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Cellular Respiration and Fermentation, Photosynthesis - Coggle Diagram

- - - - 2 ATP are used to split glucose into 2 three-carbon sugars
    - - 4 ATP are produced, NAD⁺ is reduced to NADH,
      - small sugars are oxidized to form 2 pyruvate and 2 H₂O
- - - - oxidation of pyruvate's carboxyl group, releasing CO₂
      - NAD⁺ is reduced to NADH
      - CoA is attached to the remaining 2-carbon fragment, forming acetyl CoA
  - - - 1) the acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate, forming citrate
      - 2-7) decompose the citrate back to oxaloacetate
- - - - molecules embedded in the inner mitochondrial membrane of eukaryotic cells
      - embedded in the plasma membrane of prokaryotic cells
    - - most of the electron carriers aside from ubiquinone and O₂
      - proteins with heme groups containing an iron atom
  - - - enzyme that makes ATP from ADP & inorganic phosphate
      - uses energy from H⁺ gradient to power ATP synthesis
      - H⁺ moves into binding site on the rotor of ATP synthase, causing it to spin in a way that catalyzes the phosphorylation of ADP to ATP
    - - another name for the H⁺ gradient that emphasizes its capacity to do work
  - - - phosphorylation and the redox reactions are not directly coupled; the ratio of NADH to ATP is not a whole number
      - ATP yield varies depending on whether electrons are passed to NAD⁺ or FAD
      - the proton-motive force is also used to drive other forms of work
- - - - the end product of the anabolic pathway inhibits the enzyme that catalyzes an early step of the pathway
- - - - pyruvate converted to ethanol in 2 steps
        
        1) releases CO₂ from pyruvate
        
        2) produces NAD⁺ and ethanol
      - alcohol fermentation of yeast is used in brewing, winemaking, and baking
    - - pyruvate is reduced directly by NADH to form lactate
      - no CO₂ is released
      - LA fermentation by fungi and bacteria is used to make cheese and yogurt
      - in humans, red skeletal muscle oxidizes glucose completely to CO₂, and white skeletal muscle produces lactate even under aerobic conditions
  - - - fermentation uses an organic molecule like pyruvate or acetaldehyde as the final electron acceptor
      - in cellular respiration, electrons are transferred to the ETC
    - - fermentation yields 2 ATP via substrate-level phosphorylation
      - cellular respiration harvests more ATP via oxidative phosphorylation; up to 32 ATP in aerobic respiration
    - - only carry out anaerobic respiration or fermentation
      - cannot survive in the presence of O₂
    - - can survive using fermentation or aerobic respiration
      - ex. yeast and many bacteria
      - pyruvate is a fork in the road that leads to different catabolic routes
  - - - harvests energy without O₂ or an ETC
      - must use alternate mechanisms to regenerate NAD⁺ (which is done via the ETC under aerobic conditions)
    - - uses ETC with a different final electron acceptor (not O₂)
- - - - partial degradation of sugars that occurs without using oxygen
    - - catabolic pathway in which oxygen is consumed as a reactant along with the organic fuel
      - anaerobic respiration
        
        like aerobic respiration, but consumes substances other than oxygen
    - - both aerobic and anaerobic processes, but used mainly for aerobic respiration
      - degradation of glucose
        
        C₆H₁₂O₆ + 6O₂ ⇾ 6CO₂ + 6H₂O + Energy (ATP & heat)
  - - - redox reactions
        
        reactions that transfer electrons between reactants
        
        oxidation
        
        loss of electrons from one substance
        
        reduction
        
        addition of electrons to another substance
        
        reduces positive charge of atom
        
        reducing agent
        
        electron donor; reduces electron accepter
        
        oxidizing agent
        
        electron accepter; oxidizes electron donor
      - some redox reactions change the degree of electron sharing in covalent bonds
      - O is very electronegative; it pulls strongly on electrons
      - the partial "gain" of electrons by O atoms and the partial "loss" of electrons by their bonding partners constitutes a redox reaction
      - electrons lose potential energy when shifting from a less electronegative atom to a more electronegative one
    - - in cellular respiration, fuel (glucose) is oxidized while O₂ is reduced
      - organic molecules abundant in hydrogen are excellent sources of high energy electrons
      - energy is released as hydrogen and electrons are transferred to O atoms
      - the oxidation of glucose transfers electrons to a lower energy state, releasing energy that is used to synthesize ATP
    - - glucose and other organic molecules are broken down in a series of steps
      - each electron travels with a proton--thus, as a hydrogen atom
      - the H atoms are first passed to an electron carrier before being transferred to O₂
      - nicotinamide adenine dinucleotide
        
        coenzyme that functions as an electron carrier
        
        NAD⁺
        
        electron accepter; functions as an oxidizing agent during respiration
        
        NADH
        
        reduced form of NAD⁺
        
        represents stored energy that's used to synthesize ATP
      - enzymes called dehydrogenases remove a pair of H atoms from the substrate and transfer the 1 electron and 2 protons to NAD⁺, forming NADH
      - the other proton is released as a hydrogen ion into the surrounding solution
      - electron transport chain
        
        consisted of a number of molecules built into the inner mitochondrial membrane (plasma membrane in prokaryotes)
        
        used in respiration to break the fall of electrons to O₂ into several energy-releasing steps
        
        NADH passes electrons to ↑↑ energy end of the ETC, where they are transferred in a series of reactions that each release small amounts of energy
        
        O₂ is the final electron acceptor at ↓↓ energy end of ETC, where it captures the electrons and the H nuclei, forming H₂O
  - - - 1) glycolysis
        
        occurs in the cytosol
        
        breaks glucose down into 2 pyruvate
      - 2) pyruvate oxidation and the citric acid cycle
        
        complete the breakdown of glucose into CO₂
      - 3) oxidative phosphorylation
        
        ETC and chemiosmosis facilitate ATP synthesis
        
        powered by redox reactions
    - - allows some ATP to be generated during glycolysis and citric acid cycle
      - occurs when an enzyme transfers a phosphate group directly from a substrate to ADP
- - - - distance between the crests of electromagnetic waves
    - - the entire range of radiation
      - visible light
        
        narrow band from 380nm to 740nm
        
        drives photosynthesis and can be detected by the human eye
    - - each photon has a fixed quantity of energy that is inversely related to the wavelength of light
      - the shorter the wavelength, the greater the energy of each photon of light
  - - - wavelengths that are not absorbed are reflected or transmitted
    - - measures a pigment's ability to absorb various wavelengths
      - sends light through pigments and measures the fraction of light transmitted at each wavelength
    - - a graph plotting a pigment's light absorption versus wavelength
    - - chlorophyll a
        
        the key light-capturing pigment that participates directly in light reactions
        
        its absorption spectrum indicates that violet-blue and red work best for photosynthesis, whereas green is the least effective
      - chlorophyll b
        
        accessory pigment
      - carotenoids
        
        separate group of accessory pigments that broaden the spectrum for photosynthesis
        
        appear yellow/orange b/c they absorb violet and blue/green light
        
        some are photoprotective (absorb excessive light that could damage chlorophyll/react with oxygen)
    - - profiles the relative effectiveness of different wavelengths
      - broader than the absorption spectrum of chlorophyll
  - - - composed of a reaction-center complex surrounded by several light-harvesting complexes
    - - organized assoc. of proteins holding a special pair of chlorophyll a molecules and a primary electron acceptor
    - - consists of various pigment molecules bound to proteins
      - transfer the energy of photons to the chlorophyll a molecules in the r-c complex
        
        these chlorophyll a molecules can transfer an excited electron to a different molecule
    - - accepts excited electrons and is reduced as a result
    - - photosystem II
        
        called P680 b/c its reaction-center chlorophyll a is best at absorbing light with a wavelength of 680 nm
      - photosystem I
        
        called P700 b/c its r-c chlorophyll a is best at absorbing light with a wavelength of 700 nm
  - - - 2) an excited electron from P680 is transferred to the primary electron acceptor (oxidized form is known as P680⁺)
      - 3) enzyme catalyzes the split of H₂O into 2 electrons, 2 H⁺, and an oxygen atom
        
        electrons transferred to P680⁺, reducing it back to P680
        
        H⁺ released into thylakoid space; O₂ is formed from oxygen atoms generated from the splitting of H₂O molecules
      - 1) a photon hits a pigment in a light-harvesting complex of PSII, and its energy is passed among pigment molecules until it excites P680
      - 4) electrons are passed from the primary electron acceptor of PSII down an ETC to PSI via redox reactions
        
        the ETC includes plastoquinone (Pq), a cytochrome complex, and the protein plastocyanin
        
        energy released is used to pump H⁺ into thylakoid space, creating a proton gradient across the thylakoid membrane
      - 5) potential energy stored in the proton gradient drives ATP production by chemiosmosis
      - 6) In PSI, transferred light energy excites P700, which loses an electron to the primary electron acceptor
        
        P700⁺ accepts an electron passed down from PSII
      - 7) electrons are passed from the primary electron acceptor of PSI down a 2nd ETC to the protein ferredoxin (Fd)
      - 8) NADP⁺ reductase catalyzes the transfer of electrons from Fd to NADP⁺
        
        2 electrons needed to reduce NADP⁺ to NADPH
        
        the formation of NADPH removes an H⁺ from the stroma
  - - - ETC pumps H⁺ across a membrane as electrons are passed through carriers
        
        some of the electron carriers and the ATP synthase complexes are quite similar in chloroplasts and mitochondria
      - ATP synthase couples the diffusion of H⁺ down their gradient to the phosphorylation of ADP to ATP
    - - mitochondria transfer chem. energy from food to ATP; chloroplasts transform light energy into the chemical energy of ATP
      - in chloroplasts, the high-energy electrons passed down the ETC come from H₂O, whereas those in mitochondria come from organic molecules
- - - - the binding of CO₂ to RuBP is catalyzed by rubisco
      - the 6-carbon intermediate splits, forming two 3-phosphoglycerate molecules
    - - each 3-phosphoglycerate molecule is altered via phosphorylation by 6 ATP and reduction by 6 NADPH to produce a G3P sugar
      - 6 molecules of G3P are formed for every 3 CO₂ molecules that enter the cycle
      - 1 G3P exits the cycle, but the other 5 are recycled
    - - the remaining 5 G3P molecules are rearranged in a series of reactions, yielding 3 RuBP molecules
      - 3 ATP molecules are used
- - - - the tissue in the interior of the leaf
      - where most chloroplasts are found
    - - connected sacs that compose a 3rd membrane system
      - may be stacked in columns called grana
    - - green pigment that gives leaves their color
      - reside in the thylakoid membranes
  - - - the O₂ given off by plants is derived from H₂O, not CO₂
      - chloroplasts split H₂O into H and O atoms, using the electrons from hydrogen to make sugar and releasing O₂ as a byproduct
      - all photosynthetic organisms require a hydrogen source, but it varies among organisms
        
        ex. sulfur bacteria uses H₂S instead of H₂O
    - - photosynthesis reverses the direction of electron flow as compared to cellular respiration
      - photosynthesis is a redox process in which H₂O is oxidized and CO₂ is reduced
      - its an endergonic process that gets its energy boost from light
  - - - the photo part of photosynthesis; occur in the thylakoids
      - split H₂O, providing electrons and protons (H⁺), and releasing O₂ as byproduct
      - reduce the electron acceptor NADP⁺ to NADPH by adding a pair of electrons along with an H⁺
      - generates ATP from ADP via photophosphorylation
    - - carbon fixation
        
        cycle begins by incorporating CO₂ into organic molecules
      - occurs in the stroma; makes sugar from CO₂ using the ATP and NADPH generated during the light reactions
      - reduces fixed carbon to carbohydrate by adding electrons provided by NADPH
      - referred to as light-independent reactions b/c it doesn't require light directly
- - - - (most plants) the initial fixation of CO₂ via rubisco forms a 3-carbon compound
  - - - 1) production of 4-carbon compound is catalyzed by PEP carboxylase in mesophyll cells
        
        PEP c can fix CO₂ even when CO₂ [ ] is low
      - 2) the 4-carbon compounds are exported to bundle-sheath cells through plasmodesmata
      - 3) CO₂ is released from the 4-carbon compound and then used in the calvin cycle
  - - - mechanism some plants use to fix carbon that helps conserve water (ex. succulents)
- - - - self-feeders; producers
      - produce organic molecules from CO₂ and other inorganic molecules
      - most plants are photoautotrophs (use energy of the sun)
    - - unable to make their own food; consume compounds produced by other organisms
      - consumers
      - most eat other organisms, but decomposers eat the remains of organisms and organic litter (ex. fungi)