• Aside from water, most biologically related molecules _contain carbon_.---__Organic molecules_ are molecules containing carbon.• Living organisms can synthesize and use this type of molecule .Exceptions: All carbon molecules, graphite, diamonds, coalCarbon dioxideCarbon monoxide• Only living organisms can create organic molecules. FALSEUnder the correct conditions organic molecules can form from non- living materials . As molecules within cells interact, they change (chemically and structurally).These changes give cells the ability to obtain and use nutrients, get rid of waste, move and grow, and reproduce.As you’ll see, these molecules have certain properties that allow for the different interactions.• Carbon atoms are the _most versatile building blocks of molecules._ Carbon is the key to the great variety of organic molecules that make life on Earth possible.Carbon has a valence of 4.Can bind to 2, 3, or 4 other atoms.• Another factor which leads to the versatility of organic molecules is the attachment of _functional groups____Functional groups are _small characteristics__ which are frequently bonded to the carbon skeleton of organic molecules.• Functional Groups Table 3.1• Functional groups:• Have specific _chemical and physical properties__.• Are regions of organic molecules which are frequently _chemically reactive_.• _Behave consistently from one organic molecule to another.• Can determine the chemical properties of the organic molecule in which they are located.• There are seven general functional groups found in organic molecules:1) _Hydrogen __ Group(-H)2) _Hydroxyl__ Group (-OH)3) _Carboxyl_ Group (-COOH)4) _Amino_ Groups (-NH2)5) _Phosphate__ Groups (-PO4)6) _Methyl _Groups (-CH3)7) _Sulfhydryl _ Groups (-SH)• 1) Hydrogen Group (-H)Hydrogen group is a functional group of a hydrogen atom bonded to a carbon atom (of the carbon skeleton).Is either a _polar group or a non-polar group__ depending on the atom to which the hydrogen is attached.Involved in _condensation__ (dehydration) and __hydrolysis__reactions• 2) Hydroxyl Group (-OH)-Hydroxyl group is a functional group of a hydrogen atom bonded to an oxygen atom which is bonded to a carbon atom (of the carbon skeleton).-Is a _polar group__-Involved in _condensation__ (dehydration) and _hydrolysis_ reactions• Biological Polymers are formed by removing water and split by adding water Figs. 3.1 and 3.2• 3) Carboxyl Group (-COOH)-Carboxyl group is a functional group in which a carbon atom is double bonded to an oxygen atom (like a carbonyl) and is also single bonded to the oxygen atom of a hydroxyl group.-Since this group can donate a proton, _it is an acid_-Involved in _peptide bonds_• 4) Amino Groups (-NH2)-Amino groups are functional groups in which two hydrogen atoms are bonded to a nitrogen atom which is bonded to a carbon atom (of the carbon skeleton).-Acts as a _weak base__ (similar to ammonia)-Involved in _peptide bonds__-• Fig. 3.19 – Protein synthesis• 5) Phosphate Groups (-PO4)Phosphate group is a functional group which is the dissociated form of _phosphoric acid__ (H3PO4)-Acts as an acid because of the _ability to donate protons_. -Links _nucleotides__-Important in _cellular energy storage and energy transfer_. Example: ATP• ATP- Adenosine triphosphate –Fig 3.23• 6) Methyl Groups (-CH3)Methyl group is a functional group which consists of three hydrogen atoms bonded to a carbon atom. -Is a _non-polar___ group.-Makes the molecule more hydrophobic• 7) Sulfhydryl Groups (-SH) ---Methyl group is a functional group which consists of a sulfur atoms bonded to a hydrogen atom. -Critical in _stabilizing protein structure___-• SYNTHESIZING ORGANIC MOLECULES: A MODULAR APPROACHBiological molecules are often put together in _subunits__, or modules, called _monomers_-.---the simple molecules condensed into more complex ones---_monomers into polymers • _Polymers__ are chains of similar building blocks or monomers.• The reaction which forms a polymer from monomers is a _dehydration synthesis_ (or condensation reaction)---Dehydration synthesis is a reaction in which the covalent linkage of the monomers is accompanied by the “removal” of a water molecule.• -One monomer loses a hydroxyl group (-OH), and the other monomer losesa hydrogen (-H) (Fig. 3.1).• Hydrolysis is the breaking of the covalent bond between two monomers by the addition of water.-One monomer _loses a hydroxyl group_(-OH), and the other monomer _loses a hydrogen (-H)(Fig. 3.2).• -Carbohydrates are used as fuels and building material -Carbohydrates are organic molecules made of _sugars and their polymers__. -Carbohydrates are classified by the _number of simple sugars_. -Monomers are simple sugars called monosaccharides---_Monosaccharides are simple sugars in which carbon, hydrogen, and oxygen occur in the ratio of CH2O. -Major source in _nutrients for cells__. -_Glucose_ is the most common -Can be produced by photosynthetic organism from CO2, H2O, and light. • Depictions of Glucose structure (Fig. 3.4)• >Monosaccharides can be joined to form _disaccharides and polysaccharides_ (Fig. 3.7)• General structure of carbohydrates 1) Each carbon has a hydroxyl group attached to it except one which is a carbonyl group.• General structure of carbohydrates 2) The size of the carbon skeleton6 and 5 carbon monosaccharides• General structure of carbohydrates 3) In aqueous solutions, monosaccharides with 5 or more carbons in the skeleton form ring structures. The chemical equilibrium favors the ring structure over the straight chain.• Disaccharides---Disaccharides are molecules which consist of _two monosaccharides__ joined by a _glycosidic linkage___. (See fig 3-2) -Glycosidic linkage is a covalent bond formed by a dehydration synthesis between two sugar monomers.• >Polysaccharides -Polysaccharides are macromolecules that are polymers of __a few hundred or thousand monosaccharides.__-Formed by enzyme-mediated condensation reactions.-Biological functions1. _Energy storage__ (starch and glycogen) 2. _Structural support_ (cellulose and chitin) • Storage polysaccharide -Stored sugars can be hydrolyzed as needed. (Fig. 3.8)• -Starch is a glucose polymer that is used as a _storage polysaccharide in plants_. • -__Glycogen in a glucose polymer that is used as a storage polysaccharide in animals. -Stored in the muscle and liver of vertebrates •
View Full Document
Unlocking...