Cell metabolism


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Cell metabolism

  1. 1. Cell Metabolism
  2. 2. Cell Respiration (Metabolism) <ul><li>Cellular Respiration- is a metabolic process used to obtain energy from organic compounds or food </li></ul><ul><li>can run under aerobic and anaerobic conditions. </li></ul><ul><li>catabolic pathway. </li></ul><ul><li>occurs in the cytoplasm and mitochondria </li></ul><ul><li>3 main steps: Glycolysis and the Kreb Cycle , also known as the citric acid cycle and tricarboxylic acid cycle, and the ETC (electron transport chain) </li></ul>
  3. 3. Cellular Metabolism Metabolism – all chemical reactions that occur in the body Two types of metabolic reactions Anabolic <ul><li>Catabolic </li></ul>
  4. 4. Goal of Cell Respiration-Make ATP
  5. 5. Anabolic Anabolism provides the substances needed for cellular growth and repair <ul><li>Dehydration synthesis </li></ul><ul><ul><li>type of anabolic process </li></ul></ul><ul><ul><li>used to make polysaccharides, triglycerides, and proteins- produces water </li></ul></ul>
  6. 7. Catabolic Catabolism breaks down larger molecules into smaller ones <ul><li>Hydrolysis </li></ul><ul><ul><li>used to decompose carbohydrates, lipids, and proteins </li></ul></ul><ul><ul><li>water is used </li></ul></ul><ul><ul><li>reverse of dehydration synthesis </li></ul></ul>
  7. 8. Control of Metabolic Reactions Enzymes- all are proteins <ul><li>lower activation energy </li></ul><ul><li>not consumed in chemical reactions </li></ul><ul><li>substrate specific </li></ul><ul><li>Controlled through feedback inhibition </li></ul>
  8. 9. Do not make anything happen that could not happen on its own Enzymes can be reused over and over Same enzymes catalyses the forward and reverse reactions. They are very specific
  9. 12. Control of Metabolic Reactions <ul><li>Metabolic pathways </li></ul><ul><ul><li>series of enzyme-controlled reactions leading to formation of a product </li></ul></ul><ul><li>Enzyme names commonly </li></ul><ul><ul><li>reflect the substrate </li></ul></ul><ul><ul><li>have the suffix – ase </li></ul></ul><ul><ul><li>sucrase, lactase, protease, lipase </li></ul></ul>
  10. 13. Control of Metabolic Reactions <ul><li>Cofactors </li></ul><ul><ul><li>make some enzymes active </li></ul></ul><ul><ul><li>ions or coenzymes </li></ul></ul><ul><li>Coenzymes </li></ul><ul><ul><li>organic molecules that act as cofactors </li></ul></ul><ul><ul><li>vitamins </li></ul></ul><ul><li>Factors that alter enzymes </li></ul><ul><ul><li>heat </li></ul></ul><ul><ul><li>radiation </li></ul></ul><ul><ul><li>electricity </li></ul></ul><ul><ul><li>chemicals </li></ul></ul><ul><ul><li>changes in pH </li></ul></ul>
  11. 14. Energy for Metabolic Reactions <ul><li>Energy </li></ul><ul><ul><li>ability to do work or change something </li></ul></ul><ul><ul><li>heat, light, sound, electricity, mechanical energy, chemical energy </li></ul></ul><ul><ul><li>involved in all metabolic reactions </li></ul></ul>
  12. 15. Cellular Respiration <ul><li>Occurs in three series of reactions </li></ul><ul><ul><li>Glycolysis </li></ul></ul><ul><ul><li>Citric acid cycle </li></ul></ul><ul><ul><li>Electron transport chain </li></ul></ul><ul><li>Produces </li></ul><ul><ul><li>carbon dioxide </li></ul></ul><ul><ul><li>water </li></ul></ul><ul><ul><li>ATP (chemical energy) </li></ul></ul><ul><ul><li>heat </li></ul></ul><ul><li>Includes </li></ul><ul><ul><li>anaerobic reactions (without O 2 ) - produce little ATP </li></ul></ul><ul><ul><li>aerobic reactions (requires O 2 ) - produce most ATP </li></ul></ul>
  13. 17. Glycolysis <ul><li>There are 10 steps and all require specific enzymes to catalyze them </li></ul><ul><li>Goal- Produce pyruvate for use in the Krebs Cycle </li></ul><ul><li>NADH used in ETC </li></ul>
  14. 18. Citric Acid Cycle <ul><li>begins when acetyl CoA combines with oxaloacetic acid to produce citric acid </li></ul><ul><li>citric acid is changed into oxaloacetic acid through a series of reactions </li></ul><ul><li>cycle repeats as long as pyruvic acid and oxygen are available </li></ul><ul><li>Makes 2 ATP 6 NADH and 2 FADH 2 </li></ul><ul><li>BP- 4 CO 2 </li></ul>
  15. 19. The Goal is the production of NADH and FADH2 for use in the ETC—they are electron carriers
  16. 20. ETC <ul><li>So far only 4 of the 38 ATP that will be produced have been, all by substrate level phosphorylation. </li></ul><ul><li>The remaining will be produced by the ETC. </li></ul><ul><li>The majority of the ATP produced comes from the energy carried in the electrons of NADH (and FADH 2 ) that were produced by the Krebs Cycle. 6 NADH and 2 FADH 2 </li></ul><ul><li>The energy in these electrons is used in the ETC to power the synthesis of ATP. </li></ul><ul><li>There are thousands of ETC’s found in each mitochondria, which can number in the 100’s depending on the cell type . </li></ul>
  17. 21. Oxygen if the Final Electron Acceptor Why do we Breath??
  18. 23. Summary of Catabolism of Proteins, Carbohydrates, and Fats 4-21
  19. 24. Carbohydrate Storage <ul><li>Excess glucose stored as </li></ul><ul><ul><li>glycogen (primarily by liver and muscle cells) </li></ul></ul><ul><ul><li>fat </li></ul></ul><ul><ul><li>converted to amino acids </li></ul></ul>
  20. 25. Regulation of Metabolic Pathways Turned off when their product is in strong supply Works by supply and demand 4-23
  21. 26. Nucleic Acids and Protein Synthesis Gene – segment of DNA that codes for one protein Genome – complete set of genes
  22. 27. The Central Dogma <ul><li>It is all about Proteins!!! </li></ul><ul><li>DNA contains the information needed to build these life giving proteins in a code on segments called genes. </li></ul><ul><li>One gene can code for more than one protein? </li></ul>
  23. 28. Structure of DNA <ul><li>two polynucleotide chains </li></ul><ul><ul><li>hydrogen bonds hold nitrogenous bases together </li></ul></ul><ul><ul><li>bases pair specifically (A-T and C-G) </li></ul></ul><ul><ul><li>forms a helix </li></ul></ul><ul><ul><li>DNA wrapped about histones forms chromosomes </li></ul></ul>
  24. 30. RNA Molecules mRNA rRNA tRNA
  25. 31. Protein Synthesis (Transcription and Translation) <ul><li>1st the DNA strand is used as a template to build a molecule of RNA called mRNA that can leave the nucleus taking the instructions for the protein to ribosome for assembly. </li></ul><ul><li>2 nd during translation the information contained in the RNA molecule is used to determine the sequence of amino acids needed to build a protein. </li></ul><ul><li>Order: DNA - RNA – protein - trait. </li></ul>
  26. 34. Translation
  27. 35. Overview: Protein Synthesis
  28. 36. DNA Replication
  29. 37. Mutations Mutations – change in genetic information <ul><li>Result when </li></ul><ul><ul><li>extra bases are added or deleted </li></ul></ul><ul><ul><li>bases are changed </li></ul></ul>May or may not change the protein Some good some bad
  30. 38. Clinical Application Phenylketonuria PKU <ul><li>enzyme that breaks down the amino acid phenylalanine is missing </li></ul><ul><li>build up of phenylalanine causes mental retardation </li></ul><ul><li>treated by diets very low in phenylalanine </li></ul>