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Biology I

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Organic CompoundsCompounds that

contain CARBON are called organic compounds.

Organic chemistry is the study of carbon compounds

Although a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules

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Giant Molecules = Polymers

Large molecules are called polymers

Polymers are built from smaller molecules (building blocks) called monomers

Biologists call them macromolecules

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Large organic molecules. Also called POLYMERS. Made up of smaller “building

blocks” called MONOMERS.Examples:

1. Carbohydrates

2. Lipids3. Proteins4. Nucleic acids (DNA and RNA)

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Most Macromolecules are Polymers

Polymers are made by stringing together many smaller molecules called

monomersNucleic

Acid Monomer

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Macromolecules in Organisms

•There are four categories of large molecules in

cells:Carbohydrates

Lipids

Proteins

Nucleic Acids

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Carbohydrates are compounds composed of C,H,& O atoms in the ratio of 1:2:1

The monomers are sugar molecules

They include:Small sugar molecules in soft

drinksLong starch molecules in pasta

and potatoesConsist of 3 major types

of sugars: Monosaccharides

Disaccharides Polysaccharides

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Monosaccharides: Called simple sugars

Include glucose, fructose, & galactose

Have the same chemical, but different structural formulas

C6H12O6

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MonosaccharidesGlucose is found in

sports drinks

Fructose is found in fruits

Honey contains both glucose & fructoseGalactose is called “milk sugar”

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Isomers• Glucose &

fructose are isomers because they’re structures are different, but their chemical formulas are the same

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Cellular FuelMonosaccharides

are the main fuel that cells use for

cellular work

ATP

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DisaccharidesA disaccharide is a

double sugar

They’re made by joining two monosaccharides

Common disaccharides include:

►Sucrose (table sugar)►Lactose (Milk Sugar)►Maltose (Grain sugar)

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DisaccharidesSucrose is composed of

glucose + fructose

Maltose is composed of 2 glucose molecules Lactose is made of galactose + glucose GLUCOSE

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PolysaccharidesComplex

carbohydrates

Composed of many sugar monomers linked togetherPolymers of monosaccharide chains

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Examples of Polysaccharides

Starch

Glycogen

Cellulose

Glucose Monomer

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StarchStarch is an

example of a polysaccharide in plants

Plant cells store starch for energy

Potatoes and grains are major sources of starch in the human diet

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GlycogenGlycogen is an example

of a polysaccharide in animals

Animals store excess sugar in the form of glycogen

Glycogen is similar in structure to starch

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Cellulose►Cellulose is the most abundant

organic compound on Earth

►It forms cable-like fibrils in the tough walls that enclose plants

►It is a major component of wood

►It is also known as dietary fiber

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Cellulose

SUGARS

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Large molecules composed of mostly carbon & hydrogen atoms

Lipids are hydrophobic –”water fearing”

They’re not soluble in water

Includes fats, waxes, steroids, & oils

FAT MOLECULE

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Function of Lipids•Fats store energy, help to

insulate the body, cushion and protect organs.

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Types of Fatty AcidsUnsaturated fatty acids~ have less than

the maximum number of hydrogens bonded to the carbons (a double bond between carbons). Usually liquids liquids at room temp.

Saturated fatty acids~ have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons). Usually solidssolids at room temp.

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Fats in Organisms• Most animal fats have a high

proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)

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Fats in Organisms

•Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils)

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Types of Fatty Acids

Single Bonds in Carbon chain

Double bond in carbon chain

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Triglyceride

Monomer of lipids

Composed of Glycerol & 3 fatty acid chainsGlycerol forms the “backbone” of the fat

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Triglyceride

Glycerol Fatty Acid Chains

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SteroidsThe carbon

skeleton of steroids is bent to form 4 fused rings

Cholesterol is the “base steroid” from which your body produces other steroids

Estrogen & testosterone are also steroids

Cholesterol

TestosteroneEstrogen

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Synthetic Anabolic Synthetic Anabolic SteroidsSteroids

They are variants of testosteroneSome athletes use them to build up their muscles quickly

They can pose serious health risks

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Are macromolecules that contain the element N as well as C, H, & O.

Proteins are polymers made of monomers called amino acids

All proteins are made of 20 different amino acids linked in different orders Proteins are used to build cells, act as hormones & enzymes, and do much of the work in a cell

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Four Types of Proteins

Structural

Contractile

Storage

Transport

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20 Amino Acid 20 Amino Acid MonomersMonomers

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Structure of Amino Acids

Amino acids have a central carbon with 4 things bonded

to it:Amino group -NH3

Carboxyl group -COOH

Hydrogen -H

Side group -R

Amino

group

Carboxylgroup

R group

Side groups

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Linking Amino Acids

Cells link amino acids together to make proteinsPeptide bonds form to hold the amino acids together

Carboxyl

Amino Side

Group

Peptide Bond

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Proteins as Enzymes

Many proteins act as biological catalysts or enzymes & end in asease

Thousands of different enzymes exist in the body

Enzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction

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Enzymes

Their folded conformation creates an area known as the active site.

Enzymes are globular proteins.

The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.

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Enzyme + Substrate = Product

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How the Enzyme Works

Enzymes are reusable!!!

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Primary Protein Structure

The primary structure is the specific sequence of amino acids in a protein

Amino Acid

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Protein StructuresSecondary protein structures

occur when protein chains coil or fold

When protein chains called polypeptides join together, the tertiary structure forms

In the watery environment of a cell, proteins become globular in their quaternary structure

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Protein Structures

Amino acid

(a) Primary structure

Alpha helix

(b) Secondary structure

(c) Tertiary structure

(d) Quaternary structure

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Changing Amino Acid Sequence

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

(b) Sickled red blood cell Sickle-cell hemoglobin

2 314 5

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Store hereditary information

Contain information for making all the body’s proteinsTwo types exist - DNA & RNA

Macromolecules that contain H, O, N, C,& P.

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Nucleic AcidsNitrogenous base

(A,G,C, or T)

Phosphategroup

Thymine (T)

Sugar(deoxyribose)

Phosphate

BaseSugar

Nucleic acids are polymers of nucleotides

Nucleotide

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Bases• Each DNA

nucleotide has one of the following bases:

Thymine (T) Cytosine (C)

Adenine (A) Guanine (G)

–Adenine (A)

–Guanine (G)

–Thymine (T)

–Cytosine (C)

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Nucleotide MonomersForm long

chains called DNA

Backbone

Nucleotide

Bases

DNA strand

Nucleotides are joined by sugars & phosphates on the side

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DNADNATwo strands of

DNA join together to form a double helix

Has the sugar deoxyribose

Bases are: A, T, C, & G

Basepair

Double helix

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RNA – Ribonucleic AcidHas the

sugar riboseSingle

strandedIt has the base uracil (U) instead of thymine (T)

A,U,C & G

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

Sugar (ribose)

Phosphategroup

Uracil

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Nucleic Acids

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Macromolecules

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Macromolecules