Chapter 6: How Cell's Harvest Chemical Energy

• Photosynthesis-
• Cellular Respiration-

• P-energy of sunlight is used to rearrange the atoms of CO2 adn H2O to produce glucose and O2.
• CR-O2 consumed as gluecose is broken down to Co2 and H2O; the cell captures the energy released in ATP. 

• Celluar Respiration in the sense of Breathing

• Exchange of gases: an organisms obtains 02 from its enviroment and releases co2 as a waste product. 

1. Glucose and 02 regroup
2. To form CO2 and H2O
3. The chemical bonds in glucose is transfered and stored in the cehmcial bonds of ATP. 

1. Redux Reaction (oxidaion reduction reaction)-
2. Oxidation-
3. Reduction-

1. rr-the movement of electrons from one molecule to another is oxidation-reduction reaction.
2. O-in RR, the loss of electrons from one substance.
3. R-addition of electrons to another substance.

When is a molecule said to become oxidized?

• Reduction or Oxidation?

When it loses one or more electrons and reduced when it gains one or more electrons. 

• oxidation and reduction always go together, it takes a receptor and donor for an electron transfer. 

1. Dehydrogenase-
2. NAD+-

Three Stages of Cellular Respiration

1. Glycolysis

•  where, does what?

• occurs in the cytoplasmic fluid of the cell, outside the organelles. 
• Glycolysis begins respiration by breaking glucose into two molecules of a three carbon compound called pyruvate.

Three Stages of Cellular Respiration

2. Citric Acid Cycle 

• where, what, main function of first 2 stages

• takes place within the mitochondria.
• Completes the breakdown of glucose by decomposing a deribvative of pyruvate to Co2.
• Main Function of CAC & G-supply the third stage of respiration with electrons. 

Three Stages of Cellular Respiration

3. Oxidative Posphorylation-

• how much of ATP created in this stage?

• involves the electron transport chain and process known as Chemiosis.
• Chemoiosis-NADH & FADH2 shuttle electrons to the electron transport chain embedded in the inner mitchondria membrane. 
• Most of ATP in cellular respitation is generated here, which uses the energy released y the downhill fall of electrongs from NADH & FADH2 to o2 to phosphorylate ADP.

Pryuvate's "haircut and conditioning" 

• transports where after Glycolysis
• enter citric acid cycle?
• groomed into?

• as it formed at the end of Glycolysis, it is transported from the cytoplasm into Mitchondrian.
• Pryuvate itself does not enter the citric acid cycle, it is "groomed"  by chemcial reactions to-
• ultimatly be converted to "Acetyl CoA"

Acetryl Coenzyme A

(acetryl Coa)

• High energy fuel molecule for the citric acid cycle.
• Each molecule of glucose that entered glycolysis, two Avetyl COA are produced and enter the citric acid cycle. 

Citric Acid Cycle Steps

1: Avcetyl Coa strones the Furnace-

2-3: NADH, ATP and Co2 are generated during redox reactions

4-5: REdox Reactions Generate FADH2 and NADH2 

1: COA stripped from acetyle COA, reaction occurs, PRODUCT: six carbon moelcule cirate,all acid compounds in the cell exist in the cell in their ionied form.

2-3: Redox reactions harvest some energy of the acetyl group by stripping hyrogen atoms and producing NADH. Two place an intermediate compound loses a CO2 molecule. Energy is havested by substratelevel of ADP to produce ATP. At the end of the third step, a four carbon compound called "Succrinate" emerges. 

4-5: Enzymes rearagnge chemical bonds, completing CAC by regenerative ocoloacetate. Redox Reactions reduce the electron carriers of NAD+ to FADH2 and NADH. 

Poisons: some can interupt critical events for cellular respiration

1. Electron Transport Blockers (3 types)

2.  ATP synthesis inhibitors

3. Uncouplers

1. ETB-Rotenone: binds tightly with electron carrier in first protein comple, preventing electrons from moving to the next one (commonly used to kill insects.) Also Cyanide and Carbon Monoxide.(look up)

2. ATPSI-Antibodic "Oligomycin" blocks the passage of H+ through the channel in ATP synthase. Used to kill skin fungus by preventing them from using the potential energy of the H+ gradient to make ATP.

3. UC-makes the membrane of the mitochondrio leaky to hydrogen ions. ELectrong trnasport contnues, but ATP cannnot be made because leakage of H+ through the membrane abolushes the H+ gradient. (1940's weight loss pills.)

"The metabolic pathway that generates ATP during fermentation."

Muscles cells, and certain bateria can regenrate NAD+ in lactic acid fermintation. 

• NADH-oxidized to-NAD+ as pyruvate is reduced to lactate.
• Lactate builds up in muscles cells during exercise is carreid in the blood to the liver, where it is converted back to pyruvate. (panting after exercise.)

Alcohol Fermentation 

"Yeast in alcohol and baking"

• Yeast are single celeld fungi that normally use Aerobic repiration to process food, but can surive in anerobic as well. 
• Alcohol: convert NADH back to NAD+ while converting "pyruvate back to Co2." Co2 provides the bubbles in beer & champagne.
• Bakers-Co2 cause the yeast to rise.
• Yeast releases their alcohol waste into enviroment, then diffuses away.
• Yeast in wine yat die when alcohol concentration=14%

Bacteria etc and ATP production

1. Obligate Anaerobes
2. Faculatative Anaerobe-

1. OA-prokaryotes that live in soil or stagnent ponds, require anerobic conditions and are poisoned by oxygen.
2. FA-can make ATP either by fermentation or by oxidative phosphorylation, depending on whether O2 is available. 

Glycosis and Evolution

"Glycosis is the universal energy'harvesting process of life."

1. Ancient prokaryotes probably used Glycolysis to produce ATP before oxygen was present. 

2. Apparent in all organisms, suggesting it evolved very early to all domains.

3. Location: implies great antuquity; the pathway does not require any of the membrane-bounded organelles of the eukaryotic cell, suggesting it survived on Prokaryotic.