Cellular Respiration Ms. Lowrie Biology 11

Energy Transformation Chemical energy in food converted into energy that cells can use Glucose to ATP Occurs in plants and animals

Figure 3 (pg 60) Photosynthesis Cellular Respiration

Compare the Equations Photosynthesis Cellular Respiration Light energy Carbon dioxide Water Glucose Oxygen Photosynthesis Glucose Oxygen Carbon dioxide Energy Water + Cellular Respiration

The Exchange of Chemicals Heat Sunlight Cellular respiration Photosynthesis Note: Products from one process are reactants for the other.

Cellular Respiration & Breathing Exchanges these gases between blood and outside air Cellular respiration Requires cells to exchange gases with surroundings Lungs Muscle cells Cellular respiration

Remember … Why does energy need to be transferred from glucose to ATP? Glucose has TOO much energy Therefore, unusable ATP – usable energy for cell

Cellular Respiration Summary Equation Glucose Oxygen Carbon dioxide Energy Water + Water

Occurs in mitochondria Three Steps Glycolysis Occurs in cytoplasm Kreb’s cycle Electron transport system Can occur with oxygen (aerobic) or without oxygen (anaerobic) Occurs in mitochondria

Cytoplasm (cytosol) Mitochondrion Glycolysis Krebs Cycle Electron Transport

Step 1 – Glycolysis Location: Does NOT require oxygen Cytoplasm Does NOT require oxygen Anaerobic phase Plants -> Bacteria -> Humans!

Glycolysis Glucose is broken down into 2 PGAL Uses 2 ATP molecules Each PGAL is converted into pyruvate a.k.a. pyruvic acid pyruvate PGAL glucose PGAL pyruvate

Glycolysis – Glucose Breakdown

Glycolysis 2 NAD+ (hydrogen carrier) gain hydrogen & electrons Creates 2 NADH 4 ATP are produced 2 ATP replace those used to initiate Net gain of 2 ATP molecules

2 Pyruvic acid Glucose

Cytoplasm NADH Glycolysis 2 Pyruvate Glucose

Kreb’s Cycle & Electron Transport System Location: Mitochondria DO require oxygen Aerobic

Step 2 – Kreb’s Cycle (Citric Acid Cycle) Pyruvate changed into usable form Acetyl coenzyme A (coA) CoA 2 1 Acetic acid 3 Pyruvic acid Acetyl-CoA (acetyl-coenzyme A) CO2 Coenzyme A

What do we do with: the C, H and O? Kreb’s Cycle Acetyl-coA goes through a series of reactions with water Uses water from atmosphere Then enters Kreb’s Cycle Glucose (C6H12O6) finishes breaking down What do we do with: the C, H and O?

Kreb’s Cycle Carbon & Oxygen create CO2 Hydrogen & electrons Which is released to atmosphere Hydrogen & electrons Picked up by NAD+ or FAD (hydrogen receptors) to form NADH or FADH2 Net gain is 2 ATP 1 from each pyruvate

Cycle Repeats Twice Krebs Cycle Input Output Acetyl coA 3 CO2 ADP 3 NAD FAD Cycle Repeats Twice

Cytoplasm Mitochondria NADH NADH & FADH2 2 Acetyl coA Glycolysis 2 Pyruvate Krebs Cycle Glucose

Step 3 – Electron Transport System Uses hydrogen from NADH & FADH2 Hydrogen (and its electrons) are passed down a “stairway” of reactions Energy is released with each step

Electron Transport System Oxygen = final hydrogen electron acceptor “Catches” hydrogen Combines with two hydrogen Forms water Net gain is 34 ATP

Electron Stairway Hydrogen electrons “falling” 1/2 (from food via NADH) Energy for synthesis of Hydrogen electrons “falling” Creates energy at each step 2 H 2 e Electron transport chain 2 e 1/2 2 H

Cytoplasm Mitochondria NADH NADH & FADH2 2 Acetyl coA Glycolysis 2 Pyruvate Krebs Cycle Electron Transport Glucose

Adding Up Aerobic ATP Glycolysis 2 ATP Kreb’s + 2 ATP Electron Transport + 34 ATP 38 ATP

Adding Up Aerobic ATP Cytoplasm Mitochondria Glycolysis 2 Acetyl- CoA Pyruvate Krebs Cycle Electron Transport Glucose Maximum per glucose:

Summary Equation + Glucose Oxygen Water Carbon dioxide Water Energy

Balanced Equation – Note Water Glucose Oxygen Water Energy

Task – Electron Transport System Use notes & pages 62 & 63 Answer: #3, 4 (page 64)

#3 – Electron Transport System Series of hydrogen (electron) acceptors As hydrogen moves, energy is released What if energy from glucose was released all at once? Too quick Cause cell damage

#4 – Energy in Electron Transport Results in: 34 ATP Water

The process of mitochondria breaking down glucose to produce ATP is … Photosynthesis Cellular respiration Glycolysis Calvin cycle

The stages, in order, of cellular respiration are … Carbon fixation, Calvin cycle, Citric acid cycle Light reactions, Kreb’s cycle, Electron transport system Glycolysis, Kreb’s cycle, Electron transport system Citric acid cycle, Glycolysis, Electron transport system