7.1 CELLULAR RESPIRATION Energy when oxygen IS available for the cells
7.11 Glycolysis
7.12 Transition Reaction
7.13 Krebs Cycle
7.14 Electron Transport System

(VIDEO)

LECTURE OBJECTIVES

AT THE END OF THIS LECTURE, YOU SHOULD BE ABLE TO:

1. Give the overall equation for cellular respiration and contrast it to that for photosynthesis, recognize that photosynthesis and cellular respiration are linked in a chemical cycle. (Note that the photosynthesis is the reverse of cellular respiration.)
2. Associate the major parts of cellular respiration with the structure of the mitochondrion.
3. List the raw materials and products of cellular respiration (including how much ATP is produced and where in the pathway it is produced): know the steps of the major parts of cellular respiration, and the two forms of alternative fermentation pathways.
4. Explain how (aerobic) cellular respiration is used to generate ATP in the presence of oxygen.
5. Explain how fermentation can be used to generate ATP in the absence of oxygen.
6. Follow a molecule through the steps of interconversion -- alternative pathways, of fats, protein, and carbohydrates. (Your textbook now calls this "the metabolic pool concept".)
7. Recognize that starvation resulting in protein being used as a source of energy usually is fatal.
8. Define selected key terms. (Contrast the term cellular respiration with the term respiration, which is often used to refer to the process of breathing.)

Key Terms:

def. Aerobic: Containing oxygen; if referring to a cellular process the process requires oxygen to run.
def. Anabolic pathways: Making of complex compounds from simple compounds requiring energy (endergonic).
def. Anaerobic: Lacking oxygen; if referring to a cellular process the process does not require oxygen to run.

def. Anorexia nervosa: Eating disorder due to sociocultural factors characterized by severe, prolonged weight loss for fear of becoming obese.
def. Bulimia: Eating disorder due to psychological factors characterized by a binge-and-purge cycle of eating (difficult to detect -- person often normal or overweight)

def. Catabolic pathways: Breakdown of food into simpler compounds releasing energy (exergonic).
def. Cellular Respiration: The transformation of chemical bond energy from food ("glucose"), into usable form that occurs in all living cells ("glucose" broken down to release large amounts of energy (ATP) required for life processes).


def. Energy: the capacity to do work; something an object has that enables it to do work.
def. Fermentation: Catabolic process that makes a limited amount of ATP from glucose, without the help of an electron transport chain, not consuming oxygen and producing alcohol or lactic acid.
def. Kinetic Energy: Energy of motion, incl. heat (molecular movement) and light (wave movement).
def. Mitochondrion: An membranous energy converting organelle in all eukaryotic cells, resembling a small bag with a larger bag inside that is folded back on itself, that serves as the site of aerobic cellular respiration.
def. Obesity: Eating disorder due to genetical and /or psychological factors characterized by overweight to the extent that a person’s health and life span are adversely affected.
def. Potential Energy: Energy stored in some chemical form (e.g., gasoline) or physical form (on top of a hill).

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If O2 available aerobic conditions

def. Aerobic: Containing oxygen; if referring to a cellular process the process requires oxygen to run.
def. Anaerobic: Lacking oxygen; if referring to a cellular process the process does not require oxygen to run.

ii. In organisms with mitochondria eukaryotic organisms

def. Eukaryotic cell: A cell that possesses a nucleus and other membrane-bound organelles.
def. Prokaryotic cell: Cell lacking the organelles found in eukaryotic cells



C6H12O6 + 6O2 -----> 6H2O + 6CO2 + 36ATP

• Cellular Respiration is not a single process


The process consists of four major parts:

-- The first part is anaerobic -- require no oxygen
-- The other parts are aerobic -- require oxygen


Anaerobic Pathway
1. -- Glycolysis

Aerobic Pathways
2. -- Transition Reaction
3. -- Krebs Cycle (Citric Acid Cycle)
4. -- Electron Transport System (Electron Transport Chain)

-- many stepwise reactions (mediated by enzymes)
-- occurs in the cytoplasm
-- anaerobic process (does not require O2)
-- cellular respiration is EXERGONIC but requires activation (2ATP activation energy)

Exergonic Reactions, Mader, ed. 8., p. 104, or energy lecture notes.
Start Product:

- GLUCOSE (6C) (from food or stored)

End Products (fr. 1 glucose molecule):

- 2 PYRUVATE (3C)
- 2ATP (4 ATP - 2 ATP activation energy)
- 2 Coenzymes (electron carrier)(NADH, w. electrons for the ETS)

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Glycolysis

7.12 Transition Reaction (NOTE: 2 reactions simultaneously)

-- two reactions connecting the two pyruvates formed in glycolysis with two cycles called the Krebs Cycles (Citric Acid Cycles)
-- occurs in the matrix (inner compartment) of the mitochondria.
-- aerobic process (requires O2)

Start Product:

- PYRUVATE (3C)

End Products (NOTE: 2 reactions simultaneously -- the numbers are for the one reaction):

- Acetyl CoA (2C) ("Acetic Acid derivative")
- CO2 (1C)
- Coenzyme (electron carrier)

- - - - - - - - - - - - - - - - - - - - - - - -




7.13 Krebs Cycle (NOTE: 2 reactions simultaneously -- the numbers are for the one reaction):

-- many stepwise reactions in two cyclical reactions mediated by enzymes
-- these occur in the matrix (inner compartment) of the mitochondria.
-- aerobic process (require O2)


Start Products:

- Acetyl CoA (2C) + Oxalacetate (4C)

Intermediate Product:

- Citric Acid (6C)

End Products (NOTE: 2 reactions simultaneously -- the numbers are for the one reaction):



- Oxalacetate (4C)
- 2CO2 (1C)
- 1ATP (from each cycle)
- 4 Coenzymes (3NADH + 1FADH2, electron carriers, from each cycle)

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Krebs Cycle

- - - - - - - - - - - - - - - - - - - - - - - -



7.14 Electron Transport System
-- occurs in the inner membrane of the mitochondria.
-- aerobic process (requires O2)

Start Products:

- 6 Coenzymes (from each 3C compound) (total of 12 coenzymes w. electrons e- & H+)
- Oxygen (O2)

End Products (fr. 1 glucose molecule -- 12 coenzymes):

- 16ATP (from each 3C compound)
- Water (H2O)


(12e- + 12H⁺) + 1/2O2 (several steps) 6H2O ("metabolic water") -- (12 coenzymes: 12 x 1/2 = 6)
- - - - - - - - - - - - - - - - - - - - - - - -
Total Final End Products of Cellular Respiration (if O2 present, from 1 glucose and 6 oxygen):

36ATP + 6H2O + 6CO2

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ETC (Memb)

ETC (Stairs)

ETC (System)

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7.3. Fermentation

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7.4. Alternative Pathways & Diet

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-- At this stage it is very hard to save a person's life

7.43 EATING DISORDERS

i. Obesity: Eating disorder due to genetical and /or psychological factors characterized by overweight to the extent that a person’s health and life span are adversely affected.

ii. Bulimia: Eating disorder due to psychological factors characterized by a binge-and-purge cycle of eating (difficult to detect -- person often normal or overweight)

iii. Anorexia nervosa: Eating disorder due to sociocultural factors characterized by severe, prolonged weight loss for fear of becoming obese.

Anorexia information online:

http://www.4woman.gov/faq/easyread/anorexia-etr.htm

http://familydoctor.org/063.xml

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Eating disorders are different from NUTRITIONAL DEFICIENCY DISEASES

-- when the level of essential nutrients in the diet is so low that a person may develop health problems that could ultimately lead to death.

i. Kwashiorkor: Protein-deficiency disease. ii. Xerophthalmia: Vitamin A-deficiency disease.
iii. Beriberi: Vitamin B1-deficiency disease. iv. Pellegra: Vitamin B3-deficiency disease.
v. Rickets: Vitamin D-deficiency disease. vi. Scurvy: Vitamin C-deficiency disease.