1 / 19

Cellular Respiration

Cellular Respiration. Glycolysis. Glycolysis. found in almost all living organisms occurs in the cytoplasm is anaerobic because it does not require any oxygen first stage of aerobic cellular respiration. Glycolysis. 10 enzyme-catalyzed reactions

yvonne-lott
Download Presentation

Cellular Respiration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cellular Respiration Glycolysis

  2. Glycolysis • found in almost all living organisms • occurs in the cytoplasm • is anaerobic because it does not require any oxygen • first stage of aerobic cellular respiration

  3. Glycolysis • 10 enzyme-catalyzed reactions • 6-carbon glucose is split into two 3-carbon pyruvate molecules • net energy gain of 2 ATP • 2 NAD+ are reduced to NADH

  4. Glycolysis Overview

  5. 2 Phases of Glycolysis • energy investment phase (reactions #1-3) • cleavage (reactions #4-5) • energy pay-off phase(reactions #6-10)

  6. Energy Investment (#1-3) • glucose undergoes: • a phosphorylation (glucose --> glucose 6-phosphate) • an isomerization to fructose (G6P --> fructose 6-phosphate) • a second phosphorylation (F6P --> fructose 1,6-biphosphate) • 2 ATP are used to power these reactions

  7. Cleavage (#4-5) • the 6-carbon molecule is split into two 3-carbon molecules: glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). • DHAP immediately isomerizes into G3P • the products of the cleavage are two G3P molecules

  8. Cleavage (#4-5) • DHAP isomerization (to G3P) catalyzed by enzyme triosephosphate isomerase

  9. Energy pay-off (#6-10) • 6. For each G3P molecule, one NAD+ molecule is reduced to NADH and G3P is phosphorylated to 1,3-biphosphoglycerate • 7. 1,3-BPG phosphorylates ADP to ATP through substrate-level phosphorylation, resulting in 3-phosphoglycerate (3PG) • 8. 3PG is isomerized to 2PG

  10. Energy pay-off (#6-10) • 9. 2PG is converted to phosphoenolpyruvate (PEP) through the removal of a water molecule • 10. PEP phosphorylates ADP to ATP through substrate-level phosphorylation, resulting in pyruvate.

  11. Glycolysis Animations • Overview of Glycolysis (simplified): http://www.science.smith.edu/departments/Biology/Bio231/glycolysis.html • Glycolysis: http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html

  12. Glycolysis Overall Reaction: glucose + 2 NAD+ + 2 ADP + 2 Pi 2 pyruvate + 2 NADH + 2 H+ + 2 ATP

  13. Energy Yield: • glycolysis produces 4 molecules of ATP per molecule of glucose • 2 molecules of ATP are used to activate glucose • overall net yield of 2 ATP per glucose molecule

  14. Net equation glucose + 2 NAD+ + 2 ADP + 2 Pi -----> 2 pyruvate + 2 NADH + 2 H+ + 2 ATP

  15. Energy Yield: Glycolysis produces 2 molecules of NADH per molecule of glucose NADH is used in a later stage of aerobic cellular respiration to generate ATP through oxidative phosphorylation

  16. Test yourself… • Try this quiz: http://www.zerobio.com/biofax12.htm

  17. Further exploration… • If you want more detail, this animation shows the enzymes involved in glycolysis as well as chemical structure of the intermediates: • http://programs.northlandcollege.edu/biology/Biology1111/animations/glycolysis.html

More Related