The importance of proteins in the control of processes and responses in organisms.
Proteins are vital in controlling responses and processes in organisms as proteins are used to create
molecules such as enzymes which controls different and specific reactions in the body such as
controlling levels of neurotransmitters in the brain.
In the synaptic cleft, the enzyme acetylcholine esterase, which are made from proteins, is used to break
down neurotransmitters. Once acetylcholine (ACH) binds to receptors if the the post synaptic neurone
and the sodium ion channels open, which are also made from proteins, and sodium ions diffuse into the
post synaptic neurone and generating an action potential, acetylcholine esterase hydrolyse ACH into
ethanoic acid and choline and it is diffused back into the presynaptic knob. This shows the importance of
proteins because if there were no proteins then no ACH would be hydrolysed into ethanoic acid and
choline, so more ACH is present in the synaptic cleft therefore they will continue to bind to receptors in
the post synaptic neurone and more action potentials would be generated. This is an issue as it can lead
to mental disorders such as schizophrenia as these constant action potentials being generated can lead
to hallucinations due to high levels of neurotransmitters in the mesolimbic pathway which can lead to
hallucinations.
Haemoglobin derives from proteins and it is essential for carrying oxygen across the body. It has a
quaternary structure in which all four polypeptides are linked together to form a spherical molecule.
Each polypeptide is associated with a haem group, which contains a ferrous (Fe2+) ion. Each Fe2+ ion
can combine with a single oxygen molecule which allows four oxygen molecules to be carried by a single
haemoglobin molecule. The first oxygen molecule will bind to one of the sites which causes it to change
shape. This makes it easier for the second and third oxygen molecule to bind to the haem group. This is
known as positive cooperativity because binding of the first oxygen molecule makes the binding of the
second and oxygen molecule easier. However, the fourth oxygen molecule is harder to bind to the
fourth binding site. This shows the importance of proteins because if there were no proteins then no
haemoglobin would be created therefore no oxygen would be carried around the body to the respiring
cells. This would lead to the respiring cells to die due to the starvation of oxygen therefore no ATP is
created as oxygen is used as the final electron acceptor in oxidative phosphorylation in aerobic
respiration.
Antibodies derives from proteins which has a variable region that is complimentary to one specific
antigen to form an antibody-antigen complex and stimulates phagocytes to destroy the pathogen. T cell
that has receptors that are complementary in shape to the antigens of a pathogen. The cells then
undergo mitosis to create cytotoxic T cells (which releases perforin which creates holes in the cell
membrane of the pathogen and release nitric oxide which is directly toxic to the pathogen) or activating
a specific B cell. Once the specific B cell is activated it then under mitosis to produce memory cells or
plasma cells which secrete a high quantity of antibodies which are complementary in shape to the
antigen to create antigen-antibody complexes (these antibodies have binding sites that are specific to
Proteins are vital in controlling responses and processes in organisms as proteins are used to create
molecules such as enzymes which controls different and specific reactions in the body such as
controlling levels of neurotransmitters in the brain.
In the synaptic cleft, the enzyme acetylcholine esterase, which are made from proteins, is used to break
down neurotransmitters. Once acetylcholine (ACH) binds to receptors if the the post synaptic neurone
and the sodium ion channels open, which are also made from proteins, and sodium ions diffuse into the
post synaptic neurone and generating an action potential, acetylcholine esterase hydrolyse ACH into
ethanoic acid and choline and it is diffused back into the presynaptic knob. This shows the importance of
proteins because if there were no proteins then no ACH would be hydrolysed into ethanoic acid and
choline, so more ACH is present in the synaptic cleft therefore they will continue to bind to receptors in
the post synaptic neurone and more action potentials would be generated. This is an issue as it can lead
to mental disorders such as schizophrenia as these constant action potentials being generated can lead
to hallucinations due to high levels of neurotransmitters in the mesolimbic pathway which can lead to
hallucinations.
Haemoglobin derives from proteins and it is essential for carrying oxygen across the body. It has a
quaternary structure in which all four polypeptides are linked together to form a spherical molecule.
Each polypeptide is associated with a haem group, which contains a ferrous (Fe2+) ion. Each Fe2+ ion
can combine with a single oxygen molecule which allows four oxygen molecules to be carried by a single
haemoglobin molecule. The first oxygen molecule will bind to one of the sites which causes it to change
shape. This makes it easier for the second and third oxygen molecule to bind to the haem group. This is
known as positive cooperativity because binding of the first oxygen molecule makes the binding of the
second and oxygen molecule easier. However, the fourth oxygen molecule is harder to bind to the
fourth binding site. This shows the importance of proteins because if there were no proteins then no
haemoglobin would be created therefore no oxygen would be carried around the body to the respiring
cells. This would lead to the respiring cells to die due to the starvation of oxygen therefore no ATP is
created as oxygen is used as the final electron acceptor in oxidative phosphorylation in aerobic
respiration.
Antibodies derives from proteins which has a variable region that is complimentary to one specific
antigen to form an antibody-antigen complex and stimulates phagocytes to destroy the pathogen. T cell
that has receptors that are complementary in shape to the antigens of a pathogen. The cells then
undergo mitosis to create cytotoxic T cells (which releases perforin which creates holes in the cell
membrane of the pathogen and release nitric oxide which is directly toxic to the pathogen) or activating
a specific B cell. Once the specific B cell is activated it then under mitosis to produce memory cells or
plasma cells which secrete a high quantity of antibodies which are complementary in shape to the
antigen to create antigen-antibody complexes (these antibodies have binding sites that are specific to
