Week 27 Cellular Respiration

Cellular respiration

​Glucose + oxygen --> carbon dioxide + water + ATP

​Cellular respiration is the process that releases energy in glucose to make ATP, the molecule that powers all the cell activities.

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​Cellular respiration involves many chemical reactions. These can be grouped into three stages:

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GLYCOLYSIS

​KREBS CYCLE (CITRIC ACID CYCLE)

​ELECTRON TRANSFER CHAIN

​GLYCOLYSIS

• ​Glycolysis occurs in the cytoplasm of the cell.

• ​Each glucose molecule is broken down into 2 pyruvate molecules.

• ​Two molecules of ATP are produced in the breakdown.

​Krebs cycle (Citric acid cycle)

• ​Occurs in the matrix of the mitochondria.

• ​As pyruvate passes around this cycle, the rearrangement of atoms occurs. CO2 and H atoms are produced.

• ​CO2 is a waster that diffuses out of the mitochondria.

• ​Hydrogen atoms are picked up by a carrier molecule (NAD)

​Electron transfer chain

• ​Occurs in the inner membrane of the mitochondria (cristae)

• ​Hydrogen atoms are ionised and their high-energy electrons are passed along a series of acceptor molecules.

• ​As the electrons are bounced along the electron transfer chain, their energy is used to form ATP from ADP.

Cellular Respiration

When cells take that glucose made during photosynthesis and use the energy to make ATP​

Energy is stored as glucose, and then it is released to make ATP through glycolysis, the Krebs Cycle, and Electron Transport Chain.

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​ATP

​One molecule of Glucose is broken down to 2 molecules of pyruvate. 2 net ATP is also Produced

​​Glycolisis

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Each molecule of pyruvate enters the cycle and produces CO₂, two more net ATP, and the electron carriers NADH and FADH₂

​​Krebs Cycle or Citric Acid Cycle

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NADH and FADH₂ donate high energy electrons to a series of proteins embedded in the inner membrane. Results in lots of ATP produced (30-40 molecules).

​​Electron Transport Chain

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So here is the overall reaction for Cellular Respiration

Glucose + Oxygen --> Carbon dioxide + Water + Energy

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

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This is respiration requiring oxygen.

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Cellular Respiration is an example of aerobic respiration because oxygen has to serve as the final electron acceptor in the electron transport chain (ETC)

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​Aerobic Respiration

ATP

• Adenosine Triphosphate

• Adenine, Ribose, Triphosphate Group

• Breaking of a bond produces energy

• when ATP Breaks a phosphate group it is now known as ADP

Photosynthesis

• Takes in light energy, CO2, and H2O produces Glucose and oxygen

• Provides food for the plant

• Occurs in the chloroplast

• 2 stages are light reactions and Calvin cycle

• Chlorophyll is the pigment that reflects green light which is seen by us.

• grana is known as a stack of thylakoids in the chloroplast.

• Chloroplast is an organelle in plant cells

What is Cellular Respiration?

• process performed by autotrophs and heterotrophs to create ATP

• Cellular respiration main purpose is to produce ATP

• Takes in Glucose and oxygen

• Produces CO2, H2O, and ATP

• Aerobic Anaerobic

• Glycolysis, Krebs Cycle, Electron Transport Chain

• Aerobic inside the mitochondria. Krebs? ETC?

Aerobic respiration

• Occurs in the mitochondria

• Uses oxygen

Anaerobic Respiration

• Occurs in the cytoplasm

• Does not use oxygen

9.2 The Process of Cellular Respiration

Key Idea: What happens during glycolysis?

1 molecule of glucose is transformed into 2 molecules of pyruvic acid and 4 ATP by "investing" 2 ATP molecules to get the process started.

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Net gain: 2 ATP

Total gained so far: 2 ATP​

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Occurs in the cytoplasm​

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Glycolysis

Key Idea: What happens during the Krebs Cycle?

Pyruvic acid (from glycolysis) is broken down into 5 carbon dioxide, 4 NADPH, 2 FADH₂, and 2 ATP

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Net gain: 2 ATP

Total gained so far: 4 ATP​

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Occurs inside the mitochondria​

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The Krebs Cycle

Key Idea: What happens during the electron transport chain

The ETC uses high energy electrons from glycolysis and the Krebs cycle (NADPH and FADH₂ to create ATP.

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Oxygen is used to clean up low energy electrons and H⁺ ions to create water.

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​The mitochondria uses a charge difference and a special enzyme (ATP synthase) to create large amounts of ATP.

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Net gain: 32 ATP

Total gained: 36 ATP

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occurs in the mitochondria​

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Electron Transport Chain (ETC)

Extra Information

The 36 ATP created represents 36% of the total energy in glucose. The rest of the energy is given off as heat.

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The total number of ATP produced in respiration can range from 30-42. 36 is an average.​