CHAPTER 9 CELLULAR RESPIRATION & FERMENTATION

Transcription

1 CHAPTER 9 CELLULAR RESPIRATION & FERMENTATION

2 Summary of Photosynthesis & Cellular Respiration

3 How much energy is stored in food? Energy stored in food is expressed in units of CALORIES. Calorie: the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius.

4 Cells use all sorts of molecules for food-fats, proteins, carbohydrates) Each of these molecule stores a different amount of energy because its chemical structure 1g fat ~ 9000kilocal. (~9calories) 1g of carbohydrates ~ 4000kilocal. (4calories) 1g of protein ~ 4000kilocal. (4calories)

5 Composition of Some Common Foods Food Protein (g) Carb(g) Fat (g) Apple, 1 medium Bacon, 2 slices Chocolate bar Eggs, 2 whole % milk, 1 cup Potato chips, 15 chips Skinless roasted turkey, 3 slices

6 Serving Size on label: Calories per serving: Total Fat grams per serving: Calories in your serving: Total Fat grams in your serving:

7 Cellular Respiration process that releases energy from food in the presence of oxygen. C 6 H 12 O 6 + 6O 2 Glucose + oxygen 6CO 2 + 6H 2 O + 36 to 38 ATP carbon + water+ energy dioxide

8 How do I get energy from the food I ate? HARVESTING CHEMICAL ENERGY Food that you eat is converted to glucose The glucose is split to release energy from it through a process known as GLYCOLYSIS. GLYCOLYSIS splitting glucose Takes place in the Cytoplasm Anaerobic process (Doesn t Use Oxygen)

9 Glycolysis Summary Note Glycolysis: Starts with 2ATP Ends with 4ATP Net Yield= 2ATP The end product of glycolysis is PYRUVIC ACID PYRUVIC ACID can follow 2 different pathways depending on the presence or absence of oxygen

10 TWO TYPES OF RESPIRATION Aerobic Respiration When cells make ATP by breaking down organic compounds in the presence of oxygen. Anaerobic Respiration When cells make ATP by breaking down organic compounds in the absence of oxygen. Note: ATP can be made with or without oxygen but more is yielded with oxygen

11 Fermentation (Anaerobic Absence of oxygen Respiration) No ATP is produced but NAD+ is generated NAD+ helps to keep glycolysis going to make more ATP 2 common fermentation pathways produce lactic acid & alcohol (depending on the enzyme used)

12 Lactic Acid Fermentation in Foods In lactic acid fermentation, an enzyme converts pyruvic acid into a carbon compound called LACTIC ACID Important in the manufacture of food products such as yogurt & cheese

13 Quick Energy (90 seconds or less) For short quick bursts of energy, the body uses ATP already in the muscles. This ATP supply usually lasts for about 90 seconds; just enough to reach a 200 or 300 meter sprint

14 Lactic Acid Fermentation in A quick sprint builds up lactic acid in the cell s cytosol and causes oxygen debt. This reduces the ability of the cells to contract resulting in muscle fatigue, cramps & pain Muscles

15 Lactic Acid Fermentation in Muscles (cont.) Heavy breathing after the race repays the oxygen debt. When oxygen becomes available, lactic acid is eventually transported to the liver through the blood where it is converted to pyruvic acid

16 Long-Term Energy (more than 90 seconds) For long term energy, cellular respiration is the only way to continue generating a supply of ATP. Cellular respiration releases energy more slowly than fermentation does, which is why well-conditioned athletes have to pace themselves during a long race or over the course of a game.

17 Your body stores energy in muscles and other tissues in the form of a carbohydrate called glycogen. This stores of glycogen usually lasts for about minutes of activity After mins, your body begins to breakdown other stored molecules, such as fats for energy.

18 This is one reason aerobic exercises such as running, dancing, swimming are beneficial for weight control.

19 Some organisms such as bears, count on energy stored in fat to get them through long periods without food.

20 ALCOHOLIC FERMENTATION Used to convert pyruvic acid to ETHYL ALCOHOL (ethanol) Some plant cells and unicellular organisms ex. Yeast use this process.

21 ALCOHOLIC FERMENTATION Basis for wine & beer making industries Basis for bread making (the alcohol evaporates during baking)

22 What are the Stages of Cellular Respiration? Glycolysis The Krebs Cycle The Electron Transport Chain Copyright Cmassengale

23 Where Does Cellular Respiration Take Place? It actually takes place in two parts of the cell: Glycolysis occurs in the Cytoplasm Krebs Cycle & ETC Take place in the Mitochondria

24 Krebs Cycle Summary Krebs Cycle when pyruvic acid is broken down into CO2 in a series of energy extracting reactions. Also known as the citric acid cycle because citric acid is the first compound formed. Produces two ATP Takes place in matrix of mitochondria

25 Electron Transport Chain (ETC) Summary ETC uses high-energy electrons from glycolysis and Krebs Cycle to convert ADP to ATP. 34 ATP & H 2 O are Produced Occurs Across Inner Mitochondrial membrane

26 Cellular respiration (Glycolysis, Krebs Cycle, and ETC) releases molecules of ATP per molecule of glucose.

27 SUMMARY OF CELLULAR RESPIRATION Pyruvic Acid P

28 Electron Transport Chain Animation