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CHAPTER 5B. CELLULAR RESPIRATION. Where does the energy of life come from?. Respiration. Photosynthesis. Radiant energy. Chemical energy. CELL ACTIVITIES. RESPIRATION. The release of chemical energy for cellular use *Takes place in small steps… Occurs in the MITOCHONDRIA
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CHAPTER 5B CELLULAR RESPIRATION
Where does the energy of life come from? Respiration Photosynthesis Radiant energy Chemical energy CELL ACTIVITIES
RESPIRATION • The release of chemical energy for cellular use • *Takes place in small steps… • Occurs in the MITOCHONDRIA • Done by HETEROTROPHS and some AUTOTROPHS
CELLULAR RESPIRATION Molecules are broken down inside the cell to release energy C6H12O6 + oxygen CO2 + H2O + energy 2 Types 1. Aerobic: oxygen is present 2.Anaerobic: no oxygen present
CYTOPLASM Ethyl Alcohol and Carbon Dioxide Alcoholic Fermentation Anaerobic Respiration Lactic Acid Fermentation Lactic Acid 2 Pyruvic Acids glucose MITOCHONDRIA CO2 Acetyl Co-A E- transport chain Aerobic Respiration H2O Krebs Cycle ATP
1. Glycolysis -Doesn’t require oxygen -Takes place in the cytoplasm -Main function is to take 1 C6H12O6 and make PYRUVIC ACID
A. Glucose is phosphorylated by 2ATP molecules forming a new 6C molecule (very unstable) B. Molecule splits into 2, 3C, PGAL • Each PGAL gains a “P” group, floating in the cells environment. • At the same time NAD+ removes two H+ atom to form NADH + H+
ATP ATP Glucose ADP ADP E. The PGAL loses 2 “P” groups each to ADP 4ADP4 ATP • PGAL is converted to PYRUVIC ACID • H2O is lost P P PGAL PGAL NAD NAD NADH NADH PGAL + P PGAL + P 2 ADP 2 ADP 2ATP Pyruvic Acid Pyruvic Acid 2ATP H2O
OVERALL ENERGY RESULTSOF GLYCOLYSIS 1. Used 2 ATP’s Made 4 ATP’s NET GAIN: 2 ATP’s 2. Gained 2 NADH+ H+ 3. 2 (3C) Pyruvic Acid’s
1. Anaerobic Respiration • Fermentation • - The breaking down of Pyruvic Acidwithout oxygen • - Occurs in the CYTOPLASM • - NO ATP produced • - Pyruvic Acid Regenerates NAD+ to be used in glycolysis • lactic acid fermentation • alcoholic fermentation
A. Lactic Acid Fermentation: Alternative pathway that converts Pyruvic acidlactic acid • During exercise breathing rates increase to supply more O2 • Enough for Aerobic Exercise (EX: Walking, swimming, jogging) • Anaerobic exercise will result in O2 debt (Ex: Weight lifting, sprinting)
Feel the Burn… • If there is not enough O2 available lactic acid will begin to accumulate in the muscles • Burning sensation is the result of lowering the muscle pH • Blood takes the lactic acid to the liver and breaks it down to pyruvate
B. Alcoholic Fermentation: • Without O2 NADH gives H+ to pyruvic acid • pyruvic acid ethyl alcohol + CO2 + NAD+ • Wine Formation: • Sugar in grapes is broken down with glycolysis • Dry Wine: Fermentation until all sugar is used up • Sweet Wine: Alcohol inhibits fermentation before all sugar is used up
To Glycolysis NAD NADH+H Pyruvic Acid Lactic Acid Fermentation Carbon Dioxide Ethyl Alcohol Pyruvic Acid Fermentation NADH+H To Glycolysis NAD
2. Aerobic Respiration • Glycolysis followed by the breakdown of pyruvic acid using oxygen • Occurs inside the MITOCHONDRIA • Pyruvic acid formed in the cytoplasm diffuses across the membrane into the MATRIX 1.Conversion of Pyruvic Acid 2. Krebs Cycle 3. Electron transport chain
A. Conversion of Pyruvic Acid NAD Pyruvic Acid NADH +H • Pyruvic acid loses a C to form CO2 and a H that is picked up by NAD + • Forming anAcetyl group&NADH + H+. 2. Acetyl group then picks up COENZYME A to form Acetyl-CoA. CoA CO2 CO A ACETYL CoA
Pyruvic Acid NAD CoA NADH + H CO2 Acetyl – CoA (2C) CoA Oxaloacetic Acid (4C) Citric Acid (6C) NADH + H NAD NADH + H NAD The Krebs Cycle CO2 Malic Acid (4C) Ketoglutaric Acid (5C) FADH NAD FAD NADH + H Succinic Acid (4C) ATP CO2 ADP
B. Kreb’s Cycle or Citric Acid Cycle • Discovered by Hans Krebs • Releases CO2 and hydrogen ions and results in the formation of ATP Steps of the Kreb’s • 1. Acetyl CoA gives up the CoA and binds with (4C) Oxaloacetic Acid to form CITRIC ACID (6C)
2. Citric Acid(6C): • releases H ion to NAD+ to form NADH + H+ • C to form CO2 - this results in KETOGLUTARIC ACID (5C) 3. Ketoglutaric Acid (5C): • H ion to NAD+ to form NADH + H+ • C to form CO2 • phosphate group to ADP to form ATP – • this results in SUCCINIC ACID (4C).
4. Succinic Acid: • gives up H to FAD to create FADH2 – • results in MALIC ACID (4C) 5. Malic Acid: • H+ ion to NAD+ to form NADH + H+ - • this results in OXALOACETICACID (4C) -the starting and stopping part of the Kreb’s Cycle
Pyruvic Acid NAD CoA NADH + H CO2 Acetyl - CoA CoA Oxaloacetic Acid Citric Acid NADH + H NAD NADH + H NAD Krebs Cycle CO2 Malic Acid Ketoglutaric Acid FADH NAD FAD NADH + H Succinic Acid ATP CO2 ADP
Overall Results Of Krebs Cycle From one C6H12O6 molecule the following is formed….. -6 NADH + H+ (3 each pyruvic acids) -4 CO2 (2 each pyruvic acid) -2 ATP (1 per pyruvic acid) -2 FADH (1 per pyruvic acid) Overall Results: Glycolysis + Kreb’s Cycle -4 ATP (2 from glycolysis, 2 from Kreb’s) -10 NADH +H+ 30ATP -2 FADH2 4 ATP
C. Electron Transport Chain -Occurs across the inner membrane of the mitochondria -Consists of enzymes, carrier molecules Steps of Electron Transport • NADH + H+ and FADH2 from the Krebs cycle arrives at the electron transport chain • e- are released and move down the chain, releasing energy. • Oxygen is the final e- acceptor
2. At the same time… • NADH+ H+ and FADH2 deliver H+, Across the inner membrane out of the matrix. • This Creates a concentration gradient 3. Ions want to diffuse across the membrane down their concentration gradient.
4. Hydrogen move across the membrane through ATPsynthetase… ATP is made. • CHEMIOSMOSIS 5. The diffused hydrogen ions are picked up by incoming oxygen to form water. *This is a continuous process, oxygen removes H+ while NADH+H+ and FADH2 replace it.
MATRIX e- MATRIX NADH + H+ ATP Synthetase MATRIX FADH2 H+ H+ ATP ADP + P O2 H+ H2O
ENERGY RESULTS • Scientists have determined…. • -After Krebs and Glycolysis- • 10 NADH give 3 ATP’s each and total 30 ATP’s • 2 FADH give 2 ATP’s each and total 4 ATP’s • 34 ATP’s/ glucose • Total ATP/glucose • Glycolysis 2 ATP • Krebs 2 ATP • e- transport 34 ATP • 38 ATP/glucose
2ATP Glycolysis 2 NADH + H+ Glucose 2PGAL 2 P.A. 2 NADH + H+ 2 Acetyl Co-A ADP 2ATP 2ATP 6 NADH + H+ KREB’S 2 FADH2 E-.Transport Chain 34 ATP 38 ATP’S
The Chemistry… • The chemical reactions of photosynthesis and respiration are opposites • Photosynthesis • CO2 + H2O + ENERGY (C6H12O6) + O2 • Respiration • C6H1206 + O2 CO2 + H2O + ENERGY