The Chemistry of Life Bio 100 Tri-County Technical College Pendleton, S. C.

Basic Beginnings Flow chart for life Biosphere  ecosystem  community  Population  organism  organ system  Organ  tissue  cell  organelle  molecule  atom  subatomic particles  who knows?

Biochemistry n The study of the chemistry associated with living system. n Much of this chemistry involves compounds containing carbon. n Carbon can form four single bonds. n Carbon can also form double covalent bonds and triple covalent bonds

Chapter 3; Continued n Hydrocarbon contains only carbon and hydrogen atoms (methane, ethane, etc.) n Functional group is group attached to hydrocarbon skeleton that makes it more (or less) reactive n Hydroxyl, carbonyl, carboxyl, amino, phosphate, sulfhydryl, and methyl n Review: remember polar and those highly electronegative atoms we discussed earlier

Single Bonds n involves sharing two electrons n represented by a single line in a structural formula n methane is an example -- CH 4

Double Bonds n involves sharing four electrons n represented by two lines in a structural formula n the carboxyl group is an example n double bond between carbon and oxygen.

Triple Bond n involves sharing 6 electrons n represented by 3 lines in a structural formula

What it are? n Macromolecule is giant molecule of living matter formed by the joining of smaller molecules n A monomer is an identical or similar repeating subunit n A polymer is composed of monomers n Monomer + monomer = dimer n For our course, more than 2 monomers joined together will equal a polymer (NOT entirely true…but will do)

Synthesis and Hydrolysis n Many biologically important compounds are polymers. –composed of many monomers –for example starch is a polymer of glucose n Synthesis is the process by which individual glucose molecules are put together to form the starch.

Synthesis n molecule of water is removed between two monomers n bonds that are left are used to make a bond between the monomers n Also called condensation reaction

Hydrolysis n the opposite of synthesis n molecule of water added across a bond n bond is split n Learn to look for where the water is located n To right of the arrow = synthesis n To left of arrow = hydrolysis

Biochemical Molecule Categories n Carbohydrates –monosaccharides and polysaccharides n Lipids –steroids, neutral fats, phospholipids n Proteins –dipeptides, tripeptides, polypeptides n Nucleic Acids –DNA and RNA

Carbohydrates

n composed of C, H, and O n monosaccharides –C 1 H 2 O 1 –ribose for example: C 5 H 10 O 5 (pentose) –hexose for example: C 6 H 12 O 6 (hexose) –Glucose is a hexose »blood sugar

Disaccharides n composed of two monosaccharides n sucrose -- table sugar -- C 12 H 22 O 11 –water removed during synthesis –1 glucose and 1 fructose n lactose -- milk sugar –1 glucose and 1 galactose n maltose -- malt sugar –two glucose molecules

Polysaccharides n composed of many monosaccharides n examples –starch –glycogen –cellulose n all three composed of glucose n different ways of putting the glucose together

Lipids

Triglycerides n composed of one glycerol molecule and three fatty acids n also called neutral fats n circulate in bloodstream n fatty acids are long chains of carbon with a carboxyl group at one end

Saturated vs. Unsaturated n Saturated fats –contain fatty acids saturated with hydrogen atoms –no double bonds in the fatty acids n Unsaturated fats –contains fatty acids not saturated with hydrogen atoms –have double bonds in the fatty acids

Phospholipids n one fatty acid in a triglyceride is replaced by a phosphate group. n one end is soluble in water –hydrophilic end n other end is insoluble in water –hydrophobic end n major component of cell membranes

Steroids n Cholesterol and the other steroids made from it n Basic steroid ring structure n Steroid hormones –produced by the adrenal and other glands

Proteins Building blocks are amino acids.

Amino acids n There are 20 amino acids that the human body has to have. n All of them –amino group –carboxyl group –R-group n The R-group makes each one unique.

Peptide Bonds n Bonds between the amino acids in a protein. n Formed between an amino group and a carboxyl group n A molecule of water is removed each time a peptide bond is formed n dipeptides, tripeptides, and polypeptides

Other proteins? n Two primary categories of proteins –structural –functional n Enzymes are functional proteins n Structural protein examples –muscle protein –tendon protein, etc.

Nucleic Acids DNA and RNA

Nucleotides n Building blocks of DNA and RNA n composed of sugar, phosphate and a base n The sugar and the bases of DNA are different from those of RNA. n The phosphate group is the same in both.

DNA-nucleotides n Sugar –deoxyribose –one less oxygen than ribose n DNA bases –adenine –thymine –guanine –cytosine

RNA-nucleotides n Sugar –ribose n Bases –adenine –uracil –guanine –cytosine

What do they do? n DNA –contains the blueprint for making all the proteins of a cell –makes up genes and chromosomes n RNA –takes the blueprint from DNA and translates it into proteins

Believe me, it matters n Hydrophilic means water loving n Hydrophobic means water fearing (hating) n Life as we know it depends on interplay between hydrophobic and hydrophilic parts of phospholipids (and others) n Review: polar and nonpolar and water as a polar molecule n Polar = hydrophilic