Biochemistry of Cells Copyright Cmassengale 1 Carbonbased Molecules

Biochemistry of Cells Copyright Cmassengale 1

Carbon-based Molecules Although a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules Organic chemistry is the study of carbon compounds Copyright Cmassengale 2

Carbon is a Versatile Atom It has four electrons in an outer shell that holds eight Copyright Cmassengale 3

Carbon can use its bonds to: : Attach to other carbons Form an endless diversity of carbon skeletons Copyright Cmassengale 4

Hydrocarbons The simplest carbon compounds … Contain only carbon & hydrogen atoms Copyright Cmassengale 5

Large Hydrocarbons: Are the main molecules in the gasoline we burn in our cars The hydrocarbons of fat molecules provide energy for our bodies Copyright Cmassengale 6

Shape of Organic Molecules Each type of organic molecule has a unique three -dimensional shape Copyright Cmassengale 7

Uses of Organic Molecules Americans consume an average of 140 pounds of sugar person per year Cellulose, found in plant cell walls, is the most abundant organic compound on Earth Copyright Cmassengale 8

Uses of Organic Molecules A typical cell in your body has about 2 meters of DNA A typical cow produces over 200 pounds of methane gas each year Copyright Cmassengale 9

Functional Groups are: Groups of atoms that give properties to the compounds to which they attach Lost Electrons Gained Electrons Copyright Cmassengale 10

Common Functional Groups Copyright Cmassengale 11

Giant Molecules - Polymers Large molecules are called polymers Polymers are built from smaller molecules called monomers Biologists call them macromolecules Copyright Cmassengale 12

Examples of Polymers Proteins Lipids Carbohydrates Nucleic Acids Copyright Cmassengale 13

Most Macromolecules are Polymers are made by stringing together many smaller molecules called monomers Nucleic Acid Monomer Copyright Cmassengale 14

Linking Monomers Cells link monomers by a process called Remove H H 2 O Forms Remove OH Copyright Cmassengale 15

Breaking Down Polymers Cells break down macromolecules by a process called hydrolysis (adding a molecule of water) Water added to split a double sugar Copyright Cmassengale 16

Macromolecules in Organisms There are four categories of large molecules in cells: Copyright Cmassengale 17

Carbohydrates include: Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes Copyright Cmassengale 18

Monosaccharides: Called simple sugars Include glucose, fructose, & galactose Have the same chemical, but different structural formulas Copyright Cmassengale 19

Monosaccharides Glucose is found in sports drinks Fructose is found in fruits Honey contains both glucose & fructose Galactose is called “milk sugar” -OSE ending means SUGAR Copyright Cmassengale 20

Isomers Glucose & fructose are isomers because they’re structures are different, but their chemical formulas are the same Copyright Cmassengale 21

Rings In aqueous (watery) solutions, monosaccharides form ring structures Copyright Cmassengale 22

Cellular Fuel Monosaccharides are the main fuel that cells use for cellular work ATP Copyright Cmassengale 23

Disaccharides A disaccharide is a double sugar They’re made by joining two monosaccharides Involves removing a water molecule (condensation) Bond called a GLYCOSIDIC bond Copyright Cmassengale 24

Disaccharides Common disaccharides include: Copyright Cmassengale 25

Disaccharides Sucrose is composed of glucose + fructose Maltose is composed of 2 glucose molecules Lactose is made of galactose + glucose Copyright Cmassengale GLUCOSE 26

Polysaccharides Complex carbohydrates Composed of many sugar monomers linked together Copyright Cmassengale 27

Examples of Polysaccharides Glucose Monomer Starch Glycogen Cellulose Copyright Cmassengale 28

Starch is an example of a polysaccharide in plants Potatoes and grains are major sources of starch in the human diet Copyright Cmassengale 29

Glycogen is an example of a polysaccharide in animals Animals store excess sugar in the form of glycogen Copyright Cmassengale 30

Cellulose is the most abundant organic compound on Earth It forms cable-like fibrils in the tough walls that enclose plants It is a major component of wood It is also known as dietary fiber Copyright Cmassengale 31

Cellulose SUGARS Copyright Cmassengale 32

Dietary Cellulose Most animals cannot derive nutrition from fiber They have bacteria in their digestive tracts that can break down cellulose Copyright Cmassengale 33

Sugars in Water Simple sugars and double sugars dissolve WATER readily in water MOLECULE They are hydrophilic, or “waterloving” SUGAR MOLECULE Copyright Cmassengale 34

Lipids are hydrophobic –”water fearing” Do NOT mix with water Includes fats, waxes, steroids, & oils FAT MOLECULE Copyright Cmassengale 35

Function of Lipids Fats store energy, help to insulate the body, and cushion and protect organs Copyright Cmassengale 36

Triglyceride Monomer of lipids Composed of Glycerol & 3 fatty acid chains Glycerol forms the “backbone” of the fat Organic Alcohol ( -OL ending) Copyright Cmassengale 37

Types of Fatty Acids Saturated fatty acids Unsaturated fatty acids h Copyright Cmassengale 38

Types of Fatty Acids Single Bonds in Carbon chain Double bond in carbon chain Copyright Cmassengale 39

Triglyceride Glycerol Fatty Acid Chains Copyright Cmassengale 40

Fats in Organisms Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening) Copyright Cmassengale 41

Fats in Organisms Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils) Copyright Cmassengale 42

Fats Dietary fat consists largely of the molecule triglyceride composed of glycerol and three fatty acid chains Fatty Acid Chain Glycerol Condensation links the fatty acids to Glycerol Copyright Cmassengale 43

Lipids & Cell Membranes • Cell membranes are made • of lipids called phospholipids Phospholipids have a head • Phospholipids also have 2 tails Copyright Cmassengale 44

Steroids The carbon skeleton of steroids is bent to form 4 fused rings Cholesterol is the “base steroid” from which your body produces other steroids Cholesterol Estrogen Testosterone Estrogen & testosterone are also steroids Copyright Cmassengale 45

Synthetic Anabolic Steroids They are variants of testosterone Some athletes use them to build up their muscles quickly They can pose serious health risks Copyright Cmassengale 46

Proteins are polymers made of monomers called amino acids All proteins are made of 20 different amino acids linked in different orders Copyright Cmassengale 47

Four Types of Proteins Storage Structural Contractile Transport Copyright Cmassengale 48

Structure of Amino Acids Amino acids have a central carbon with 4 things boded to it: Amino group Carboxyl group R group Amino group –NH 2 Carboxyl group -COOH Hydrogen Side group -H Side groups -R Serine-hydrophillic Leucine -hydrophobic Copyright Cmassengale 49

Linking Amino Acids Carboxyl Cells link amino acids together to Amino Side make proteins Group The process is called condensation or dehydration Dehydration Synthesis Peptide Bond Copyright Cmassengale 50

20 Amino Acid Monomers Copyright Cmassengale 51

Primary Protein Structure The primary structure is the specific sequence of amino acids in a protein Called polypeptide Amino Acid Copyright Cmassengale 52

Protein Structures Secondary protein structures occur when protein chains coil or fold When protein chains called polypeptides join together, the tertiary structure forms because R groups interact with each other In the watery environment of a cell, proteins become globular in their quaternary structure Copyright Cmassengale 53

Protein Structures or CONFORMATIONS Hydrogen bond Pleated sheet Amino acid Polypeptide (single subunit) (a) Primary structure Hydrogen bond Alpha helix (b) Secondary structure (c) Tertiary structure (d) Quaternary structure Copyright Cmassengale 54

Proteins as Enzymes Many proteins act as biological catalysts or enzymes Thousands of different enzymes exist in the body Copyright Cmassengale 55

Enzymes are globular proteins. Their folded conformation creates an area known as the active site. The nature and arrangement of amino acids in the active site make it specific for only one type of substrate. Copyright Cmassengale 56

Enzyme + Substrate = Product Copyright Cmassengale 57

How the Enzyme Works Enzymes are reusable!!! Active site changes SHAPE Called INDUCED FIT Copyright Cmassengale 58

Denaturating Proteins Changes in temperature & p. H can denature (unfold) a protein so it no longer works Cooking denatures protein in eggs Milk protein separates into curds & whey when it denatures Copyright Cmassengale 59

Changing Amino Acid Sequence Substitution of one amino acid for another in hemoglobin causes sickle-cell disease 1 2 (b) Sickled red blood cell 6 7. . . 146 4 5 Normal hemoglobin (a) Normal red blood cell 1 3 2 3 6 7. . . 146 4 5 Sickle-cell hemoglobin Copyright Cmassengale 60

Other Important Proteins • Blood sugar level is controlled by a protein called insulin • Insulin causes the liver to uptake and store excess sugar as Glycogen Copyright Cmassengale 61

INSULIN Cell membrane with proteins & phospholipids Copyright Cmassengale 62

Nucleic Acids Store hereditary information Contain information for making all the body’s proteins Two types exist --- DNA & RNA Copyright Cmassengale 63

Copyright Cmassengale 64

Nucleic Acids Nitrogenous base (A, G, C, or T) Nucleic acids are polymers of nucleotides Phosphate group Thymine (T) Sugar (deoxyribose) Phosphate Base Sugar Nucleotide Copyright Cmassengale 65

Nucleotide – Nucleic acid monomer Copyright Cmassengale 66

Bases Each DNA nucleotide has one of the following bases: Thymine (T) Adenine (A) Copyright Cmassengale Cytosine (C) Guanine (G) 67

Nucleotide Monomers Backbone Form long chains called DNA Nucleotides are joined by sugars & phosphates on the side Bases DNA string Copyright Cmassengale 68

DNA Base pair Double helix Copyright Cmassengale 69

RNA – Ribonucleic Acid Nitrogenous base (A, G, C, or U) Ribose sugar has an extra –OH or hydroxyl group It has the base uracil (U) instead of thymine (T) Uracil Phosphate group Sugar (ribose) Copyright Cmassengale 70

ATP – Cellular Energy • ATP is used by cells for energy • Adenosine triphosphate • Made of a nucleotide with 3 phosphate groups Copyright Cmassengale 71

Summary of Key Concepts Copyright Cmassengale 72

Nucleic Acids Copyright Cmassengale 73

Macromolecules Copyright Cmassengale 74

Macromolecules Copyright Cmassengale 75

End Copyright Cmassengale 76