Dehydration Synthesis & Hydrolysis

Monomers and Polymers Monomer- subunit or building block Polymer- large molecule made up of many parts

Forming Polymers Dehydration Synthesis - joining monomers to make polymers by losing water De = without or to lose Hydro=water Synthesis = to make polymer “remove water make a bond”

Breaking Polymers Hydrolysis - breaking polymers into monomers by adding water Hydro = water Lysis = to break “add water break a bond”

Dehydration Synthesis

Dehydration Synthesis H2O

Dehydration Synthesis

(a) Dehydration reaction in the synthesis of maltose Fig. 5-5 1–4 glycosidic linkage Glucose Glucose Maltose (a) Dehydration reaction in the synthesis of maltose 1–4 glycosidic linkage Figure 5.5 Examples of disaccharide synthesis Glucose Fructose Sucrose (b) Dehydration reaction in the synthesis of sucrose

Hydrolysis H2O

Dehydration synthesis to make disaccharide Remove water from here - one oxygen atom left behind

Dehydration Synthesis to make a molecule of Fat

Dehydration Synthesis to make a Small Protein (dipeptide)

Carbohydrates serve as fuel and building material Carbohydrates include sugars and the polymers of sugars The simplest carbohydrates are monosaccharides, or single sugars Carbohydrate macromolecules are polysaccharides, polymers composed of many sugar building blocks Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Sugars Monosaccharides have molecular formulas that are usually multiples of CH2O C H O 1:2:1 Glucose (C6H12O6) is the most common monosaccharide Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Disaccharides to know: Glucose + glucose = maltose Glucose + fructose = sucrose (table sugar) Glucose + galactose = lactose (milk sugar) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Polysaccharides Polysaccharides, the polymers of sugars, have storage and structural roles The structure and function of a polysaccharide are determined by its sugar monomers and the positions of glycosidic linkages Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Energy Storage Polysaccharides Starch, a storage polysaccharide of plants, consists entirely of glucose monomers Plants store surplus starch as granules within chloroplasts and other plastids Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Glycogen is a storage polysaccharide in animals Humans and other vertebrates store glycogen mainly in liver and muscle cells Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Structural Polysaccharides The polysaccharide cellulose is a major component of the tough wall of plant cells Like starch, cellulose is a polymer of glucose, but the carbon 1,4 bonds differ Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

(b) Starch: 1–4 linkage of  glucose monomers Fig. 5-7bc (b) Starch: 1–4 linkage of  glucose monomers Figure 5.7 Starch and cellulose structures (c) Cellulose: 1–4 linkage of  glucose monomers

Cell walls Cellulose microfibrils in a plant cell wall Microfibril Fig. 5-8 Cell walls Cellulose microfibrils in a plant cell wall Microfibril 10 µm 0.5 µm Cellulose molecules Figure 5.8 The arrangement of cellulose in plant cell walls Glucose monomer

Some microbes use enzymes to digest cellulose Enzymes that digest starch by hydrolyzing  can’t break bond in cellulose Cellulose in human food passes through the digestive tract as insoluble fiber Some microbes use enzymes to digest cellulose Many herbivores, from cows to termites, have symbiotic relationships with these microbes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-9 Figure 5.9 Cellulose-digesting prokaryotes are found in grazing animals such as this cow

Chitin, another structural polysaccharide, is found in the exoskeleton of arthropods Chitin also provides structural support for the cell walls of many fungi Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

(a) The structure of the chitin monomer. (b) (c) Chitin forms the Fig. 5-10 (a) The structure of the chitin monomer. (b) Chitin forms the exoskeletons of arthropods and found in fungal cell walls. (c) Chitin is used to make a strong and flexible surgical thread. Figure 5.10 Chitin, a structural polysaccharide

Time for you to take notes lipids (focus on only what is highlighted in RED)

Lipids are a diverse group of hydrophobic molecules Lipids are the one class of large biological molecules that do not form polymers Lipids do not interact with water Lipids are hydrophobic becausethey consist mostly of hydrocarbons, which form nonpolar covalent bonds The most biologically important lipids are fats, phospholipids, and steroids Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fats Fats are constructed from two types of smaller molecules: glycerol and fatty acids Glycerol is a three-carbon alcohol with a hydroxyl group (-OH)attached to each carbon A fatty acid consists of a carboxyl group attached to a long carbon carbon and hydrogen chain Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fat molecule (triacylglycerol) Fig. 5-11b Ester linkage Figure 5.11 The synthesis and structure of a fat, or triacylglycerol (b) Fat molecule (triacylglycerol)

Unsaturated fatty acids have one or more double bonds See note page for information on saturated vs. unsaturated fats and follow along. Fatty acids vary in length (number of carbons) and in the number and locations of double bonds Saturated fatty acids have the maximum number of hydrogen atoms possible and no double bonds Unsaturated fatty acids have one or more double bonds Animation: Fats Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Most animal fats are saturated Fats made from saturated fatty acids are called saturated fats, and are solid at room temperature Most animal fats are saturated Fats made from unsaturated fatty acids are called unsaturated fats or oils, and are liquid at room temperature Plant fats and fish fats are usually unsaturated Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

A diet rich in saturated fats may contribute to cardiovascular disease through plaque deposits Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The major function of fats is energy storage Humans and other mammals store their fat in adipose cells Adipose tissue also cushions vital organs and insulates the body Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Phospholipids In a phospholipid, two fatty acids and a phosphate group are attached to glycerol The two fatty acid tails are hydrophobic (“water-fearing”, but the phosphate group and its attachments form a hydrophilic head (“water-loving”) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Know this diagram: Choline Hydrophilic head Phosphate Glycerol Fig. 5-13 Choline Hydrophilic head Phosphate Glycerol Know this diagram: Fatty acids Hydrophobic tails Hydrophilic head Figure 5.13 The structure of a phospholipid Hydrophobic tails (a) Structural formula (b) Space-filling model (c) Phospholipid symbol

Draw a labeled picture of cell membrane Fig. 5-14 Draw a labeled picture of cell membrane (outside of cell) Hydrophilic head WATER Figure 5.14 Bilayer structure formed by self-assembly of phospholipids in an aqueous environment Hydrophobic tail (Cytoplasm of cell) WATER

Steroids Steroids are lipids characterized by a carbon skeleton consisting of four fused rings Cholesterol, an important steroid, is a component in animal cell membranes Although cholesterol is essential in animals, high levels in the blood may contribute to cardiovascular disease For the Cell Biology Video Space Filling Model of Cholesterol, go to Animation and Video Files. For the Cell Biology Video Stick Model of Cholesterol, go to Animation and Video Files. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Steroids Cholesterol Draw only the rings In orange to represent Fig. 5-15 Steroids Draw only the rings In orange to represent The steroid. Figure 5.15 Cholesterol, a steroid Cholesterol

Proteins account for more than 50% of the dry mass of most cells 8. Proteins have many structures, resulting in a wide range of functions Proteins account for more than 50% of the dry mass of most cells Protein functions include structural support, storage, transport, cellular communications, movement, and defense against foreign substances, & ENZYMES Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

What Enzymes Do

Table 5-1 Table 5-1

Enzymes have specific shapes 12. Enzymes are a type of protein that acts as a catalyst to speed up chemical reactions Enzymes can perform their functions repeatedly, functioning as workhorses that carry out the processes of life Enzymes have specific shapes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Substrate (sucrose) Glucose Enzyme (sucrase) OH H2O Fructose H O Fig. 5-16 Substrate (sucrose) Glucose Enzyme (sucrase) OH H2O Fructose Figure 5.16 The catalytic cycle of an enzyme H O

2. Polypeptides Polypeptides are polymers built from the same set of 20 amino acids A protein consists of one or more polypeptides Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

(1, 2, 3) Amino Acid Monomers Amino acids are organic molecules with carboxyl (-COOH) and amino groups (NH2) COOH and NH2 are functional groups and make the molecule an amino acid. Amino acids differ in their properties due to differing side chains, called R groups Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig. 5-UN1  carbon Amino group Carboxyl group

Substitute in a hydrogen (H) for R and the amino acid is glycine

4. These are amino acids. There are 20. They bond together by peptide Fig. 5-17 Nonpolar 4. These are amino acids. There are 20. They bond together by peptide bonds to make up all proteins! Glycine (Gly or G) Alanine (Ala or A) Valine (Val or V) Leucine (Leu or L) Isoleucine (Ile or I) Methionine (Met or M) Phenylalanine (Phe or F) Trypotphan (Trp or W) Proline (Pro or P) Polar Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y) Asparagine (Asn or N) Glutamine (Gln or Q) Figure 5.17 The 20 amino acids of proteins Electrically charged Acidic Basic Aspartic acid (Asp or D) Glutamic acid (Glu or E) Lysine (Lys or K) Arginine (Arg or R) Histidine (His or H)

Amino Acid Polymers Amino acids are linked by special covalent bonds called peptide bonds A polypeptide is a polymer of amino acids Each polypeptide has a unique linear sequence of amino acids Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Peptide bond (a) Peptide bond (b) Fig. 5-18 Figure 5.18 Making a polypeptide chain (b)

Dehydration Synthesis to make a polypeptide (or protein) Remove water from here

Protein Structure and Function A functional protein consists of one or more polypeptides twisted, folded, and coiled into a unique shape Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Shape determines function Fig. 5-19 Shape determines function Groove Groove Figure 5.19 Structure of a protein, the enzyme lysozyme (a) A ribbon model of lysozyme (b) A space-filling model of lysozyme

A protein’s shape determines its function The sequence of amino acids determines a protein’s three-dimensional structure A protein’s shape determines its function Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

This loss of a protein’s structure or shape is called denaturation What Determines Protein Structure? Remember these things about liver lab In addition to primary structure, physical and chemical conditions can affect structure Alterations in pH, salt concentration, temperature, or other environmental factors can cause a protein to unravel This loss of a protein’s structure or shape is called denaturation A denatured protein is biologically inactive Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Denaturation Normal protein Denatured protein Renaturation Fig. 5-23 Figure 5.23 Denaturation and renaturation of a protein Normal protein Denatured protein Renaturation

Fig. 5-UN5