Exam 2 (6-8) Flashcards
energy
ability to do work (movement of matter)
potential energy
stored energy available to do work (chemical energy, ATP)
kinetic energy
energy being used to do work, energy of movement (whale surfacing ocean)
how efficient are cells at converting potential energy to kinetic energy?
cells are only 40% efficient at generating energy, 60% remaining comes in product of heat
heat
random motion of molecules
thermodynamic law of conservation of energy
energy cannot be created or destroyed, rather it changes form
thermodynamic law of entropy
energy cannot change from one form to another without the loss of usable energy
entropy
heat energy is disordered, all energy transformations will increase disorder, and therefore energy
Ex: cellular respiration - glucose + O2 converts to CO2 + H2O + ATP
generates energy, and ATP has a lot of potential energy, making it less stable
examples of potential energy
ATP, starting a car, water about to fall over a dam, concentration gradients
metabolism
all the chemical reactions in a cell. energy converting forms
endergonic reactions
reactions have less energy than the products +delta G and the reaction requires the input of energy
examples of kinetic energy
anything with movement, water falling over dam, car driving
exergonic reactions
reactants have more energy than the products -delta G and the reaction will occur spontaneously (no energy input needed)
examples of endergonic reactions
photosynthesis, the formation of ATP
examples of exergonic reactions
cellular respiration, break down of ATP into ADP
ATP functions
- chemical work - synthesizing macromolecules
- mechanical work - contraction of muscles
- transport work - moving things across concentration gradient
coupled chemical reactions
both energy favorable and unfavorable reactions occur in same place at the same time
Ex: ATP hydrolysis and ATP synthesis
calorie
unit to measure energy, the energy required to raise the temperature of 1g of a substance by 1 degree C
kCal
1000 calories, a single calorie in food is refers to a single kCal
enzymes
molecules that catalyze chemical reactions without being consumed, reduce energy activation, end in -“ase”
metabolic pathways
a series of linked reactions that are each catalyzed by an enzyme, need the previous enzyme and substates product to create next reaction
degradation reaction
substrate is broken down into smaller products
synthesis reaction
substrates are combined to create a larger product
enzyme denaturation
factors that change shape of an active site preventing efficient binding of substrate
factors that affect enzyme activity
pH, temperature, concentration of substrate, regulating molecules (competitive and noncompetitive inhibitors, cofactors)
concentration of a substrate
need for a certain number of substrates to allow for adequate enzyme function
temperature for enzymes
impacts speed of enzyme, an optimal temperature is the point where an enzyme functions best, and a range around this optimal point also allows the enzyme to function, depends on type of enzyme
regulation - promoting enzymes
cofactors and coenzymes - increase enzyme activity
cofactors
inorganic, bind to an enzyme, examples include FAD, NADP+, and NAD+
coenzymes
organic, non protein molecules
regulation - inhibiting enzymes
competitive inhibitors and allosteric inhibitors - decreases / limits enzyme activity
allosteric inhibitors
non active site inhibition, prevent enzyme function, such as binding to allosteric site and changing shape of active site
competitive inhibitors
bind to active site to prevent enzyme function
noncompetitive inhibition
negative feedback loop that prevents wasteful production of products due to activity through regulating enzyme activity
REDOX reactions
oxidation and reduction reactions that are facilitated by specific enzymes to move electrons. essential for photosynthesis and cellular respiration!
oxidation
OIL - oxidize is lost - the loss of electrons / hydrogen ions
reduction
RIG - reduce is gain - the gain of electrons / hydrogen ions
redox in photosynthesis / photosynthesis equation
6 CO2 + 6 H2O –> C6H12O6 + 6 O2
–> Reduction occurs from 6 CO2 to C6H12O6 (H+ are gained)
–> Oxidation occurs from 6 H2O to 6 O2 (H+ are lost)
redox in cellular respiration / cellular respiration equation
C6H12O6 + 6 O2 –> 6 CO2 + 6 H2O + ATP
–> Oxidation occurs from C6H12O6 to 6 CO2 (H+ are lost)
–> Reduction occurs from 6 O2 to 6 H2O (H+ are gained)
helper molecules
the molecules necessary for the oxidation of glucose. include enzymes and coenzymes
aerobic CR
final electron acceptor is Oxygen
anaerobic CR
final electron acceptor is NOT Oxygen
molecules involved in CR
- ATP
- Pyruvate (3 carbon molecule)
- Acetyl CoA (2 carbon coenzyme)
- NAD+ / NADH (electron carrier molecule)
- FADH / FADH+ (electron carrier molecule)
order of CR processes
glycolysis, (preparatory step), krebs cycle, oxidative phosphorylation
glycolysis
- first phase of CR
- occurs in cytoplasm
- involves converting glucose (a 6 carbon) into pyruvate (3 carbon)
- leads to a gain of 2 ATP
- is an anaerobic process, and therefore primative
glycolysis inputs and outputs
Inputs
6C glucose
2 NAD+
2 ATP
4 ADP + 4 P
Outputs
2 (3C) Pyruvate
2 NADH
2 ADP
4 ATP
Net gain: 2 ATP