Cell Respiration

What is Cell Respiration? Its related to the respiratory system in that the lungs bring in the oxygen needed for cell respiration Its related to the respiratory system in that the lungs bring in the oxygen needed for cell respiration

Oxygen goes in Oxygen goes in Carbon dioxide goes out Carbon dioxide goes out

How does the Oxygen change to CO 2 ?? Process happens at cellular level Process happens at cellular level

In the alveoli of the lungs, O 2 is exchanged for CO 2 into the capillaries by diffusion

The circulatory system brings the oxygen to the cells

In the capillaries, O 2 diffuses into cells and CO 2 diffuses out

The circulatory system also brings Sugar (glucose) to the cells So sugar and oxygen are delivered to cells So sugar and oxygen are delivered to cells

Cellular Respiration The complex process of cells “burning” sugar (glucose) with oxygen to form usable energy (ATP) The complex process of cells “burning” sugar (glucose) with oxygen to form usable energy (ATP)

There are 2 types of cell respiration Aerobic – Occurs in presence of oxygen Anaerobic – Occurs without oxygen

Aerobic cell respiration The “Usual” process of respiration Aerobic means “air” Occurs with oxygen Produces up to 38 ATP per glucose

Anaerobic respiration Occurs without oxygen Produces only 2 ATP per glucose Fermentation is anaerobic

Fermentation Yeast and some bacteria obtain energy through anaerobic respiration Yeast and some bacteria obtain energy through anaerobic respiration Fermentation forms Alcohol, Vinegar or Lactic acid Fermentation forms Alcohol, Vinegar or Lactic acid

Bacteria can only use fermentation Prokaryotes have NO Membrane organelles  No mitochondria Prokaryotes have NO Membrane organelles  No mitochondria

Lactic acid can form from over exercise or lack of training Not enough oxygen can cause painful lactic acid build up in muscles

In Eukaryotic cells, Aerobic respiration occurs in the mitochondria

Respiration Reaction: Sugar + O 2  CO 2 + H 2 0+ Energy (ATP) (glucose) (glucose)

Respiration is the opposite of Photosynthesis Photosynthesis Photosynthesis In Chloroplasts CO 2 + H 2 O + SUN  Sugar + O 2 Respiration Respiration In Mitochondria Sugar + O 2  CO 2 + H 2 O + ATP Sugar + O 2  CO 2 + H 2 O + ATP

Respiration occurs in both plants and animals

3 Stages of Cell Respiration: 1) Glycolysis 1) Glycolysis 2) Krebs cycle 2) Krebs cycle 3) Electron transport chain 3) Electron transport chain

1) Glycolysis Occurs in the cytoplasm Occurs in the cytoplasm Glucose breaks into 2 pyruvates and forms 2 ATP. Glucose breaks into 2 pyruvates and forms 2 ATP. C-C-C-C-C-C  C-C-C + C-C-C + 2 ATP

ATP synthesis by Substrate level phosphorylation Glycolysis uses 2 ATP to gain 4ATP Glycolysis uses 2 ATP to gain 4ATP - 2ATP - 2ATP + 4ATP + 4ATP Net 2 ATP Net 2 ATP

Substrate level Phosphorylation ATP phosphorylated (phosphate added) by substrate PEP ATP phosphorylated (phosphate added) by substrate PEP

2 NADH also produced in Glycolysis NAD + is reduced with e - and gains a H + NAD + is reduced with e - and gains a H + e - e - NAD + + H + NADH NAD + + H + NADH It can be oxidized later into ATP in ETC It can be oxidized later into ATP in ETC

Energy overview glycolysis

Each Pyruvate must become Acetyl CoA to enter Krebs cycle Each pyruvate forms 1 NADH = 2 per glucose Each pyruvate forms 1 NADH = 2 per glucose

2) Krebs Cycle Also called Citric acid cycle Also called Citric acid cycle Occurs in the Mitochondria Occurs in the Mitochondria Pyruvate is broken into C0 2 molecules Pyruvate is broken into C0 2 molecules Energy molecules form Energy molecules form (2 ATP, 6 NADH and 2 FADH 2 ) (2 ATP, 6 NADH and 2 FADH 2 ) 2 C-C-C + O 2  6 CO ATP + 6 NADH + 2 FADH 2

Each Acetyl CoA enters Krebs separately. Adds 2 carbons to a 4 carbon (oxaloacetate) Acetyl CoA + Oxaloacetate  Citrate + CoA Acetyl CoA + Oxaloacetate  Citrate + CoA

Products of One Krebs Cycle 2 C0 2 2 C0 2 3 NADH 3 NADH 1 ATP (substrate level Phos.) 1 ATP (substrate level Phos.) 1 FADH 2 1 FADH 2

Products from 1 glucose molecule Each Acetyl CoA must go around cycle Two turns per glucose molecule TOTALS From 1 glucose 4 C0 2 4 C0 2 6 NADH 6 NADH 2 ATP (substrate level Phos.) 2 ATP (substrate level Phos.) 2 FADH 2 2 FADH 2

3) Electron Transport Chain (system) Occurs in the inner Occurs in the inner Mitochondria membrane NADH and FADH 2 are Oxidized NADH and FADH 2 are Oxidized (lose electrons) to form 34 ATP Oxygen is used up (final electron acceptor) Oxygen is used up (final electron acceptor) Water is produced from H + and OH- Water is produced from H + and OH-

ETC molecules : Energy molecules NADH and FADH 2 carry H + and e - to Inner Mito. membrane where there are a lot of protein complexes Energy molecules NADH and FADH 2 carry H + and e - to Inner Mito. membrane where there are a lot of protein complexes

ETC electron flow Electrons flow along protein chain in inner membrane Electrons flow along protein chain in inner membrane At End, Oxygen accepts electrons forming water At End, Oxygen accepts electrons forming water

1 st - NADH and FADH 2 are oxidized Electrons are removed from them releasing energy which is used to pump H+ into the inner membrane space Electrons are removed from them releasing energy which is used to pump H+ into the inner membrane space Later -Oxygen is the final acceptor of these electrons which will produce water Later -Oxygen is the final acceptor of these electrons which will produce water

2 nd - Protons pumped out across membrane Proton pump sets up gradient by chemiosmosis

Chemiosmosis is the diffusion of ions across a selectively- permeable membrane. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration. is the diffusion of ions across a selectively- permeable membrane. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration.ionsATPhydrogen membraneionsATPhydrogen membrane

3 rd - ATP formed by Oxidative phosphorylation in electron transport chain ATP synthase phosphorylates using proton gradient pump in inner mitochondrial membrane ATP synthase phosphorylates using proton gradient pump in inner mitochondrial membrane OXIDATION OXIDATION NOT substrate level phoshorylation

4 th - Oxygen At end of ATP phosphorylation, Oxygen accepts the electrons from the ETC and combines with the H+ ions and forms water as a by product of respiration At end of ATP phosphorylation, Oxygen accepts the electrons from the ETC and combines with the H+ ions and forms water as a by product of respiration

ATP amounts NADH – forms 3 ATP each NADH – forms 3 ATP each FADH2 – forms 2 ATP each FADH2 – forms 2 ATP each Note – NADH produced in cytosol must use one ATP to transport into mitochondria Note – NADH produced in cytosol must use one ATP to transport into mitochondria

ATP calculation Why is second chart different?

Animation ETC Electron transport Electron transport ATP synthase ATP synthase flash.htm flash.htm flash.htm flash.htm

QUIZ What are the 3 stages of cell respiration? 1) Glycolysis Purpose – Split glucose into pyruvate, form 2 ATP 2) Krebs Cycle Purpose – Form CO 2, form NADH, FADH +ATP 3) Electron transport chain Purpose – Use NADH + FADH 2 to form ATP + H 2 O