Cellular Respiration: Day 04 Process whereby cells breakdown glucose and other food molecules to release energy.
Updates We will test on Cellular Respiration before moving onto Photosynthesis Test will be next week sometime When? It depends on if we miss school for the elections or not check our WIKI!! Lab Lets talk about that first!
Lets Review the Cellular Respiration Cycle Lets begin with a Respiration Tutorial Take a look at the big picture!
When you exercise: Muscles need energy in order to perform work. Enzymes in muscle cells help the cell convert glucose and oxygen into ATP (usable energy).
Terms we have discussed: Aerobic Metabolism Anaerobic Metabolism Autotrophs Heterotrophs Producers Consumers
The ingredients for photosynthesis are carbon dioxide and water. CO 2 is obtained from the air by pores on a plants leaves. H 2 O is absorbed from the damp soil by the roots. Veins transport the water from roots to leaves. Chloroplasts rearrange the atoms of these ingredients to produce sugars (glucose) and other organic molecules (key products = glucose and oxygen). Oxygen gas is a by-product of photosynthesis Chemical Cycling Between Photosynthesis and Cellular Respiration
Cellular respiration: CELLULAR RESPIRATION: AEROBIC HARVEST OF FOOD ENERGY The main way that chemical energy is harvested from food and converted to ATP This is an aerobic processit requires oxygen
A common fuel molecule for cellular respiration is glucose. This is the overall equation for what happens to glucose during cellular respiration. GlucoseOxygenCarbon dioxide WaterEnergy Cellular respiration can produce up to 38 ATP molecules for each glucose molecule consumed.
Cellular respiration is an example of a metabolic pathway (a series of chemical reaction in cells). All of the reactions involved in cellular respiration can be grouped into three main stages: 1.Glycolysis 2.The Krebs cycle 3.Electron transport The Metabolic Pathway of Cellular Respiration
Why does electron transfer to oxygen release energy? When electrons move from glucose to oxygen, it is as though they were falling This fall of electrons releases energy during cellular respiration Figure 6.5 Release of heat energy
The path that electrons take on their way down from glucose to oxygen involves many stops NADH and Electron Transport Chains Figure 6.6 1/21/2 (from food via NADH) 2 H 2 e Energy for synthesis of Electron transport chain 2 e 2 H 1/21/2
A Road Map for Cellular Respiration Cytosol Mitochondrion High-energy electrons carried by NADH High-energy electrons carried mainly by NADH Glycolysis Glucose 2 Pyruvic acid Krebs Cycle Electron Transport
I. Glycolysis (click) Process whereby one glucose molecule is broken in half producing two pyruvate molecules.Glycolysis Takes place in cells cytoplasm. Does not require O 2 to take place. Occurs very rapidly, however, low energy yield (Net 2 ATP and 2 NADH produced)
Cell with Mitochondria (red spots)
Mitochondria Site of Krebs cycle and Electron Transport Chain
II. Krebs Cyle (click) Process whereby pyruvate is broken down into CO 2 in a series of energy releasing reactions.Krebs Cyle Only occurs if O 2 is present (aerobic respiration). Takes place within the mitochondria of the cell. Each pyruvate that goes through the cycle produces 1 ATP, 4 NADH, 1 FADH 2 and 3 CO 2 (2 X that amount for each glucose molecule).
III. Electron Transport Chain (click) Uses the high energy electrons from NADH and FADH 2 to convert ADP into ATP.Electron Transport Chain Occurs in proteins that are embedded within the inner membrane of the mitochondria. As high energy electrons from NADH and FADH 2 are passed from protein to protein in the chain, H+ ions are pumped across the membrane. H+ ions flow back through ATP synthase which converts ADP into ATP. Final electron acceptor in the chain is O 2 forming a H 2 O molecule. 10 NADH and 2 FADH 2 make a total of 34 ATPs.
Adding Up the ATP from Cellular Respiration Figure 6.14 Cytosol Mitochondrion Glycolysis Glucose 2 Pyruvic acid 2 Acetyl- CoA Krebs Cycle Electron Transport by direct synthesis by direct synthesis by ATP synthase Maximum per glucose:
The Versatility of Cellular Respiration Cellular respiration can burn other kinds of molecules besides glucose. Diverse types of carbohydrates Fats Proteins
FERMENTATION: ANAEROBIC HARVEST OF FOOD ENERGY Some of your cells can actually work for short periods without oxygen. For example, muscle cells can produce ATP under anaerobic conditions. Fermentation The anaerobic harvest of food energy
Without Oxygen!!! We cannot enter the Krebs Cycle Must use Anaerobic Respiration Alcohol Fermentation Lactic Acid Fermentation
In order for Glycolysis to continue NAD+ must be present. Without O 2 (anaerobic respiration) the NADH can not move onto the Krebs cycle. Think of NADH as full moving trucks which must be unloaded for the company to survive. Like our lab!!
2 ways to unload the NADH in anaerobic environments Alcohol Fermentation NADH passes electron back to pyruvic acid creating alcohol molecules. Occurs in yeast and other microorganisms Lactic Acid Fermentation NADH passes electron back to pyruvic acid creating lactic acid molecules. Occurs with our muscle cells and other prokaryotes (helps make yogurt, kimchi and cheese!)
Human muscle cells can make ATP with and without oxygen They have enough ATP to support activities such as quick sprinting for about 5 seconds A secondary supply of energy (creatine phosphate) can keep muscle cells going for another 10 seconds To keep running, your muscles must generate ATP by the anaerobic process of fermentation Fermentation in Human Muscle Cells
Glycolysis is the metabolic pathway that provides ATP during fermentation. Pyruvic acid is reduced by NADH, producing NAD+, which keeps glycolysis going In human muscle cells, lactic acid is a by- product
2 ADP+ 2 Glycolysis Glucose 2 NAD 2 Pyruvic acid + 2 H 2 NAD 2 Lactic acid (a) Lactic acid fermentation
Various types of microorganisms perform fermentation. Yeast cells carry out a slightly different type of fermentation pathway This pathway produces CO 2 and ethyl alcohol Fermentation in Microorganisms
Figure 6.15b 2 ADP+ 2 2 ATP Glycolysis Glucose 2 NAD 2 Pyruvic acid 2 CO 2 released + 2 H 2 NAD 2 Ethyl alcohol (b) Alcoholic fermentation
The food industry uses yeast to produce various food products Figure 6.16
Respiration tutorial Both high and low oxygen settings Copy and paste the questions into your onenote and answer there. Read the blurb at the beginning of each section before pressing play.