Macromolecules PDF

 Raise both hands - if you have encountered the term and have fully understood.  Raise right hand - if you have encountered the term but did not fully understand its meaning.  Do not raise hands - if you have never encountered the term at all.  Macromolecule  Polymer  Monomer ...

 Raise both hands - if you have encountered the term and have fully understood.  Raise right hand - if you have encountered the term but did not fully understand its meaning.  Do not raise hands - if you have never encountered the term at all.  Macromolecule  Polymer  Monomer  Dehydration reaction  Hydrolysis  Carbohydrates  Monosaccharides  Disaccharides  Glycosidic linkage  Polysaccharide  Starch  Glycogen  Cellulose  Chitin  Lipids  Fat  Fatty acid  Triacylglycerol  Saturated fatty acid  Unsaturated fatty acid  Trans fat  Phospholipids  Steroids  Cholesterol MACROMOLECULES  Objectives: 1. Define carbohydrates, its chemical structure and function. 2. Explain the roles played by carbohydrates and lipids in biological systems. 3. Detect the presence of carbohydrates and lipids in food products.  MACROMOLECULES  All living things are made up of four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids.  Macromolecules are large molecules composed of thousands of covalently connected atoms.  Molecular structure and function are inseparable. How are macromolecules formed?  Macromolecules are polymers, built from monomers. POLYMERS are made from repeating units like monomers. MONOMERS are the small building blocks of polymers.  The synthesis of macromolecules: Formed from condensation reaction called Dehydration reaction. - when two monomers bond together through the loss of water.  The breakdown of macromolecules: Polymers are disassembled to monomers by hydrolysis reaction. - water is added and the lysis of polymer occurs.  CARBOHYDRATES  are organic compounds made up of carbon, hydrogen, and oxygen.  these compounds have a general formula of CnH2mOm. This means that the hydrogen and oxygen atoms are present in a ratio of 2:1. glucose - C6H12O6 sucrose - C12H22O11.  CARBOHYDRATES Monomer: MONOSACCHARIDES Linkage: GLYCOSIDIC LINKAGE  CARBOHYDRATES Monomer: MONOSACCHARIDES Linkage: GLYCOSIDIC LINKAGE  CARBOHYDRATES GLYCOGEN - stored form of carbohydrates in humans and animals. STARCH - stored form of carbohydrates in plants. How are carbohydrates classified?  1. MONOSACCHARIDES  also called simple sugars. MONO means “single” SACCHARIDES means “sugar”  major cellular nutrient often incorporated into more complex carbohydrates.  1. MONOSACCHARIDES  also called simple sugars. MONO means “single” SACCHARIDES means “sugar”  major cellular nutrient often incorporated into more complex carbohydrates.  GLUCOSE  an important source of energy in humans. A product of photosynthesis and the substrate for respiration that provides energy. GLUCOSE  FRUCTOSE  found in many plants, in fruits and is often bonded to glucose. FRUCTOSE  GALACTOSE  part of lactose or milk sugar GALACTOSE  2. DISACCHARIDES  forms when a glycosidic linkage forms between two monosaccharides.  energy source, sweetener and dietary component.  MALTOSE  (glucose + glucose)  malt sugar often found in sprouting grains, malt-based energy drinks, or beer.  LACTOSE  (glucose + galactose)  milk sugar that is a source of energy for infants  SUCROSE  (glucose + fructose)  found in table sugar processed from sugar cane, sweet fruits, and storage roots like carrots  3. POLYSACCHARIDES POLY means “many” SACCHARIDES means “sugar”  forms when hundreds to thousands of monosaccharides are joined by glycosidic linkages.  storage material for important monosaccharides, structural material for the cell or the entire organism.  STARCH  these are present in plant parts like potato tubers, corn, and rice and serve as major sources of energy.  GLYCOGEN  found in animals and fungi; often found in liver cells and muscle cells.  CELLULOSE  tough sheet-like structures that make up plants that may be processed to form paper- based products.  CHITIN  used for structural support in the walls of fungi and in external skeletons of arthropods.  PEPTIDOGLYCAN  used for structural support in bacterial cell walls. What is unique about lipids?  Recap!  What is the monomer of carbohydrates?  Monosaccharides  What is the linkage that forms between the monomers of carbohydrates?  Glycosidic Linkage  Three classifications of carbohydrates:  Monosaccharides  Disaccharides  Polysaccharides  LIPIDS  a class of large biomolecules that are not formed through polymerization.  they have diverse structures but are all non- polar and mix poorly, if at all, with water.   they also function for the cushioning of vital organs and for insulation.   LIPIDS  they play important roles in plasma membrane structure.   serve as precursors for important reproductive hormones.  act as an energy storage.  LIPIDS Linkage: ESTER BOND  Lipids can be divided into three main classes according to differences in structure and function.  1. FATS  (triacylglycerols or triglycerides)  acts as an energy storage, cushioning of vital organs (adipose tissue), and insulation Fatty acids may be:  SATURATED FATTY ACIDS  have the maximum number of hydrogen atoms bonded to each carbon (saturated with hydrogen); there are no double bonds between carbon atoms.  SATURATED FATTY ACIDS  the linear structure allows for the close packing of the fat molecules forming solids at room temperature.  SATURATED FATTY ACIDS  diets high in these fats may increase the risk of developing atherosclerosis, a condition in which fatty deposits develop within the walls of blood vessels, increasing the incidence of cardiovascular disease. SATURATED FATTY ACIDS  UNSATURATED FATTY ACIDS  have at least one double bond, H atoms are arranged around the double bond in a cis configuration (same side) resulting in a bend in the structure.  UNSATURATED FATTY ACIDS  the bent structure prevents close packing and results in oils or fats that are liquid at room temperature. UNSATURATED FATTY ACIDS UNSATURATED FATTY ACIDS  UNSATURATED FATTY ACIDS  industries have developed a process called hydrogenation that converts unsaturated fats into saturated fats to improve texture spreadability.  TRANS FAT  the cis double bonds are converted to trans double bonds (H atoms on opposite sides) resulting in fats that behave like saturated fats. TRANS FAT TRANS FAT LIPIDS  2. PHOSPHOLIPIDS  major component of cell membranes. Phospholipids self- assemble into bilayers when surrounded by water and form the characteristic structure of plasma membranes.  3. STEROIDS & STEROLS  regulate fluidity of cell membranes  serves as base of sex  hormones and emulsification of fats during digestion. 3. STEROIDS & STEROLS  Recap!  What is/are the monomers of lipids?  Glycogen & fatty acids  What is the linkage that forms between the monomers of lipids?  Ester bond  Three classifications of carbohydrates:  Fats (triglycerides/triacylglycerol)  Phospholipids  Steroids  PROTEINS  are the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules.  may be structural, regulatory, contractile, or protective  they may serve in transport, storage, or membranes; or they maybe toxins or enzymes.  PROTEINS Monomer: AMINO ACIDS Linkage: PEPTIDE BOND PROTEINS PROTEINS PROTEINS PROTEINS PROTEINS PROTEINS PROTEINS PROTEINS 2 types of proteins:  1. ENZYMES  are produced by living cells, are catalysts in biochemical reactions and are usually complex or conjugated proteins.  They are essential for respiration, digesting food, muscle and nerve function, among thousands of other roles.  1. ENZYMES  A substrate binds to the active site of an enzyme and is converted into products. 1. ENZYMES  1. ENZYMES  Cofactors can consist of one or more inorganic ions (such as Fe3+, Mg2+, Mn2+, or Zn2+) or more complex organic molecules, known as coenzymes. Some enzymes require both types of cofactors.  1. ENZYMES  Cofactors are non-protein molecules attached to enzymes to function and be activated.  For instance, carbonic anhydrase, an enzyme that helps maintain the pH of the body, cannot function unless it is attached to a zinc ion.  1. ENZYMES  Coenzymes are organic compounds that bind to the active site of enzymes or near it.  They modify the structure of the substrate or move electrons, protons, and chemical groups back and forth between enzyme and substrate. 1. ENZYMES  1. ENZYMES There are thousands of enzymes in the human body, here are just a few examples:  Lipases – a group of enzymes that help digest fats in the gut.  Amylase – helps change starches into sugars. Amylase is found in saliva.  Maltase – also found in saliva; breaks the sugar maltose into glucose.  1. ENZYMES  Trypsin – found in the small intestine, breaks proteins down into amino acids.  Lactase – also found in the small intestine, breaks lactose into glucose and galactose.  Acetylcholinesterase – breaks down the neurotransmitter acetylcholine in nerves and muscles.  Helicase – unravels DNA.  DNA polymerase – synthesize DNA from deoxyribonucleotides.  1. ENZYMES 3 Types of Enzymes: 1. Catabolic Enzymes - this are enzymes that break down their substrate. 2. Anabolic Enzymes - this are enzymes that build more complex molecules from their substrate. 3. Catalytic Enzymes - this are enzymes that affect the rate of reaction.  ENZYMES CONDITION  Enzymes can only work in certain conditions.  Most enzymes in the human body work best at around 37°C – body temperature. At lower temperatures, they will still work but much more slowly.  Similarly, enzymes can only function in a certain pH range (acidic/alkaline). For instance, enzymes in the intestines work best at 7.5 pH, whereas enzymes in the stomach work best at pH 2 because the stomach is much more acidic.  ENZYMES CONDITION  If the temperature is too high or if the environment is too acidic or alkaline, the enzyme changes shape; this alters the shape of the active site so that substrates cannot bind to it – the enzyme has become denatured.  1. ENZYMES There are two models or theories that describe the way that the substrate interacts with the enzyme lock-and-key model induced fit model. 1. ENZYMES 1. ENZYMES  2. HORMONES  Chemical-signaling molecules  act to control or regulate specific physiological processes, including growth, development, metabolism, and reproduction.  E.g. Insulin is a protein hormone that helps to regulate the blood glucose level.  AMINO ACIDS  are the monomers that makeup proteins.  the name “amino acid” is derived from the amino group and the carbonyl acid group that make up the amino acid.  Each amino acid has the same fundamental structure.  AMINO ACIDS Fundamental Structure: AMINO ACIDS  PROTEINS Monomer: AMINO ACIDS Linkage: PEPTIDE BOND  The products formed by such linkages are called peptides.  As more amino acids join to this growing chain, the resulting chain is known as a polypeptide. AMINO ACIDS  PROTEINS There are 20 amino acids present in proteins.  PROTEINS Four Levels of Protein Structure: 1. Primary Structure 2. Secondary Structure 3. Tertiary Structure 4. Quaternary Structure  PRIMARY STRUCTURE  the simplest level of protein structure.  simply the sequence of amino acids in a polypeptide chain.  SECONDARY STRUCTURE  the local folding of the polypeptide in some regions.  hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern. SECONDARY STRUCTURE  TERTIARY STRUCTURE  the overall three-dimensional structure of a polypeptide is called its tertiary structure.  the tertiary structure is primarily due to interactions between the R groups of the amino acids that make up the protein.  three-dimensional folding pattern of a protein due to side chain interactions. TERTIARY STRUCTURE  QUATERNARY STRUCTURE  in nature, some protein are formed from several polypeptide, also known as subunits, and the interaction of these subunits forms the quaternary structure.  protein consisting of more than one amino acid chain. QUATERNARY STRUCTURE  PROTEINS Denaturation and Protein Folding  if the protein is subject to changes in temperature, pH, or exposure to chemicals, the protein structure may change, losing its shape without losing its primary sequence in what known as denaturation.  PROTEINS Denaturation and Protein Folding  when a protein loses its higher-order structure, but not its primary sequence, it is said to be denatured. Denatured proteins are usually non-functional.  PROTEINS Denaturation and Protein Folding  For some proteins, denaturation can be reversed.  RENATURATION  Other times, however, denaturation is permanent. One example of irreversible protein denaturation is when an egg is fried.  PROTEINS Denaturation and Protein Folding  CHAPERONE PROTEIN: molecular chaperones are proteins that assist the covalent folding or unfolding and the assembly or disassembly of other macromolecular structures. PROTEINS  Recap!  What is the monomer of proteins?  amino acids  What is the linkage that forms between the monomers of carbohydrates?  Peptide bond  Two main type of proteins:  Enzymes  Hormones  NUCLEIC ACIDS  Nucleic acids are the most important macromolecules for the continuity of life.  They carry the genetic blueprint of a cell and carry instructions for the functioning of the cell.  NUCLEIC ACIDS Monomer: NUCLEOTIDES Linkage: PHOSPHODIESTER BOND  NUCLEIC ACIDS The two main types of nucleic acid:  Deoxyribonucleic Acid (DNA) is the genetic material found in all living organisms.  DNA forms a complex with histone proteins to form chromatin, the substance of eukaryotic chromosomes.  Many genes contain the information to make protein products;  NUCLEIC ACIDS The two main types of nucleic acid:  Ribonucleic Acid (RNA) is mostly involved in protein synthesis.  The DNA molecules never leave the nucleus but instead use an intermediary to communicate with the rest of the cell.  NUCLEIC ACIDS Each nucleotide is made up of three components:  NITROGENOUS BASES  an important component of nucleotides are organic molecules because they contain carbon and nitrogen.  Each nucleotide in DNA contains one of four possible nitrogenous bases, namely: 1. Adenine (A) 2. Guanine (G) 3. Cytosine (C) 4. Thymine (T)  NITROGENOUS BASES  Nitrogenous bases are often just referred to by their one-letter symbols, A, T, G, C, and U. DNA contains A, T, G, and C, while RNA contains A, U, G, and C (that is, U is swapped in for T). NITROGENOUS BASES  PENTOSE SUGAR DNA is deoxyribose, and in RNA, the sugar is ribose.  These two are very similar in structure, with just one difference: the second carbon of ribose bears a hydroxyl group, while the equivalent carbon of deoxyribose has a hydrogen instead. PENTOSE SUGAR  PHOSPHATE  residue is attached to the hydroxyl group of the 5’ carbon of one sugar and 3’ carbon of the sugar of the next nucleotide which form a 5’ – 3’ phosphodiester linkage/bond. PHOSPHATE  DNA  DNA has a double-helix structure, with sugar and phosphate on the outside of the helix, forming the sugar-phosphate backbone of the DNA.  DNA  Only certain types of base pairing are allowed.  A can only pair with T, and G can only pair with C, as shown below.  This is known as the base complementary rule.  DNA 5’- A A T T G G C C -3’ 3’- _ _ _ _ _ _ _ _ -5’  DNA 5’- A A T T G G C C -3’ 3’- T T A A C C G G -5’  RNA  mainly involved in the process of protein synthesis under the direction of DNA. RNA, unlike DNA, is usually single-stranded.  RNA 5’- A A T T G G C C -3’ 3’- _ _ _ _ _ _ _ _ -5’  DNA 5’- A A T T G G C C -3’ 3’- U U A A C C G G -5’  RNA Four major types of RNA: 1. Messenger RNA (mRNA) - carries the message from DNA, which controls all of the cellular activities in a cell. 2. Ribosomal RNA (rRNA) - major constituent of ribosomes on which the mRNA binds. It ensures the proper alignment of the mRNA and the ribosomes.  RNA Four major types of RNA: 3. Transfer RNA (tRNA) - carries correct amino acids to the site of protein synthesis. 4. micro RNA or miRNA - their roles involves the regulation of gene expression by interfering with the expression of certain mRNA messages.