Unit 5: Cellular Respiration

Endergonic Reaction

• Energy is absorbed → more product than reactant

• Requires energy

EX: Photosynthesis because it needs energy from the sun

Exergonic Reaction

• Energy is released → More reactant than product

EX: Cellular respiration because it releases ATP

Equation

C6H1260 = 6CO2+6H20+ATP+Heat

Mitochondria

Outermembrane - membrane enclosing the entire mitochondira

Innermembrane - membrane within mitochondria

Cristae - folds of innermembrane “finger like structure”

Intermembrane space - space beteen outer and innter membrane

Matrix - “maze-like” space ithin inner membrane space

Cellular Respiration

A controlled breakdown of food over many steps

• Only 40% of food energy is captured by ATP → Most is lost as heat

Oxidation

A subtance loses electrons

LEO - Lose electrons is oxidation

Reduction

A substance gains electrons

GER - Gain electrons is reduction

Redox

Series of oxidation-reduction reactions

NAD+ and FAD

Electron carries that pick up electrons and prtons as glucose breaks apart

Aerobic respiration

Requires oxygen

Anaerobic Respiration

Does not require oxygen

Glycolysis

Breakdown of glucose *focusing on carbons

1. Glucose/Carbon is broken down into 2 pyruvate

2. From breaking down Carbon, electrons are released and picked up by 2NAD+, forming 2NADH

   • Remaining energy released from breaking of carbon, is stored in ADP and its third phosphorus, forming 2 ATPS.

Products: ATP, NADH

Pyruvate Oxidation

1. Pyruvate break off the last carbon on the chain becoming acedic acids

   • Through the bonds being broken, electrons released and picked up by NAD+

2. Broken off carbons leave into the cytoplasm and attaching to oxygen, forming CO2

3. Coenzyme A (CoA) attaches to remaining acedic acids, turning them into Acetyl-CoA

Kreb Cycle

1. Acetyl CoA repeatedly broken down, releasing electrons, which are picked up by FAD and NAD

2. Acetyl CoA when broken down releases enough energy to be stored in ADP and its third phosphate

   • Creating 2 ATP

3. The broken down carbon leaves the cytoplasm and connects to O2, creating 4CO2.

Products: CO2, FADH, NADH, ATP

Oxidative Phosphorylation

1. NADH and FADH release their electrons into the electron transport chain

2. As electrons move across the electron transport chain, hydrogen is pumped into the intermembrane → creating a proton gradient

3. Oxygen acts as a final acceptor as its extremely electronegative and attracts electrons through the chain

4. High concentration gradient of hydrogen flows through ATP synthase, creating an energy that is stored with ADP and P, forming ATP.

Products: H20, 32-34 ATP

Fermentation Process

Occurs when there is no oxygen present, making glycolysis repeat over and over

Lactic Acid Fermentation

Cheese, Yogurt, Muscles

1. Glucose bonds break, creating pyruvates (2x), and releasing electrons → electrons stored in NAD+

• Because NADH cant drop off electrons, it releases electrons on to the pyruvates

• Turning pyruvates into lactic acid

→NAD+ gets recycled

Alcohol Fermentation

Bread, beer, wine

1. Glucose bonds break, creating 2 pyruvates, and released electrons

   → Stored in NAD+

   → Left over energy stored in ADP and P, creating 2ATP

2. Two pyruvates chop off the last carbon

   • Released carbon attracts Oyxgen, creating CO23.

3. Acetaldehyde is formed, picking up electrons and hydrogens, forming into 2 Ethanols

Universal process

Glycolysis is universal because it’s simple, doesn’t require oxygen, happens in all cells, and is essential for producing energy