Pre-AP Biology Ms. Haut

 Organic Compounds  Contain Carbon  Derived from living things  Carbon atom has four outer electrons, which can covalently bond with an electron from another atom

 A carbon atom forms four covalent bonds  It can join with other carbon atoms to make chains or rings Figure 3.1, top part Structural formula Ball-and-stick model Space-filling model Methane The 4 single bonds of carbon point to the corners of a tetrahedron. Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

Figure 3.2

 The simplest organic compounds are hydrocarbons.  These are organic molecules containing only carbon and hydrogen atoms.  The simplest hydrocarbon is methane.  Larger hydrocarbons  Are the main molecules in the gasoline we burn in our cars.  The hydrocarbons of fat molecules provide energy for our bodies.

 Functional groups are the groups of atoms that participate in chemical reactions  Hydroxyl groups are characteristic of alcohols  The carboxyl group acts as an acid

Table 3.2 Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 Most of the large molecules in living things are macromolecules called polymers  Polymers are long chains of smaller molecular units called monomers  A huge number of different polymers can be made from a small number of monomers

 Cells link monomers to form polymers by dehydration synthesis Figure 3.6a

 Polymers are broken down to monomers by the reverse process, hydrolysis Figure 3.6b

 Carbohydrates  Lipids  Proteins  Nucleic Acids

 Compounds made up of carbon, hydrogen, and oxygen  1C:2H:1O (C 6 H 12 O 6 )  Monomer units are monosaccharides (simple sugars)  Disaccharides are made up of 2 simple sugars Glucose ➞ ← Fructose Sucrose

Glucose Maltose Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 Polysaccharides —long chains of simple sugars  Function as storehouse of energy  Starches —storage form of glucose in plants  Glycogen —storage form of glucose in animals  Cellulose —tough fibers give plant strength and rigidity (found in wood and paper)

 Large nonpolar molecules, made mostly of carbon and hydrogen  Fats  Phospholipids  Steroids  Can be used to store energy  Carbon-hydrogen bond store a lot of energy  Lipids do not mix with water (hydrophobic)

Fats are lipids whose main function is energy storage They are also called triglycerides –One glycerol molecule linked to three fatty acids Figure 3.15a

 The fatty acids of unsaturated fats (plant oils) contain double bonds  These prevent them from solidifying at room temperature  Saturated fats (lard, animal fats) lack double bonds  They are solid at room temperature Figure 3.8C Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

Fats perform essential functions in the human body:  Energy storage  Cushioning  Insulation

 Steroids are very different from fats in structure and function.  The carbon skeleton is bent to form four fused rings.  Cholesterol helps keep cell membrane fluid  Cholesterol is the “base steroid” from which your body produces other steroids.  Example: sex hormones

 Make up the lipid bilayer of cell membranes  Keeps inside of cell separate from the external environment sets/membranes/graphics/bilayer.jpg

 A protein is a polymer constructed from amino acid monomers.  Proteins perform most of the tasks the body needs to function  cellular structure  movement  defense  transport  communication  Enzymes regulate chemical reactions Proteins Figure 3.11 Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 Proteins are the most structurally and functionally diverse of life’s molecules  Their diversity is based on different arrangements of amino acids Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 Each amino acid contains: –an amino group –a carboxyl group –an R group, which distinguishes each of the 20 different amino acids Amino group Carboxyl (acid) group Figure 3.12A Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 Each amino acid has specific properties Leucine (Leu) Figure 3.12B Serine (Ser)Cysteine (Cys) HYDROPHOBICHYDROPHILIC Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 Cells link amino acids together by dehydration synthesis  The bonds between amino acid monomers are called peptide bonds

 A protein, such as lysozyme, consists of polypeptide chains folded into a unique shape  The shape determines the protein’s function  A protein loses its specific function when its polypeptides unravel Figure 3.14AFigure 3.14B Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

Primary structure  The specific sequence of amino acids in a protein

Figure 3.23 A slight change in the primary structure of a protein affects its ability to function.  The substitution of one amino acid for another in hemoglobin causes sickle-cell disease.

Figure 3.15, 16 Amino acid Hydrogen bond Alpha helix Pleated sheet Primary structure Secondary structure  Secondary structure is polypeptide coiling or folding produced by hydrogen bonding Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

Figure 3.17, 18 Polypeptide (single subunit of transthyretin) Transthyretin, with four identical polypeptide subunits Tertiary structure Quaternary structure  Tertiary structure is the overall shape of a polypeptide  Quaternary structure is the relationship among multiple polypeptides of a protein Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 A protein’s shape is sensitive to the surrounding environment.  Unfavorable temperature and pH changes can cause a protein to unravel and lose its shape.  This is called denaturation.

 Nucleic acids are information-rich polymers of nucleotides  Nucleic acids such and DNA and RNA serve as the blueprints for proteins  They ultimately control the life of a cell Nucleic Acids

 The monomers of nucleic acids are nucleotides Phosphate group Sugar Figure 3.20A –Each nucleotide is composed of a sugar, phosphate, and nitrogenous base Nitrogenous base (A) Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

 The sugar and phosphate form the backbone for the nucleic acid Copyright © 2001 Pearson Education, Inc. publishing Benjamin Cummings

 DNA consists of two polynucleotides twisted around each other in a double helix  The sequence of the four kinds of nitrogenous bases in DNA carries genetic information Fig Fig. 3.28

 Stretches of a DNA molecule called genes program the amino acid sequences of proteins  DNA information is transcribed into Ribonucleic acid (RNA), a single-stranded nucleic acid  RNA is then translated into the primary structure of proteins Fig. 3.25

DNARNA Double helixSingle strand Adenine Cytosine Guanine ThymineUracil A—T C—G A—U C—G

 ESSENTIALS IN BIOLOGY WITH PHYSIOLOGY 2 nd edition, by Campbell and Reece, These images have been produced from the originals by permission of the publisher. These illustrations may not be reproduced in any format for any purpose without express written permission from the publisher.  BIOLOGY: CONCEPTS AND CONNECTIONS 4th Edition, by Campbell, Reece, Mitchell, and Taylor, ©2003. These images have been produced from the originals by permission of the publisher. These illustrations may not be reproduced in any format for any purpose without express written permission from the publisher.  BIOLOGY: CONCEPTS AND CONNECTIONS 4th Edition, by Campbell, Reece, Mitchell, and Taylor, ©2001. These images have been produced from the originals by permission of the publisher. These illustrations may not be reproduced in any format for any purpose without express written permission from the publisher.  Background on slides is a painting, by Jon Lomberg,