Chapter 8 Flashcards
catabolic pathway
breaks down complex molecules into simple molecules
anabolic pathway
builds simple molecules into complex molecules
chemical energy
refers to the potential energy available for release in a chemical reaction
potential energy
energy the object possesses but is not in motion
heat energy
kinetic energy associated with the random movement of molecules
kinetic energy
moving energy
1st law of thermodynamics
energy cannot be created or destroyed but it can be transferred or transformed
2nd law of thermodynamics
each energy transfer increases the entropy of the universe. unusable energy is released as heat
free energy
the more ΔG available (the more negative the reaction) the more work can be done
high altitude -> low altitude
increase in stability and decrease in ΔG
entropy
measure of randomness
endergonic reaction
absorbs energy to complete the reaction
exergonic reaction
releases energy from the start of the reaction to the end
enthalpy
change in total energy
energy coupling
energy that was released from an exergonic reaction to power an endergonic reaction
hydrolysis of ATP
the addition of a water molecule to break off a phosphate to create ADP
catalyst
increases the rate of reactions by lowering the activation energy
cofactor
non-protein helpers during catalyzation
coenzymes
organic cofactors ex: vitamins
enzymes
macromolecule that acts as a catalyst in a reaction
activation energy
the initial energy for starting a reaction
enzymes affect activation energy
more enzymes = faster reactions until saturation occurs
limits to reaction rates
high temperature denatures proteins’ activation sites and kills cells. pH acidity can cause enzymes to die
active sites
only part of the enzyme that a substrate binds to
enzyme substrate complex
enzymes binds to its substrate forming a complex
Redox reactions
a reaction that involves both a oxidative and reductive process
NAD+
functions as an oxidizing agent during respiration
NADH
transport electrons to the mitochondria where the cell can harvest energy stored in the electrons
stages of cellular respiration and locations
Glycolysis: Cytoplasm Pyruvate Oxidation: Mit. Matrix Citric Acid Cycle: Mit. Matrix ETC: Inner Mit. Membrane ATP Synthase: Inner Mit. Memebrane
stepwise energy harvesting
During cellular respiration the fuel (such as glucose) is oxidized and the oxygen is reduced.
substrate level phosphorylation
uses an enzyme to bring in the additional phosphate group from a substrate molecule
oxidative phosphorylation
stores energy released form each step of the ETC to make ATP
Glycolysis 2 phases
Investment phase: uses 2 ATP to break a 6-Carbon molecule into 2 pyruvate
Payoff Phase: gains 4 ATP and ends with G3P
kinase
transfer of phosphate
isomerase
en enzyme that catalyzes the conversion of a specified compound to an isomer
dehydrogenase
an enzyme that catalyzes the removal of hydrogen atoms from a particular molecule
Reaction in Pyruvate oxidation forming Acetyl CoA
- ) Pyruvate carboxyl group is given off as 1 molecule of Co2
- ) Remaining 2 - Co2 are oxidized, forming acetate. The extracted electrons are transferred to NAD+ forming NADH.
- ) Coenzyme A is attached to acetate forming Acetyl CoA
Citric Acid Cycle 1st reaction. Why is it a cycle? Decarboxylation?
1.) Acetyl CoA binds with Oxaloacetate to form Citrate (a 6-Carbon mol).
It is a cycle because without the product oxaloacetate, Acetyl CoA can not bind to it to form citrate.
Decarboxylation: removes carboxyl groups and releases Co2
Electron Transport Chain
a group of compounds that pass electrons from one to another via redox reactions coupled with the transfer of protons across a membrane to create a proton gradient that drives ATP synthesis
Cytochromes
function as electron transfer agents in many metabolic pathways
cytochrome oxidase
last enzyme in the respiratory ETC
what is the final electron acceptor of the ETC?
the ATP Synthase protein
How free energy changes and its relation to ATP synthesis
because there is a proton gradient in the form of hydrogen ions the ATP Synthase uses the pumping of hydrogen to create ATP
chemiosmosis
the movement of ions across a semipermeable membrane down their electrochemical gradient
ATP Synthase
the enzyme that actually make ATP from ADP and an inorganic phosphate.
Proton-Motive Force
emphasis on the capacity of the gradient to perform work. the force drives H+ back across the membrane through the H+ channels provided by the ATP synthase
Energy obtained from 1 molecule of glucose
Glycolysis makes: 2 ATP, 2 NADPH
Pyruvate Oxidation makes: 2 NADPH
Citric Acid Cycle makes: 2 ATP, 6 NADPH, 2 FADH2
Total: 4 ATP, 10 NADPH, 2 FADH2
ΔG for ATP
ΔG for NADPH
ΔG for FADH2
ΔG for ATP = -7.3 kcal/mol
ΔG for NADPH = -53 kcal/mol
ΔG for FADH2 = (0.66 x -53) kcal/mol
alcoholic fermentation
pyruvate is converted to ethanol.
1.) a mol of Co2 is release and pyruvate is converted to acetaldehyde.
2.) acetaldehyde is reduced by NADH to ethanol.
this than regenerates NAD+
Lactic Acid fermentation
pyruvate is directly reduced by NADH to form lactate as an end product with no release of Co2
anaerobic respiration
harvesting chemical energy without oxygen
aerobic respiration
O2 is consumed as a reactant along with organic fuels to harvest energy
thylakoid
each of the flattened sacs inside the chloroplast
stroma
the dense fluid inside the chloroplast
granum
the entire stack of thylakoids embedded in the stoma
thylakoid space
the inside of the thylakoid
wavelength
the distance between the crests of the electromagnetic waves
photon
the fundamental particle of visible light. each of their own quantity of energy
fluorescence
the property of absorbing light of a short wavelength and emitting light of a longer wavelength
absorption
the process by with things are absorbed or is absorbed by another thing
reflection
the throwing back by a body or surface of light, heat, or sound without absorbing it
transmission
the action of transmitting something or the state of being transmitted
photoexcitation
the process of exciting the atoms or molecules of a substance by the absorption of radiant energy
resonance transfer
a mechanism describing energy transfer between two light-sensitive molecules
antenna pigments
is an array of protein and chlorophyll molecules embedded in the thylakoid membrane plants, which transfer light energy to one chlorophyll A molecule at the reaction center of a photosystem.
carotenoids
hydrocarbons that are various shades of yellow and orange because they absorb violet and blue-green light. may broaden the spectrum of colors that can drive photosynthesis
photophosphorylation
the synthesis of ATP from ADP and phosphate that occurs in a plant using radiant energy absorbed during photosynthesis. Occurs during photosystem 1
Light reactions
need light to produce organic energy molecules, ATP and NADPH. initiated by colored pigments, mainly green colored chlorophylls
