Bio 109 Chapter 2

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Biology 109

lab handouts ($15) available in Biology Office KC 231

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Biological Hierarchy

atom molecules organelles cells tissues

organs

organ systems

organismpopulation

community

ecosystem

biosphere

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Emergent Properties

- With each step upward in biological

hierarchy, novel properties emerge thatwere not present at the simpler levels oforganization

- Result from interactions between thecomponents

- Structural arrangement of parts important

- organism is a living whole greater than thesum of its parts

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Fundamental Properties of Life

1. Growth and development

2. Reproduction (life comes from life)

3. Response to environment

4. Evolutionary Adaptation

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Fundamental Properties of Life

4. Metabolism - the sum total of all chemical

reactions that occur in living organisms(energy transfer)

5. Homeostasis regulatory mechanisms

that maintain the organisms internalenvironment within tolerable limits

6. Organized structure the cell is the basicunit of life (unicellular or multicellular)

7. Organic composition

carbohydrates, proteins, lipids, and

nucleic acids

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Element

-the smallest unit of matter that cannot be brokendown into a simpler substance by chemical

reactions (composed of atoms)

- 92 naturally occurring elements (25 essential forlife)

Periodic Table ofElements

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Macronutrients- required for life

- nine elements make up 99.5% of plant living matter

Naturally Occurring

Elements in the Human

Body

0.1

1.5

0.4

3.3

9.5

65.0

18.5

1.0

0.3

Percent Dry Weight

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Micronutrients

- required for life

- trace elements

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molecule two or more atoms held together by

chemical bonds

O2 N2 NaCl CO2 CH4

compound any substance formed by two or moreelements in a fixed ratio

NaCl CO2 CH4

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The Atom

- the smallest part of an element that retains the

physical and chemical properties of that element

proton positive charge

atomic nucleus

electron negative charge

8n

8p

neutron no charge

shell

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Atom

atomic number the number of protons in the atomic

nucleus

Hydrogen = 1

Carbon = 6

Oxygen = 8

Uranium = 92

8n

8p

Section of Periodic Table

Atomic number

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Atom

atomic mass (mass number) the number of protons

and neutrons in the atomic nucleus

Hydrogen = 2

Carbon = 12

Oxygen = 16

8n

8p

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Isotope

Atoms of an element with a different mass number

- different number of neutrons in the atomicnucleus

12C 13C 14C

8n

6p

6n

6p

radioactive isotope

nucleus decays

spontaneously (releases

particles of energy)

7n

6p

stable isotopes

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Chemical Bonds

Valence

- the bonding capacity of an atom

- number of unpaired electrons in the outer orbital(shell)

Na

C

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Atoms

Cl

HO

He

N

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Chemical Bonds

Covalent Bond

Ionic Bond

Hydrogen Bond

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Ionic Bond

- Chemical bond formed when ions of opposite

charges attract

- one atom donates an electron to another to forma positive and negative ion (charged particle)

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Covalent Bond

H H

H H

-chemical bondformed whenatoms share apair (at least onepair) of electrons

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Campbell & Reece 2005

Covalent Bond

Single

DoubleTriple

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nonpolar covalent bond when electron pairs areshared equally

H H

Covalent Bond

H H

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polar covalent bond when electron pairs are

shared unequally between two atoms due todifferences in their ability to attract electrons

O

HH

Covalent Bond

H H

O

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Hydrogen Bond

- weak chemical bond formed when molecules of

opposite charges attract (polar molecules)


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Water

- Hydrogen bonds between molecules

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Water

- ionic molecules tend

to dissolve in water

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Molecules of Life OrganicMolecules

Carbon-based covalent bonds

(C, H, O, N, P, S)

Macromolecule (polymers) complexorganic molecule formed by joiningsimilar or identical subunits

(monomers)

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Major Classes of Moleculesof Life

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids

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Carbohydrates

- Includes sugars, starches, cellulose

- Composed of C, H, O

Functions: sources of energy

structural materialsMonosaccharides

Disaccharides

Polysaccharides

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Monosaccharides

Simple Sugars, smallest carbohydrate

molecules

General Formula = CnH2nOn (n=3-7)

Examples:Ribose C5H10O5

Glucose, Fructose C6H12O6

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Monosaccharides

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Glucose

Fructose

Monosaccharides

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Disaccharides

sugar consisting of two monosaccharides

(simple sugar molecules)Sucrose (table sugar) Maltose (malt sugar)

= glucose + fructose = glucose + glucose

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Dehydration Synthesis / Hydrolysis

Dehydrationsynthesis

-the synthesis of acompound ormoleculeinvolving theremoval of water

- require energyinput

Hydrolysis

-the splitting ofone moleculeinto two by theaddition of the H+and OH- ions ofwater

-yield energy

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Polysaccharides

a polymer composed of hundreds to

thousands of monosaccharides

examples: repeating glucose molecules

starch - energy storage (plants)glycogen energy storage (fungi,

bacteria, and animals)

cellulose structural molecule (plants)

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Polysaccharides

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Cellulose

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Lipids

composed of C and H, some O

insoluble in water

includes triglycerides (fats, oils), waxes,

steroids, and phospholipids

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Lipids

energy storage (trigylcerides)

structural (phospholipids, cholesterol,waxes)

hormones (steroids)

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Trigylcerides

a fat or an oil

source of energy

three fatty acids bonded to a molecule ofglycerol

Trigylceride

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Trigylceride

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Saturated Fats

fatty acids contain all single bonds

between the carbon atoms and have themaximum number of hydrogen atoms(saturated with hydrogen)

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Unsaturated Fats

one or more double bonds between the

carbon atoms and consequently fewerhydrogen atoms

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Waxes

long chain lipids

combine with cutin and/or suberin tohelp prevent water loss

From the leaves of the

carnauba wax palm from

Brazil

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Phospholipid

two fatty acids and a phosphate group

attached to a glycerol

occurs in a bilayer in biological membranes

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Steroids

four fused rings of carbon (steroid

backbone) with various side chains

Structural molecule (Cholesterol)

Hormones (Testosterone)

testosterone

S

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Steroids

sterol OH group attached to C-3

important components of membranes,stabilize phospholipid tails

Proteins

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Proteins

large complex macromolecules

composed of amino acids contain C, H, O, N, and S

function:

structural materials

enzymes (biological catalysts)

regulatory molecules

transport molecules

A i A id

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Amino Acids

20 different amino acids

backbone with 1 N and 2 C atoms, differonly in the side group (called an R-group)

Amino group Carboxyl groupIonized form found in cells

(pH = 7)

A i A id

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Amino Acids

R

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R-groups

nonpolar hydrophobic (aggregate on inside

of protein)

R

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R-groups

polar, uncharged hydrophilic (surface of

proteins)

R

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R-groups

polar, negatively charged - hydrophilic

polar, positively charged - hydrophilic

- both are usually found on the surface ofproteins

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Protein Primary Structure

amino acids joined together by peptide

bonds to form a long chain (polypeptide)


P t i St t

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Protein Structure

Protein Str ct re

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Protein Structure

Primary amino acid chain, covalent bonds

(peptide)Secondary alpha helix, beta pleated sheet,hydrogen bonds

Protein Structure

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Protein Structure

Tertiary R-group interactions, attraction,

repulsion, disulfide bonds (Cys-Cys)Quaternary two or more amino acid chainslinked together (various types of interactions)

Protein Structure

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Protein Structure

Protein Structure

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Protein Structure

Denaturation disruption of the tertiary

structure of proteins (unfolds)- Caused by physical (heat) or chemical (pH)changes in the environment

- causes a loss of the biological activity of theprotein

Nucleic Acids

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Nucleic Acids

contain C, H, O, N and P

composed of nucleotides

Two types:

1. deoxyribonucleic acid (DNA)

2. ribonucleic acid (RNA)

Nucleotide

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Nucleotide

single unit of nucleic

acid composed of

- a phosphategroup

- a five-carbonsugar ribose ordeoxyribose

- a nitrogenousbase (purine or apyrimidine)

Nucleotide

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Nucleotide


U

Nit b

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Nitrogenous bases

Uracil (inRNA)


DNA

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- hereditary material of life

- double helix

ATP

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ATP

energy carrier in the cell (nucleotide)

ATP = Adenine + ribose + 3 phosphates

Secondary Metabolites (Compounds)

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- Produced along secondary metabolicpathways

- Many are derived from lipids, amino acids,carbohydrates

- Diverse functions- chemical signals

- attract pollinators

- inhibit bacterial and fungal pathogens

- deter grazing by animals and insects

- inhibit growth of competing plants

Secondary Metabolites (Compounds)

Secondary Compounds

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Used by human society

medicine, flavoring, toxins, perfumes

Four Main Classes Of Secondary Compounds:

1.Terpenes (essential oils, latex, taxol,carotenoids)

2.Glycosides (digitoxin, cyanogenic glyc.)

3. Phenolics (flavonoids, tannins, lignin)

4.Alkaloids (caffeine, nicotine, morphine)

Secondary Compounds

Secondary Compounds

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Secondary Compounds

Bio 109 Chapter 2

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