CH 3 Biological Molecules

(Biomolecules)

Biochemistry Review

Elements are substances that cannot be broken down or converted into another substance

They are composed of atoms which are the smallest units of matter (recall the levels of organization)

Biochemistry Review

An atom is composed of a nucleus, an electron cloud, and 3 subatomic particles: Protons (p+) Neutrons (n0) Electrons (e-)

Protons and neutrons are located in the nucleus of an atom and electrons in the electron cloud

p+

n0

e-

Nucleus

Electron cloud

Section 3.1Carbon in Biomolecules

Carbon & Biomolecules

Molecules are particles composed of atoms (from elements) held together by chemical bonds Classified as organic and inorganic

Organic molecules are important because they are general types of molecules that all living organisms synthesize and use; they are essential for life

Carbon & Biomolecules

The term “organic” describes molecules that contains the element carbon (C) and some hydrogen atoms

“Inorganic” molecules are all molecules that do not contain carbon, with the exception of carbon dioxide (CO2)

Carbon & Biomolecules

Although they have a common structure and function, the tremendous variety of organic molecules contributes to the diversity of structures within an individual organism and even individual cells

The reason for this? Carbon’s structure is very versatile when it

comes to forming bonds with other atoms

Carbon & Biomolecules

Macromolecules – large molecules composed of similar repeating units

There are 4 main groups of macromolecules that compose living things:

1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids

Section 3.2 Synthesizing Organic

Molecules

Modular Approach

The modular approach involves building organic molecules piece by piece (like a train with individual cars): Monomer: individual subunits (car) Polymer: long chains of monomers (train)

Mono- means “one” Poly- means “many”

Biomolecules & Water

Biomolecules are joined together or broken apart by removing or adding water:Water can break apart polymers

(biomolecule), freeing up the monomers

OR…When polymers (biomolecules) are

formed, water is often produced as a by-product

Biomolecules & Water

Dehydration synthesis reactions: when monomers are joined together by removing water to make biomolecules (polymers)

A H+ is removed from one monomer and an OH- from the other…they will form water

The spaces left open allow the monomers to bond together, creating a biomolecule (polymer)

Dehydration Synthesis

Biomolecules & Water

Hydrolysis reactions: when molecules are broken apart by water Water is added to a molecule (polymer),

causing it split back into the original monomers

CH 3.3What are Carbohydrates?

Carbohydrates

OH

OH

H

H

HO

CH2OH

HH

H

OH

O

Carbohydratesenergy

molecules

Carbohydrates-Sugars

Composed of carbon, hydrogen, and oxygen (1:2:1)

Overall function: used by organisms for short term energy and structural support

Monosaccharides

1 sugar molecule (monomer) Function: mainly used to form

polymers or for cell activities Most common: glucose C6H12O6

Others: Fructosefruits Galactoselactose RiboseRNA DeoxyriboseDNA

Disaccharides

2 sugar molecules linked together Function: mainly used for short-term

energy Examples:

Sucroseglucose + fructose Lactoseglucose + galactose Maltoseglucose + glucose

Polysaccharides

Many sugar molecules linked together Function: used for long-term energy storage Examples:

Starch: found in plant seeds & roots (FYI: 1000 to ½ million glucose)

Glycogen (animals): found in animal muscles & liver (much smaller than starch)

Cellulose: found in plant cell walls Animals can’t digest it, has to be broken down by

microbes so its usually just roughage/fiber for us Chitin: found in exoskeletons and fungi cell walls

Cellulose Structure & Location

Chitin Structure & Location

Section 3.4What are Lipids?

Lipids: Fats & Oils

Lipidsenergy storage

Lipids

Composed of mainly carbon and hydrogen

Have nonpolar regions that make them insoluble in water (meaning they won’t dissolve)

Types of lipids: Fats Oils Waxes Phospholipids Steroids

Oils, Fats, and Waxes

Triglyceride: the chemical name of fats and oils

Difference between fats & oils: Fats are solid, oils are liquid

Saturated Fats

Saturated fats are made of mainly hydrogen so the FA chains are “saturated” in hydrogen

Where we get them from: butter, bacon fat, steak; tends to come from animals

Unsaturated Fats

Unsaturated fats have a smaller amount of hydrogen in their FA chains

Where we get them from: the seeds of plants (they’re stored for the embryo) such as corn oil, peanut oil, etc.

FYI: Unsaturated fats

Unsaturated fats can be converted to a fat by breaking some of the double bonds and adding some hydrogens…this is known as a “hydrogenated oil” (allows margarine to be solid at room temp)

Partial hydrogenation creates trans fats which are also solid at room temperature Read Health Watch: Cholesterol-Friend or Foe

on pg. 45

FYI: Saturated & Unsaturated Fats

Saturated

Unsaturated

Waxes

Function: used as a waterproof covering for: plant leaves and stems mammalian fur insect exoskeletons to construct beehives

FYI: Chemically similar to fats, but they aren’t a food source because we and most other animals don’t have the enzymes necessary to break them down

Fats & Waxes

Phospholipids

Make up the plasma (cell) membrane

Head is hydrophilic or “water loving”

Tail is hydrophobic or “water fearing”

Steroids

Structurally different from all other lipids because it is a ring while the others were chains

Common steroid: cholesterol Component of animal cell

membranes

Section 3.5What are Proteins?

Proteins

Amino Acids and Proteins

Monomer: amino acids (AAs); there are 20 different AAs in all

Polymer: protein (chains of AAs)

Bond between the AAs when they are making polymers is known as a peptide bond

Amino Acids and Proteins

Peptide: short chains of AAs (FYI: 2-49 AAs)

Polypeptide: long chains, aka a protein (FYI: 50 or more AAs)

Protein Structure

1. Primary structure (1o)-the chain of AAs that make up the protein

2. Secondary structure (2o)- when the protein takes on a coiled or pleated shape

Primary/Secondary Level

Primary

Secondary

Protein Structure

Tertiary structure (3o)-the 3-D shape a polypeptide becomes (like balling up a piece of paper)

Quaternary structure (4o)-when polypeptide chains link together

Tertiary/Quaternary Levels

Tertiary

Quaternary

Types of Proteins

Can be classified as functional or structural

Functional: Enzymes: proteins that speed up almost all

chemical reactions that occur inside the cell Albumin (egg white) & Casein (milk):

provides AAs for developing young animals Some hormones such as insulin & growth

hormone Antibodies

Types of Proteins

Structural Elastin: gives skin its

elasticity Keratin: main protein

found in hair, nails, horns, scales, and feathers

Gossamer: the silk protein in spiders and silk moth cocoons

Section 3.6What are Nucleic Acids?

Nucleic AcidsInformation

storage

Nucleic Acids

Monomers: nucleotides

Polymers: nucleic acids (NAs)

2 types of nucleic acids: DNA-deoxyribonucleic acid RNA-ribonucleic acid

Other Nucleotides

Not all nucleotides are part of NAs Cyclic nucleotides: used as intracellular

messengers

Adenosine triphosphate (ATP): energy molecule found in all organisms

Coenzymes: assist enzymes in promoting and chemical reactions