Chp 7/8 Flashcards
the metabolic harvesting of energy by oxidization, ultimately dependent on molecular oxygen; carried out by the citric acid cycle and oxidative phosphorylation
cellular respiration
a molecule that becomes reduced (to NADH) as it carries high-energy electrons from oxidized molecules and delivers them to ATP-producing pathways in the cell
NAD+
the process that results in the complete oxidation of glucose using oxygen as the final electron acceptor. Oxygen acts as the final electron acceptor for an electron transport chain that produces a proton gradient for the chemiosmotic synthesis of ATP
aerobic respiration
the enzyme-catalyzed extraction of energy from organic compounds without the involvement of oxygen
fermentation
the passage of energetic electrons through a series of membrane-associated electron-carrier molecules to proton pumps embedded within mitochondrial or chloroplast membranes
electron transport chain
the anaerobic breakdown of glucose; this enzyme-catalyzed process yields two molecules of pyruvate with a net of two molecules of ATP
glycolysis
synthesis of ATP by ATP synthase using energy from a proton gradient. The proton gradient is generated by electron transport, which requires oxygen
oxidative phosphorylation
the multi-subunit membrane protein that catalyzes the phosphorylation reaction to produce ATP. The enzyme uses energy from a proton gradient, and is found in both mitochondria and chloroplasts, as well as in prokaryotes
ATP synthase
metabolic intermediate consisting of acetyl group linked to coenzyme A, produced by the transition reaction in cellular respiration and oxidation of fatty acids
acetyl-coA
the mechanism by which ATP is generated in mitochondria and chloroplasts; energetic electrons excited by light (in chloroplasts) or extracted by oxidation in the Krebs cycle are used to drive proton pumps, creating a proton concentration gradient ; when protons subsequently flow back across the membrane, they pass through channels that couple their movement of synthesis of ATP
chemiosmosis
the use of electron transport to generate proton gradient for chemiosmosis synthesis of ATP using a final electron acceptor other than oxygen
anaerobic respiration
a 3-carbon molecule that is the end product of glycolysis - each glucose molecule yields to two of these molecules
pyruvate
loss of an electron by an atom or molecule - often associated with a gain of oxygen or loss of hydrogen
oxidation
a type of paired reaction in living systems in which electrons lost from one atom are gained by another atom
redox reaction
the gain of an electron by an atom, often associated with a proton
reduction
enzyme-catalyzed transfer phosphate group directly to ADP
substrate-level phosphorlation
the primary type of light-absorbing pigment in photosynthesis (appears green)
chlorophyll
in photosynthesis, the reactions in which light energy is captured and used in production of ATP and NADPH. In plants this involves the action of two linked photosystems.
light-dependent reactions
the conversion of CO2 into organic compounds during photosynthesis; the first stage of the dark reactions of photosynthesis, in which carbon dioxide from the air is combined with ribulose 1,5-bisphosphate.
carbon fixation
an organized complex of chlorophyll, other pigments, and proteins that traps light energy as excited electrons
photosystem
the dark reactions of C3 photosynthesis; also called the Calvin–Benson cycle
calvin cycle
the four-subunit enzyme in the chloroplast that catalyzes the carbon fixation reaction joining CO2 to RuBP
rubisco
glycolysis (cellular respiration)
- glycolysis-glucose<pyruvate (forming two ATP and NADH in the process)
- pyruvate oxidation: pyruvate-acetyl CoA
- citric acid (krebs cycle) NAD+ carries protons and electrons shuttling them to
- electron transport chain
epithelial cell structures found in tree leaves and needles that help promote plant growth and exchange carbon dioxide and water with the surrounding environment.
stomata
a cell-like organelle present in algae and plants that contain chlorophyll (and usually other pigments) and carries out photosynthesis
chloroplast
in chloroplasts, a complex, organized internal membrane composed of flattened disks, which contain the photosystems involved in the light-dependent reactions of photosynthesis
thylakoids
chemical reaction involving the loss of a hydrogen atom
dehydrogenation
what role do electron carriers play in energy metabolism
Nad+ carries an electron and drops it off but never stops with it
ATP’s role in biological systems
cells need to control their contents by moving substances across the plasma membrane, or moving organelles within cells - this can be powered by ATP
cells also use ATP to power endergonic reactions that would not happen spontaneously
what is the difference between aerobic respiration and fermentation?
oxygen has a high affinity for electrons in aerobic respiration
oxygen is unavailable in fermentation
what is the structure of the electron transport chain?
collection of membrane-embedded proteins and organic molecules most of them organized into four large complexes
what is the function of the electron transport chain?
high energy electrons harvested from catabolized molecules are transported by mobile electron carriers between three complexes of membrane proteins - these use portions of the electrons energy to pump protons out of the matrix and into the intermembrane space - electrons are finally used to reduce oxygen and form h 2 0
explain how the proton gradient connects electron transport with ATP synthesis
chemiosmosis creates a concentration gradient of protons across the inner membrane - this electrochemical gradient is a form of potential energy that can be used for ATP synthase - this enzyme couples the reentry of protons to the phosphorylation of ADP to form ATP.
what is the reaction of photosynthesis?
light energy+co2+h20–> C6H12O6 (glucose) + O2 (oxygen)
what is the structure of the chloroplast?
oval-shaped and have two membranes an outer membrane and an inner membrane
inner membrane -> there are flattened disks aligned in columns - the rest of the interior is filled with a semifluid substance called stroma
what is the difference between light-dependent reactions and light-independent reactions?
light-dependent reactions need light and absorb energy and transfer them to molecules
light-independent reactions do not need light - their energy is used and stored in food molecules
why are pigments important to photosynthesis?
absorb light energy from the sun - when pigments absorb light energy it puts it in the visible range
absorption spectrum of a pigment to its color
The relationship of absorbance vs. wavelength for a pigment molecule. This indicates which wavelengths are absorbed maximally by a pigment.
chlorophyll a absorbs most strongly in the violet-blue and red regions.
photosytem slides in powerpoint
read them
see slide 22 on chapter 8
light reaction generating NADPH and ATP
