Chapter - Molecules of Life

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Molecules of Life : 

Molecules of Life Chapter 3 Part 1

From Chapter One….. : 

From Chapter One….. “The pattern (of biological organization) reaches the threshold of life as certain molecules are assembled as cells. Complex carbohydrates, complex fats and other lipids, proteins, DNA, and RNA=these are the molecules of life.” A CELL is the smallest unit of life; it has a capacity to survive and reproduce on its own, given raw materials, an energy source, information encoded in its DNA, and suitable environmental conditions.

Impacts, Issues:Fear of Frying : 

Impacts, Issues:Fear of Frying Trans fats in hydrogenated vegetable oil raise levels of cholesterol in our blood more than any other fat, and directly alter blood vessel function

Organic Molecules : 

Organic Molecules The molecules of life are called ORGANIC This means they are Carbon based and contain at least one Hydrogen We can use different models to highlight different aspects of the same molecule

3.1 Carbon – The Stuff of Life : 

3.1 Carbon – The Stuff of Life Organic molecules are complex molecules of life, built on a framework of carbon atoms Carbohydrates Lipids Proteins Nucleic acids

Carbon – The Stuff of Life : 

Carbon – The Stuff of Life Carbon atoms can be assembled and remodeled into many organic compounds How many electrons in the outer shell of carbon? 4 So, Carbon can form a bond with up to 4 other atoms to fill its shell Carbon can form polar or nonpolar bonds Can form chains or rings

Carbon Rings : 

Carbon Rings

Representing Structures of Organic Molecules : 

Representing Structures of Organic Molecules Structural model of an organic molecule Each line is a covalent bond; two lines are double bonds; three lines are triple bonds

Molecular Formulas : 

Molecular Formulas Molecular formula=# of each type of atom (count them up) How many carbons in glucose? 6 How many hydrogens in glucose? 12 How many oxygens in glucose? 6 So what is the molecular formula for glucose? C6H12O6

Representing Structures of Organic Molecules : 

Representing Structures of Organic Molecules Carbon ring structures are represented as polygons; carbon atoms are implied

Representing Structures of Organic Molecules : 

Representing Structures of Organic Molecules Ball-and-stick models show positions of atoms in three dimensions; elements are coded by color

Representing Structures of Organic Molecules : 

Representing Structures of Organic Molecules Space-filling models show how atoms sharing electrons overlap

Three Models of a Hemoglobin Molecule : 

Three Models of a Hemoglobin Molecule

Slide 14: 

red blood cell Fig. 3-3 (top), p. 37

Slide 15: 

Fig. 3-3a, p. 37 A A space-filling model of hemoglobin shows the complexity of the molecule.

Slide 16: 

Fig. 3-3b, p. 37 B A surface model of the same molecule reveals crevices and folds that are important for its function. Heme groups, in red, are cradled in pockets of the molecule.

Slide 17: 

Fig. 3-3c, p. 37 C A ribbon model of hemoglobin shows all four heme groups, also in red, held in place by the molecule’s coils.

3.2 From Structure to Function : 

3.2 From Structure to Function The Structure of biological molecules dictate their Function The arrangement of their bonds is the key to knowing the difference between the carbohydrates, lipids, proteins and nucleic acids

Functional Groups : 

Functional Groups Hydrocarbon Carbon + hydrogen Most biological molecules have at least one functional group A cluster of atoms that imparts specific chemical properties to a molecule (polarity, acidity)

Common Functional Groupsin Biological Molecules : 

Common Functional Groupsin Biological Molecules

Slide 21: 

Fig. 3-4, p. 38 Stepped Art

Effects of Functional Groups: Sex Hormones : 

Effects of Functional Groups: Sex Hormones

Slide 23: 

Fig. 3-5a, p. 38 one of the estrogens testosterone

Slide 24: 

Fig. 3-5b, p. 38 female wood duck male wood duck

What Cells Do to Organic Compounds : 

What Cells Do to Organic Compounds Metabolism Activities by which cells acquire and use energy to construct, rearrange, and split organic molecules Allows cells to live, grow, and reproduce Requires enzymes (proteins that increase the speed of reactions)

What Cells Do to Organic Compounds : 

What Cells Do to Organic Compounds Monomers Molecules used as subunits to build larger molecules (polymers) Polymers Larger molecules that are chains of monomers May be split and used for energy

Slide 27: 

Fig. 3-6, p. 39 B) Hydrolysis. A molecule splits, then an —OH group and an H atom from a water molecule become attached to sites exposed by the reaction. A) Condensation. An —OH group from one molecule combines with an H atom from another. Water forms as the two molecules bond covalently. Stepped Art

Monomer to Polymer : 

Monomer to Polymer Condensation Covalent bonding of two molecules to form a larger molecule Water forms as a product

Polymer to Monomer : 

Polymer to Monomer Hydrolysis The reverse of condensation Cleavage reactions split larger molecules into smaller ones Water is split

What Cells Do to Organic Compounds : 

What Cells Do to Organic Compounds

Condensation and Hydrolysis : 

Condensation and Hydrolysis

Animation: Condensation and hydrolysis : 

Animation: Condensation and hydrolysis

3.1-3.2 Key Concepts:Structure Dictates Function : 

3.1-3.2 Key Concepts:Structure Dictates Function We define cells partly by their capacity to build complex carbohydrates and lipids, proteins, and nucleic acids All of these organic compounds have functional groups attached to a backbone of carbon atoms

3.3 Carbohydrates : 

3.3 Carbohydrates Carbohydrates are the most plentiful biological molecules in the biosphere Cells use some carbohydrates as structural materials; others for stored or instant energy

Carbohydrates : 

Carbohydrates Carbohydrates Organic molecules that consist of carbon, hydrogen, and oxygen in a 1:2:1 ratio Three types of carbohydrates in living systems Monosaccharides Oligosaccharides Polysaccharides

Simple Sugars : 

Simple Sugars Monosaccharides (one sugar unit) are the simplest carbohydrates Used as an energy source or structural material Backbones of 5 or 6 carbons Example: glucose Please note numbering of carbons

Short-Chain Carbohydrates : 

Short-Chain Carbohydrates Oligosaccharides Short chains of monosaccharides Example: sucrose, a disaccharide (table sugar)

Slide 38: 

Fig. 3-7b, p. 40 glucose + fructose sucrose + water

Slide 39: 

Fig. 3-7b, p. 40 Stepped Art

Complex Carbohydrates : 

Complex Carbohydrates Polysaccharides Straight or branched chains of many sugar monomers The most common polysaccharides are cellulose, starch, and glycogen All consist of glucose monomers Each has a different pattern of covalent bonding, and different chemical properties

Cellulose, Starch, and Glycogen : 

Cellulose, Starch, and Glycogen

Different Organism, Different Complex Carbohydrate : 

Different Organism, Different Complex Carbohydrate Glycogen: main storage product in ANIMALS Cellulose: complex carbohydrate made in PLANTS, we can’t digest This is “Dietary Fiber” Amylose (starch) Main storage product in PLANTS Chitin Ticks, fungi, spider

Slide 43: 

Fig. 3-8a, p. 41 Cellulose

Slide 44: 

Fig. 3-8b, p. 41 amylose

Slide 45: 

Fig. 3-8c, p. 41 glycogen

Chitin : 

Chitin Chitin A nitrogen-containing polysaccharide that strengthens hard parts of animals such as crabs, and cell walls of fungi

3.3 Key Concepts:Carbohydrates : 

3.3 Key Concepts:Carbohydrates Carbohydrates are the most abundant biological molecules They function as energy reservoirs and structural materials Different types of complex carbohydrates are built from the same subunits of simple sugars, bonded in different patterns

3.4 Greasy, Oily – Must Be Lipids : 

3.4 Greasy, Oily – Must Be Lipids Lipids function as the body’s major energy reservoir, and as the structural foundation of cell membranes Lipids Fatty, oily, or waxy organic compounds Insoluble in water (hydrophobic)

Fatty Acids : 

Fatty Acids Many lipids incorporate fatty acids Simple organic compounds with a carboxyl group joined to a backbone of 4 to 36 carbon atoms Essential fatty acids are not made by the body and must come from food Omega-3 and omega-6 fatty acids

Fatty Acids : 

Fatty Acids Saturated, monounsaturated, polyunsaturated

Slide 51: 

Fig. 3-10, p. 42 stearic acid oleic acid linolenic acid

Fats : 

Fats Fats Lipids with one, two, or three fatty acids “tails” attached to glycerol Triglycerides Neutral fats with three fatty acids attached to glycerol The most abundant energy source in vertebrates Concentrated in adipose tissues (for insulation and cushioning)

Triglycerides : 

Triglycerides

Slide 54: 

Fig. 3-11a, p. 42 triglyceride, a neutral fat three fatty acid tails + 3H2O glycerol

Slide 55: 

Fig. 3-11b, p. 42

Animation: Triglyceride formation : 

Animation: Triglyceride formation

Saturated and Unsaturated Fats : 

Saturated and Unsaturated Fats Saturated fats (animal fats) Fatty acids with only single covalent bonds Pack tightly; solid at room temperature Unsaturated fats (vegetable oils) Fatty acids with one or more double bonds Kinked; liquid at room temperature

Trans Fats : 

Trans Fats Trans fats Partially hydrogenated vegetable oils formed by a chemical hydrogenation process Double bond straightens the molecule Pack tightly; solid at room temperature

Cis and Trans Fatty Acids : 

Cis and Trans Fatty Acids

Phospholipids : 

Phospholipids Phospholipids Molecules with a polar head containing a phosphate and two nonpolar fatty acid tails Heads are hydrophilic, tails are hydrophobic The most abundant lipid in cell membranes

Phospholipids : 

Phospholipids

Slide 62: 

Fig. 3-13a, p. 43

Slide 63: 

Fig. 3-13b, p. 43 hydrophilic head two hydrophobic tails

Slide 64: 

Fig. 3-13c, p. 43 c Cell membrane section

Waxes : 

Waxes Waxes Complex mixtures with long fatty-acid tails bonded to long-chain alcohols or carbon rings Protective, water-repellant covering

Wax : 

Wax

Cholesterol and Other Steroids : 

Cholesterol and Other Steroids Steroids Lipids with a rigid backbone of four carbon rings and no fatty-acid tails Cholesterol Component of eukaryotic cell membranes Remodeled into bile salts, vitamin D, and steroid hormones (estrogens and testosterone)

Cholesterol : 

Cholesterol

3.4 Key Concepts:Lipids : 

3.4 Key Concepts:Lipids Lipids function as energy reservoirs and waterproofing or lubricating substances Some are remodeled into other substances Lipids are the main structural components of cell membranes

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