An Introduction to Bioenergetics
1. Bioenergetics Introduction
Bioenergetics – The study of the transformation of energy in living organisms.
Metabolism – The sum of all chemical reactions in the body.
There are two types of metabolic reaction: catabolic and anabolic. Catabolic reactions
involve the breakdown/degradation of molecules allowing them to release energy. Anabolic
reactions involve the synthesis of new molecules and the energy released from these
reactions allows us to build these new molecules.
Catabolic pathways (-lysis) include lipolysis, glycolysis and glycogenolysis.
Anabolic pathways (-genesis) include protein synthesis, lipogenesis, and glycogenesis.
These reactions are continually occurring within each cell of our body however, they do not
occur simultaneously – a molecule cannot be both broken down and synthesised. They are
regulated in three different ways…
Substrate supply – food and other compounds.
Hormonal control – switch on or turn off pathways and alter enzyme activity.
Allosteric control – speed or slow enzyme activity.
Our body is fuelled by ATP – the energy currency of the cell. The food we consume is
digested and used to generate ATP. This is what we use to fuel all our metabolic reactions.
Metabolic reactions rely on enzymes
(enzymes are proteins.) Enzymes can
speed up reactions and without them
we would die. In a reaction, enzymes
lower the activation energy; the initial
energy required for the reaction to take
place.
Essentially, they move molecules into
the correct position and then roll them
over the edge.
,The activation energy is the energy required to get the reactants into the right position.
Once the enzyme is attached to the substrate it forms a complex. The enzyme catalyses the
formation of a product.
Enzymes show specificity by only binding to certain substrates.
Interaction and specificity can be explained in two ways: lock and key and induced fit.
Lock and key – the binding site has a complementary shape to the substrate.
Induced fit – contact between part of the binding site and the substrate induces a change in
shape of the active site to bind to the substrate.
Energy status – enzymes needed to generate
energy can be switched off or turned on by
allosteric binding, depending on the energy
status of the cell.
Allosteric enzymes are vital in some
circumstances (still to sprint.) Molecules
that activate these enzymes are known
as allosteric effectors.
Enzyme Activity and the Effect of its Local Environment:
Substrate concentration – an increase in this can augment reaction rate but only to a point.
pH – this can change active site structure and alter the affinity for substrates.
Enzyme concentration – an increase in this can augment reaction rate because more active
binding sites become available.
Temperature – an increase in this augment’s enzyme activity until 37.5 degrees.
Back to ATP:
Only 40-50 grams of ATP can be
stored in the muscle tissue, and this
is all used in 2-4 seconds.
, However, there are many fuel sources for supplying ATP which are both aerobic
(slowest) and anaerobic (fastest.)
Aerobic sources include protein breakdown,
fat oxidation and carbohydrate oxidation.
Anaerobic sources include phosphocreatine
and ATP. Glycolysis has elements that are both
aerobic and anaerobic.
, 2. Basic Biochemistry
Atom – building blocks of all things (matter.)
Element – a pure substance which cannot be broken down into simpler substance by a
chemical reaction. It contains only one type of atom.
Elements in the body include oxygen, carbon, hydrogen, nitrogen, calcium,
phosphorus, potassium, sulphur, sodium, and magnesium.
96% of body mass consists of four elements these being oxygen, carbon, hydrogen,
and nitrogen. 50-75% of the body mass is water.
All organic compounds have carbon and hydrogen.
Elements are made up of one type of atom. The centre of the atom is the nucleus, and this
houses protons (+ charge) and neutrons (neutral charge.) Outside of the nucleus, circling
around it are electrons (- charge.)
The electrons in the ‘cloud’ are not random but are organised into a series of layers called
shells and sub-shells.
Each cell and sub-shell can accommodate a specific number of electrons and no more. An
atom is most stable when its outermost shell or sub-shell is completely full of electrons.
Atoms can bind together based on electrons in the outer cell. Sharing electrons with another
atom leads to the formation of a covalent bond.
Giving an electron to another atom/receiving an electron from another atom leads to the
formation of an ionic bond.
Ion - an atom becomes an ion when its charge has been altered by losing or gaining an
electron. This process is ionisation.
Negatively charged ions are know as anions (electron gain) and positively charged ions are
known as cations (electron loss.)
Chemical bonds are how atoms join and bonds are formed through the action of electrons.
Ionic bond formation depends on electronegativity (the attraction of an atom for electrons.)
Electronegativity varies between atoms – increasing from bottom to top and from left to
right in the periodic table. These bonds are most easily formed when the electronegativity is
very high >1.7.
Covalent bonds from when electrons are shared. If the shell is not full, there is space for
electrons to be shared to fill these shells. A covalent bond is formed for each shared pair of
electrons.
1. Bioenergetics Introduction
Bioenergetics – The study of the transformation of energy in living organisms.
Metabolism – The sum of all chemical reactions in the body.
There are two types of metabolic reaction: catabolic and anabolic. Catabolic reactions
involve the breakdown/degradation of molecules allowing them to release energy. Anabolic
reactions involve the synthesis of new molecules and the energy released from these
reactions allows us to build these new molecules.
Catabolic pathways (-lysis) include lipolysis, glycolysis and glycogenolysis.
Anabolic pathways (-genesis) include protein synthesis, lipogenesis, and glycogenesis.
These reactions are continually occurring within each cell of our body however, they do not
occur simultaneously – a molecule cannot be both broken down and synthesised. They are
regulated in three different ways…
Substrate supply – food and other compounds.
Hormonal control – switch on or turn off pathways and alter enzyme activity.
Allosteric control – speed or slow enzyme activity.
Our body is fuelled by ATP – the energy currency of the cell. The food we consume is
digested and used to generate ATP. This is what we use to fuel all our metabolic reactions.
Metabolic reactions rely on enzymes
(enzymes are proteins.) Enzymes can
speed up reactions and without them
we would die. In a reaction, enzymes
lower the activation energy; the initial
energy required for the reaction to take
place.
Essentially, they move molecules into
the correct position and then roll them
over the edge.
,The activation energy is the energy required to get the reactants into the right position.
Once the enzyme is attached to the substrate it forms a complex. The enzyme catalyses the
formation of a product.
Enzymes show specificity by only binding to certain substrates.
Interaction and specificity can be explained in two ways: lock and key and induced fit.
Lock and key – the binding site has a complementary shape to the substrate.
Induced fit – contact between part of the binding site and the substrate induces a change in
shape of the active site to bind to the substrate.
Energy status – enzymes needed to generate
energy can be switched off or turned on by
allosteric binding, depending on the energy
status of the cell.
Allosteric enzymes are vital in some
circumstances (still to sprint.) Molecules
that activate these enzymes are known
as allosteric effectors.
Enzyme Activity and the Effect of its Local Environment:
Substrate concentration – an increase in this can augment reaction rate but only to a point.
pH – this can change active site structure and alter the affinity for substrates.
Enzyme concentration – an increase in this can augment reaction rate because more active
binding sites become available.
Temperature – an increase in this augment’s enzyme activity until 37.5 degrees.
Back to ATP:
Only 40-50 grams of ATP can be
stored in the muscle tissue, and this
is all used in 2-4 seconds.
, However, there are many fuel sources for supplying ATP which are both aerobic
(slowest) and anaerobic (fastest.)
Aerobic sources include protein breakdown,
fat oxidation and carbohydrate oxidation.
Anaerobic sources include phosphocreatine
and ATP. Glycolysis has elements that are both
aerobic and anaerobic.
, 2. Basic Biochemistry
Atom – building blocks of all things (matter.)
Element – a pure substance which cannot be broken down into simpler substance by a
chemical reaction. It contains only one type of atom.
Elements in the body include oxygen, carbon, hydrogen, nitrogen, calcium,
phosphorus, potassium, sulphur, sodium, and magnesium.
96% of body mass consists of four elements these being oxygen, carbon, hydrogen,
and nitrogen. 50-75% of the body mass is water.
All organic compounds have carbon and hydrogen.
Elements are made up of one type of atom. The centre of the atom is the nucleus, and this
houses protons (+ charge) and neutrons (neutral charge.) Outside of the nucleus, circling
around it are electrons (- charge.)
The electrons in the ‘cloud’ are not random but are organised into a series of layers called
shells and sub-shells.
Each cell and sub-shell can accommodate a specific number of electrons and no more. An
atom is most stable when its outermost shell or sub-shell is completely full of electrons.
Atoms can bind together based on electrons in the outer cell. Sharing electrons with another
atom leads to the formation of a covalent bond.
Giving an electron to another atom/receiving an electron from another atom leads to the
formation of an ionic bond.
Ion - an atom becomes an ion when its charge has been altered by losing or gaining an
electron. This process is ionisation.
Negatively charged ions are know as anions (electron gain) and positively charged ions are
known as cations (electron loss.)
Chemical bonds are how atoms join and bonds are formed through the action of electrons.
Ionic bond formation depends on electronegativity (the attraction of an atom for electrons.)
Electronegativity varies between atoms – increasing from bottom to top and from left to
right in the periodic table. These bonds are most easily formed when the electronegativity is
very high >1.7.
Covalent bonds from when electrons are shared. If the shell is not full, there is space for
electrons to be shared to fill these shells. A covalent bond is formed for each shared pair of
electrons.
