Biochemistry for Medical Laboratory Science PDF

# Biochemistry ## Introduction - 3 units lecture (3 hours) - 2 units laboratory (6 hours) - Focus on biological substances that humans encounter, which are processed in the human body and cause problems or disorders. - 2 Possibilities: - Deficiency of Substance (lack) - Excess of Substance -...

# Biochemistry ## Introduction - 3 units lecture (3 hours) - 2 units laboratory (6 hours) - Focus on biological substances that humans encounter, which are processed in the human body and cause problems or disorders. - 2 Possibilities: - Deficiency of Substance (lack) - Excess of Substance - Book Reference: 2020-Present ## Clinical Chemistry - Includes analysis and measurement of biochemical substances that become important in daily life. - Monitoring biochemical substances is important in monitoring the body in daily life. ## Biochemistry ### Carbohydrates (Sugars) - Blood glucose (measuring diabetes) - FBS (Fasting Blood Sugar) - RBS (Random Blood Sugar) using skin puncture. - "ose" (Sucrose, Maltose, Lactose) ### Lipids (Fats) - Source of production - Metabolism - use to develop substances. - cholesterol, triglycerides. - Metabolic Pathways - Consequences of high fats - increase risk in cardiovascular diseases. - How fats are produced? ### Proteins (Total protein, Albumin) - Albumin - Major carrier protein. - Major abundant protein. ### 4 Structures 1. Fischer Projection 2. Haworth Projection 3. Chair Conformation 4. Mutarotation ### Carbohydrates - Defined as "hydrates of carbon". - Chemical Formula: CHO ### Classification of Carbohydrates - Saccharides - Derived from the Latin word saccharum, which means "sugar". - Monosaccharides - One molecule of sugar (simple sugar) - Examples: Glucose, Fructose, Galactose - Expressed as one molecule of carbohydrates structure. ### Functional Groups - Aldehyde - Ketone - Aldose - structure under aldehyde - Ketose - structure under ketone ## Enzymes - Very important in transport. - Majority of proteins are transport carriers or substances (move from one place to another). - High albumin levels are typically the result of dehydration or severe dehydration. - "ase" - Amylase, SGPT/ALT (Alanine Aminotransferase) - Important in terms of co-relation. - Also known as "markers". - Enzymes higher than normal: there is a problem in a specific organ. - High SGPT – problem in liver. - Hormones and enzymes are under protein. - Purpose of hormones: stimulate, regulate, and counterfeit or counter effect. - TSH (Thyroid-Stimulating Hormone) - FSH (Follicle-Stimulating Hormone) - LH (Luteinizing Hormone) - Testosterone ## Nucleic Acids (Nucleotides) - DNA, RNA ## Metabolic Pathways - Also known as "synthesis" - Mono: simple, Poly: complex - Metabolism is also a synthesis. ### Catabolism - Complex to simple. - Breaking down. ### Anabolism - Simple to complex. - Building up. ### Lesson 1: Carbohydrates - The family of D-ketoses - Ketoses: - 3- triose - 4- tetrose - 5- pentose - 6- hexose - Penultimate Carbon: - Second to the last carbon. - Define D or L form. - D - Configuration - D-right "OH" – p.c. - L - left "OH" - p.c. - Aldoses - 3- triose - 4- tetrose - 5- pentose - 6- hexose - Ketoses - 3- triose - 4- tetrose - 5- pentose - 6- hexose - Emil Fischer - Observation that all structures have L configuration. - Enantiomers - Optical Isomers: mirror image of structures. - "2 dimensional" - Haworth Projection - Cyclic structure. - Pyran Rings - Furan Rings - Mono + pyranose/furanose - D - Glucopyranose - β (beta) - OH (same side) – (A.C. or Anomeric Carbon) up location - α (alpha) – OH (opposite side) – (A.C.) downward - Anomeric Carbon - Carbon attached to the C - functional group. - Aldoses - C1 - Ketoses - C2 - Converting a Carbohydrate Fischer Projection To A Haworth - Step 1. Draw the Haworth projection for pyranose ring by placing the oxygen in the upper right corner and pointing the C6 CH₂OH on carbon up. The OH on the anomeric carbon pointing up for the B isomer, and pointing down for the az isomer: - Step 2. Draw the H's and OH groups: all the groups on the right side in the Fischer projection point down, the groups on the left are pointing up. - Step 3. Convert the Haworth to a chair conformation. The groups pointing "up" in a Haworth stay "up" in the chair and "down" stay down (either axial or equatorial). - Outline - Simple Carbohydrates - Nomenclature - Structures - Cyclization - Modifications - Saccharides - Monosaccharides - Glucose (C6H12O6) - Fructose (C6H12O6) - Ribose (C5H10O5) - Galactose (C6H12O6) - Glyceraldehyde (C3H6O3) - Different Sizes - Triose - 3 - Tetrose - 4 - Pentose - 5 - Hexose - 6 - Heptose - 7 - Octose - 8 - Common Sugars - Aldose and Ketose - Simple Sugars - Asymmetric Carbons - Multiple Asymmetric Centers - Enantiomers - Aldehyde - Structure - Ketone - Structure ### Lesson 1: Carbohydrates - Simple Carbohydrates - Nomenclature - Structures - Cyclization - Modifications - Saccharides - Monosaccharides - Glucose (C6H12O6) - Fructose (C6H12O6) - Ribose (C5H10O5) - Galactose (C6H12O6) - Glyceraldehyde (C3H6O3) - Different Sizes - Triose - 3 - Tetrose - 4 - Pentose - 5 - Hexose - 6 - Heptose - 7 - Octose - 8 - Common Sugars - Aldose and Ketose - Simple Sugars - Asymmetric Carbons - Multiple Asymmetric Centers - Enantiomers ## Biochemistry ### Sir Merto/Midterm/1st Semester - D-Glucose - L-Glucose - Diastereomers - Same chemical type & size, non-mirror images - Same Configuration - Different Configurations - Same Configuration - Epimers - Diastereomers differing in configuration of one carbon only. - Haworth Structures - Anomers - Common Furanoses - Conformation Isomers - Cyclic Structures - Cyclization of Sugars - New Asymmetric Center - Modified Sugars ### Sir Merto/Midterm/1st Semester - Sugar Alcohol - Sorbitol (Glucitol) - Sugar alcohol obtained by reduction of glucose. - Artificial Sweeteners - Sucralose - "artificial sweetener" - "3 hydroxyl groups replaced with CHLORINE atoms" - Disaccharides - Sucrose (glucose + fructose) - With ALPHA-1,2 GLYCOSIDIC BOND - "TABLE SUGAR"; NON-REDUCING SUGAR - Lactose (glucose + galactose) - With BETA-1,4 GLYCOSIDIC BOND - "PRESENT IN MILK"; NON-REDUCING SUGAR - Maltose (glucose + glucose) - With ALPHA-1,4 GLYCOSIDIC BOND - "PRESENT IN BARLEY, CEREAL GRAINS"; NON- REDUCING SUGAR - Alpha, beta D and L - Di-astere-omer hell - Nomenclature - Disaccharides - Comprised of two sugars - Sucrose - Lactose and Maltose - Polysaccharides - Cellulose - Glycogen - Amylose - Amylopectin - Chitin - Sugar Polymers with Glycosidic Bonds - Cellulose - Amylose - component of starch - Glycogen - Modified Polysaccharides - Chitin - Pectin - gelling agent - Galacturonic acid polymer - Polysaccharides Binding - Lectins - Phytohemagglutinins in plants - Glycolipids - Glycoglycerolipids and Glycosphingolipids - Glycoglycerolipids - Diacylglycerol - Glycosphingolipids - Cerebrosides - Gangliosides - Glycosylation - Glycosaminoglycans - Hyaluronic Acid - Chondroitin Sulfate - Heparin - Structural Lullaby - Metabolic Melody ### Sir Merto/Midterm/1st Semester - Lipids - It includes: - fatty acids - triglycerides - phospholipids - steroids - waxes - terpenes - prostaglandins - Characteristics of Lipids - Lipids are mostly hydrophobic - they don't mix well with water. - They are made up of mostly C-H bonds (Hydrocarbons) - Useful for long term energy storage - Make up the membranes of cells. - Provide thermal insulation and protection. - Fatty Acids - Hydrophilic Fatty Acids - Types of fatty acid - saturated fatty acid it contains the maximum number of hydrogen atoms. There are no double bonds. Saturated fatty acids are solid at room temperature. - Unsaturated fatty acid has a double bond. Because of the presence of the double bond in the structure, this molecule bends. For every double bond present, it loses two hydrogen atoms. It have a cis double bond because the hydrogen atoms across the carbons that are double bonded are on the same side of the double bond Unsaturated fatty acids tend to be liquid at room temperature. - Triglycerides - Triglycerides to simple structure: - Triglyceride transporters: - Chylomicrons - VLDL or Very Low Density Lipoprotein - Phospholipids - We have a saturated fatty acid and an unsaturated fatty acid. - Phospholipids contain carbon, hydrogen, oxygen, phosphorus, and nitrogen. Phospholipids make up the cell membrane. - Steroids - Steroids contain four fused rings. - cholesterol - High Density Lipoprotein (HDL) - Low density Lipoprotein (LDL) - The precursor of sex hormones is PROGESTERONE - estradiol - testosterone - cortisol is another steroid hormone that is used to reduce inflammation by suppressing the immune system. When your stress levels are high your cortisol levels will be high. - When used as a medication, cortisol is known as hydrocortisone. - Waxes - Paraffin wax with 31 carbon atoms - Wax ester - Terpene - the basic unit of terpene is isoprene. isoprene has five carbon atoms and it's a diene. it's an alkane, it has a double bond. "Di" means two so a diene is a substance with two double bonds trine would be three double bonds. - Isoprene - Myrcene - Limonene - B-Carotene - Eicosanoids - 3 derivatives of arachidonic acids: prostaglandins, Thromboxane, leukotrienes - Prostaglandins - Thromboxane - leukotrienes ### Sir Merto/Midterm/1st Semester - Proteins - Proteins are composed of its basic unit called amino acids. - Amino Acids are building blocks of proteins. - Peptides are small molecules that join together to form chains, which are assembled into larger proteins. - Peptide bonds - bonding of 2 amino acids - the amino acid structure always have an acid and alkaline group. - 9 Non-polar (Insoluble to Water) - Glycine - Methionine - Tryptophan - Phenylalanine - Isoleucine - Leucine - Proline - Alanine - Valine - 6 Polar (Soluble in Water) - Threonine - Cysteine - Tyrosine - Serine - Asparagine - Glutamine - 2 Acidic - Aspartic Acid - Glutamic Acid - 3 Basic - Histidine - Lysine - Arginine - Glycine- simplest amino acid and the only acid that is achiral. - Cysteine - consists of -SH (sulfhydryl group; polar) - Ex. GLYCYLACYLSERINE - Structure - Primary - Secondary - Tertiary - Quaternary - Denaturation - Other derivatives: - Phenylalamine (phe) to tyr to dopamine to epinephrine (adrenaline hormone- fight or flight response) - Tryptophan (trp)- non-polar, precursor of hormone serotonin (relaxing hormone) - Derivatives of proteins: - Pro to hydroxyproline - Lys to hydroxylysine - Tyr to thyroxine - Functions - Proteins - storage of special components such as: - Ferritin - storage of iron (iron is important in oxygen supply) - Structure - Hair and nails = keratin - Bones and skin = collagen - Catalyst = enzyme; can facilitate chemical reaction - Movements - Actin and myosin are protein components of muscles that facilitate movements - Transport protein - Lack of protein such as albumin means MALNUTRITION. - Transferrin - Excobalamin - transport vitamin B12 - Caeruloplasmin - Thyroxine – stimulate thyroid hormone - Hemoglobin - transport oxygen - Vasopressin - regulate water reabsorption (ADH - antidiuretic hormone) - Oxytocin – important in females during pregnancy and facilitates lactation - Total protein test = measures albumin, globulin - Gammaglobulin is also known as immunoglobulin or antibodies - Acts as hormone - Insulin - Erythropoietin - Protection = for immune system - Gammaglonulin- antibodies - Classification: - IgG - IgA - IgM - IgD - IgE - Antibodies is specific response - Peptide Bonding - Alanylglycine - Dipeptides consist of 2 amino acids + 1 peptide bonds - Tripeptides consist of 3 amino acids + 2 peptide bonds - Enzymes - Definition: Enzymes are organic substances (of human body) that speed up the chemical processes in living organisms. - Function: They also help to lower the activation energy of a reaction hence enhancing the process. - Nature: Enzymes mainly consist of proteins though there are some RNA molecules known as ribozymes that act as catalysts. - Active Site: Enzymes have particular regions which are known as the active sites where the substrate attaches and the reaction takes place. - Enzymes are under the classification of proteins. - Enzymes act as biological catalysts that can speed up chemical reactions or processes. - Enzymes are markers of inflammation of various diseases. - Citric acid is one of the most important metabolic pathways. - ENZYMES ARE NAMED: - General Rule: The nomenclature for enzymes is that they, as a rule, end in the suffix '-ase,' and are usually named after the substrate or the reaction they involve. - Naming Based on Substrate: For example, lactase is the enzyme responsible for hydrolyzing lactose. - Naming Based on Reaction: Also, oxidation enzymes are catalysts that can be described by the work they perform, such as oxidases. - CLASSIFICATION OF ENZYMES - Based on the types of chemical changes they bring about enzymes can be classified broadly into six groups: - OXIDOREDUCTASES: These enzymes catalyze oxidation and reduction reactions in other chemical processes (for instance, dehydrogenases). - CLASS 1. OXIDOREDUCTASES - Enzymes which catalyse redox reactions involving transfer of electrons/hydrogen atom/oxygen atom. - eg. Peroxidases, catalases, oxygenases reductases - Examples: - LDH (lactate dehydrogenase) - TRANSFERASES: These classifications of enzymes are capable of transferring a functional group from one compound or substrate to another (for instance, kinases). - CLASS 2. TRANSFERASES - Enzymes which catalyse transfer of an atom or a functional group between two molecules. - eg. Acyl transferases, kinases, transaldolases - Examples: - AST (Aspartate aminotransferase) - ALT (Alanine aminotrasferase) - it transfer alanin and its product is SGPT (Serum Glutamic Pyruvic Transaminase). If the ALT increase, it has inflammation in the liver. - HYDROLASES: They find application in the commencement of bond cleavage of complex macromolecules with the aid of water (for instance, proteases). It facilitates hydrolysis. - CLASS 3. HYDROLASES - Enzymes which catalyse hydrolytic reactions and their reversal. - eg. Lipases, amylases, proteases, nucleases - AB + H2O→AOH + BH - Examples: - Amylases (starch) - Phosphatase (Alkaline phosphatase = liver and bone disease, Acid phosphatase = prostate cancer) - Lipase (lipids) - Acetylcholinesterase - LYASES: Such classes of enzymes are helpful in the formation of double bonds by addition or removal of specific group (for example, decarboxylases). It is the elimination reaction. - CLASS 4. LYASES/ SYNTHASES - Enzymes involved in elimination reactions in the absence of water, leading to formation of double bonds or addition across a double bond. - eg. Aldolase, decarboxylase - Example: - Aldolases (muscles) - Aconitase - Isomerases: These are special types of enzymes, which cause change in the position of atoms in a molecule (for instance, epimerases). It catalyze the isomerization. - CLASS 5. ISOMERASES - Enzymes which catalyse isomerisation and racemization reactions. - eg.Epimerase, isomerase, intramolecular transferase - A-X + B-YA-B - Epimerases - Phosphohexose isomerase - Ligases: These enzymes assist in linking two single molecules together by making the molecules join via formation of chemical bonds which referred to as covalent bonding (for instance, ligase in DNA). - CLASS 6. LIGASES/SYNTHETASES - Enzymes which catalyse synthesis of a C-X bond while utilizing ATP. - eg. Peptide synthetase, amino-acid RNA ligase - A + B + ATP→AB + ADP + P; - Examples: - Carboxylases - Synthetases - Tyrosine t-RNA synthetase - TERMS - Cofactors - Cofactors are non-protein chemical compounds or metallic ions( such as zin, iron, magnesium) that are required for an enzyme's biological activity. - Apoenzyme - An apoenzyme is the protein portion of an enzyme that is inactive on its own. It requires a cofactor (either a coenzyme (organic cofactor) or a metal ions (inorganic cofactor)) to form a complete, active enzyme. - Holoenzyme- once there is a cofactor in the inactive, it will be holoenzyme - APOENZYME and HOLOENZYME - The enzyme without its non protein moiety is termed as apoenzyme and it is inactive. - Holoenzyme is an active enzyme with its non protein component. - Coenzyme - A coenzyme is a specific type of organic cofactor. These are small, non-protein molecules (often derived from vitamins) that bind temporarily to an enzyme and assist in the enzyme's catalytic activity. - NAD (nicotinamide adenine dinucleotide) - Substrate - A substrate is the specific molecule upon which an enzyme act. During a biochemical reaction, the enzyme binds to the substrate at its active site, leading to a chemical reaction that transforms the substrate into one or more products. - Activation - Activation refers to the process by which an enzyme's activity is increased or initiated. - Allosteric activation - Binding of cofactors - Inhibition - Inhibition refers to the process that decreases or stops the activity of an enzyme. Inhibitors can be molecules that bind to the enzyme, preventing the enzyme from interacting with its substrate. - Activators are example of cofactors - Inhibitors is important to balance enzyme activity. - There are two types of inhibitors: natural inhibitors and artificial inhibitors. - Isoenzyme - an enzyme that performs the same functions but have different combination of "subunits" and with different quaternary structures. - FACTORS INFLUENCING ENZYME ACTIVITY - Temperature - Enzymes work best at specific temperatures. Too hot or too cold can reduce their activity or even damage them. If the temperature is too high, the enzyme will undergo protein denaturation (destruction or disruption (change) of structure). If the temperature is too low, the enzyme activity will slow down. The preferred temperature is 37 degrees Celsius. -Heat labile - it means heat sensitive. - pH - Each enzyme has an ideal pH level. Changes in pH can alter enzyme's shape and reduce its ability to function. -Extreme pH levels can damage the enzyme. If the pH is too low or too high, the rate of reaction is low. The pH neutral rate is 7. - MODELS OF ENZYME ACTION - Lock and Key Hypothesis - It was pioneered by a scientist named Emil Fischer (in 1894). - The particular substrate perfectly fits into the enzyme's cleft (active site) for the reaction to occur. - The amino acid residues enable the enzyme's active site to bind specifically with the substrate. Thus, this model explains an enzyme's specificity to which only the substrate can bind those with a shape corresponding to an active site's shape. - The lock and key model have many loopholes like: - This experiment fails to explain the broad specificity of an enzyme. - It did not explain the binding mechanism of the substrate with an enzyme. - The lock and key model could not give any information about the mechanism of enzyme catalysis or product formation. - Induced Fit Model - It is widely accepted model to study the mechanism of enzyme action and pioneered by the scientist Daniel Koshland (in 1959). - According to his theory, an active site is a flexible region of the enzyme, which can undergo conformational changes. It is also popular by the name of the hand in glove model. - Explains that the enzyme's active site possesses two specific locations (buttressing and catalytic site). The substrate initially attaches to the buttressing region, after which the catalytic site brings some conformational changes in the E-S complex. - How are enzymes regulated? - Allosteric Regulation - Allosteric regulation is responsible for the transitions between different functional states of proteins (or other macromolecules) in response to changes in environmental conditions. - There is a modification or change in the enzyme molecule. - It can change the active site of the enzyme - It allows the activator and inhibitors to regulate or control the reaction of the substrate. - Cofactors can modify the activate site of the enzyme. - Feedback Inhibition - A biological process known as feedback inhibition occurs when the final result of an enzyme's pathway inhibits the enzyme's activity. This aids in controlling the volume of goods produced. As in the case of producing amino acids, when the amino acid itself inhibits the first enzyme in its synthesis pathway, it usually targets the first enzyme specific to a pathway. - Same as allosteric regulation - Can modify structure - Proteolytic Cleavage - The most frequent alteration is cleavage by proteases. In contrast to having to go through transcription and translation, or even just translation, some pre-cleavage polypeptides are instantly cleaved, while others are stored as inactive precursors to form a pool of enzymes (or other types of proteins) that can be activated very quickly, on a timescale of second to minutes. - Interestingly, many proteins have methionine (Met) cleaved off, even though Met is always the first amino acid a newly produced polypeptide (this is also true for some bacterial f-Met). - Another name: proteinase - It is the breakdown of peptide bonds - It interferes or prevent of reaction by breaking down of peptide bond - Competitive Inhibition - Enzymes in Major Diagnostic Use - Acid phosphatase - Alkaline phosphatase - Amylase - Aspartateaminotransferase - Alanineaminotransferase - Creatininekinase - Lactate dehydrogenase - Lipase - How are Enzymes used in medicine/medical diagnosis? - Disease Diagnosis - Enzymes-linked Immunosorbent Assays (ELISA) - ELISA enzyme level: - horseradish peroxidase - alkaline phosphatase - Blood test - Therapeutic Use - Enzyme replacement therapy - Clot-busting enzymes - Digestive enzymes - Biosensors - Glucose Monitoring - Cancer Treatment - Asparaginase is used in the treatment of lymphoblastic leukemia ## Neurotransmitters and Hormones - Receptors- is a molecule such as protein where a signal molecule can bind - Ligand- smaller molecule that typically binds to a typically larger molecules, ligands are generally smaller than the receptors they bind - General sequence of cell signaling - Receptions: signal molecule binds a receptor - Transduction: the receptors gets activated by this binding, this often means the receptor will change its shape, it could involve a whole series of molecules changing their conformation in something called a signal transduction pathway - Response- The cell's machinery carries out a response, such as activating genes, opening ion channels, or initiating cellular changes, transcribing a DNA - Termination- After the response, signaling pathways are often turned off to reset the cell for future signals. - Cell signaling involved: - Intracellular- which occurs within the cell itself - Intercellular- cell communicates with other cell - Direct Cell-to-Cell Contact - In some cases, cells communicate directly through physical contact. This can happen when two cells have complementary receptors and ligands on their surfaces. - Gap Junctions: Specialized channels in animal cells allow ions and small molecules to pass directly from one cell to another. This is crucial in tissues like heart and smooth muscle, where coordinated contraction is required. - Plasmodesmata: In plant cells, small channels connect cells, allowing the transport of molecules and ions across cell walls. - Paracrine Signaling (Local Signaling) - In paracrine signaling, cells release signaling molecules, such as hormones or growth factors, into the extracellular space. These molecules affect nearby cells but do not travel far. - This type of signaling is essential for tissue development, immune responses, and inflammation. - Example: In wound healing, cells release growth factors that stimulate nearby cells to grow and repair damaged tissue. - Synaptic Signaling (Neural Communication) - Synaptic signaling is a specialized form of paracrine signaling seen in the nervous system. - When a neuron is activated, it releases neurotransmitters across a synapse (the small gap between neurons) to communicate with the next neuron or muscle cell. - This process enables rapid and targeted communication, which is essential for muscle control, sensory processing, and thought processes. - Example: When you touch something hot, sensory neurons quickly transmit signals through synaptic connections to motor neurons, allowing you to react instantly. - Endocrine Signaling (Long-Distance Signaling) - In endocrine signaling, cells release hormones into the bloodstream. These hormones travel throughout the body and can affect cells in distant organs. - Example: The pancreas releases insulin into the bloodstream, where it travels to various tissues and helps regulate blood sugar levels. - Autocrine Signaling - In autocrine signaling, a cell releases signaling molecules that bind to receptors on its own surface, essentially "talking" to itself. - This type of signaling is common in immune cells, where it helps regulate cellular responses. - Example: Some cancer cells use autocrine signaling to promote their own growth, supporting unchecked cell proliferation. - Neurotransmitters are chemical messengers that the body can't function without. Their job is to carry chemical signals ("messages") from one neuron (nerve cell) to the next target cell. The next target cell can be another nerve cell, a muscle cell or a gland. - Neurotransmitters are under proteins. This neurotransmitter are released into the synaptic gap by a terminal of a stimulated presynaptic nerve cell, transmitting a nerve signal to its neighboring postsynaptic nerve cell. - Belongs to the nervous system - Released by presynaptic nerve terminal into the synapse - Transmitted across the synaptic cleft - In direct apposition to their target cells - Only stimulate the postsynaptic neurons - Some of the examples of neurotransmitters are acetylcholine, norepinephrine, dopamine, gamma- aminobutyric acid (GABA), glutamate, serotonin, and histamine. - Neurotransmitters are chemicals that transmit signals from a neuron to a target cell across a synapse. Some neurons produce only one type of a neurotransmitter. The coexistence of multiple neurotransmitters at the same time in the synapse allows neurons to exert several influences at the same time. Neurotransmitters are stored in synaptic vesicles, which are present at the terminal of the presynaptic neuron cells. Once the presynaptic neuron is stimulated by a nerve impulse, neurotransmitters are released into the synapse from the axon terminal. The released neurotransmitters diffuse across the synapse and bind to the specific receptors on the postsynaptic neuron. - Hormone is a product of living cells, which circulates in fluids like blood or sap, and produces a specific, usually stimulatory effect on the activity of cells, remote from its point of origin. Therefore, hormones are chemical messengers that aid the communication between different parts of the body by sending chemical signals from one to the other. - Hormones can be either proteins, lipids or cholesterol-based molecules. - Hormones are produced in endocrine glands and are released into the bloodstream where they find their targets of action at some distance from its origin. - Belong to the endocrine system - Polypeptides, amines, terpenoids, steroids, or phenolic compounds - Produced in endocrine glands and are secreted into the bloodstream - Act on a distant site from where it is produced. - Diverse functions in controlling growth, development, and reproduction - Capable of regulating target organs or tissues - Examples of hormones include oxytocin, cortisol, testosterone, and - estrogen (in animals) and abscisic acid, cytokines, and gibberellins (in plants) - Example: The pancreas releases insulin into the bloodstream, where it travels to various tissues and helps regulate blood sugar levels. - Hormones can be polypeptides, amines, terpenoids, steroids, or phenolic compounds. By the contact of a hormone, growth, and development of cells and tissues, initiation and maintenance of sexual development, food metabolism, body temperature, and mood can be affected. Since hormones are extremely powerful molecules, a few hormones may have a major effect on the body. - Hormones travel throughout the body affecting physiological processes such as growth and development, metabolism, mood, sexual function, reproduction, etc. while, Neurotransmitters only communicate between neurons and mostly affect brain functions such as mood, memory, focus, and cognition. - Are neurotransmitters that use the chemical acetylcholine to communicate between. neurons and other cells in the body. - Acetylcholine (ACh) - messenger that acts as a neurotransmitter in the body. - How cholinergic messengers work: - Acetylcholine synthesis and release - Acetylcholine is synthesized in the nerve terminal from choline and acetyl-CoA, a reaction catalyzed by the enzyme choline acetyltransferase. - Binding to Receptors - Nicotinic Receptors: (lonotropic) - These are ligand-gated ion channels that mediate rapid, short-lasting responses. - Muscarinic receptors: (metabotropic) - These are G protein coupled receptor(GPCRs) that mediate slower, longer-lasting responses. - Effect on the Postsynaptic Cell - Nicotinic Activation: causes excitation of the cell - Muscarinic Activation: modulating enzyme activity, or altering cell signaling processes. - Termination of Signal - The action