3.2 Macromolecules Notes

IB Biology HL 1Mrs. PetersFall 2013

Macromolecules

• Polymer: a long molecule consisting of many similar or identical building blocks linked by covalent bonds Ex: carbohydrates, proteins, nucleic acids

Polymers

• Polymers are made up of monomers Monomers are small repeating units; the

building blocks of polymers. Ex: Glucose is a monomer, starch is a polymer:

many glucose bonded together make starch.

GlucoseStarch

3.2.5 Condensation Reaction

• Condensation Reaction- building polymers Two molecules are joined to form a larger molecule, held

by covalent bonds; requires an enzyme and produces one water molecule.

Each monomer contributes to water that is made, one provides the -OH, one the -H.

Also known as dehydration reaction

3.2.5 Condensation Reaction

Condensation Example:

Glucose + Galactose Lactose + water(monomer) + (monomer) (polymer) + water

** Lactose is really called a dimer (only two monomers are bonded together) Di- means 2

** Polymer is for many monomers bonded together; Poly- means many

3.2.5 Hydrolysis

• Hydrolysis- How to break polymers into monomersbonds between monomers of a polymer are broken by the addition of water molecules; requires enzymes a H from water attaches to one monomer OH from water attaches to the other monomer

3.2.5 Hydrolysis

Hydrolysis Example:

Lactose + water Glucose + Galactose

(polymer) + water (monomer) + (monomer)

Classes of Macromolecules

• Carbohydrates• Lipids• Proteins• Nucleic Acids

3.2.3 Monosaccharides

• Monosaccharides: simplest carbohydrates simple sugars General formula (CH2O)n

Major nutrients for cells Serves as raw material for

synthesis of other molecules

Used to make disaccharides and polysaccharides

Ex: glucose, fructose, galactose C6H12O6

3.2.3-4 Monosaccharides

• **Glucose: energy source carried by the blood to cells

• **Fructose: used to make fruit sweet tasting and attractive to animals

• Galactose: used to make milk

3.2.2 Glucose Structure

Draw a glucose molecule!

(You must be able to ID this molecule from others!)

3.2.3 Disaccharides

• Disaccharides: two monosaccharides joined by a glycosidic linkage (covalent bond between monosaccharides using condensation) Ex: sucrose;

maltose; lactose

3.2.3-4 Disaccharides

• **Sucrose: glucose + fructose; carried by phloem to transport energy to cells in plants

• Maltose: 2 glucose; used in creating starch

• **Lactose: glucose + galactose; the sugar in milk; source of energy

3.2.3 Polysacchrides

• Polysaccharides: storage and structural macromolecules made from a few hundred to a few thousand monosaccharides Ex: starch, glycogen, cellulose

3.2.3-4 Polysaccharides

Storage Polysaccharides Starch: found in

plants, polymer made of glucose molecules, used for energy

**Glycogen: found in animals, a highly branched polymer of glucose (short term energy storage in liver and muscle cells)

3.2.3-4 Polysaccharides

Structural Polysaccharides **Cellulose: used to

make strong fibers; major components on plant cell walls

Bioweb.wku.edu

Time to Build!!

• Practice condensation and hydrolysis reactions by building different types of carbohydrates.

3.2.6 Lipids

• Long term energy storage molecules in plants and animals

• Solids are known as fats; liquids are known as oils Animals: store fat Plants: store oils

3.2.6 Lipids

• Functions Long term energy storage Insulation Buoyancy Prevent water loss in plants

Types of Lipids

Fatty Acid: a long hydrocarbon “tail” with a carboxyl group at the head end Saturated: have no

double bonds in the carbon chains

Unsaturated: have double bonds in carbon chains

3.2.2 Fatty Acid Structue

Fatty Acid: Draw a fatty acid

You must be able to ID it from others!

Types of Lipids

• Fat: Composed of a fatty acid attached to glycerol

• Triglyceride: Consists of three fatty acids linked to glycerol by condensation reactions

Draw the general lipid Structure:

• Glycerol attached to one or more fatty acids

General Lipid Structure

Draw the general lipid structure:• Glycerol attached to one or more fatty acids

Types of Lipids

Phospholipids: major components of cell membranes Hydrophilic head Two fatty acid

tails (hydrophobic)

Draw and label a phospholipid

3.2.7 Carbohydrates vs. Lipids

Carbohydrates• Easily digested,

energy is released more rapidly

• Soluble in water, easy to transport

• Short term energy storage

• Stored as glycogen in animals and starch in plants

Lipids• Twice as much energy

per gram than carbs, but harder to break down (slow process)

• Non-polar, insoluble• Long term energy

storage• Lipid storage is lighter

for same amount of carbs

• Used for insulation and buoyancy in animals

Time to build!!

• Practice condensation and hydrolysis reactions by building different types of lipids.

Proteins

• Functions: Structural support Storage (not of energy) Digestion Transport Signaling Movement Defense Hormones Enzymes

• Function depends on structure and interactions of amino acids of polymer

Proteins

• Made up of amino acids• Amino acid chains form

polypeptides, based on a specific sequence and vary in length from a few to thousands

• Proteins consist of one or more polypeptides folded and coiled into specific formations

Amino Acids

• Amino Acid Structure:• An amino group

bonded to a central carbon bonded to a carboxyl group, an “R” group (some other functional group) bonded to the central carbon

3.2.2 Amino Acid Structure

• Amino Acid: Draw an amino acid

• You must be able to ID it from others.

Amino Acids

• Types of Amino Acids 20 different (don’t

memorize) Grouped by the

properties of side chain Non-polar side chains =

hydrophobic Polar side chains =

hydrophillic

7.5.1 Protein Structure

• Four levels of Structure Primary Secondary Tertiary Quaternary

7.5.1 Protein Structure

• Primary Structure: polypeptide chain Unique sequence of amino acids

held together by a peptide bond Created by condensation

reactions (amino acids are monomers)

Chain can be 100’s of amino acids long

Primary structure determines the next three levels, a slight change in one amino acid can affect the protein’s form and function

7.5.1 Protein Structure

• Secondary Structure: Coiling and folding of the polypeptide Created by H bonds

between the oxygen in one carboxyl group and the hydrogen of an amino group

7.5.1 Protein Structure

• Secondary Structure Types of structures

Alpha Helix: delicate coil held by H bonds between every fourth amino acid

Beta Pleated Sheet: two or more regions of polypeptide chains lie parallel to each other with H bonds holding structure together

7.5.1 Protein Structure

• Tertiary Structure: polypeptide bends and folds over itself. Irregular

contortions resulting in interactions between R groups of amino acids

Forms a definite 3D structure important in determining the specificity of the protein

7.5.1 Protein Structure

Tertiary Structure Types of bonds:

Disulfide bridges: strong covalent bond between sulfur atoms

H bonds between Polar side chains

Van der Waals: strong interactions between Hydrophobic side chains

Ionic bonds between + and – charged side chains

7.5.1 Protein Structure

• Quaternary Structure Overall protein structure Involves multiple

polypeptide chains combined to form a single protein structure

All types of bonds in other levels involved in this level also

7.5.2 Types of Proteins

• Two types of proteins Fibrous Globular

7.5.2 Types of Proteins

Fibrous: composed of many polypeptide chains in long narrow shape, usually insoluble in water

Ex:• Collagen: connective

tissue of humans• Actin: component of

human muscle, involved in contractions

7.5.2 Types of Proteins

Globular: 3D in shape, mostly water soluble

Ex: Hemoglobin:

delivers oxygen to body tissue

Insulin: involved in regulating blood glucose levels

7.5.4 Examples of Proteins

Protein Function

Hemoglobin (haemoglobin)Contains iron, transports oxygen in the body (transport)

Actin and MyosinInteract in muscle contractions of animals (movement)

InsulinHormone that aids in the maintenance of blood glucose levels in vertebrates

Immunoglobulins Act as antibodies to fight bacteria and viruses (defense)

Amylase Digestive enzyme that breaks up starch (digestion)

Pepsin Digestive enzyme that breaks down protein in stomach (digestion)

Collagen Strengthens bone, component of tendons, ligaments and skin (structural)

Proteins

• Denaturation (break down) of proteins is caused by: Change in pH Salt concentration Temperature Other environmental aspects

Time to Build!!

• Practice condensation and hydrolysis reactions by building proteins.

• Create models of the four protein structures.

Nucleic Acids

• Types: DNA and RNA• Made of repeating units

of nucleotides• Nucleotides created by a

sugar, phosphate group and a nitrogen base.

• DNA contains deoxyribose sugar

• RNA contains ribose sugar

3.2.2 Ribose Structure

• Draw a Ribose molecule

• You have to be able to ID it from others.

3.2.2 Identify the following

• Glucose• Ribose• Fatty Acid• Amino acid

3.2.5 Role of Condensation and Hydrolysis

• Describe how condensation