Compare aerobic respiration, anaerobic respiration and fermentation. How are the processes similar? How are they different? How do these processes determine which environment the organism can live in? [Key terms to use in answer: electron transport chain, cytochrome, ATP, glucose, glycolysis, obligate aerobe, facultative anaerobe, microaerophile, obligate anaerobe, oxidase, catalase, peroxidase, CO 2, organic acids and alcohols, alternative substrates (other than glucose) ]

Differences in meaning

Areobic respiration: takes place in the presence of oxygen

Anareobic respiration: takes place in the absence of oxygen or no oxygen

Feramtation: Takes palce in low oxygen concenration of oxgen.

End products.

1. Aerobic - energy (ATPs), 38ATPs water, C02

2. Anerobic - (organic acid; lactic acid, C02 and 8ATPs

3. fermentation - carbondioxide and water 4ATPs, ethanol,

Energy

1. Aerobic - 38ATPs

Anaerobic - 8ATPs

Fermentation - (No prodcution, only the 4ATPs from Glycolysis)

Mechanisms

1. Aerobic-makes use of electron transport chain (ETC) in the cytochrome to generate Proton motive force (PMF) needed for electrical potential energy for ATPs synthesis. Anaerobic - uses electron acceptor instead of ETC, with enzyme Oxidase. Therefore both aerobic and anaerobic make use of electrochemical gradients.

Fermentation makes use of oxidative phosphorylation; does not use electrochemical gradients. it only use decaboxylation and dehydrogenation of pyruvate to obtain products.

Glycolysis

All three process were preceded by Glycolysis.

Oxygen sensitivity.

1, Anaerobes - organisms that can respire without the presence of oxygen are known are obligate anaerobes. They depend on fermentation. They die in presence of oxygen. These organisms can not produce enzyme Catalase to detoxify the Superoxide and peroxide build up in their cells from the two unpaired electrons in the orbitals of oxygen, therefore the concentration kill them.

Organisms that can survive only in limited concentration of oxygen, are known as Microaerophile. They are killed in high concentration. some can also only survive in high C02 concentration, They care called Capnophiles,

Falcutative anaerobes can reproduce aerobically or anaerobically. They can produce enzyme Catalase to breakdown hydrogen peroxides and superoxides in the cells so the effects of these oxides build up is neutralized. They are not killed by presence of oxygen.

Substrate

Fermentation makes use of Hexose sugar as its only substrate. Hexose sugars, and other molecules; fatty acids can be metabolized in both aerobic and anaerobic respiration.

Living Environment

Due to the need to use energy for survival aerobic organisms live in habitats of abundant oxygen. They have catalase enzyme to detoxify oxides build up.

Anaerobes because of inability to produce catalase enzymes, inability to prevent the formation of disulfide which inhibit growth usually live in habitats where the oxygen concentration is low or not present at all. And makes use of fermentation fro survival.