Molecules of Life

Contain carbon

 Outer shell of carbon has 4 electrons (AKA tetravalent); can hold 8  Each carbon atom can form covalent bonds with up to four other atoms  This electron structure allows carbon to bond with itself easily as well as other atoms (creates a wide variety & abundance or organic compounds)

structural formula for methane ball-and-stick model space-filling model p.34b

 Carbon atoms can form chains or rings  Other atoms project from the carbon backbone

or p.34e Simplified structural formula for a six-carbon ring icon for a six-carbon ring Organic Compounds

 Ex: butane C 4 H 10

 Atoms or clusters of atoms that are covalently bonded to carbon backbone  Give organic compounds their different properties  All are hydrophilic except for one

Hydroxyl group - OH Amino group- NH 3 + Carboxyl group- COOH Phosphate group- PO 3 - Sulfhydryl group- SH Carbonyl -COH Methyl-CH 3

Fig. 3-4, p.36

 Estrogen and testosterone are hormones responsible for observable differences in traits between male and female wood ducks  Differences in position of functional groups attached to ring structure (pg 36) An EstrogenTestosterone

 Large molecules made of many similar smaller building blocks called MONOMERS  Are formed and broken by adding or removing water

 The loss of water  Monomers bond together to make polymers  Requires energy (endothermic)

Condensation Fig. 3-6a, p.38

 Adds water  Breaks polymers into monomers  Gives off energy (exothermic)  Ex: digestion

Hydrolysis Fig. 3-6b, p.38

 Carbohydrates  Lipids  Proteins  Nucleic Acids

The body’s main source of energy Monomer is a monosaccharide Contain carbonyl functional group

 Simplest  General formula is C n H 2n O n  Most have 5- or 6-carbon backbone Glucose (6 C)Fructose (6 C) Ribose (5 C)Deoxyribose (5 C)

glucosefructose Fig. 3-7, p.38

 Type of oligosaccharide  Two monosaccharides covalently bonded by a Glycosidic Bond  Formed by condensation reaction  Ex: sucrose and maltose (isomers) + H 2 O glucosefructose sucrose Fig. 3-7b, p.38

 Straight or branched chains of many sugar monomers linked by condensation  Most are for structural or storage purposes  Ex: ◦ Cellulose—in plant cell wall ◦ Starch (such as amylose)—sugar storage in plants ◦ Glycogen—sugar storage in animal muscle & liver cells (when blood sugar drops, glycogen is broken down to glucose) ◦ Chitin—in arthropod exoskeleton & fungal cell wall

Fig. 3-8, p.38

Fig. 3-9, p.38

 Polysaccharide  Nitrogen-containing groups attached to glucose monomers  Structural material for hard parts of invertebrates, cell walls of many fungi

J0

◦ Fats ◦ Phospholipids ◦ Waxes ◦ steroids  Tend to be insoluble in water (hydrophobic)

 Monomer is 3 Fatty acid(s) attached to glycerol  Triglycerides are most common  Linked by ester bonds Fig. 3-12, p.40

 Carboxyl group (-COOH) at one end  Carbon backbone (up to 36 C atoms) ◦ Saturated - Single bonds between carbons with max. amt. of H ◦ Unsaturated - One or more double C bonds

Three Fatty Acids Fig. 3-11, p.40

 Main components of cell membrane  Monomer is 1 glycerol + Fatty acids

 No fatty acids  four fused-together carbon rings with hydrocarbon tail  Ex:Cholesterol & hormones such as cortisol, testosterone, estrogen, and adrenaline Fig. 3-14, p.41

RIU

 Monomer is amino acids linked by peptide bonds (formed by condensation)

 Enzymes—speed up rxns (Ex: catalase & pepsin)  Contractile—for movement (Ex: myosin in muscle cells)  Structural—in hair & nails (Ex:collagen, elastin, keratin)  Storage Ex: casein  Transport Ex: hemoglobin (contains heme group)  Hormones—Ex: insulin

 Receive signals—Ex: neurotransmitters  Defense—Ex: antibodies

amino group carboxyl group R group

Fig. 3-15b, p.42

 Linear Sequence of amino acids  Two linked amino acids = dipeptide  Three or more = polypeptide  Backbone of polypeptide has N atoms: -N-C-C-N-C-C-N-C-C-N- one peptide group

a Normal amino acid sequence at the start of a beta change for hemoglobin VALINE HISTIDINELEUCINETHREONINEPROLINEGLUTAMATE Fig. 3-18a, p.45

VALINE HISTIDINELEUCINETHREONINEPROLINEVALINEGLUTAMATE b One amino acid substitution results in the abnormal beta chain in HbS molecules. During protein synthesis, valine was added instead of glutamate at the sixth position of the growing polypeptide chain. Fig. 3-18b, p.45

c Glutamate has an overall negative charge; valine has no net charge. The difference gives rise to a water-repellant, sticky patch on HbS molcules. They stick together because of that patch, forming rod- shaped clumps that distort normally rounded red blood cells into sickle shapes. (A sickle is a farm tool that has a crescent-shaped blade.) sickle cell normal cell Fig. 3-18c, p.45

 Hydrogen bonds form between different parts of polypeptide chain  These bonds give rise to coiled or extended pattern  Alpha Helix or beta pleated sheet

Folding as a result of interactions between R groups Involves disulfide bonds heme group coiled and twisted polypeptide chain of one globin molecule

final protein structure formed by interaction of 2 or more polypeptide chains Hemoglobin

heme alpha globin beta globin Fig. 3-17, p.44

 Lipoproteins ◦ Proteins combined with cholesterol, triglycerides, phospholipids  Glycoproteins ◦ Proteins combined with oligosaccharides

 Disruption of three-dimensional shape (unraveling of its shape)  Causes of denaturation: ◦ pH ◦ Temperature—cooking an egg denatures the egg white’s albumin which goes from clear to white ◦ salinity  Destroying protein shape disrupts function

 Chaperone proteins—assist proteins with their folding  Vitamins—may acts as coenzymes

hM

 Composed of monomers called nucleotides Adenine Cytosine

C4udkA Fw

 5 C Sugar ◦ Ribose or deoxyribose  phosphate group  Nitrogen Base (A, C, G, T, U) ◦ Single or double ring structure

three phosphate groups sugar base

THYMINE (T) base with a single-ring structure CYTOSINE (C) base with a single-ring structure Fig. 3-20, p.46

 A, G  Larger (double rings)  C, T, U  Smaller (single rings)

 Double-stranded  Consists of four types of nucleotides  A bound to T  C bound to G

 Usually single strands  Four types of nucleotides  Unlike DNA, contains the base uracil in place of thymine  Three types are key players in protein synthesis

 Make sure you color the label the same color as the actual structure.  Ex: enzyme (A)—if you choose to color the label red, the structure A must also be red