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Overall Photosynthesis Reaction. 6CO 2 + 6 H 2 O + energy C 6 H 12 O 6 + 6O 2. 7 C-O bonds + 5 C-C bonds + 7 C-H bonds + 5 H-O bonds + 12 O-O bonds 36 covalent bonds. 24 C-O bonds + 12 H-O bonds 36 covalent bonds. Overall Respiration Reaction.
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Overall Photosynthesis Reaction 6CO2 + 6H2O + energyC6H12O6 + 6O2 7 C-O bonds + 5 C-C bonds + 7 C-H bonds + 5 H-O bonds + 12 O-O bonds 36 covalent bonds 24 C-O bonds + 12 H-O bonds 36 covalent bonds
Overall Respiration Reaction C6H12O6 + 6O2 6CO2 + 6H2O + energy 7 C-O bonds + 5 C-C bonds + 7 C-Hbonds + 5 H-O bonds + 12 O-O bonds 36 covalent bonds 24 C-O bonds + 12 H-O bonds 36 covalent bonds
Basis of photosynthesis: Light energy is used to transform C-O and H-O bonds into C-C and H-C bonds C C C C H H C C O O C C H + + Energy + Increased potential energy O Basis of respiration: Energy is liberated by transforming C-C and C-H bonds into C-O and H-O bonds H + + + Energy Decreased potential energy O
Uphill and downhill reactions. Only the downhill reaction will go forward spontaneously. Uphill reactions require an input of free energy from some other source. Any uphill reaction needs to be combined with a downhill reaction to provide the energy needed. products have more energy than reactants did C + D substrates Free energy Free energy substrate A + B products have less energy than reactant did Fig. 8-8, p. 129 Progress of reaction
ATP ATP + H2O ADP + Pi + energy ADP + Pi + energy ATP + H2O ATP is ideally suited as energy currency The amount of energy released is twice as much as is needed to drive most cellular reactions. ATP does not cross the cell membrane and is short lived. The third phosphate bond of ATP is weak, unstable, breaks easily.
Enzyme Enzyme ATP-binding domain ATP-binding domain C + D Proteins can bind ATP Most proteins (enzymes) that catalyze uphill reactions bind ATP and use its energy. ATP ATP ADP + Pi
nicotin- amide adenine ribose ribose nicotin- amide adenine + ribose ribose Fig. 8-10, p. 131 The oxidation of nicotinamide adenine dinucleotide by oxygen The NADH loses one H and one chemical bond between H and C, which represents two electrons. The electrons may be transferred to a series of compounds before they reach oxygen.
NADH and NADPH • NADH is used predominantly to make ATP during respiration • NADPH is predominantly used during photosynthesis (formation of energy storage compounds)
Respiration Chapter 9
Overall Respiration Reaction C6H12O6 + 6O2 6CO2 + 6H2O + energy 7 C-O bonds + 5 C-C bonds + 7 C-Hbonds + 5 H-O bonds + 12 O-O bonds 36 covalent bonds 24 C-O bonds + 12 H-O bonds 36 covalent bonds
DIGESTION Most of the glucose in a plant is stored as starch (see section on photosynthesis). Starch is a polymer of glucose. Before glucose can be respired, it needs to be produced from starch via hydrolysis. This enzymatic process does not require any energy input and is known as digestion. Fig. 9-1, p. 135
Stages in the Respiration of glucose • Glycolysis (does not require O2) • TCA cycle (require O2) • Electron transport chain
Cytoplasm Overview of respiration steps glucose energy Input(ATP) 2 ATP Glycolysis (net) 2 NADH 2 pyruvate 2 CO2 2 NADH 4 CO2 TCA Cycle 6 NADH 2 ATP 2 FADH2 water 34 ATP Electron transport chain phosphorylation oxygen Mitochondrion Fig. 9-5, p. 138
Locations of respiration stages in the plant cell Digestion Cell wall CHLOROPLAST CHLOROPLAST MITOCHONDRIUM Glycolysis NUCLEUS TCA cycle MITOCHONDRIUM MITOCHONDRIUM CYTOSOL CHLOROPLAST CHLOROPLAST MITOCHONDRIUM Electron transport chain Notes: 1) cytosol is the same as cytoplasm 2) not all of the plant cell structures and organelles are shown 3) Digestion is by some authors considered as part of the respiration process
Stages in Respiration • Glycolysis • TCA cycle • Electron transport chain
ENERGY-REQUIRING STEPS OF GLYCOLYSIS: glucose 2 ATP invested glucose 6-phosphate fructose 6-phosphate fructose 1,6-bisphosphate Fig. 9-3a, p. 137 No need to memorize intermediates
ENERGY-RELEASING STEPS OF GLYCOLYSIS: 2 glyceraldehyde 3-phosphate dihydroxyacetone phosphate 2 NAD+ 2 NADH 2 Pi 2 1,3-bisphosphoglycerate 2 ADP phosphorylation, 2 ATP produced 2 ATP 2 3-phosphoglycerate No need to memorize intermediates 2 2-phosphoglycerate H2O 2 PEP 2 ADP phosphorylation, 2 ATP produced 2 ATP 2 Net energy yield 2 ATP 2 NADH pyruvate (to TCA cycle) Fig. 9-3b, p. 137
Overall Glycolysis Reaction Glucose + 2 ADP + 2 Pi + 2 NAD+2 pyruvate + 2 ATP + 2 NADH + 2H+ H H C O H H H O H C O O H C C O H C C H H O C C C H O O H H H H O H Glucose Pyruvate
H H C H O H O Glucose + 2 ADP + 2 Pi + 2 NAD+2 pyruvate + 2 ATP + 2 NADH+ 2H+ O H H C O H C C H C O H O C H C C C H O O H H H H O H Pyruvate Glucose 10 C-O bonds + 4 C-C bonds + 6 C-Hbonds + 2 H-O bonds 22 covalent bonds 7 C-O bonds + 5 C-C bonds + 7 C-Hbonds + 5 H-O bonds 24 covalent bonds
H H C H O H O Glucose + 2 ADP + 2 Pi + 2 NAD+2 pyruvate + 2 ATP + 2 NADH + 2H+ H O H C O H C C H C O H H C O C C C H O O H H H H O H Pyruvate Glucose 10 C-O bonds + 4 C-C bonds + 6 C-Hbonds + 2 H-O bonds 22 covalent bonds and….. 7 C-O bonds + 5 C-C bonds + 7 C-Hbonds + 5 H-O bonds 24 covalent bonds
nicotin- amide adenine ribose ribose nicotin- amide adenine + ribose ribose Fig. 8-10, p. 131 The oxidation of nicotinamide adenine dinucleotide by oxygen NADH loses one H and one chemical bond between H and C, which represents two electrons. The electrons may be transferred to a series of compounds before they reach oxygen (see electron transport chain). The inverse is also possible: reduction of nicotinamide adenine dinucleotide NAD+ can gain an electron pair (of high energy) and together with a H+ can form the C-H bond again. 2e- H+