Download Macromolecules - David Brotherton CCCMC

Biology
Class Notes
Lesson 3 Structure and Function of Macromolecules
Objectives: 4.1.1
Organic Compounds
• Contain carbon bonded to other carbon atoms as well as other elements including: H, O and N
• Four types:
– Carbohydrates
– Proteins
– Lipids (fats/oils)
– Nucleic Acids
Carbon Bonding
• Carbon has four valence electrons (e-s,) which means it has four e-s that can form single, double or triple
covalent bonds.
• Note carbon can bond with itself to form straight chains, branched chains, or rings.
Building Carbon Compounds
• The molecules are built up from smaller molecules known as Monomers: a repeated, single-molecule
unit, or a building block.
• Polymers: More complex carbon molecules consisting of repeated, linked monomers.
Condensation Reaction: Allows monomers to link together to form polymers and result in a “leftover”
OH- and an H+, that bond to form a water molecule (H2O).
Hydrolysis: Refers to reaction in which complex molecules such as polymers are broken down.
 Note hydrolysis is the reversal of a condensation reaction. Water is added and the bonds
holding molecules together are broken.
 Therefore, hydrolysis reactions are part of the food digestion process.
Build structures 1 and 2 from above, and combine them as in a condensation reaction…
Molecules of Life
Carbohydrates
Lipids (fats and oils)
Proteins
Nucleic acids
• All are built from carbon, hydrogen and oxygen in different ratios with different bonds, along with a
few other elements.
Carbohydrates (Hydrated Carbon)
Organic compounds composed of carbon, hydrogen and oxygen, including: sugars, starches and cellulose.
*Many are isomers.
*Classified according to their size and solubility.
Monosaccharides (simple sugars): Single chain or single ring carbohydrates.
Chemical formula = (CH2O) or 1:2:1
*Glucose
C6H12O6 “Blood Sugar”
Fructose
C6H12O6
Galactose
C6H12O6
Deoxyribose C5H10O5
Ribose
C5H10O5
Disaccharides (double sugars): Formed when two simple sugars are joined by condensation reaction.
C6H12O6 + C6H12O6  C12H22O11 + H2O
Glucose + Fructose  Sucrose + H2O
*Since they are too large to pass through cell membranes, they must be broken down by a
hydrolysis reaction before utilized.
C12H22O11 + H2O  C6H12O6 + C6H12O6
Sucrose + H2O  Glucose + Fructose
Ex:
Sucrose (Glucose + Fructose)
From sugar cane
Lactose (Galactose + Glucose)
From Milk
Maltose (Glucose + Glucose)
From **Starch**
*Starch: Naturally abundant carbohydrate, found in the seeds, fruits, tubers, roots,
and stem pith of plants such as, corn, potatoes, wheat, and rice.
Functions:
A readily available source of cellular fuel utilized during cellular respiration. The byproducts are
CO2 and H2O.
The bond energy released by cellular respiration is transferred to the molecular bonds of adenosine
triphosphate (ATP).
Adenosine Triphosphate (ATP): Organic molecule that stores and releases chemical energy
for use in cells.
Digestion >> Glucose + O2  CO2 + H2O + ATP
Proteins
Organic compounds composed mainly of carbon, hydrogen, oxygen and nitrogen.
Amino acids:
 20 monomer building blocks that form proteins.
 Carbon atom w/ four other atoms: carboxyl group (COOH), an amine group NH , and a functional
2
group designated with the letter R.
Amino Bonding
Dipeptide: The bonding of two amino acids
Two amino acids form a bond called a peptide bond.
Polypeptide: A long chain of amino acids bonded together.
*Proteins are composed of one or more polypeptide chains.
Add information about hormones.
Lipids (Fats/Oils)
Relatively large nonpolar molecules that do not dissolve in water.
 Have a higher ratio of carbon and hydrogen atoms to oxygen atoms than carbs.
 Have large number of carbon-hydrogen bonds that store more energy than the carbon-oxygen bonds
in other organic compounds.
1) Fatty Acids
Unbranched carbon chains that make up most lipids.
Hydrophilic: Water loving.
Hydrophobic: water fearing.

Made of long, straight carbon chains with a carboxyl group at one end (polar end, hydrophilic) and a
hydrocarbon end (non-polar, hydrophobic).
Saturated Fats: Have all single bonds.
Ex: animal fats/solid at room temperature.
Unsaturated Fats: Have one or more double or triple bond Ex: Vegetable fats (liquid at room
temperature).
Trans Fats: Unsaturated fatty acids that have been chemically altered to create a vegetable fat that
is solid at room temperature.
 Contain one or more double bonds in trans pattern
2) Complex Lipids: Classes of lipids important to living things that are categorized according to their
structure.
Triglyceride: Three molecules of fatty acid joined to one molecule of the alcohol glycerol.
Saturated triglycerides are made of saturated fatty acids and are solid at room temp.
Unsaturated trigs are made of unsaturated fatty acids and mostly found in plant seeds
and fruits where they provide energy for sprouting plants.
Phospholipids: Composed of two fatty acids joined together by a molecule of glycerol.
 Cell membranes are composed of two layers of phospholipids known as the lipid
bilayer.
 The inability of lipids to dissolve in water allows the membrane to form a
barrier/membrane.
Don’t draw the following diagram.
Draw the following diagram.
Nucleic Acids
Very large complex organic molecules that store important information in the cell.
Deoxyribonucleic acid (DNA): Contains information that is essential to cell activities (i.e. genetic
information).
Ribonucleic Acid (RNA): Stores and transfers information from DNA that is essential for making
proteins.
DNA>RNA>Protein
Nucleotides: Monomers (i.e. building blocks) that compose DNA and RNA.
 Have three parts: a phosphate group, a five-carbon sugar, and a ring-shaped nitrogen base.
Nucleotide Groups:


DNA uses the nucleotides: adenine, guanine, cytosine and thymine, not uracil.
RNA uses: adenine, guanine, cytosine and uracil, not thymine.
Distribute Biochemistry and Carbohydrate/Protein problem sets.
Key Words:
Macromolecule
Carbohydrate
Protein
Amino Acid
Hormone
Enzyme
Lipid
Nucleic Acid