* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Lecture 6
Survey
Document related concepts
Magnesium in biology wikipedia , lookup
Butyric acid wikipedia , lookup
NADH:ubiquinone oxidoreductase (H+-translocating) wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Phosphorylation wikipedia , lookup
Mitochondrion wikipedia , lookup
Photosynthesis wikipedia , lookup
Microbial metabolism wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Electron transport chain wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
Biochemistry wikipedia , lookup
Transcript
Cellular respiration and fermentation 04/18/2016 BI102 Announcements • Exam 1 after lecture • Don’t forget to do the online assignments every week! • Quiz 2 and lab 2 review Cellular Respiration Cells require lots of energy • Cell require a constant supply of energy to perform metabolic reactions • Energy is transferred from energy-storage molecules like glucose to energy-carrier molecules like ATP • The energy used on earth comes almost entirely from the Sun Energy storage • Plants convert glucose to sucrose or starch • Animals convert glucose to glycogen and fat • We will not cover the conversion of storage molecules to glucose • We will cover the breakdown of glucose during respiration The energy carrier molecule, ATP • A nucleoside with three phosphates • AMP is a nucleotide in RNA • Paired with endergonic reactions dephosphorylation of ATP Electron (energy) carriers • FAD (vitamin B2) and NAD (vitamin B3) are electron carriers • They can be easily reduced (add e-) or oxidized (give out e-) Oxidative phosphorylation – chemiosmosis in the cell for ATP production • In eukaryotes, oxidative phosphorylation takes place in mitochondria. In prokaryotes, this process takes place in the plasma membrane. Photosynthesis 6 CO2 + 6 H2O + light energy C6H12O6 + 6 O2 Cellular respiration C6H12O6 + 6 O2 6 CO2 + 6 H2O + 38 ATP + heat Cellular respiration • Animals do this too • We just bypass photosynthesis by eating, breathing (exhaled) Cellular Respiration Cellular respiration • Glycolysis – generates 2 ATP • Kreb’s cycle – generates 2 ATP Identified in 1937 by Hans Adolf Krebs • Electron Transport Chain – generates 34 ATP 38 ATP total (in theory) Glycolysis • Glyco – sweet • Lysis – split apart • Happens outside the mitochondria • Cytoplasm • One glucose molecule is converted to two pyruvate molecules • 2 ATP and 2 NADH are generated Kreb’s or Citric acid cycle • If oxygen is available, the 2 pyruvate will be broken down into 6 CO2 and ATP • Takes place in the matrix Oxidation of pyruvate • First, each pyruvate is split, releasing a CO2, leaving an acetyl behind • Acetyl reacts with CoA, transferring two electrons to NAD+ • The CO2 has two of the original six carbons from glucose Kreb’s or Citric acid cycle • Start with one molecule of Acetyl CoA • By the end of the cycle, two CO2 will be generated and chemical energy will be stored in 1 ATP, 3 NADH, and 1 FADH2 • CO2 diffuses from the mitochondrial matrix into your blood where it is transported finally to your lungs Kreb’s or Citric acid cycle • If oxygen is available, the 2 pyruvate will be broken down into 6 CO2 and ATP Energy inventory • Glycolysis • Each glucose 2 pyruvate + 2 ATP • Kreb’s cycle • Each pyruvate 3 CO2 + 1 ATP • Total is 4 ATP per glucose • But the cell has charged up 10 NADH and 2 FADH2 per glucose • These will release electrons during the electron transport chain • The depleted energy carriers can be recharged again Electron Transport Chain (ETC) • High-energy electrons jump from molecule to molecule releasing small amounts of energy • Energy is used to pump H+ across the inner membrane into the intermembrane space Electron Transport Chain (ETC) • The concentration gradient of H+ across the membrane is used to drive ATP production by ATP synthase • The electrons, the H+, and O2 combine to form water (1 water molecule/2 electrons) Electron Transport Chain (ETC) ATP is recycled by the cell • A protein carrier takes the ATP molecules to the intermembrane space (and then the ADP molecules to the matrix) • The ATP molecules diffuse through the large pores in the outer membrane and enter the cytosol • Then, ADP molecules diffuse back into the intermembrane space Fermentation What happens when oxygen is unavailable? • Cells must generate ATP without oxygen • Fermentation • Less efficient – 2 ATP per glucose • Waste products • Lactic acid (animals, bacteria (yogurt)) • C6H12O6 2 Lactic acid + 2 ATP + heat • Lactic acid fermentation Fermentation • Waste products in yeast: ethanol and CO2 C6H12O6 2 CO2 + 2 Ethanol + 2 ATP + heat Alcoholic fermentation Cellular respiration - summary Amino acids can be sent to glucose canabolism Glycogen, fats, and proteins can be fed into cell respiration