Chapter 5 Microbial Metabolism (Pages 114-152) and Chapter 2 Chemical Principles (pages 37-49) Class Notes Power Point 2013. Introduction Metabolism - refers to the sum of all chemical reactions within a living organism. Metabolism can be divided up into two classes of chemical reactions.
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Metabolism- refers to the sum of all chemical reactions within a living organism. Metabolism can be divided up into two classes of chemical reactions.
Catabolism– the enzyme-regulated chemical reactions that involve the breakdown of complex organic compounds into simpler ones. Energy, generally in the form of ATP is released.
Catabolic reactions are generally hydrolytic, water is used in the break down of chemical bonds.
These reactions are exergonic- produce more energy than they consume energy.
sugar carbon dioxide + water + ATP
Anabolism - the enzyme-regulated energy requiring chemical reactions that involve the building of complex organic compounds from simpler ones. These reactions are anabolic or biosynthetic reactions and involve dehydration synthesis, that is they release water.
These reactions are endergonic- consuming more energy than they produce.
Amino acids protein (Hemoglobin)
Nucleotides nucleic acids (DNA & RNA)
Simple sugars polysaccharides (starch &
A new protein chain is formed by the instructions in our genes.
II. The Structure and Role of ATP in Coupling
Anabolic and Catabolic Reactions
A. The Structure of Adenosine triphosphate
ATP exists in two forms:
ATP Adenosine Triphosphate - A kind of
chemically charged form of ATP.
ADP Adenosine diphosphate– A kind of
chemically discharged form of ATP.
Adenosine triphosphate ATP
ATP and ADP Conversions
H 2 O + ATP ADP + P
( G = -7.3 kcal / mole) or (–31 kj/ mole)
This reaction represents 7.3 kcal /mole of energy that can be used to do cellular work.
P + ADP ATP + H 2 O
( G = +7.3 kcal / mole) or (+31 kj/ mole)
This reaction represents 7.3 kcal /mole of energy that is needed to replenish or recharge ADP to ATP.
transfer the bond energy of a molecule
such as glucose into the bonds of ATP.
compounds such as glucose and store it in the form of ATP, processes in the cells of the organism pass electrons from one compound to another through a series of oxidation-reduction reactions.
III. Catabolism A Closer Look
A. Fermentation – A catabolic process that is a partial degradation of sugars that occurs without the help of oxygen.
Glucose (6 C) 4ADP
2 ATP4 ATP
2 Pyruvic Acid (3C)
Various End Products Depending on the Bacteria
Acids Alcohols CO2 H2
Fermentation produces a net yield of 2 ATP:
2 ATP X 7.3 kcal/mole ATP = 14.6 kcal
14.6kcal/686 kcal ~ 2% Efficiency
B. The most prevalent and efficient catabolic pathway is cellular respiration, in which oxygen is consumed as a reactant along with an organic fuel such as sugars.
Overview: Glucose (6 C)
2 ATP 4 ATP
2 Pyruvic Acid (3C)
2 ( 2C ) acetyl Co A
Kreb’s Cycle 6 NADH 4 CO2
Electron Transport &10 NADH
ATP Yield by Oxidative Phosphorylation 32 – 34 36-38 ATP/
ATP Yield by substrate level Phosphorylation 4 glucose
IIf Energy is released from a fuel all at once, it cannot be harnessed efficiently for constructive work. (ie a gas tank exploding) Glucose and other organic fuels are broken down in a series of steps, each catalyzed by an enzyme. At key steps, electrons are stripped from glucose . These electrons travel with a proton , thus as a hydrogen atom. The H atoms are not transferred to O2 directly but instead are usually passed through first to an electron carrier, o coenzyme called NAD+ (nicotinamide adenine dinucleotide) .
IV.The Effect of Oxygen
Prokaryotes display a wide range of responses to molecular
oxygen(O2). (See pgs 165-167)
A. Obligate aerobes require O2 for growth and cannot grow with out it. O2 is used as the final electron acceptor in aerobic respiration. These organisms are at a disadvantage in poor oxygenated waters. Many of the aerobic bacteria have developed or retained the ability to continue to grow in the absence of O2 .Such organisms are called:
B.Facultative anaerobes organisms that can use O2 when it is present but are able to continue growth by using fermentation when O2 is not available. What happens to their efficiency when O2 absent?
E-coli is a familiar example.
C. Obligate anaerobes organisms that are unable to use O2. In fact O2 is a toxic substance, which either kills or inhibits their growth. Obligate anaerobes live by fermentation, bacterial photosynthesis, or methanogenesis. Members of the Clostridium genus that cause tetanus and botulism are examples.
D. Aerotolerant anaerobes are bacteria with an exclusively anaerobic ( fermentative) type of metabolism but they tolerate O2 fairly well. They live by fermentation alone whether or not O2 is present in their environment. They can grow on the surface of a nutrient agar plate with out the special techniques required for obligate anaerobes. Many of these bacteria ferment carbohydrates to lactic acid, which as it accumulates inhibits aerobic competitors.
V. A Bit of Chemistry
Compounds that contain CARBON are
Macromolecules are large organic
B. Examples include:
VI. Polymers and Monomers
The arrangement of cellulose in plant cells
Starch-the storage form of carbohydrates in plants. How do plants produce glucose? Why do plants store glucose as starch?
Glycogen- a polysaccharide and the storage form of glucose in the humans and other vertebrates.
1.Disacccharides- a carbohydrate sugar consisting of two monosaccharide sugars joined by a glycosidic linkage.Important disaccharides include: Sucrose – the transport form of sugar in plants. sucrose = glucose + fructose Lactose – the sugar found in breast milk.Lactose = glucose + galactoseMaltose – malt sugar used in brewing.Maltose = gulcose +glucose
2. Important Monosaccharide sugars include:glucose – blood sugarfructose – fruit sugar( the sweetest sugar) galactose – less sweet than glucose
Aldehyde Sugar Ketone Sugar
Monosaccharide sugars – generally have formulas that are some multiple of the unit CH2O. Examples:The 6 carbon sugar: C6H12O6 The 5 carbon sugar: C5H10O5
Carbohydrate sugars – generally have formulas that are some multiple of the unit CH2O. Examples:The 6 carbon sugar: C6H12O6 The 5 carbon sugar: C5H10O5
Lipids – used for structural and long term
Lipids are made up of 1 glycerol molecule linked to 3 fatty acid molecules
1 gram of fat releases 8,893 calories when it is burned. That is ~8.9 Kcals or Food Calories1gram fat ~ 9 kcal/gram
What is the evolutionary significance of fat?
A 5g hummingbird needs ~ 45kcal of stored energy to make it’s annual migration.
Burning fat it needs to add ___________
Burning carbohydrate it needs to add ___________
Glycerol – One of the structural components of a fat and other lipids.
Is glycerol a carbohydrate? Explain.
Hint: Write the molecular formula for glycerol:
Amino Acids are the monomers building blocks of proteins.
Proteins can be 100’s of amino acids’s long! And the order of the amino acids, determines the particular protein. There are 1,000’s of different proteins!
Our genes tell our cells how to arrange the amino acids in the correct order to make a particular protein!
A new protein chain is formed by the instructions in our genes.
Cytochrome c is primarily known as an electron-carrying mitochondrial protein. Cytochrome c is an efficient biological electron-transporter and it plays a vital role in cellular oxidations in both plants and animals. It is generally regarded as a universal catalyst of respiration, forming an essential electron-bridge between substrates such as NADH and oxygen. Its main function in is to transport electrons from cytochrome C reductase(Complex III) to cytochrome C oxidase(Complex IV).
Some enzymes do not need any additional components to show full activity. However, others require non-protein molecules called cofactors to be bound for activity. Cofactors can be either inorganic or organic.
Cu, Fe, Mg, Mo, Se Zn Vitamins
4. Nucleic acids (DNA and RNA)