Macromolecules (Learning Objectives) • Recognize the role of water in synthesis and breakdown of polymers • Name &recognize the monomer and the chemical bond that holds the polymeric

structure of all biomolecules (where that applies). Which group of biomolecules are distinctly hydrophobic and lack a uniform monomer?

• Identify the function of monomers and polymers of each group with specific examples: – Carbohydrates: Recognize common mono-, di-, and polysaccharides (note the

structural and functional differences). – Lipids: Name the three groups of lipids, their structure and function. – Proteins: Name the generic monomer of proteins and identify the reason each of the

20 monomers provides any protein with structural and functional properties. • What are the levels of protein structure? Name the chemical bond(s) involved with maintaining

each level. • What determines the function of a protein and how can a protein lose its activity? What does

denaturation mean?

– Nucleic Acids: Name the generic monomer and its components. Learn the monomers that are found in DNA & RNA. Contrast the chemical bonds that hold the polymeric structure of nucleic acids that holding the two strands of poly-nucleotides together in DNA. Which chemical bond can be broken by physical means i.e by heat?

Short polymer Unlinked monomer

Dehydration synthesis removes a water molecule, forming a new bond

Dehydration reaction in the synthesis of a polymer Longer polymer

Hydrolysis adds a water molecule, breaking a bond

Hydrolysis of a polymer

a. Synthesis of polymers

b. Release of monomers

Role of Water in Polymer Synthesis and Breakdown

Example of nutritional information on packaged macaroni and cheese

Single Serving %DV

Serving Size 1 cup (228g)

Calories 250

Calories from Fat 110

Total Fat 12g 18%

Trans Fat 1.5g

Saturated Fat 3g 15%

Cholesterol 30mg 10%

Sodium 470mg 20%

Total Carbohydrate 31g 10%

Dietary Fiber 0g 0%

Sugars 5g

Protein 5g

Vitamin A 4%

Vitamin C 2%

Calcium 20%

Iron 4%

Food consists of simple and complex biomolecules Four Groups 1. Carbohydrates: simple sugars & complex carbs 2. Lipids: triglycerides, phospholipids, steroids 3. Protein 4. Nucleic acids: DNA & RNA

Vitamins (other organic molecules) Minerals- chemical elements

Four groups of biologic polymers in living tissues

Only three are made of monomers Names of the monomer of each of the three

polymers

N/A

Structures and Functions of Carbohydrates:

Monosaccharides and Polysaccharides

Summary of Carbohydrate Functions

Monomers Polymers Monosaccharides Polysaccharides Source of Storage of energy-

cellular energy short term (animals) long term (plants) Source of carbon Structural -

skeleton for the cell Plant cell wall Animal exoskeleton

Monosaccharides

Triose sugars (C3H6O3)

Glyceraldehyde

Pentose sugars (C5H10O5)

Ribose

Hexose sugars (C5H12O6)

Glucose Galactose

Dihydroxyacetone

Ribulose

Fructose

Functions 1.Cellular

fuel

2.Carbon skeletons, raw material for other molecules

Linear and ring forms

Abbreviated ring structure

Linear structure that form rings in aqueous solutions

Monosaccharides

- Chemical Structure: - Monomers vary in carbon chain length - Functional groups: hydroxyl and carbonyl (aldehyde and ketone) groups - Water solubility: - Linear and ring forms

Common Disaccharides

Common Plant Polysaccharides (glucose polymers): Energy storage and structural roles

Cellulose is a structural polysaccharide, a major component of the tough wall of plant cells.

Common Animal Polysaccharide (glucose polymers): energy storage

Common Animal Polysaccharide (glucose polymers): structural role

Exoskeleton of arthropods Cell wall of fungus Fiber for humans!

Lipids - Diverse Hydrophobic Molecules

- Contain long hydrocarbon chains: saturated and unsaturated - Three major groups of lipids with different functions 1. Simple fats (glycerides)- long term energy storage 2. Phospholipids- make up cell membranes 3. Steroids- regulation

• A simple fat is made of glycerol and fatty acids.

A triglyceride has three fatty acids joined to glycerol by an ester linkage, creating a triacylglycerol.

The same or different fatty acid may be present

Fatty acids may vary in: - length of hydrocarbon chain (number of carbons). - number and locations of double bonds. Saturated fatty acids - have no carbon-carbon double bonds. - solid at room temperature.

Unsaturated fatty acid are kinked because they contain a double bond

Common Fatty acids

Polyunsaturated fatty acids

Chemical structure of docosahexaenoic acid, or DHA (22:6n-3), and

eicosapentaenoic acid, or EPA (20:5n-3). Enhanced by Neuroinformation

http://lansbury.bwh.harvard.edu/polyunsaturated_fatty_acids.htm http://www.omega3sealoil.com/Chapter2a.html

difference between omega 3, 6, and 9.

Polyunsaturated fatty acids

Key omega-3 and omega-6 fatty acids - found primarily in oily cold-water fish such

as tuna, salmon, and mackerel. - Fresh seaweed - Plant sources: Leafy greens, nuts, seeds Omega-9 are not essential in humans

Phospholipids - two fatty acids attached to glycerol and a

phosphate group at the third position. - Important component of cell membrane

In the presence of water, phospholipids form micelles or bilayers.

• Steroids have a carbon skeleton consisting of four fused carbon rings. – Include cholesterol and other regulatory

hormones

Proteins carry out most of the functions of the cell

1. Storage 2. Structural 3. Transport 4. Enzymes 5. Hormones 6. Receptors 7. Contractile

Proteins • 20 monomers, amino acids. • peptide bonds, polypeptides • complex three-dimensional shape or

conformation. • may consist of one or more polypeptides

• Essential Amino acids

http://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.html

• Discovering Nutrition

- Google Books Result by Paul M. Insel, R. Elaine Turner, Don Ross - 2005 - Medical - 646 pages

R

• The physical and chemical characteristics of the R group determine the unique characteristics of a particular amino acid.

Amino acid have enantiomers:

L-Alanine D-Alanine http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/Enantiomers.html

19 of the 20 amino acids have an asymmetric carbon surrounded by four different groups or atoms L & D forms

R groups are either • Non-polar • Polar • Charged: acidic or basic

Essential amino acids

Corn

Beans and other legumes Lysine

Tryptophan Isoleucine Leucine Phenylalanine Threonine (Histidine) Valine Methionine

Complementary food combinations

Peptide bonds link the amino acids of the polypeptide

Protein structure www.pdb.org catalase (7cat) or lysozyme (1hsw) 1. Primary structure- unique sequence of its amino

acids. 2. Secondary structure- alpha helix or a pleated

sheet. 3. Tertiary structure, the three dimensional shape

or conformation. 4. Quaternary structure arises when two or more

polypeptides join to form a protein.

Chemical bonds that hold the tertiary structure of a protein forming among R groups:

– Relatively weak bonds - hydrogen bonds

- ionic bonds - hydrophobic interactions - van der Waals interactions – Strong bonds disulfide bridges covalent bonds that form

between the sulfhydryl groups (SH) of cysteine monomers, stabilize the structure.

• The folding of a protein: – can occur spontaneously for some – aided by other protein complexes,

chaperonins

Polypeptide Correctly folded protein

An unfolded poly- peptide enters the cylinder from one end.

Steps of Chaperonin Action:

The cap comes off, and the properly folded protein is released.

The cap attaches, causing the cylinder to change shape in such a way that it creates a hydrophilic environment for the folding of the polypeptide.

• The function of any protein is an emergent property resulting from its specific order of its amino acids.

• Quarternary structure results from the aggregation of two or more polypeptide subunits.

Collagen is a fibrous protein of three polypeptides that are supercoiled like a rope.

Hemoglobin is a globular protein with two copies of two kinds of polypeptides.

• A slight change in primary structure can affect a protein’s conformation and therefore its function.

• Sickle-Cell disease http://www.ygyh.org/

• Physical and chemical conditions affecting the bonds folding the structure of a protein can change its conformation (pH, salt concentration, temperature), or denature it.

Functionally active Functionally inactive

Nucleic Acids - Informational Polymers

1. Polymers of nucleotides.

2. Direct the activities and functions within a single cell.

2. Store and transmit hereditary information.

Two major types of nucleic acids: ribonucleic acid (RNA) deoxyribonucleic acid (DNA)

Nucleotide Structure

Each nucleotide consists of three parts: a nitrogen base- A, T, G, C a pentose sugar- ribose (RNA) &

deoxyribose (DNA) a phosphate group

The DNA double helix

• The sugar-phosphate backbones of the two polynucleotides are on the outside of the helix.

• nitrogenous bases connect the polynucleotide chains with hydrogen bonds.

Base-pairing rule of nucleotides in nucleic acids

H-bonds form between A & T A & U G & C The two strands of DNA are complementary