Biological Macromolecules PDF

Biological Macromolecules GENERAL BIOLOGY 1 2ND QUARTER  Biological Macromolecules are large organic molecules (has atoms of carbon that are bonded to atoms of hydrogen) 4 Groups of Biomolecules:  Biological Macromolecules are considered to be polymers formed through...

Biological Macromolecules GENERAL BIOLOGY 1 2ND QUARTER  Biological Macromolecules are large organic molecules (has atoms of carbon that are bonded to atoms of hydrogen) 4 Groups of Biomolecules:  Biological Macromolecules are considered to be polymers formed through polymerization reaction. “poly” -- many,” “-mer” – unit Polymers are large molecules made of many repeating subunits called monomers. Monomers are molecules considered as building block for larger molecules (polymers). For example, an amino acid acts as the building blocks for proteins.  Dehydration Synthesis Most macromolecules are made from single subunits, or building blocks, called monomers. The monomers combine with each other using covalent bonds to form larger molecules known as polymers. In doing so, monomers release water molecules as byproducts. This type of reaction is known as dehydration synthesis, which means “to put together while losing water.” Glycosidic bond Glycosidic bonds are covalent chemical bonds that hold together a glycoside. A glycoside is simply a ring-shaped sugar molecule that is attached to another molecule.  Peptide bond A peptide bond links two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another, along a peptide or protein chain. Phosphodiester bond a covalent linkage between the phosphate of one nucleotide and the hydroxyl (OH) group forming the “sugar- phosphate backbone” of DNA.  Ester bond An ester bond forms when a hydroxyl (-OH) group from the glycerol bonds with the carboxyl (-COOH) group of the fatty acid.  Food Diary 1. Keep a food diary for a week, noting the types of macromolecules present in your meals. 2. Reflect on your food diary and discuss how your macromolecule intake aligns with nutritional guidelines. What changes would you make based on your findings?  What to put in your food diary Date and Quantity Food Calories Carbs Proteins Fats Day description (grams) (grams) (grams) Breakfast (Time eaten) Snack (Time) Lunch (Time) Snack (Time) Dinner (Time) Snack (Time) Total Sample food diary 1. Carbohydrates  Carbohydrates ▪ refers to any of the group of organic compounds consisting of carbon, hydrogen, and oxygen, usually in the ratio of 1:2:1 ▪ general formula: Cn(H2O)n ▪ Carbohydrates = hydrates of carbon (ratio of H:O = 2:1) ▪ the most abundant among the major classes of biomolecules. Classification of Carbohydrates Monosaccharides Glucose, galactose and fructose have the same chemical formula (C6H12O6) Glucose and fructose are isomers because they have an identical molecular formula but different structures Glucose consists of an aldehyde group while fructose consists of a ketone functional group. Aldehydes contain the carbonyl group bonded to at least one hydrogen atom. Ketones contain the carbonyl group bonded to two carbon atoms.  Monosaccharides Glucose Common name: Blood sugar; also known as dextrose Sources: honey, agave, molasses, dried fruit, fruits, fruit juices, and sweet corn Galactose Common Name: Milk sugar Sources: dairy products Fructose Common name: fruit sugar Sources: fruits, fruit juices, some vegetables and honey  Disaccharides composed of two monosaccharide units linked together by a glycosidic bond The glycosidic bonds between residues use an oxygen molecule to bridge two carbon rings. A Hydroxyl group will be lost from one monosaccharide, and a hydrogen will be removed from the Hydroxyl group of the other to leave a free oxygen → dehydration reaction  Polymerization Polymers are made up of a Dehydration reaction, or condensation combination of smaller reaction or dehydration synthesis occurs molecules called monomers, when two molecules are joined by through a process called removing water. This allows for the polymerization. creation of a larger molecule from two smaller molecules  Disaccharides Sucrose = glucose + fructose Common name: table sugar Sources: sugar cane, sugar beets, apples, oranges, carrots, and other fruits and vegetables Maltose = glucose + glucose Common Name: Malt sugar Sources: beer, bread, breakfast cereal Lactose = glucose + galactose Common name: milk sugar Sources: exclusively found in the milk of mammals—including cows, goats and humans (naturally occurring)  Polysaccharides Polysaccharides are long chains of more than 10 monosaccharide molecules linked by glycosidic bonds. structure can vary widely depending upon the shape and size of the residues that make it up, the locations of the bonds holding those residues together, where and how the polysaccharide is made, where it is stored, and its function  Polysaccharides Starch Found in granules in plants Storage of carbohydrates for plant cells to use as energy Made up of glucose molecules in a coil structure Makes up about 50% of our dietary carbohydrate intake Glycogen Found in granules in animal cells, especially liver and muscle cells Storage of carbohydrates for animal cells to use as energy Made up of glucose residues in a branched structure About 70% of the glycogen in the human body is stored in the skeletal muscle Cellulose Fibrous carbohydrate that makes up plants' cell walls Provides structure for plant cells, the chains have hydrogen bonds that link them together to increase their strength Linear structure that binds together into fibers Cellulose is used to produce over 70% of textiles  Natural starch contains 10-20% amylose and 80- 90% amylopectin Amylose less soluble in water Starch chain 500-2 million glucose units Cellulose can have 2000- 14000 glucose Glycogen is highly branched and more compact and 60,000 glucose units  Functions of Carbohydrates 1. Provide energy to organisms Monosaccharides, in particular, are the main source of energy for metabolism. When they are not yet needed, they are converted into energy-storing polysaccharides, such as starch in plants and glycogen in animals. 2. Important structural components At the cellular level, polysaccharides (e.g. cellulose) are constituents of the cell walls of plant cells and many algae. Cells without cell walls are more prone to structural and mechanical damage. In plants, the cell wall prevents the cell from bursting into a hypotonic solution.  Assignment : Carbohydrates Answer the following questions : 1.What is the primary function of carbohydrates in the human body? 2. What is the function of glycogen in the liver? In the skeletal muscles? 2. Proteins Proteins A protein is a biomolecule composed of amino acids joined together by peptide bonds. Example: Glutathione (cysteine, glutamic acid, and glycine) An amino acid is a molecule consisting of the basic amino group (NH3), the acidic carboxylic group (COOH), a hydrogen atom, and an organic side group (R) attached to the carbon atom. Amino Acids Amino Acids and R groups Dehydration Synthesis  Common Sources of Proteins Eggs | Milk | Yogurt | Fish and seafoods | Chicken and turkey | Soya | Nuts and seeds | Pork | Beef | Lentils A food is considered a complete protein when it contains all nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine Nine Major Categories of Proteins ▪ Enzymes ▪ Structural Proteins ▪ Motility Proteins ▪ Regulatory Proteins ▪ Transport proteins ▪ Signaling proteins ▪ Receptor proteins ▪ Defensive proteins ▪ Storage proteins 1. Enzymes - serve as catalysts that greatly increase the rates of the thousands of chemical reactions on which life depends Exa: Amylase – mouth and pancreas – breaks down complex carbohydrates Lipase – pancreas – breaks down fats Proteases – breaks down proteins 2. Structural Proteins - provide physical support and shape to cells and organelles, giving them their characteristic appearances Exa: Collagen – connective tissue Keratin – hair, nails, feathers Actin (intermediate filaments), Tubulin (microtubules) 3. Motility Proteins - play key roles in the contraction and movement of cells and intracellular materials Exa: Actin – most abundant protein in eukaryotic cells; functions in muscle contraction and cell movements Myosin – muscle contraction and movement 4. Regulatory Proteins - responsible for control and coordination of cellular functions, ensuring that cellular activities are regulated to meet cellular needs Exa: Insulin – regulator of glucose metabolism CDK – cyclin-dependent kinase – controls cell cycle progression 5. Transport proteins are involved in the movement of other substances into, out of, and within the cell. Exa: Channel proteins, carrier proteins, sodium-potassium pump, hemoglobin 6. Signaling proteins mediate communication between cells in an organism Exa: Thyrotropin releasing hormone (TRH) triggers the release of thyroid stimulating hormone (TSH), which, in turn, triggers the release of thyroxine from the thyroid gland. Insulin is released by the pancreatic beta cells in response to a rise in blood sugar after a meal. 7. Receptor proteins enable cells to respond to chemical stimuli from their environment Exa: B cell, T cell, Stem cell receptor protein 8. Defensive proteins provide protection against disease Exa: antibodies (Immunoglobulin A), lectins (plants – defense proteins and are harmful to insects or pathogens), and antiviral proteins 9. Storage proteins serve as reservoirs of amino acids. Exa: Casein, found in mammalian milk, and ovalbumin, found in egg white, both provide a developing organism with a ready source of amino acids and organic nitrogen Ferritin stores iron in hemoglobin  Key Points: Proteins Each amino acid contains a central C atom, an amino group (NH2), a carboxyl group (COOH), and a specific R group. The R group determines the characteristics (size, polarity, and pH) for each type of amino acid. Peptide bonds form between the carboxyl group of one amino acid and the amino group of another through dehydration synthesis. A chain of amino acids is a polypeptide. Levels of Protein Structure Which of the following best explains why proteins differ in their structure and function? [A] Different proteins contain the same composition of amino acids that form the same polypeptide chain, but this chain folds in different ways. [B] Different proteins have different numbers and arrangements of amino acids in their polypeptide chains, which interact in different ways. [C] Each protein consists of only one type of amino acid joined into polypeptide chains, but this amino acid differs between proteins. [D] All proteins have very similar structures and functions. Primary Level of Structure is the amino acid sequence in its polypeptide chain. Covalent, peptide bonds which connect the amino acids together maintain the primary structure of a protein. genetic disorders, such as cystic fibrosis, sickle cell anemia, albinism, etc., are caused by mutations resulting in alterations in the primary protein structures → lead to alterations in the secondary , tertiary and quaternary structure. Primary Level of Structure: Insulin  Primary Level of Structure Dipeptides: Compound formed when two amino acids linked by 1 peptide bond. Examples: Carnosine ( β-alanyl-L-histidine) Anserine (β-alanyl-N-methylhistidine) Aspartame (Asparagine-phenylalanine)  Primary Level of Structure Tripeptides formed when three amino acids linked by 2 peptide bond. Examples: Glutathione (cysteine, glutamic acid, and glycine) Opthalmic acid (l-γ-glutamyl-l-2-aminobutyryl-glycine)  Primary Level of Structure Oligopeptides formed when more than 2 and less than 20 amino acids are linked by peptide bonds. Exa: Tetrapeptide → Tulfsin ( thrionine-lysine-proline-Arginine) → Endomorphin-1 ( Tyrosine-proline-tryptophan-phenylalanine) Decapeptide → Amanitin (found in a number of poisonous mushrooms) Netropsin → antibiotic and antiviral  Primary Level of Structure Polypeptides Compound formed when more than 20 amino acids are linked by peptide bond. Examples: Growth hormone (191 amino acids)  Secondary Level of Structure Secondary structure refers to the local folded structure of protein The secondary structure is held together by hydrogen bonds The most common types of secondary structures are α – helix and β – pleated sheet Secondary Level of Structure Tertiary Level of Structure refers to the three-dimensional arrangement of a polypeptide chain that has assumed its secondary structure. It gives rise to two major molecular shapes called fibrous and globular. The main forces which stabilize the secondary and tertiary structures of proteins are hydrogen bonds, disulphide linkages, van der Waals and electrostatic forces of attraction. Examples: Collagen, myoglobin Quaternary Level of Structure made from two or more polypeptide chains Examples of proteins with quaternary structure include hemoglobin, DNA polymerase, ribosomes, antibodies, and ion channels. Hemoglobin How hemoglobin works