Announcements ●GE Survey-available on Blackboard ●Tutoring Center SCI I, 407 M 12-3, 5:30-6:30; W 8-9, 5:30-6:30, Th 8-12, 6-7; F 8-9 ●MasteringBiology.

Announcements

●GE Survey-available on Blackboard●Tutoring Center

SCI I, 407M 12-3, 5:30-6:30; W 8-9, 5:30-6:30, Th 8-12, 6-7; F 8-9

●MasteringBiology Assignment

Review

●Process of Science●Chemistry of Life

atoms, elements, chemical bonding●Properties of Water

Carbon and Organic Chemistry

– Carbon is a versatile atom.

– Carbon forms large, complex, and diverse molecules necessary for life’s functions.

– Organic compounds are carbon-based molecules.

Structuralformula

Ball-and-stickmodel

Space-fillingmodel

– Larger hydrocarbons form fuels for engines.

– Hydrocarbons of fat molecules fuel our bodies.

Hydrocarbons

• Variations in Carbon skeletons Carbon skeletons vary in length

Carbon skeletons may be unbranched or branched

Carbon skeletons may have double bonds,which can vary in location

Carbon skeletons may be arranged in rings

Carbon and Organic Chemistry

• The unique properties of an organic compound depend not only on its carbon skeleton but also on the atoms attached to the skeleton

– These atoms are called functional groups– Some common functional groups include:

Hydroxyl group Carbonyl group Amino group Carboxyl group

Found in alcoholsand sugars

Found in sugarsFound in amino acidsand urea in urine (fromprotein breakdown)

Found in amino acids,fatty acids, and somevitamins

Carbon and Organic Chemistry

Macromolecules

– On a molecular scale, many of life’s molecules are gigantic, earning the name macromolecules.

– Three categories of macromolecules are• Carbohydrates

• Proteins

• Nucleic acids

*most macromolecules are polymerspolymer

monomer

The making and breaking of polymers:

Dehydration reaction: Hydrolysis:

Macromolecules

• Carbohydrates include

Carbohydrates

– Small sugar molecules in soft drinks• Monosaccharides & Disaccharides

– Long starch molecules in pasta and potatoes• Polysaccharides

• Monosaccharides are simple sugars

Monosaccharides

– Glucose, found in sports drinks

– Fructose, found in fruit

• Honey contains both glucose and fructose

Glucose Fructose

Isomers

• In aqueous solutions, monosaccharides form rings

(b) Abbreviated ring structure

Monosaccharides

• A disaccharide is a double sugar

Disaccharides

• Disaccharides are joined by the process of dehydration synthesis

Glucose Glucose

Maltose

• The most common disaccharide is sucrose, common table sugar

– It consists of a glucose linked to a fructose

– Sucrose is extracted from sugar cane and the roots of sugar beets

Disaccharides

Polysaccharides

(a) Starch

Starch granules inpotato tuber cells

Glucosemonomer

(b) Glycogen

GlycogenGranulesIn muscletissue

(c) Cellulose

Cellulose molecules

Cellulose fibril ina plant cell wall

– They are long chains of sugar units

– They are polymers of monosaccharides

• Most animals cannot derive nutrition from fiber

– How do grazing animals survive on a diet of cellulose?

Polysaccharides

Proteins• Proteins perform most of the tasks the body

needs to function– They are the most elaborate of life’s molecules

MAJOR TYPES OF PROTEINS

Structural Proteins Storage Proteins Contractile Proteins Transport Proteins Enzymes

• All proteins are constructed from a common set of 20 kinds of amino acids

The Monomers: Amino Acids

Aminogroup

Carboxylgroup

Sidegroup

Carboxylgroup

Aminogroup

Sidegroup

Sidegroup

Amino acid Amino acid

Dehydrationsynthesis

Sidegroup

Sidegroup

Peptide bond

• Cells link amino acids together by dehydration synthesis

Proteins as Polymers

– The resulting bond between them is called a peptide bond

• Primary structure

– The specific sequence of amino acids in a protein

1 510 15

20253035

4045

5055

6065

70

75 80 85

9095

100

105110 115

120125

129

Amino acid

– The arrangement of amino acids makes each protein different

Protein Structure

• 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

(a) Normal red blood cell Normal hemoglobin

12 3

4 56

7. . . 146

(b) Sickled red blood cell Sickle-cell hemoglobin

2 314 5

67. . . 146

Protein Structure

• Proteins have four levels of structure

Hydrogen bond

Pleated sheet

Amino acid

(a) Primary structure

Hydrogen bond

Alpha helix

(b) Secondary structure

Polypeptide(single subunit)

(c) Tertiary structure

Completeprotein,with fourpolypeptidesubunits

(d) Quaternary structure

Protein Structure

Gene

DNA

RNA

Protein

Amino acid

Nucleic acids

Nucleic Acids

● Include DNA and RNAInformation storage moleculesThey provide the directions for building proteins

Phosphategroup

Nitrogenous baseA, G, C, or U

Uracil U

Sugar ribose

Nitrogenous base(A,G,C, or T)

Phosphategroup

Thymine (T)

Sugar(deoxyribose)

Phosphate

Base

Sugar

●Nucleic acids are polymers of nucleotides

– DNA, deoxyribonucleic acid– RNA, ribonucleic acid

Nucleic Acids

Nucleic Acids●Each DNA nucleotide has one of the following bases:

Adenine (A)Guanine (G)Thymine (T)Cytosine (C)

Adenine A Guanine G

Thymine T Cytosine C

Nucleic Acids

Sugar-phosphatebackbone

NucleotideBasepair

Hydrogenbond

Bases

a DNA strandpolynucleotide

b Double helixtwo polynucleotide strands

●Nucleic Acid Structure

●Lipids are:

Neither macromolecules nor polymers

Hydrophobic, unable to mix with water

Lipids

Oil (hydrophobic)

Vinegar (hydrophilic)

Figure 3.10

●FATS● Dietary fat consists largely of the molecule triglyceride

Lipids

– A combination of glycerol and three fatty acids

Fatty acid

Glycerol (a) A dehydration reaction linking a fatty acid to glycerol

(b) A fat molecule with a glycerol “head” and three energy-rich hydrocarbon fatty acid “tails”

●Unsaturated fatty acids

Lipids (Fats)

– Have less than the maximum number of hydrogens bonded to the carbons

●Saturated fatty acids – Have the maximum number of hydrogens bonded to

the carbons

Lipids (Fats)

Saturated FatsTYPES OF FATS

Unsaturated Fats

Margarine

Plant oils Trans fats Omega-3 fats

INGREDIENTS: SOYBEAN OIL, FULLY HYDROGENATED

COTTONSEED OIL, PARTIALLY HYDROGENATED

COTTONSEED OIL AND SOYBEAN OILS, MONO AND

DIGLYCERIDES, TBHO AND CITRIC ACID ANTIOXIDANTS

Cholesterol

Testosterone A type of estrogen

●STEROIDSSteroids are very different from fats in structure and function.

Lipids

Visual Summary 3.2

Biological Molecules