Metabolic Processes Chapter 4 + 5 - Pop Quiz 3 Flashcards
Where does the ETC occur
In the cristae of the mitochondria
What makes up the ETC
A series of electron carriers and multi-enzyme complexes
What is happening in the ETC
NADH and FADH2 from the prior cellular respiration steps are being oxidized
How much ATP in percent is being made by the oxidation of the coenzymes
When oxidized, the ETC releases energy producing approximately 90% of the ATP molecules in cell
In the ETC, what type of reactions are occurring
A series of coupled redox reactions
In the coupled redox reactions of the ETC, what is happening
As the electrons are transferred from one carrier to another, energy is released from each step. The electrons move to a stronger oxidizing agent every time (Higher electronegativity), finishing off with 1/2 O2 (Oxidative level phosphorylation)
Compare Oxidative and Substrate Level phosphorylation
Oxidative phosphorylation can produce a lot more ATP molecules per glucose
What happens to the ETC if oxygen is ABSENT
There will be no final electron acceptor meaning that there would be no ETC and no ATP produced by the pathway
Describe the electron transport process in terms of its characteristics of energy
Highly exergonic reaction and the energy released is used to pump protons (H+) from the matrix into the inter membrane space
Say the CHANT
As the electrons move through the ETC, they lose POTENTIAL ENERGY, which is released as FREE ENERGY, which is used to PUMP PROTONS from the MATRIX to the INTER-MEMBRANE SPACE.
Now we have ELECTROCHEMICAL POTENTIAL ENERGY!!
In Chemiosmosis:
The PROTONS are going to move DOWN THEIR CONCENTRATION GRADIENT, which releases FREE ENERGY, which is trapped as CHEMICAL BOND ENERGY in the molecule ATP.
In general, how much ATP is made per NADH
In general, 3 ATP are made per NADH in the ETC and chemiosmosis
How many ATP are made by FADH2 in the ETC
In general, 2 ATP are made per FADH2
What protein enzyme complex does NADH pass through
NADH Dehydrogenase
What protein enzyme complex does FADH2 pass through
Ubiquinone (Q)
How many protein enzyme complexes are their, and which of them are in our learning?
There are 4 complexes, only the first two NADH dehydrogenase and Ubiquinone (Q) are for us
What complex is found in Chemiosmosis
ATP Synthase complex
What does ATP Synthase complex do
provides channels through which protons can travel back into the mitochondrial matrix which provides energy to form ATP
Why is there a difference in ATP yields between NADH and FADH2
FADH2 carries electrons that do not have as high a energy level as NADH
How many electrons come from NADH and FADH2
Both coenzymes carry 2 high energy electrons
Howmany protons can the NADH electrons pump
3 protons
Howmany protons can the FADH2 electrons pump
2 protons
How many ATP molecules are made in the ETC
No ATP are made in the ETC, the theoretical 32 ATP are made in Chemiosmosis
What are the major structures in the mitochondria
Outer membrane, INTER membrane space, Inner membrane (Folds/Cristae), Mitochondrial matrix
What is the exception of NADH from glycolysis in the ETC
Since ATP made through glycolysis is in the cytoplasm, its electrons are moved through the mitochondria’s membrane but are then transferred to FAD which means only 2 ATP are produced from this NADH type
In reality, howmuch ATP is actually made in a real life scenario
30 ATP instead of 36 ATP
Why is there a lower yield of ATP in reality
The intermembrane is a leaky membrane meaning protons move into the matrix losing ATP production potential, also some protons end up being used for other cellular processes
Howmuch available free energy does aerobic respiration capture of glucose
32%
How do the protein enzyme complexes work
They have cofactors that alternate between from reduced and oxidized forms as they pull electrons from upstream molecules and donate them to more electronegative molecules downstream
What else happens when 1/2 O2 removes 2 electrons from Complex 4 to end the ETC
the oxygen also reacts with 2 protons (H+) to create a single molecule of water as waste
How fast is the ETC
almost instantaneous
What is a protein gradient
A difference in proton (H+ ion concentration) across a membrane
What is the definition of chemiosmosis
The ability to use proton-motive force to do work
What is proton-motive force
A force that moves protons because of a chemical gradient of protons across a membrane
Who proposed chemiosmosis
Nobel Prize winner Peter Mitchell
What are other uses of chemiosmosis other than ATP synthesis
pumps other substances across membranes and drives the rotation of flagella in prokaryotes
What is ATP synthase
A molecular motor that spans the inner mitochondrial membrane
What structures make up ATP synthase
A basal unit embedded in the inner mitochondrial membrane and connected to a headpiece by a stalk.
What happens to the molecular motor when ATP is synthesized
The binding of protons to the headpiece causes it to rotate in a way that catalyzes ATP synthesis, this makes the headpiece the smallest molecular rotary motor
What is the main use of uncoupling
maintaining body temperature by producing thermal energy
What can uncoupling be caused by
making the inner mitochondrial membrane permeable to protons
What is Creatine Phosphate
When excess ATP is available, creatine is phosphorylated to become high energy creatine phosphate
What is metabolic rate
The amount of energy that is expended per unit time in an organism
What is Basal Metabolic Rate
The metabolic rate of an organism at rest
what are three ways to increase metabolism
Exercise, Eat regular balanced meals, and get good sleep consistently
What is beta oxidation
The process of breaking fatty acids into Acetyl-CoA
Why are carbohydrates heavier than lipids
the significant mass of water attached to them
What is fermentation
A process in which hydrogen atoms of NADH are transferred to organic compounds other than the ETC
What is needed for both types of fermentation we looked over
pyruvic acid or pyruvate from Glycolysis
What is special about fermentation about how it works
It is an anaerobic pathway
What is alcohol Fermentation
Occurs in yeast, 2 Pyruvate into 2 Acetaldehyde into 2 ethanol, first reaction produces CO2, second reaction regens NAD+ from NADH
What is the whole reason for fermentation
The regeneration of coenzymes allowing glycolysis to continue
What is Lactic Acid fermentation
Occurs in animal cells, specifically muscle cells in humans, 2 Pyruvate into 2 Lactate or Lactic Acid also regenerating NAD+ from NADH
In humans, what is happening to the muscles that facilitates fermentation
strenuous physical activity, depleting their oxygen
What does lactic acid do to the body
causes muscle pain and fatigue, lactic acid is oxidized back to pyruvate in the liver once the physical activity is over
How much ATP is produced from fermentation
0 ATP are made directly, however 2 ATP are made indirectly by the regen of NAD+ facilitating glycolysis
What is the reaction of photosynthesis
6CO2 + 6H2O —sunlight,chlorophyll——-> C6H12O6 + 6O2
What in sunlight is being used as energy
Photons
What are the two types of reactions in photosynthesis
Light Reactions and Light Independent Reactions
Where do light reactions occur
The thylakoid membranes and require chlorophyll
Where are light independent reactions happening
Occur in stroma of chloroplast
What is the cycle involved in the light independent reactions
Calvin Cycle (Carbon fixation)
What is a photoautotroph
An organism that makes its own food using energy from the sun
What is the difference in coenzymes in photosynthesis
NADPH (phosphate added)
What does the calvin cycle produce
2 G3P turning into 1 Glucose, leaving as sucrose for transport and starch for storage
How is the calvin cycle facilitated
ATP produced from the light reactions have free energy synthesizing organic compounds like glucose from inorganic materials
What is the process of turning inorganic carbon molecules (CO2) into organic carbon molecules called
Carbon Fixation
In photosynthetic prokaryotes where do all photosynthetic reactions occur
chloroplasts
What is the stroma
aqueous (liquid) environment in a chloroplast
Following light absorption, what are the three possibilities for excited electrons within a pigment molecule
Energy released as thermal/fluorescence, energy is transferred to another pigment molecule, the whole electrons gets transferred to an electron accepting molecule
what is an antenna complex
a cluster of light-absorbing pigments embedded in the thylakoid membrane able to capture and transfer energy to chlorophyll a in the reaction center
what is the reaction centre
a complex of proteins and pigments that contain the primary electron acceptor
explain the nature of pigment molecules absorbing wavelengths
pigment molecules do not absorb all wavelengths of light, the ones not absorbed pass through the object or reflect.
Why do some plants appear green
The green and yellow light is reflected back making chlorophyll a containing plants appear green
What is an absorption spectrum
A plotted graph of light wavelengths that get absorbed by the substance
What is an action spectrum
A plotted graph of the effectiveness of different wavelengths of light in driving a chemical process
What is the relation between action and absorption spectra
If an action spectrum for a physiological phenomenon matches the absorption spectrum of a pigment, there is a high chance the two are linked
What was Theodor Engelmann known for
Produced the first action spectra, placed a strand of green alga, spirogyra, on a glass microscope slide, along with water containing aerobic bacteria, he adjusted the prism so that it split a beam of light into separate colours, after some time the bacteria began to cluster around the algal strand where oxygen was released in the greatest rate (where photosynthesis was occurring at the greatest rate), the regions linked to the wavelengths of light being absorbed effectively by the alga (blue and violet and red absorbed most effectively), green least bacteria found
What are pigment proteins organized into
photosystems
What are the two photosystems
Photosystem II (P680)
Photosystem I (P700)
What is the key difference between the two photosystems
The number in the names of the photosystems represent the wavelengths at which light is optimally absorbed
What is the difference between the reaction centers of P680 and P700
P680 contains P680 molecules which are specialized chlorophyll a molecules and vice versa
What photosystem comes first
Photosystem II (P680) comes before PSI
What is the general process happening in photosystems
Photosystems trap photons of light and use the energy to energize a chlorophyll a molecule in the reaction centre. The chlorophyll a molecule is then oxidized as it transfers a high-energy electron to the primary electron acceptor.
Where does the splitting of water into electrons, protons and oxygen occur
Photosystem II (P680)
What is the significance of P680+
Strongest Oxidant known in biology
What does cyclic electron flow produce
ATP ONLY
What does Non-Cyclic electron flow produce
ATP and NADPH
What happens as a result of cyclic electron flow
NO CALVIN CYCLE
What is the point of Photosystems
Harvest Light Energy
What is the cuticle
The waxy coating on leaves to prevent water and gas loss
What facilitate gas exchange in leaves
Stoma and Guard Cells
Where does the calvin cycle occur
stRoma
What is the difference in energy between P680 and P700
Higher wavelength = LOWER energy (E=1/Wavelength, inversely proportional)
Why are the stoma on the bottom of the leaf
to prevent water loss
What is the end product of Calvin cycle
2 G3P turned into glucose which can be put into sucrose which can be transported or polymerized into starch for long term energy
Explain what happens in photosystems
Photons of light are absorbed and their energy is transferred between multiple antenna complexes all the way to the reaction center chlorophyll a whose electrons get excited from ground state to excited state and are transferred to the primary electron acceptor and then the electron transport chain
What do accessory pigment molecules and chlorophyll b do
absorb different wavelengths of light
What photosystems are involved in non cyclic electron flow
Both P680 and P700
What photosystems are involved in cyclic electron flow
ONLY P700
under what circumstance will Calvin cycle occur
When both P680 and P700 occur during non cyclic electron flow
In photosystem II, what does water provide
2 electrons, 1/2 O2, and 2 H+ protons
During Non cyclic electron flow, what is the cycle that pumps protons in the first ETC
Q Cycle
During cyclic electron flow what is the role of ferredoxin
The oxidation of ferredoxin results in the transfer of the electron to NADP+ reducing it to NADP, a second electron and proton from the stroma are added by NADP+ reductase to create NADPH
Howmany protons are pumped during Q cycle
4 protons are pumped
What do the 4 protons pumped by Q cycle create
1 ATP that goes to calvin cycle
What are the three stages of photosynthesis
Capturing light energy (photosystems), Using that energy to create ATP and NADPH (light reactions), Using the free energy of ATP and the reducing power of NADPH to synthesize organic compounds from inorganic ones
What type of reaction is the production of NADPH and ATP
endergonic reaction
What is the name of the process where ATP and NADPH molecules are used to produce glucose in the calvin cycle
Non cyclic photophosphorylation because electrons are not being cycled back into photosystem 680
What is the name of the process where P700 is used to create ATP only generating a proton gradient for chemiosmotic ATP synthesis, no calvin cycle
cyclic photophosphorylation
Howmany steps are in the calvin cycle
11 enzyme catalyzed steps
