Biology I for Non-Majors

1. Biology I for Non-Majors Important Biological Macromolecules

2. Carbon and Carbon Bonding • Carbon- “foundation” element for molecules in living things • Carbon Bonding- carbon contains 4 electrons so it can form four covalent bonds • Any hydrogen atoms can be replaced with another carbon atom covalently bonded to the first carbon atom- long and branching chains of carbon compounds can e made • Carbon atoms may bond with atoms of other elements • Molecules may also form rings that can’t link to other rings

3. Structure and Function of Carbohydrates • Molecular Structures- represented by CH2O • Ratio of carbon to hydrogen to oxygen is 1:2:1 • Monosaccharides • Disaccharides • Polysaccharide

4. Monosaccharides • Simple sugars, most commonly known as glucose • Number of carbons ranges from three to seven • Names end with suffix –ose • If sugar is aldehyde group- known as aldose • If sugar is ketone group- known as keose • Also may be known as trioses, pentoses, or hexoses

5. Disaccharides • When two monosaccharides undergo dehydration reaction • Common Disaccharides include lactose, maltose, and sucrose • Lactose- contains monomers of glucose and galactose (milk) • Maltose- formed by dehydrated reaction between two glucose molecules • Sucrose (sugar)- composed of monomers glucose and fructose

6. Polysaccharides • Long chain of monosaccharides linked by covalent bonds • Starch, glycogen, cellulose, and chitin • Starch- form of sugars in plants- able to synthesize glucose and stored as starch • Glycogen- form of glucose in humans made of monomers of glucose • Cellulose- cell walls of plants which provides support to cell • Chitin- nitrogenous carbohydrate

7. Lipids- Characteristics • Largely nonpolar in nature • Hydrocarbons that include mostly nonpolar carbon-hydrogen bonds • Insoluble in water • Cells store energy for long-term use in form of fats • Provide insulation from environment- help keep aquatic animals dry • Include fats, oils, waxes, phospholipids, and steroids

8. Fats and Oils • Fatty acids can be saturated or unsaturated- only single bonds between carbons • Unsaturated fats are liquid at room temperature and are called oils • Monounsaturated (one double bond, olive oil) or polyunsaturated (more than one double bond, canola oil) • Saturated fats get packed tightly and are solid at room temperature • Unsaturated fats usually of plant origin • Essential fatty acids are required but not synthesized by human body

9. Phospholipids • Major constituent of plasma membrane • Composed of fatty acid chains attached to glycerol • Phosphate group modified by addition of an alcohol • Both hydrophobic and hydrophilic regions • Fatty acid chains are hydrophobic • Phosphate is hydrophilic • Cells surrounded by membrane- face away from water

10. Steroids and Waxes • Cholesterol is a steroid- synthesized in liver and is precursor of many steroid hormones such as testosterone • Waxes are made up of hydrocarbon chain with an alcohol group and fatty acid • Beeswax and lanolin- plants also contain waxes on their leaves

11. Proteins • One of most abundant organic molecules in living systems • Structural, regulatory, contractile, or protective • Serve in transport, storage, or membranes • Functions are very diverse- can be either enzymes or hormones • Different shapes and molecular weights • Amino acids are monomers that make up proteins • Sequence and number determines protein shape, size, and function

12. Protein Structure • Unique sequence for every protein is determined by gene that encodes protein • Secondary structure- patterns from interactions between non-R group portions of amino acids • Tertiary structure- caused by chemical interactions between various amino acids • Quaternary structure- proteins formed from several polypeptides • Denaturation- when protein structure loses shape- often reversible

13. Function of Proteins

14. Structure of Nucleic Acids • DNA and RNA • DNA- genetic material • RNA- protein synthesis • Made up of monomers • DNA has double-helical structure- composed of two strands formed with bonds between phosphate and sugar groups

15. DNA and RNA • DNA: • Heritable information passed along to each generation of cells • Strands are unzipped with small amount of energy when DNA needs to replicate • Transcribed into RNA • RNA: • Messenger- transports information to make a protein from nucleus to cytoplasm • Ribosomal, transfer, small nuclear, and microRNA

16. Types of Biological Macromolecules • Carbohydrates- vital energy source for cell, provide structural support, and found on surface of cell- monosaccharides, disaccharides, polysaccharides • Lipids- nonpolar and hydrophobic in nature- fats and oils, waxes, phospholipids, and steroids • Proteins- help in metabolism by providing structural support- primary, secondary, tertiary, and quaternary • Nucleic acids- molecules made up of repeating units of nucleotides that direct cellular activities- DNA and RNA

17. Quick Review • Why is it said that life is carbon-based and what are the bonding properties of carbon? • How can you distinguish between monosaccharides, disaccharides, and polysaccharides? • What are several major functions of carbohydrates? • Can you distinguish between different kinds of lipids? Identify several major functions? • What are the component parts of proteins? • Can you define the different layers of protein structure? • Are you able to identify several major functions of proteins? • Please describe the basic structure of nucleic acids? • What are the differences/similarities between structure of DNA & RNA? • Can you define “macromolecule” and distinguish between the 4 classes?