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Bellringer: 1. What is an organic molecule?2. Which of these are organic molecules? Nucleic Acids, Water, Protein, Sugar, Carbohydrates, Salt, Vitamin C.

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Macromolecules

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Proteins Lipids

Nucleic acids Carbohydrates

Chemical BondsCovalent bonds form between atoms of nonmetals by sharing of electrons

- Molecules bond covalenty

Ionic bonds form between oppositely charged ions after the transfer of electrons

- Salts bond ionically

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Carbon-based Molecules• Although a cell is

mostly water, the rest of the cell consists mostly of carbon-based molecules• Organic chemistry is the study of carbon compounds Copyright Cmassengale

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Carbon (C)• Carbon has 4 electrons in

outer shell.• Carbon can form covalent

bonds with as many as 4 other atoms (elements).

• Usually with C, H, O or N.

• Example: CH4(methane)copyright cmassengale

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Organic Compounds

• Compounds that contain CARBON are called organic.

• Macromolecules are large organic molecules.


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Macromolecules• Large organic molecules.• Also called POLYMERS.• Poly = many, mer = part• Made up of smaller “building

blocks” called MONOMERS.• Examples:

1. Carbohydrates2. Lipids3. Proteins4. Nucleic acids (DNA and

RNA) copyright cmassengale

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Question:How Are

Macromolecules

Formed?copyright cmassengale

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Answer: Dehydration Synthesis

• Also called “condensation reaction”

• Forms polymers by combining monomers by “removing water” through covalent linkages.

HO H

HO HO HH

H2O


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Question: How are

Macromolecules separated or

digested?


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Answer: Hydrolysis• Hydo = water; lysis =

loosening• Separates monomers by

“adding water”

HO HO HH

HO H

H2O


Biochemistry• Organic compounds, in which carbon

atoms are combined with hydrogen and usually oxygen, are needed for life to exist.

• Carbon atoms can combine in long chains that form the backbone of large complex molecules, or macromolecules.

II. Classes of Organic Molecules:

• What are the four classes of organic molecules?

• Carbohydrates• Lipids• Proteins• Nucleic Acids

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Carbohydrates


Juniper sap

A sucrose molecule (above) depicted as a stick molecule.

Milk (right) contains the disaccharide

, lactose.

Glycogen is abundant in metabolically active tissues such as liver (left) and skeletal muscle

(right). The glycogen stains dark magenta.

A. Carbohydrates• Sugars• Carbo = carbon, hydrate = water;

carbohydrates have the molecular formula (CH2O)n

• All known types of living cells contain carbohydrates which contain carbon atoms and hydrogen and oxygen atoms in the same two-to-one ratio as water.

Carbohydrates are used by humans as a cheap food source...

Carbohydrates are important as both energy storage molecules and as the structural elements in cells and tissues.

Sugars (mono-, di-, and trisaccharides)play a central role in energy storage. Functions:

– Store energy in chemical bonds– Glucose is the most common monosaccharide– Glucose is produced by photosynthetic autotrophs– Structures

Carbohydrates are the major componentof most plants (60-90% of dry weight).

Carbohydrates

...and as a source of fuel,...

Carrying wood

...housing and clothing. Cotton, linen, and coir are all made up of cellulose, a carbohydrate polymer.

Collecting thatch for roofing

Weaving cloth

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Carbohydrates• Small sugar molecules to

large sugar molecules.• Three types

A. monosaccharideB. disaccharideC. polysaccharide


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CarbohydratesMonosaccharide: one sugar

unitMay contain three to seven carbon atoms in their carbon skeleton

Examples: glucose (C6H12O6)

deoxyriboseriboseFructoseGalactose

glucose


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CarbohydratesDisaccharide: two sugar

unit or 2 monosaccharides, may bond to form a double sugar

Examples: – Sucrose (glucose+fructose)– Lactose (glucose+galactose)– Maltose (glucose+glucose)glucoseglucose


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CarbohydratesPolysaccharide: many sugar

unitsExamples: starch (bread,

potatoes)glycogen (beef

muscle)cellulose

(lettuce, corn)

glucoseglucose

glucoseglucose

glucoseglucose

glucoseglucose

cellulose


Polysaccharides• Structure: Polymers of a few hundred or a few

thousand monosaccharides.• Functions: energy storage molecules or for

structural support:

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Lipids


Phospholipids form the structural framework of cellular

membranes, e.g. the plasma membrane (above).

Lipids are concentrated sources of energy and can be broken

down (through fatty acid oxidation in the mitochondria) to

provide fuel for aerobic respiration

Mitochondrion (false color TEM)

Waxes and oils, when secreted on to surfaces provide waterproofing in plants and animals.

Fat absorbs shocks. Organs that are prone to bumps and

shocks (e.g. kidneys) are cushioned with a relatively thick

layer of fat.

The white fat tissue (arrows) is visible in this ox

kidney

Stored lipids provide insulation in extreme

environments. Increased body fat levels in winter reduce heat

losses to the environment.

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Lipids• General term for compounds

which are not soluble in water = nonpolar.

• Lipids are soluble in hydrophobic solvents.

• Remember: “stores the most energy”

• Examples: 1. Fats/oils/triglycerides

2. Phospholipids3. Waxes4. Steroid hormonescopyright cmassengale

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LipidsSix functions of lipids:

1. Long term energy storage2. Protection against heat loss (insulation)3. Protection against physical shock4. Protection against water loss5. Chemical messengers (hormones)6. Major component of membranes (phospholipids)


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LipidsTriglycerides (fats and oils):

composed of 1 glycerol and 3 fatty acids.

HH-C----O

H-C----O

H-C----O

H

glycerol

OC-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3

=

fatty acids


=

OC-CH2-CH2-CH2-CH =CH-CH

2 -CH2-CH

2 -CH2-CH

3

=copyright cmassengale

Lipid: Fatty Acids• Long chains of mostly carbon and

hydrogen atoms with a -COOH group at one end.

• Building blocks of lipids, called fatty acids and glycerol, make up the simple fats.

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Fatty AcidsFatty acids – long hydrocarbon chains

1. Saturated fatty acids: no double bonds (bad); solid at room temp; most animal fats

2. Unsaturated fatty acids: double bonds (good); liquid at room temp; most plant fats


=

saturated

OC-CH2-CH2-CH2-CH =CH-CH

2-CH2 -CH

3

=

unsaturated

Oils have at least one unsaturated fatty acidFats have three saturated fatty acids

copyright cmassengale 28

Saturated fatty acid

Saturated fatty acid

Unsaturated fatty acid

• Fats are a more efficient form of energy storage than are carbohydrates because fats contain a larger number of hydrogen atoms and less oxygen.

Two other types of lipids important in cells are phospholipids and cholesterol.

Lipids

Phospholipids form when a molecule of glycerol combines with two fatty acids and a phosphate group.

Together with proteins, phospholipids form cellular membranes.

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Phospholipids• Cell membranes are

mostly made of phospholipids

• Phosphate head that is polar & attract water (hydrophilic)

• Two fatty acid tails that are nonpolar and do not attract water (hydrophobic)

Phospholipids in Water

Lipid:Steroids• Structure: Four carbon rings with no fatty acid

tails• Functions:• Component of animal cell membranes• Cholesterol is part of the membrane structure

of animal cells and is important in nutrition.

Warm-Up: Use your notes to fill in the

poem…

• C_ _ _ _ _• l A c t o s e• _ _ _R _ _ • B e e f m u s c l e• O _ _ _ _ _ _• H _ _ _ _ _ _ _• _ _ Y _ _ _ _ _ • D e o x y r i b o s e• R _ _ _ _ _ • _ A _ _ _ _ _ _ _ _ • F r u c T o s e • E _ _ _ _ _ • S _ _ _ _ _ 37

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Proteins


Reversible protein denaturation is responsible

for the “perm”.Disulfide linkages are

responsible for keratin’s tertiary structure. These are broken and then reset during

the chemical process of perming.

The denatured albumin protein

uncurls and coagulates forming a

solid white substance.

The hydrogen bonds in the egg white albumin are

broken by the heating process during cooking. The egg white albumin

protein is heat denatured.

Raw egg57 grams in weight(about 7.4g or 13%

protein).

Many fruits contain enzymes that are used in commercial processes. Pineapple (Ananas comosus, right) contains the enzyme papain which is used in meat tenderization processes and also medically as an anti-inflammatory agent.

C. Proteins • Every living cell contains from several

hundred to several thousand different macromolecules known as

• The most essential role of proteins is as enzymes, specialized molecules that assist the many reactions occurring in cells.

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Proteins (Polypeptides)• Amino acids (20 different kinds of aa)

bonded together by peptide bonds (polypeptides).

• Six functions of proteins:1. Storage: albumin (egg white)2. Transport: hemoglobin3. Regulatory: hormones4. Movement: muscles5. Structural: membranes, hair, nails6. Enzymes: cellular reactions copyright cmassengale

Proteins• Structure:• Covalent bonds between the acid group of one

amino acid molecule and the amino group of another are called

• Additional peptide bonds may form, resulting in a long chain of amino acids, or

• Have a 3 dimensional globular shape

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Proteins (Polypeptides)

Four levels of protein structure:A. Primary StructureB. Secondary Structure C. Tertiary Structure D. Quaternary Structure


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Primary StructureAmino acids bonded

together by peptide bonds (straight chains)

aa1 aa2 aa3 aa4 aa5 aa6

Peptide Bonds

Amino Acids (aa)


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Secondary Structure• 3-dimensional folding

arrangement of a primary structure into coils and pleats held together by hydrogen bonds.

• Two examples:

Alpha Helix

Beta Pleated Sheet

Hydrogen Bondscopyright cmassengale

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Tertiary Structure• Secondary structures bent and

folded into a more complex 3-D arrangement of linked polypeptides

• Bonds: H-bonds, ionic, disulfide bridges (S-S)

• Call a “subunit”.Alpha Helix

Beta Pleated Sheetcopyright cmassengale

Proteins: Tertiary Structure• One of the major forces

controlling how a protein folds is hydrophobicity, or the tendency for nonpolar amino acids to avoid water.

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Quaternary Structure

• Composed of 2 or more “subunits”

• Globular in shape• Form in Aqueous

environments• Example: enzymes

(hemoglobin)subunits


Protein: Quaternary Structure

• Each individual protein has a unique shape and, therefore, a specific function.

• A few proteins become active only when two or more tertiary forms combine to form a complex

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Hemoglobin

Hemolysin

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Nucleic Acids


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Nucleic acids• Made of 5 elements: Carbon,

Hydrogen, Oxygen, Nitrogen, Phosphorous (CHONP)

• Two types:a. Deoxyribonucleic acid

(DNA- double helix) b. Ribonucleic acid (RNA-single strand)

• Nucleic acids are composed of long chains of nucleotides linked by dehydration synthesis.

• Stores genetic informationcopyright cmassengale

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Nucleic acids• Nucleotides include:

phosphate grouppentose sugar (5-carbon)nitrogenous bases:

adenine (A)thymine (T) DNA

onlyuracil (U) RNA onlycytosine (C)guanine (G)


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Nucleotide

OO=P-O O

Phosphate Group

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

CH2

O

C1C4

C3 C2

5

Sugar

copyright cmassengaleDeoxyribose in DNA

Ribose in RNA

Nucleic Acids

Four nitrogen bases that occur in nucleotides. Symbols are used to represent the nucleotides adenine, guanine, cytosine, and thymine. Note that cytosine and thymine have a single-ring structure; adenine and guanine have a double ring.

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DNA - double helix

P

P

P

O

O

O

1

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4

5

5

3

3

5

P

P

PO

O

O

1

2 3

4

5

5

3

5

3

G C

T A


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DNA Structure

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RNA Structure

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Copyright Cmassengale

60Copyright Cmassengale

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