bioenergetics - s3.studentvip.com.au

400883 BIOENERGETICS Autumn 2018

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BIOENERGETICS

Biochemistry and Molecular Biology ……………………………………………………………… page 2

Chemical Thermodynamics ……………………………………………………………………….…… page 5

Genetic Material ……………………………………………………………………………………….…… page 14

Energy Substrates ……………………………………………………………………….……………….… page 23

Enzymes and Reactions ……………………………………………………………………….……….… page 36

Energy Systems and High Energy Carriers ………………………………………………………. page 42

Anaerobic Glycolysis ………………………………………………………………………………….…… page 51

Aerobic Pathways ………………………………………………………………………………….….…… page 60

Energy Producing Reactions ………………………………………………………………….….…… page 67

Energy Metabolism and Enzyme Control ………………………………………………….…… page 73

Metabolic and Genetic Responses to Exercise ………………………………………….…… page 77

Metabolic Acidosis ………………………………………………………………………………….….… page 87

Biochemistry Applied in Sport and Exercise ……………….…………………………….…… page 88


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LECTURE 1

Bioenergetics:

Study of biological energy producing and using body systems.

Inheritance of traits = genetics.

Proteins give you your physiological and biochemical traits.

Biochemistry

– The Chemistry of living things

– Full definition

1. chemistry that deals with the chemical compounds and processes occurring in organisms

2. the chemical characteristics and reactions of a particular living organism or biological

substance

Molecular Biology

– a branch of biology and chemistry (Biochemistry) dealing with the ultimate

physicochemical organization of living matter and especially with the molecular basis of

inheritance and protein synthesis.

Biotechnology

• the manipulation (as through genetic engineering) of living organisms or their components

to produce useful usually commercial products (as pest resistant crops, new bacterial

strains, or novel pharmaceuticals); also : any of various applications of biological science

used in such manipulation

Genetics

Ø the scientific study of how genes control the characteristics of plants and animals.

Ø a branch of biology that deals with the heredity and variation of organisms.

Ø the genetic make-up and ‘phenomena’ of an organism, type, group, or condition.

Ø Enzymes (proteins) are coded within the genes ® gene coding determines how the

enzyme act.


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LECTURE 2

Atoms:

Protons (+ charge) ® hydrogen

Neutrons (neutral)

Electrons (- charge)

Atomic number = number of protons

Atomic mass = protons + electrons

Molecule = 2 or more atoms, chemically bonded.

Atoms are joined by covalent bonds to form molecules.

Ionic: Metal (+) with non–metal (-) ® donates electrons

Covalent: between non-metallic atoms ® share electrons

Ions are electrically charge atoms.

Ø Cations = negatively charged ions

Ø Anions = positively charged ions

Constitutional formula shows which ion the charge belongs to.

Each line linking/connecting atoms together = 2 electrons shared.

A double bond (two lines) signifies 4 shared electrons.

Non-polar bond ® equally shared/distributed electrons

Polar bond ® unequal sharing of electrons

® one end is more + and the other end more – charged

Water is polar

Lipids/fat are no-polar


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LECTURE 3

ATP is the cellular energy currency.

It is the only way to get the energy to do biological work.

ATP – adenosine triphosphate

ADP – adenosine diphosphate

AMP – adenosine monophosphate

ATP:

Three phosphate groups.

The phosphate molecules are surrounded by Oxygen molecules.

Three possible high energy bonds.

Donates a phosphate.

Generates energy for mechanical work.

Inorganic phosphate = Phosphate surrounded by oxygens/hydrogen ®

Carbon molecules make things ORGANIC.

Inorganic phosphate = Pi

The energy in nutrient bonds (carbohydrates, lipids, protein) must be transferred to

Adenosine Triphosphate (ATP) before it can be used by the cells.

The energy from a substrate bond is a packet of energy which is too large for the cell to use

directly for any of its energy requiring activities without great waste of energy (too many

bonds need to be broken for the process to happen in a single step, which will generate too

much heat energy).


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LECTURE 4

Nutrition = energy for biological work.

Achieved through anabolism and catabolism.

Nutrients:

Macronutrients ® carbs, fats, proteins

Micronutrients ® vitamins, minerals

Water

Macronutrients provide energy ® protein is not a preferred fuel for energy.

Protein has structural and functional roles within the body.

Micronutrients do not provide energy, however they help regulate energy production.

role in regulating the anabolic and catabolic reactions in the body.

When bonds are formed energy is absorbed (stored)

When bonds are broken energy is released.

Energy that is accessible to human cells:

We can access energy from covalent bonds ® carbon-carbon bonds, carbon-hydrogen,

carbon-nitrogen, nitrogen-hydrogen.

The energy in bonds involving Oxygen (O) is not available.

1 mole C-C or C-H bond has ~227kJ of energy accessible to the cell.

Enzymes control the reactions for energy ® enzymes are protein


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LECTURE 5

Enzyme (causes reaction)

Reactants (A + B) ¬® Product/s (C+D)

Mg+2 (cofactor)

(arrows indicate whether it is an equilibrium reaction or a completion reaction)

If two enzymes are present in the equation:

Top enzyme = forward reaction

Bottom enzyme = reverse reaction

If one enzyme is present in the equation:

Enzyme takes care of both forward and reverse reaction

Enzymes are biological catalysts

Enzymes change the rate of reactions by altering the activation energy

Enzyme control the rate of chemical reactions

Enzymes produce activation energy ® speed up reactions

Enzymes are globular protein molecules

Act alone or in complexes with cofactors/coenzymes

Most common cofactor = magnesium

The can be more than one cofactor or coenzyme

Enzymes have protein structures ® primary, secondary, tertiary, quaternary

Enzymes are not used up in reactions

® Enzymes change form during the reaction, but are returned to their original state.

Therefore, an enzyme is neither a product nor a reactant of a reaction.


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LECTURE 6

Chemical energy stored in the substrate bonds ® transferred to ATP ® energy for

biological work.

Available to humans is the energy stored in the bonds between:

Two Carbon (C) atoms

Ø single C-C

Ø double C=C

Ø triple C�C

A Carbon and

Ø a Hydrogen (H) atom; C-H

Ø a Nitrogen (N) atom; C-N

A Nitrogen and a Hydrogen atom N-H

The energy in bonds involving Oxygen (O) is not available.

1 mole C-C or C-H bond has 227kJ of energy accessible to the cell.

The energy in these Nutrient bonds must be transferred to Adenosine Triphosphate (ATP)

before it can be used by the cells.

Levels of energy substrates (CHO, Lipid, Protein) in the body are not a sensitive indicator of

the energy status of the cell.

Cells need an energy currency in which small changes in its levels will be noticed readily so

that the process that restores levels can be up-regulated.

Present in low levels of 5mmols ® a small absolute change is a big %age change and is thus

noticed quickly.


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LECTURE 7

Lactic acid is joined to hydrogen and doesn’t occur in the human body [COOH]

Lactate is not joined to a hydrogen ion and is present in the human body [COO- +H]

ANAEROBIC GLYCOLYSIS: [THE LACTATE SYSTEM] ® END PRODUCT IS LACTATE

• WITHOUT OXYGEN

• Produces ATP from glucose (blood and muscle/cell), glycogen (muscle/cell).

• Product is pyruvate for oxidation via the citric acid (TCA) cycle.

• Occurs in the cytosol of the cell.

• It is the only source of ATP/energy for RBCs.

• Involves Substrate Level phosphorylation

® energy direct from substrate bonds to form the high energy bond in ATP.

• The electron transport system is not involved in anaerobic glycolysis.

Pyruvate is where anaerobic glycolysis and aerobic differ

Pyruvate goes to lactate in anaerobic glycolysis

Pyruvate goes to oxidation

GLUCOSE vs. GLYCOGEN:

Glucose + 2ADP +2Pi � 2 lactate +2H+ + 2ATP

Glycogen + 3ADP +3Pi � 2 lactate +3H+ + 3ATP

Anaerobic glycolysis system is used when the other systems cannot handle the stress of

exercise intensity.

High power, low capacity.

Quick to respond.

Low efficiency ® 8% of energy in substrate bonds is used for ATP.


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LECTURE 8

AEROBIC ENERGY PATHWAYS:

Use oxygen.

Oxygen is consumed.

Distant from the breakdown of the carbon skeleton of the negy substrate.

Carbon-carbon bonds and carbon-hydrogen bonds store energy.

Fuels for aerobic energy = carbohydrates, fats, proteins.

Stored as glycogen in the liver or muscle (muscle glycogen trapped)

Liver glycogen is released into the blood.

Every muscle cell has a storage of fat ® intramuscular fat.

Fat is very energy dense ® significant quantities of energy.

Free fatty acids released from adipose tissue (as well as glycerol) transported by the blood

to the muscle.

Protein ® animo acids enter energy pathways by tansemination and denimation.

Carbohydrate = aerobic glycolysis (same steps as anaerobic glycolysis ® stops at pyruvate)

Pyruvate enters the mitochondria and enters the TCA cycle.

Fats and lipids = free fatty acids via lipolysis enters beta-oxidation.

Produces acetyl-CoA which enters the TCA cycle or ETC.

Proteins = amino acids.

Nitrogen removed.

Enters the TCA cycle or ETC.

Fats

Glycerol enters aerobic glycolysis at phosphoglyceraldehyde

Fatty acids enter the aerobic energy system at Acetyl CoA

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