The Amazing Molecule: Water

All living things are made of chemicals. Understanding life requires an understanding of chemistry. Biochemistry- the chemistry of life helps us understand todays biological questions!

Covers 75% of the earths surface Single most abundant compound in all living things Average male = 60% water Average female = 50% water Average infant = 73% water

H 2 O Neutral Molecule 10 protons 10 electrons

With 8 protons in its nucleus, an oxygen atom has a much stronger attraction for electrons than does a hydrogen atom with its single proton. The oxygen end of the molecule has a slight negative charge and the hydrogen end of the molecule has a slight positive charge

The attraction between a hydrogen atom on one water molecule and the oxygen atom Because of their partial positive and negative charges, polar molecules such as water can attract each other.

Cohesion Adhesion Surface tension High Heat of Vaporization Universal Solvent Facilitate Chemical Reactions

water molecules are drawn together, which is why drops of water form beads on a smooth surface. Cohesion also produces surface tension, explaining why some insects and spiders can walk on a pond s surface.

attraction between molecules of different substances. a meniscus: because the adhesion between water molecules and glass molecules is stronger than the cohesion between water molecules.

A result of Cohesion explaining why some insects and spiders can walk on a pond s surface

large amount of heat energy is needed to cause those molecules to move faster and raise the temperature of the water until becomes vapor Large bodies of water (oceans and lakes) can absorb large amounts of heat with only small changes in temperature. This protects organisms living within from drastic changes in temperature

Honor s Biology

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 that are necessary for life 14

It has four electrons in an outer shell that holds eight Carbon can share its electrons with other atoms to form up to four covalent bonds 15

Attach to other carbons Form an endless diversity of carbon skeletons 16

Large molecules are called polymers Polymers are built from smaller molecules called monomers Biologists call them macromolecules 17

Proteins Lipids Carbohydrates Nucleic Acids 18

Polymers are made by stringing together many smaller molecules called monomers Nucleic Acid Monomer 19

Cells link monomers by a process called dehydration synthesis (removing a molecule of water) Remove H H 2 O Forms Remove OH This process joins two sugar monomers to make a double sugar 20

Also called condensation reaction Forms polymers by combining monomers by removing water. HO H HO H H 2 O HO H 21

Cells break down macromolecules by a process called hydrolysis (adding a molecule of water) Water added to split a double sugar 22

Separates monomers by adding water HO H H 2 O HO H HO H 23

Carbohydrates: Made up of monosaccharides Lipids: Made up of glycerol and fatty acid molecules Proteins: Made up of Amino acids Nucleic acids: Made up of nucleotides 24

Carbohydrates are made up of simple sugars (monosaccharides): Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes Copyright Cmassengale 25

CHO Examples: A. monosaccharide B. disaccharide C. polysaccharide 27

Monosaccharide: one sugar unit Examples: Glucose (C 6 H 12 O 6 ) Fructose Galactose glucose 28

Glucose is found in sports drinks Fructose is found in fruits Galactose is called milk sugar -OSE ending means SUGAR 29

Glucose & fructose are isomers because their structures are different, but their chemical formulas are the same 30

Disaccharide: two sugar unit Examples: Sucrose (glucose+fructose) Lactose (glucose+galactose) Maltose (glucose+glucose) glucose glucose 31

A disaccharide is a double sugar They re made by joining two monosaccharides Involves removing a water molecule (dehydration synthesis) 32

Polysaccharide: many sugar units Examples: starch (bread, potatoes) glycogen (stored in liver) cellulose (lettuce, corn) glucose glucose glucose glucose cellulose glucose glucose glucose glucose 33

Complex carbohydrates Composed of many sugar monomers linked together Polymers of monosaccharide chains 34

Glucose Monomer Starch Glycogen Cellulose 35

Starch is an example of a polysaccharide in plants Plant cells store starch for energy Potatoes and grains are major sources of starch in the human diet 36

Glycogen is an example of a polysaccharide in animals Animals store excess sugar in the form of glycogen Glycogen is similar in structure to starch because BOTH are made of glucose monomers 37

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 38

SUGARS 39

Most animals cannot derive nutrition from fiber They have bacteria in their digestive tracts that can break down cellulose 40

Simple sugars and double sugars dissolve readily in water They are hydrophilic, or waterloving WATER MOLECULE -OH groups make them water soluble SUGAR MOLECULE 41

Do NOT mix with water Lipids are hydrophobic water fearing CHO FAT MOLECULE 42

General term for compounds which are not soluble in water. Lipids are soluble in hydrophobic solvents. stores the most energy Examples: 1. Fats 2. Phospholipids 3. Oils 4. Waxes 5. Steroid hormones 6. Triglycerides 43

Five functions of lipids: 1. Long term energy storage 2. Protection against heat loss (insulation) 3. Protection against physical shock 4. Chemical messengers (hormones) 5. Major component of membranes (phospholipids) 44

Triglycerides: composed of 1 glycerol and 3 fatty acids. H H-C----O H-C----O H-C----O H O C-CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 3 O C-CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 3 O C-CH 2 -CH 2 -CH 2 -CH fatty acids glycerol 45

Glycerol Fatty Acid Chains 46

Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons) Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons) 47

Single Bonds in Carbon chain Double bond in carbon chain 48

Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening) 49

Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils) 50

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 51

Cell membranes are made of lipids called phospholipids Phospholipids have a head that is polar & attract water (hydrophilic) Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic) 52

The carbon skeleton of steroids is bent to form 4 fused rings Cholesterol Cholesterol is the base steroid from which your body produces other steroids Testosterone Estrogen & testosterone are also steroids Estrogen 53

Proteins are polymers made of monomers called amino acids CHONS All proteins are made of 20 different amino acids linked in different orders Proteins are used to build cells, act as hormones & enzymes, and do much of the work in a cell 55

Amino acids have a central carbon with 4 things boded to it: Amino group NH 2 Carboxyl group -COOH Hydrogen -H Variable group -R 57

Cells link amino acids together to make proteins The process is called dehydration synthesis Peptide bonds form to hold the amino acids together 59

Four levels of protein structure: A. Primary Structure B. Secondary Structure C. Tertiary Structure D. Quaternary Structure 60

Hydrogen bond Hydrogen bond 61

Amino acids bonded together by peptide bonds (straight chains) Amino Acids (aa) aa1 aa2 aa3 aa4 aa5 aa6 Peptide Bonds 62

The primary structure is the specific sequence of amino acids in a protein Called polypeptide Amino Acid 63

Secondary protein structures occur when protein chains coil or fold Coil alpha helix Fold beta sheet Results from hydrogen bonds 64

Secondary structures bent and folded into a more complex 3-D arrangement of linked polypeptides Bonds: H-bonds, ionic, disulfide bridges (S-S) Call a subunit. Alpha Helix Beta Pleated Sheet 65

Composed of 2 or more subunits Globular in shape Form in Aqueous environments Example: enzymes (hemoglobin) subunits 66

Substitution of one amino acid for another in hemoglobin causes sickle-cell disease (a) Normal red blood cell 1 2 7... 146 3 6 4 5 Normal hemoglobin (b) Sickled red blood cell 1 2 7... 146 3 6 4 5 Sickle-cell hemoglobin 67

Blood sugar level is controlled by a protein called insulin Insulin causes the liver to uptake and store excess sugar as Glycogen The cell membrane also contains proteins Receptor proteins help cells recognize other cells 68

INSULIN Cell membrane with proteins & phospholipids 69

Enzymes are an important class of catalysts in living organisms Mostly protein Thousands of different kinds Each specific for a different chemical reaction Often end in ase (lactase breaks down lactose)

Enzymes work on substances called substrates Substrates must fit into a place on an enzyme called the active site Enzymes are reusable!

The lactase enzyme breaks the bond between glucose and galactose so you can digest lactose (milk). Lactose free milk contains the same sugars but they are already broken down = easier to digest for those lactose intolerant.

Nucleic acids are composed of long chains of nucleotides linked by dehydration synthesis. CHONP Function: Dictate amino acid sequences/how proteins are made Source of all genetic information Two types: a. Deoxyribonucleic acid (DNA) b. Ribonucleic acid (RNA) 75

Phosphate Group O O=P-O O CH2 C 4 Sugar (deoxyribose) 5 O C 3 C 2 C 1 N Nitrogenous base (A, G, C, or T) 77

Nitrogenous base (A,G,C, or T) Nucleic acids are polymers of nucleotides Phosphate group Thymine (T) Phosphate Sugar (deoxyribose) Sugar Base Nucleotide 79

Nucleotides include: phosphate group pentose sugar (5-carbon) nitrogen bases: adenine (A) thymine (T) DNA only uracil (U) RNA only cytosine (C) guanine (G) 80

Each DNA nucleotide has one of the following bases: Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Thymine (T) Adenine (A) Cytosine (C) Guanine (G) 81

Two strands of DNA join together to form a double helix Base pair Double helix 82

5 O 3 P 3 O 5 P P 5 4 5 3 O O 1 2 T G A C 2 3 1 O 3 4 5 P P 3 83 O 5 P

Ribose sugar has an extra OH or hydroxyl group base uracil (U) instead of thymine (T) 84

ATP is used by cells for energy Adenosine triphosphate Made of a nucleotide with 3 phosphate groups 85

Organic Compounds Lab

A substance used to show the presence of another substance Color change = positive test (the substance is present)

Use it as a control to make sure the indicators are working. No color change with water = indicators are working

Sudan III stain red is a positive test Brown paper bag Lipids leave translucent spots (grease spots)

Starch Iodine- blue/black is a positive test Sugar Benedict s solution **MUST BE HEATED!!!!* blue/green changes to orange/yellow = positive test

Biuret reagent - varying shades of purple = positive test