Cellular Respiration Notes

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December 09, 2013

Cellular Respiration

Remember: Cells use oxygen and break down organic compounds to make ATP in order to do work. The waste products are CO2 and water.

• Organisms obtain energy in a process called cellular respiration­Both plants and animals

• The equation for cellular respiration is the opposite of the equation for photosynthesis

• Cellular respiration occurs in two main parts.

• Glycolysis

• Aerobic respiration

Cellular Respiration Notes

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December 09, 2013

Glycolysis­organic compounds are broken into 3 carbon molecules called pyruvic acid

This produces a small amount of ATP and NADH, it does not require oxygen­anaerobic

Glycolysis

2 Pyruvic acid

• 2 molecules of ATP and 2 molecules of NADH are formed for each molecule of glucose that is broken down

Cellular Respiration Notes

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December 09, 2013

What types of cells perform anaerobic respiration? Lactic Acid formation­bacteria (dairy products) muscle cells during exercise; Alcoholic Fermentation­yeast (beer, wine, bread)

Cellular Respiration Notes

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December 09, 2013

Aerobic Respiration

Aerobic Respiration occurs in 2 stages1. the Krebs Cycle2. the electron transport chain

• Glycolysis has a net result of two ATP and two pyruvate

• Most of the energy from the glucose is still contained in the pyruvate

In eukaryotes these reactions occur inside the mitochondria­first the 2 pyruvates diffuse into the mitchondrial matrix

Cellular Respiration Notes

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December 09, 2013

• The series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle

Once in the mitochondrial matrix each pyruvic acid reacts with coenzyme A to form Acetyl CoA and 1 CO2

Each Acetyl CoA enters the Krebs cycle

• The net yield from 1 glucose molecule­2 turns of the Krebs cycle is 4 CO2 molecules, 2 ATP, 6 NADH, and 2 FADH2.

Cellular Respiration Notes

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December 09, 2013

Electron Transport Chain and Chemiosmosis

• Point at which the majority of ATP is produced • Produces 24 ATPThe electron transport chain is a series of molecules in a membrane that transfer electrons from 1 molecule to another­found in inner membrane of mitochondria in folds called cristae along with ATP synthase

The NADH and FADH2 produced in the Krebs Cycle move to the electron transport chain

The electrons from the hydrogen atoms are at a high energy level. NADH and FADH2 also give up protons. This drives the synthesis of ATP by chemiosmosis. Protons move through ATP synthase down their concentration and electrical gradients.

Oxygen is the final acceptor of the protons and electrons­they all combine to make H2O­this keeps the chain moving

Cellular Respiration Notes

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December 09, 2013

In addition to making energy­molecules formed in different steps of glycolysis and the Krebs Cycle are used to make compounds missing from food­up to 10 different amino acids