GenBio1 Lecture - Biomolecules PDF

THE BASICS OF BIOCHEMISTRY ARGEL JOSEPH C. MAYO, RN, LPT, MAN, MSc.Bio SHS Teacher III / SHS Nurse BIOCHEMISTRY Biochemistry, the study of the chemical substances and processes that occur in plants, animals, and microorganisms and of the changes they undergo during development an...

THE BASICS OF BIOCHEMISTRY ARGEL JOSEPH C. MAYO, RN, LPT, MAN, MSc.Bio SHS Teacher III / SHS Nurse BIOCHEMISTRY Biochemistry, the study of the chemical substances and processes that occur in plants, animals, and microorganisms and of the changes they undergo during development and life. All chemical changes within the organism—either the degradation of substances, generally to gain necessary energy, or the buildup of complex molecules necessary for life processes—are collectively called metabolism. BIOCHEMISTRY These chemical changes depend on the action of organic catalysts known as enzymes, and enzymes, in turn, depend for their existence on the genetic apparatus of the cell. It is not surprising, therefore, that biochemistry enters into the investigation of chemical changes in disease, drug action, and other aspects of medicine, as well as in nutrition, genetics, and agriculture.  STRUCTURE AND FUNCTIONS OF BIOLOGICAL MOLECULES: THE BASICS ARGEL JOSEPH C. MAYO, RN, LPT, MAN, MSc.Bio SHS Teacher III / SHS Nurse BIOLOGICAL MOLECULES (Biomolecules) Any of numerous substances that are produced by cells and living organisms. Biomolecules have a wide range of sizes and structures and perform a vast array of functions. Biomolecules are the most essential organic molecules, which are involved in the maintenance and metabolic processes of living organisms. BIOLOGICAL MOLECULES (Biomolecules) TYPES OF BIOMOLECULES BIOLOGICAL MOLECULES BIOLOGICAL MOLECULES BIOLOGICAL MOLECULES BIOLOGICAL MOLECULES CARBOHYDRATES  CARBOHYDRATES - Sugars, starches, and cellulose are carbohydrates. - Sugars and starches are energy sources for cells; cellulose is the main structural component of the cell walls that surround the plant cells. - Carbohydrates contain carbon, hydrogen, and oxygen atoms in a ratio approximately one carbon to two hydrogens to one oxygen (CH2O). - The term carbohydrate, meaning “hydrate (water) of carbon”. MONOSACCHARIDE  MONOSACCHARIDE - All monosaccharides have the same general formula of (CH2O)n, which designates a central carbon molecule bonded to two hydrogens and one oxygen. - The oxygen will also bond to a hydrogen, creating a hydroxyl group. Because carbon can form 4 bonds, several of these carbon molecules can bond together.  MONOSACCHARIDE - One of the carbons in the chain will form a double bond with an oxygen, which is called a carbonyl group. If this carbonyl occurs at the end of the chain, the monosaccharide is in the aldose family. If the carboxyl group is in the middle of the chain, the monosaccharide is in the ketose family. Identify the aldose and ketose COMMON NATURALLY OCCURING MONOSACCHARIDES Glucose / dextrose Fructose Galactose  GLUCOSE (C6H12O6) - The most abundant monosaccharide - Used as energy source - Glucose molecules can be broken down in glycolysis, providing energy and precursors for cellular respiration. If a cell does not need any more energy at the moment, glucose can be stored by combining it with other  GLUCOSE (C6H12O6) - Plants store these long chains as starch, which can be disassembled and used as energy later. Animals store chains of glucose in the polysaccharide glycogen, which can store a lot of energy  FRUCTOSE (C6H12O6) - Although almost identical to glucose, fructose is a slightly different molecule. The formula is the same, but the structure is much different.  FRUCTOSE (C6H12O6) - Notice that instead of the carbonyl group being at the end of the molecule, as in glucose, it is the second carbon down.  GALACTOSE (C6H12O6) - Galactose is a monosaccharide produced in many organisms, especially mammals. - Mammals use galactose in milk, to give energy to their offspring. - Glucose, galactose, and fructose are all hexoses. They are structural isomers, meaning they have the same chemical formula (C6H12O6) - but a different arrangement of atoms. DISACCHARIDES  DISACCHARIDES Disaccharides (di– = “two”) form when two monosaccharides undergo a dehydration reaction. During this process, the hydroxyl group of one monosaccharide combines with the hydrogen of another monosaccharide, releasing a molecule of water and forming a covalent bond.  DISACCHARIDES A covalent bond formed between a carbohydrate molecule and another molecule (in this case, between two monosaccharides) is known as a glycosidic bond.  DISACCHARIDES Three common disaccharides: sucrose — common table sugar = glucose + fructose. lactose — major sugar in milk = glucose + galactose. maltose — product of starch digestion = glucose + glucose. POLYSACCHARIDES  POLYSACCHARIDES A long chain of monosaccharides linked by glycosidic bonds is known as a polysaccharide (poly– = “many”). The chain may be branched or unbranched, and it may contain different types of monosaccharides.  POLYSACCHARIDES Starch is the stored form of sugars in plants and is made up of a mixture of amylose and amylopectin (both polymers of glucose). Plants are able to synthesize glucose, and the excess glucose, beyond the plant’s immediate energy needs, is stored as starch in different plant parts, including roots and seeds.  POLYSACCHARIDES The starch in the seeds provides food for the embryo as it germinates and can also act as a source of food for humans and animals. The starch that is consumed by humans is broken down by enzymes, such as salivary amylases, into smaller molecules, such as maltose and glucose. The cells can then absorb the glucose. PROTEINS  PROTEINS Proteins are biological polymers composed of amino acids. Amino acids, linked together by peptide bonds, form a polypeptide chain.  AMINO ACIDS - Amino acids contain carbon- hydrogen bonds. - All amino acids have the same basic structure. - Each molecule has a central carbon atom linked together with a basic amino group, a carboxylic acid group, a hydrogen atom and an R- group, or side-chain group  AMINO ACIDS - Amino acids are organic compounds that contain: - amine (-NH2) - carboxyl (-COOH) functional group - side chain(R group) specific to each amino acid. STRUCTURE OF PROTEINS - Primary Structure describes the unique order in which amino acids Primary Structure are linked together to form a protein. Proteins are constructed from a set of 20 amino acids. - Sequences with fewer than 50 amino acids are generally referred to as peptides, while the terms protein or polypeptide are used for longer sequences. A protein can be made up of one or more polypeptide molecules.  21 Amino Acids Essential Amino Acids Non-essential Amino Acids (Mnemonics: Almost (Mnemonics: All Girls Go Crazy PVT TIM After Getting Taken HALLS) Prom Shopping)  21 Amino Acids Essential Amino Acids (Mnemonics: PVT TIM HALLS) P = Phenylalanine V = Valine T = Threonine T = Tryptophan Non-essential Amino Acids (Mnemonics: I = Isoleucine Almost All Girls Go Crazy After Getting M = Methionine Taken Prom Shopping) H = Histidine A = Arginine L = Leucine L = Lysine S = Selenocysteine  21 Amino Acids Non-essential Amino Acids (Mnemonics: Almost All Girls Go Crazy After Getting Taken Prom Shopping) A = Alanine A = Asparagine Essential Amino Acids G = Glutamate (Mnemonic: PVT TIM HALLS) G = Glutamine C = Cysteine A = Aspartate G = Glycine T = Tyrosine P = Proline S = Serine  21 Amino Acids Non-essential Amino Acids (Mnemonics: Essential Amino Acids Almost All Girls Go Crazy After Getting (Mnemonic: PVT TIM HALL) Taken Prom Shopping) P = Phenylalanine A = Alanine V = Valine A = Asparagine T = Threonine G = Glutamate T = Tryptophan G = Glutamine I = Isoleucine C = Cysteine M = Methionine A = Aspartate H = Histidine G = Glycine A = Arginine T = Tyrosine L = Leucine P = Proline L = Lysine S = Serine Secondary Structure refers to the coiling or folding of a Secondary Structure polypeptide chain that gives the protein its 3-D shape. There are two types of secondary structures observed in proteins: - alpha (α) helix structure = This structure resembles a coiled spring - beta (β) pleated sheet = This structure appears to be folded  Tertiary Structure Tertiary Structure refers to the comprehensive 3-D structure of the polypeptide chain of a protein.  Quaternary Structure Quaternary Structure refers to the structure of a protein macromolecule formed by interactions between multiple polypeptide chains. LIPIDS - Lipid, any of a diverse group Lipids of organic compounds including fats, oils, hormones, and certain components of membranes that are grouped together because they do not interact appreciably with water. - Major lipid groups include fats, phospholipids, steroids, and waxes.  Fats Fats are composed of: three fatty acids and glycerol. These so called triglycerides can be solid or liquid at room temperature.  Fats - Saturated fats raise LDL (low- density lipoprotein) cholesterol levels in the blood. This increases the chances for developing cardiovascular disease. - Unsaturated fats lower LDL levels and reduce the risk for disease  Phospholipid A phospholipid is composed of two fatty acids, a glycerol unit, a phosphate group. The phosphate group and polar head region of the molecule is hydrophillic (attracted to water), while the fatty acid tail is hydrophobic (repelled by water).  Steroids and Waxes Steroids have a carbon backbone that consists of four fused ring-like structures. Steroids include cholesterol, sex hormones (progesterone, estrogen, and testosterone) produced by gonads and cortisone.  Steroids and Waxes Waxes are composed of an ester of a long-chain alcohol and a fatty acid. Many plants have leaves and fruits with wax coatings to help prevent water loss. Some animals also have wax-coated fur or feathers to repel water. NUCLEIC ACIDS  Nucleic Acids - Nucleic acids are molecules that allow organisms to transfer genetic information from one generation to the next. - These macromolecules store the genetic information that determines traits and makes protein synthesis possible  Nucleotides - Nucleic acids include DNA and RNA. These molecules are composed of long strands of nucleotides. - Nucleotides are composed of: - nitrogenous base - five-carbon sugar - phosphate group.  Nucleotides DNA is composed of: - phosphate-deoxyribose sugar backbone - nitrogenous bases adenine (A) - guanine (G) - cytosine (C), - thymine (T).  Nucleotides RNA has: - ribose sugar - nitrogenous bases - A, G, C, and uracil (U).  Chargaff’s Rule Named for the great Austrian- American biochemist Erwin Chargaff  Chargaff’s Rules - The rules of base pairing (or nucleotide pairing) are: A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T) C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G)