Basic Building Blocks of Life

Basic Building Blocks of Life

Organic Molecules

• Organic molecules contain carbon and hydrogen atoms
• Both atoms can form hydrocarbon chains and rings
• The four major classes of organic molecules: carbohydrates, proteins, lipids and nucleic acids.

Functional groups

• Functional groups are reactive molecules that usually contain oxygen, nitrogen, phosphorus or sulfur
• They are responsible for some of the unique properties of a molecule
• Some examples of functional groups

• Alcohols
• Aldehyde
• Amides
• Carboxyl groups
• Ketones

Carbohydrates (basic building blocks of life)

Carbohydrates

• These are organic molecules that contain carbon, hydrogen and oxygen
• Their general formula is C_nH_2nO_n
• Carbohydrates are a source of energy
• Carbohydrates are also known as sugars
• They have a suffix of “ose”
• Some types of carbohydrates

• Monosaccharide
• These are simple sugar carbohydrates
• Example of monosaccharide are hexose sugars
• glucose, fructose, galactose
• Disaccharides
• These are two monosaccharides joined together covalently
• Some examples:
• Sucrose (table sugar)
• Glucose + fructose
• Lactose
• Glucose + galactose
• Polysaccharides
• These are numerous monosaccharides that are joined together covalently
• Examples:
• Starch
• Glycogen
• Cellulose

Lipids (basic building blocks of life)

Lipids

• These are molecules that are insoluble in polar solvents
• Lipids are nonpolar and hydrophobic
• Lipids dissolve in nonpolar solvents  
• Lipids consists of hydrocarbon chains and rings
• Triglyceride (Triacylglycerol)
• Includes fat and oil
• Triglycerides are formed by condensation of one glycerol molecule with three fatty acid molecules
• Each fatty acid is a nonpolar chain with a carboxyl group (COOH)
• Saturated
• Carbon atoms within the hydrocarbon chain are joined by single covalent bonds   
• Unsaturated
• There are double covalent bonds within the hydrocarbon chain
• Ketone bodies
• Fatty acids that are converted in liver
• Ketosis = rapid breakdown of fat and an increase of ketone bodies in the blood
• Ketoacidosis = a sufficient amount of ketone bodies that can lower the blood pH
• Phospholipids
• These are lipids containing phosphate groups
• A 3 carbon glycerol is attached to two fatty acids and a phosphate group
• Micelles
• These are polar hydrophilic heads of phospholipids that face outside, while the hydrophobic tails are sequestered (covered) inside
• Sterols
• These are lipids (nonpolar and insoluble in water)
• Sterols have three 6-carbon rings joined to one 5-carbon ring
• Cholesterol is the precursor for steroid hormones, bile salts and vitamin D3
• Prostoglandins
• This is a type of fatty acid with cyclic hydrocarbon group
• It helps regulate blood vessel diameter, ovulation, inflammation, and blood clots.

Proteins (basic building blocks of life)

• Proteins are large molecules composed of amino acid subunits
• There are 20 different amino acids
• The difference between the amino acids is the functional group “R”
• Amino acids are joined together by dehydration synthesis
• In the dehydration synthesis, a hydrogen of the amine group from one amino acid end combines with an OH group of the carboxyl group of another amino acid
• Amino acids are held together by peptide bonds
• Proteins have different levels or structures
• 1° structure
• This portion entails the sequence of amino acids in protein
• 2° structure
• Weak hydrogen bonds form between the hydrogen of the amino group of one amino acid and the oxygen of the carboxyl group of another amino acid
• Forms polypeptide chain
• Can have two shapes
• Alpha helix
• Beta pleated sheet
• 3° structure
• The polypeptide chains will bend and fold themselves to form a 3D shape.
• 3° structure is stabilized by covalent bonds  (i.e. disulfide bond) or hydrogen bonds
• Each protein will have its own unique 3° structure because the folding that is produced by different bonds between different amino acids will occur at different regions
• In other words, bonds can form in different regions of the polypeptide chain
• However, the 3D shape can be disrupted by high temperatures or pH change causing denaturation
• Denaturation is irreversible such that the same exact 3D form will unlikely form
• 4° structure
• Different polypeptide chains will covalently bond together
• One example is hemoglobin
• Some different types of proteins
• Glycoproteins 
• Proteins that are combined with carbohydrates
• Lipoproteins
• Proteins that are combined with lipids
• Functions of protein
• Protein can act as enzymes, antibodies, receptors, carriers, channels and structural components
• Enzyme
• Enzymes are proteins and are also known as biological catalysts
• Catalyst is a chemical that:
• Increase the rate of reaction
• Catalysts will speed up the reaction by lowering activation energy
• Doesn’t change the nature of the reaction or the product result
• Itself is not changed at the end of the reaction
• Enzyme names will end with the suffix –ase
• Some exceptions are pepsin, trypsin  and renin
• Isoenzymes refer to the different models of the same enzymes

Also, visit the what is protein page

Nucleic Acids (basic building blocks of life)

Nucleic Acids

• DNA (deoxyribonucleic acid)
• Contains a 5 carbon sugar, phosphate group and nitrogen base
• These are the three components of a nucleotide
• Nucleotides are subunits of nucleic acids that bind together by dehydration synthesis
• In DNA, the 5 carbon sugar (ribose) lacks an oxygen atom at the 2’ carbon position
• This carbon sugar is called deoxyribose
• In DNA, the nitrogen bases are: Adenine, Guanine, Cytosine and Thymine
• Adenine and Guanine are purines
• Cytosine and Thymine are pyrimidines
• Adenine bonds with Thymine
• There are 2 hydrogen bonds
• Guanine bonds with Cytosine
• There are 3 hydrogen bonds

• RNA (ribonucleic acid)
• Contains a 5 carbon sugar, phosphate group and nitrogen base
• But what’s the difference?
• RNA contains the sugar called ribose
• DNA has deoxyribose
• Uracil replaces Thymine
• DNA does not have Uracil, but instead it has Thymine
• RNA is normally composed on single nucleotide strand
• DNA is normally double stranded

What is the function of RNA?

Visit the page, what is atp, in order to learn about the basic source of energy

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