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Dive into the world of carbohydrates and lipids, the organic molecules crucial for human health. Understand their structures, functions, and impact on the body's physiology.
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BIOL 2401-094 • Fundamentals of Anatomy and Physiology • Chapter 2 • wgrant4@alamo.edu • (210) 643-8968
2-9 Carbohydrates Organic Molecules • Contain H, C, and usually O • Are covalently bonded • Contain functional groups that determine chemistry • Carbohydrates Lipids Proteins (or amino acids) Nucleic acids Grouping of atoms occurring repeatedly that influence the properties of any molecule they are in.
2-9 Carbohydrates • Carbohydrates Contain carbon, hydrogen, and oxygen in a 1:2:1ratio • Monosaccharide — simple sugar • Disaccharide — two sugars • Polysaccharide — many sugars
2-9 Carbohydrates • Monosaccharides • Simple sugars with 3 to 7 carbon atoms • Glucose, fructose, galactose • Disaccharides • Two simple sugars condensed by dehydration synthesis • Sucrose, maltose • Polysaccharides • Many monosaccharides condensed by dehydration synthesis • Glycogen, starch, cellulose
Carbohydrates Isomers are molecules with the same types of and numbers of atoms—but different structure. How many hydroxyl groups does a molecule of glucose have? How many carbon atoms are part of glucose’s carbon skeleton?
Figure 2-12a The Formation and Breakdown of Complex Sugars Two monosaccharides joined together form a disaccharide. Add additional monosaccharides or dissacharides, and you get polysaccharides. They are formed in a process called dehydration synthesis (condensation). Water is released. DEHYDRATION SYNTHESIS Sucrose Glucose Fructose
Figure 2-12b The Formation and Breakdown of Complex Sugars Hydrolysis reverses the steps of dehydration synthesis. A complex molecule is broken down by the addition of water. HYDROLYSIS Sucrose Glucose Fructose
Figure 2-13 The Structure of the Polysaccharide Glycogen (animal starch) Glucose molecules Which body cells store glycogen? Muscle Cells
2-10 Lipids • Lipids • Mainly hydrophobic molecules such as fats, oils, and waxes • Made mostly of carbon and hydrogen atoms • Include: • Fatty acids • Eicosanoids • Glycerides • Steroids • Phospholipids and glycolipids
2-10 Lipids • Fatty Acids • Long chains of carbon and hydrogen with a carboxyl group (COOH) at one end • Are relatively nonpolar,except the carboxyl group • Fatty acids may be: • Saturatedwith hydrogen (no covalent bonds) • Unsaturated (one or more double bonds) • Monounsaturated = one double bond • Polyunsaturated = two or more double bonds
Figure 2-14a Fatty Acids Lauric acid (C12H24O2) Lauric acid demonstrates two structuralcharacteristics common to all fatty acids: along chain of carbon atoms and a carboxylgroup (—COOH) at one end.
Figure 2-14b Fatty Acids Saturated Unsaturated Double Bond A fatty acid is either saturated (has singlecovalent bonds only) or unsaturated (hasone or more double covalent bonds). Thepresence of a double bond causes asharp bend in the molecule.
BIOL 2401 Something to Consider: A diet containing large amounts of saturated fatty acids has been shown to increase the risk of heart disease and other cardiovascular problems. The healthiest choices of unsaturated oils to use are canola oils and olive oil. Be careful of trans fatty acids (compounds from polyunsaturated oils such are margarine) seem to increase the risk of heart disease. Foods high in omega-3 fatty acids (fish flesh and fish oils) seem to reduce the risk of heart disease and other inflammatory diseases. (rheumatoid arthritis).
2-10 Lipids • Eicosanoids (Derived from the fatty acid called arachidonic acid) • Leukotrienes –Active in the immune system • Prostaglandins –Local hormones, short-chain fatty acids that produce sensation of pain and in the uterus, help trigger labor contractions. • Prostaglandins are called local hormones
2-10 Lipids • Glycerides are fatty acids attached to a glycerol molecule • Monoglyceride (glycerol + one fatty acid) • Diglyceride (glycerol + two fatty acids) • Triglycerides are the three fatty-acid tails • Also called triacylglycerols or neutral fats • Have three important functions • Energy source • Insulation • Protection
Figure 2-16 Triglyceride Formation Glycerol Fatty acids Fatty Acid 1 Saturated Saturated Fatty Acid 2 Fatty Acid 3 Unsaturated DEHYDRATION SYNTHESIS HYDROLYSIS Breakdown Formation Triglyceride
2-10 Lipids • Steroids(large lipid molecules with a distinctive carbon framework) • Four rings of carbon and hydrogen with an assortment of functional groups • Types of steroids: • Cholesterol • Component of plasma (cell) membranes • Estrogens and testosterone • Sex hormones • Corticosteroids and calcitriol • Metabolic regulation • Bile salts • Derived from steroids What is the danger of a diet high in cholesterol? The development of heart disease is the danger of high cholesterol blood levels.
Figure 2-17 Steroids Cholesterol Testosterone (males) Estrogen (females)
2-10 Lipids • Phospholipids and Glycolipids • Diglycerides attached to either a phosphate group (phospholipid) or a sugar (glycolipid) • Generally, both have hydrophilic heads and hydrophobic tails and are structural lipids, components of plasma (cell) membranes
Which portion of a phospholipid is hydrophilic, and which portion is hydrophobic?
Table 2-5 Representative Lipids and Their Functions in the Body
2-11 Proteins • Proteins • Are the most abundant and important organic molecules • Contain basic elements • Carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) • Basic building blocks • 20 amino acids
Support Structural proteins Movement Contractile proteins Transport Transport (carrier) proteins Buffering Regulation of pH Metabolic Regulation Enzymes Coordination and Control Hormones Defense Antibodies 2-11 Proteins • Seven Major Protein Functions
2-11 Proteins • Protein Structure • Long chains of amino acids • Five components of amino acid structure • Central carbon atom • Hydrogen atom • Amino group (—NH2) • Carboxyl group (—COOH) • Variable side chain or R group Hydrogen atom Central Carbon Amino Acid Carboxyl Group R group(variable side chain)
2-11 Proteins Hooking Amino Acids Together • Requires a dehydration synthesis between: • The amino group of one amino acid and the carboxyl group of another amino acid • Forms a peptide bond resulting in a peptide Two amino acids – dipeptide Three amino acids – tripeptide Chain of amino acids - polypeptide
Figure 2-20 The Fomation of Peptide Bonds Peptide Bond Formation Glycine (gly) Alanine (ala) DEHYDRATIONSYNTHESIS HYDROLYSIS Peptide bond
BIOL 2401 Essential Amino Acids: Arginine Isoleucine Histidine Leucine Methionine Lysine Phenylalanine Tryptophan Threonine Valine These cannot be made by the body and must be obtained in the foods we eat. Non-Essential Amino Acids: Alanine Asparagine Aspartic Acid Cysteine Glutamic Acid Cysteine Glutamine Glycine These are made by the body. Differentiate between essential amino acids and non-essential amino acids.
2-11 Proteins • Protein Shape • Primary structure • The sequence of amino acids along a polypeptide • Secondary structure • Hydrogen bonds form spirals or pleats • Tertiary structure • Secondary structure folds into a unique shape • Quaternary structure • Final protein shape — several tertiary structures together
Figure 2-21 Protein Structure Primary A5 A7 A3 A4 A6 A8 A9 A1 A2 Linear chain of amino acids A2 A4 A3 A1 Hydrogen bond A5 Hydrogenbond A9 A6 A8 A7 A6 A2 A10 A9 OR A1 A5 A13 A7 A12 A3 A11 A14 Alpha-helix Pleated sheet Secondary OR Heme units Tertiary Keratin or collagen(fibrous protein) Hemoglobin(globular protein) Do all proteins have a quaternary structure? Quaternary
2-11 Proteins Classes of proteins are based on overall shape and properties. • Fibrous Proteins • Structural sheets or strands • Globular Proteins • Soluble spheres with active functions • Protein function is based on shape • Shape is based on sequence of amino acids • 20 amino acids can be linked in many combinations creating many proteins of varied shape and function.
2-11 Proteins • Enzyme Function • Enzymes are catalysts • Proteins that lower the activation energy of a chemical reaction • Are not changed or used up in the reaction • Enzymes also exhibit: • Specificity — will only work on limited types of substrates • Saturation Limits— by their concentration • Regulation — by other cellular chemicals
Figure 2-22 A Simplified View of Enzyme Structure and Function • Cofactors and Enzyme Function • Cofactor • An ion or molecule that binds to an enzyme before substrates can bind -- Ca2+Mg2+ • Coenzyme • Non-protein organic cofactors (vitamins) • Isozymes • Two enzymes that can catalyze the same reaction
2-11 Proteins • Effects of Temperature and pH on Enzyme Function • Denaturation • Loss of shape (tertiary or quaternary) and function (becomes non-functional) • Due to heat (temperatures above 1100 pH (acidic or basic depending on enzyme)
2-11 Proteins • Glycoproteins and Proteoglycans • Glycoproteins • Large protein + small carbohydrate • Includes enzymes, antibodies, hormones, and mucus production • Proteoglycans • Large polysaccharides + polypeptides • Promote viscosity
2-12 Nucleic Acids • NucleicAcids • Are large organic molecules, found in the nucleus, which store and process information at the molecular level • Deoxyribonucleic acid (DNA) • Determines inherited characteristics • Directs protein synthesis • Controls enzyme production • Controls metabolism • Ribonucleic acid (RNA) • Controls intermediate steps in protein synthesis
2-12 Nucleic Acids Structure of Nucleic Acids DNA and RNA are strings of nucleotides Nucleotides are the building blocks of DNA and RNA Have three molecular parts • Apentose sugar (deoxyribose or ribose) • Phosphate group • Nitrogenous base (A, G, T, C, or U) Sugar Phosphate Group Nitrogenous Base
Purines Adenine Guanine Pyrimidines Cytosine Thymine DNA only Uracil RNA only
2-12 Nucleic Acids • DNA and RNA • DNA is double stranded, and the bases form hydrogen bonds to hold the DNA together • Sometimes RNA can bind to itself but is usually a single strand • DNA forms a twisting double helix • Complementary base pairs • Purines pair with pyrimidines • DNA • Adenine (A) and thymine (T) • Cytosine (C) and guanine (G) • RNA • Uracil (U) replaces thymine (T) • Types of RNA Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA)
Figure 2-24 The Structure of Nucleic Acids Phosphategroup Deoxyribose Adenine Thymine Hydrogen bond DNA strand 1 DNA strand 2 RNA molecule. Which bases always pair with each other? A to T and G to C Cytosine Guanine DNA molecule.
2-13 High-Energy Compounds • Nucleotides Can Be Used to Store Energy • Adenosine diphosphate (ADP) • Two phosphate groups; di- = 2 • Adenosine triphosphate (ATP) • Three phosphate groups; tri- = 3 • Phosphorylation • Adding a phosphate group to ADP with a high-energy bond to form the high-energy compound ATP • Adenosine triphosphatase (ATPase) • The enzyme that catalyzes the conversion of ATP to ADP
Figure 2-25 The Structure of ATP Adenine Phosphate Phosphate Phosphate Ribose High-energy bonds Adenosine Adenosine monophosphate (AMP) Adenosine diphosphate (ADP) Adenosine triphosphate (ATP) Adenine Phosphate groups Ribose Adenosine
2-14 Chemicals and Cells • Chemicals and Cells • Biochemical building blocks form functional units called cells • Metabolic turnover lets your body grow, change, and adapt to new conditions and activities • Your body recycles and renews all of its chemical components at intervals ranging from minutes to years
Table 2-7 Classes of Inorganic and Organic Compounds Critical Thinking Question: During chemistry lab, Maria places sucrose (table sugar) in a glass beaker, adds water and stirs. As the table sugar disappears, she loudly proclaims that she has chemically broken down the sucrose into fructose and glucose. Is Maria’s chemical analysis correct?
