Organic Compound Of Life

Organic Compounds of life:

• 4 Types: Carbohydrates, Lipids, Proteins & Nucleic acids

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CARBOHYDRATES:

• Includes: Sugars, starches, cellulose & glycogen

• Made of Carbon ( C ), Hydrogen ( H ), and Oxygen (O )

• Following ratio of elements CnH2nOn

o Sugars: Provide & store energy for cells

o Simple sugars include Glucose & Fructose since these are made of only 1 Carbohydrate molecule they are known asMonosaccharides.

• Monosaccharides can be linked together through the process of Dehydration Synthesis

o Water is removed from 2 monocaccharides - resulting in a covalent bond between the 2 molecules

• Sucrose (table sugar) is made of 2 sugars linked together and these are called Disaccharides

o Often referred to as transport saccharides

o Require some digestion to be used by cells

Dehydration Synthesis

• Starches are many monosaccharides linked together in a single chain. These are called Polysaccharides.

o Plants use this for energy storage e.g. Potatoes

o Two types

 Amylose - Long strait unbranched chains

 Pectins - many linked short Amylose chains

Starch

• Cellulose is made of long polysaccharide chains

o Plants use this for structure (e.g. Wood) - not very digestible

o Due to the reverse orientation of the monosaccharide sububnits, digestive enzymes cannot hydrolize the bonds between them

Cellulose

• Glycogen is a moderately branched polysaccharide

o Animals use this for energy storage.

Glycogen

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Lipids:

• Lipids are macromolecules including fats, waxes & oils

o Primary function is energy storage.

 Energy is stored in C-H bonds.

 More efficient in storing energy

o Lipids are made of 2 parts

 Glycerol - an alcohol - Serves as backbone of the molecule

 3 Fatty acids - Long hydrocarbon chains

• Saturated fats have long chains with no double-bonds

• Unsaturated fats have double bonds

• Polyunsaturated fats have many double bonds

• Each time a double bond is encountered, the molecule "Bends" slightly, resulting in a lower density of the lipid. This makes the molecule more likely to remain liquid at room or body temperatures.

• 4 Major types of biologically important Lipids

• Phospholipids - Important for membrane structure

• Steroids - eg. Cholesterol & testosterone. Provide membrane support / serve as hormones

• Terpenes - serve as important components of pigments

• Prostaglandins - appear to act like localized hormones to induce cellular/tissue responses.

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Proteins

• Proteins are made of Amino Acids

• There are 20 different amino acids. Each having a similar general structure - Differ only in their "R" groups

example amino acids

• Amino acids form proteins via deyhdration sythesis forming peptide bonds

• Two amino acids linked together are called dipeptides

• More than 2 linked together are called polypeptides - polypeptides can be thousands of amino acids long

• Protein types include globular proteins which are usually enzymes and Fiberous proteins which usually serve for structure (eg. Hair)

• Proteins Exhibit 4 "levels of structure.

o Primary Structure of a protein is it’s sequence of amino acids.

o The Sequence (primary structure) causes parts of a protein molecule to fold into sheets or bend into helix shapes - this is a protein’s Secondary Structure.

o The protein then can compact and twist on itself to form a mass called it’s Tertiary Structure

o Several Proteins then can combine and form a protein’s Quaternary Structure.

• Various conformations are usually caused by the formation of hydrogen or disulfide bonds

• PH, changes or heat can disrupt these bonds, permanently denaturing the protein.

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Nucleic Acids

• Two types of Nucleic acids

• DNA (Deoxyribonucleic Acid)

• RNA (Ribonucleic acid)

o DNA is Formed of in a "Double Helix" - like a spiral staircase.

DNA Molecule-note "double helix" shape

• DNA is formed by Nucleotides

o These are made from 3 components

 A 5-Carbon Sugar

 A Nitrogenous base

 A Phosphate group

• Nucleotides form a backbone through linkages from the OH group of the 3rd carbon to a phosphate group of the adjoining nucleotide. These are called Phosphodiester bonds

• For DNA There are 4 different Nucleotides categorized as either Purines (double ring) or Pyramidines (single ringed). These are usually represented by a letter. These Are:

o Adenine (A)

o Cytosine (C)

o Guanine (G)

o Thymine (T)

• Each "Rung" of the DNA "staircase" is formed by the linking of 2 Nucleotides through Hydrogen Bonds.

• These Hydrogen bonds form only between specific Nucleotides. This is known as Base Pairing. The rules are as follows:

o Adenine (A) will ONLY bond to Thymine (T)

o Cytosine (C) will ONLY bond to Guanine (G)

• RNA differs from DNA in several important ways.

1. It is much smaller

2. It is single-stranded

3. It does NOT contain Thymine, but rather a new nucleotide called Uracil which will bind to Adenine.

Comparison of DNA & RNA

• ATP is closely related to nucleic acids.

• Composed of Ribose, Adenine & a phosphate group

o Phosphate group has ability to bind/release additional phosphate group allowing it to store or release energy.