products have less energy than starting substances; occurs spontaneously
exergonic
Reactions move towards ___.
equilibrium
When does chemical equilibrium occur?
if neither a forward nor reverse reaction is dominant
What prevents equilibrium?
“disappearance” of a product
Do reactions run at the same/different rates in forward and reverse directions?
the same rate
In forward and reverse reactions, are the rates of product and reactant formation equal/different?
equal
What does ATP stand for?
Adenosine Tri-Phosphate
nucleotide that acts like cell’s currency; directly powers chemical reactions in cells; energy form immediately useable by all body cells
Adenosine Tri-Phosphate (ATP)
Energy from ATP is stored when phosphate groups are added onto ADP in ___ reactions.
phosphorylation
in this process ADP and a free phosphate form ATP, storing energy in a form the cell can use
ADP phosphorylation
in this process the last phosphate is broken off; ATP becomes ADP and a free phosphate; energy released is used to power a reaction
ATP hydrolysis
ATP links what reactions?
endergonic to exergonic
Reactions release and store energy in ___.
ATP
All cells depend on the ___ in ATP.
potential energy
Metabolic reactions in cells are ___ reactions.
coupled
Burning glucose directly is an ___ method of acquiring energy. Why?
inefficient,
most energy lost as heat
The electron transport chain is an ___ method of acquiring energy. Why?
efficient,
works like a staircase
method of acquiring energy in which molecules give and accept electrons in steps; ATP is produced
electron transport chain
Which parts of the electron transport chain have the highest and lowest amounts of energy?
highest energy: start of chain,
lowest energy: end of chain
What type of reactions does the electron transport chain use to ultimately produce ATP?
oxidation-reduction
Exergonic reactions are spontaneous and can occur on their own, why haven’t they all occurred already?
requires an activation energy input to break the bonds and start the reaction
anything that speeds up a reaction
catalyst
In biology, catalysts ___ the activation energy and ___ the speed of a reaction making the reaction more likely to occur.
lower,
increase
example of a biological catalyst
enzyme
proteins; do not make anything happen that couldn’t happen on its own (just faster); not used up or altered; same works in forward and reverse reaction; are reaction specific; usually end in -ase
enzymes
An enzyme has a specific ___ to bind to a specific substrate.
shape
In an enzyme, the substrate fits into the ___.
active site
groove in the enzyme’s surface
active site
must be present for enzyme to work; act as helpers; often oxidized or reduced; not consumed
cofactors
Organic cofactors are ___.
coenzymes
What factors affect enzyme activity?
temperature,
pH
Small increases in temperature increases ___ and reaction rates.
molecular collisions
High temperatures disrupt bonds and ___.
destroy the shape of the active site
What is the ideal pH range for most enzymes?
6-8 (neutral)
Enzyme regulation occurs through ___.
allosteric regulators
allosteric regulators:
binds to the enzyme at a site other than the active site called the ___
allosteric site
Allosteric repression is also called ___.
non-competitive inhibition
Allosteric regulators alter the shape of the active site to either allow or inhibit substrate binding through allosteric ___ and ___.
activation,
repression
special type of allosteric repression; product of the reaction is the allosteric repressor
feedback inhibition
Feedback inhibition is also called ___.
negative feedback
blocks or occupies active site; prevents binding of substrates
competitive inhibition
rarer form of feedback in which product activates the pathway leading to its own production
positive feedback
example of positive feedback
blood clotting and child birth
List some everyday uses of enzymes.
found in detergents, used to make breads, used to make wine and beer, used to make cheese, meat tenderizers break down muscle tissue, fruit enzymes breakdown proteins
