Bioenergetics Flashcards
the study of energy relationships and energy transformations in living organisms.
Bioenergetics
Transforms Chemical energy into useful energy (ATP)
Cellular Respiration
Converts solar energy into chemical energy stores (occurs in plants, algae, certain protists)
Photosynthesis
How cells obtain energy from food
STAGE 1: Breakdown to simple units
(Protein->Simple AAs; Carbs->Simple Sugars; Fat->Fatty Acids)
STAGE 2: Breakdown of simple units to acetyl CoA; Production of limited amounts of ATP and NADH
STAGE 3: Complete oxidation of acetyl CoA to H2O and CO2; Production of large amounts of ATP in mitochondrion
What is the protein pathway in energy absorption?
Proteins -> Amino Acids -> Pyruvate, Acetyl-CoA, or directly into Citric Acid Cycle, NH3 is put as waste products ->Produces NADH and CO2
What is the Sugar pathway in energy absorption?
Carbohydrates -> Sugars -> Glucose -> Glycolysis -> Pyruvate -> Acetyl CoA -> Citric Acid Cycle -> Produces NADH and CO2
What is the pathway of fats in energy absorption?
Fats -> Fatty Acids -> Beta oxidation -> Acetyl CoA -> Citric Acid Cycle -> Produces NADH and CO2
Steps of ATP Production and products
- Glycolysis: Glucose-> 2 Pyruvate, 2 ATP & 2 NADH
- Pyruvate: 2 Acetyl CoA & 2 NADH
- Citric Acid Cycle -> 6 NADH, 2 FADH, & 2 ATP
- Oxidative Phosphorylation: 26/28 ATP
Antiporters that transports Malate and Glutamate from intermembrane space to matrix
Malate-Aspartate Shuttle
Malate-aKetoglutarate Antiporter and Glutamate-Aspartate Antiporter
What is the significance of the Malate-Aspartate Shuttle?
Allows for recycling of NADH moving it from intermembrane to matrix indirectly.
Mostly in muscle and brown adipose tissues (more rapid but inefficient). Allows for transport of electrons by converting FAD to FADH2 for use by the quinone system (Mitochondrial Complex II) that allows transfer in ETC. Usually faster in producing the necessary ATP.
Glycerol-3-Phosphate Shuttle
Generation of ATP by movement of hydrogen ions across a selectively permeable membrane, down their electrochemical gradient
Chemiosmosis in photosynthesis and cellular respiration
Mitochondrial electron transport chain generates reactive oxygen species (ROS). Since this leads to damage, how is ROS production limited?
Uncoupling Proteins (UCP) increases rate of ETC. (Proton leaks)
What happens to ATP production in the presence of UTP
UCP decreases ATP production, acting like a shunt to help alleviate the H+ pressure
UCP helps release the energy how?
Releases energy in the form of heat to release excess ATP
Mitochondrial depolarization increases _________.
Mitochondrial calcium efflux
Prolonged mitochondrial depolarization induces _________.
mitophagy or apoptosis
Methods of mitigating mitochondrial damage
Biogenesis (synthesis of new), Fusion (recycling ok parts from diff mitochondria) and fission (maximizing efficiency of fused mitochondria by removing non functional units)
Where do Lipophilic cations go when using TMRE/TMRM dyes? Why?
Mitochondria is even more negative than cell, this means lipophilic cation dyes will go into the mitochondria which will fluoresce. If the membrane is depolarized, it becomes more positive and thus the dye will disperse out of the mitochondria
Major locations of photosynthesis
Mesophyll of leaves
Green pigment with chloropplasts
Chlorophyll
Microscopic pores in the leaf where CO2 enters and O2 exits
Stomata
Conversion of 6 CO2, 12 H2O, and Light energy into glucose, 6 oxygen gas, and 6 water molecules
Photosynthesis
Two Stages of Photosynthesis
Light Reaction and Dark Reaction (Calvin Cycle)
Photo and Synthesis
Occurs in photosystems of thylakoids (chlorophyll a and b).
Light Reactions
This is where the Primary electron acceptor is found for plants.
In the photosystems.
Absorb excessive light that would damage chlorophyll
Carotenoids (those not absorbed are either reflected or transmitted)
Observed when electrons from Photosystem II is transfered to Photosystem I through an Electron Transport chain
Linear Electron Flow
The first electron acceptor from PS II that varies from animals.
Plastoquinone (Pq)
Occurs when NADPH is high so that only ATP is produced, recycling of electrons from ferredoxin.
Cyclic Electron Flow
Path of Electron in Linear Flow
Photosystem II excites P680 -> Plastoquinone (Pq) -> Cytochrome Complex produces ATP -> Plastocyanin (Pc) -> Photosystem I exciting P700 -> Ferredoxin -> NADP+ Reductase -> NADPH -> ATP and NADPH go to Calvin Cycle
Path of Electron in Cyclic Flow
Photosystem II excites P680 -> Plastoquinone (Pq) -> Cytochrome Complex produces ATP -> Plastocyanin (Pc) -> Photosystem I exciting P700 -> Ferredoxin -> Goes back to cytochrome complex producing ATP -> Pc -> repeat
Transports protons into the thylakoid space creating the proton gradient
Plastoquinone
Occurs in stroma of chloroplasts
* Uses ATP and NADPH from the thylakoids
* Converts CO2 to sugar [glyceraldehyde-3-phospate (G3P)]
Calvin Cycle
Generalized steps in Calvin Cycle
- Carbon Fixation
- Reduction
- Regeneration of the CO2 acceptor (RuBP)
