© 2010 Pearson Education, Inc. Organic Compounds.

© 2010 Pearson Education, Inc.

Organic Compounds


ORGANIC COMPOUNDS

A cell is mostly water.

The rest of the cell consists mainly of carbon-based molecules.

Carbon forms large, complex, and diverse molecules necessary for life’s functions.

Organic compounds are carbon-based molecules.


Carbon Chemistry

Carbon is a versatile atom. It has four electrons in an outer shell that holds eight.

Carbon can share its electrons with other atoms to form up to four covalent bonds.


Form & Function of Organic Molecules

Each type of organic molecule has a unique three-dimensional shape.

The shapes of organic molecules relate to their functions.


Properties of Organic Compounds

The unique properties of an organic compound depend on Its carbon skeleton The atoms attached to the skeleton

The groups of atoms that usually participate in chemical reactions are called functional groups. Two common examples are Hydroxyl groups (-OH) Carboxyl groups (C=O)


Giant Molecules from Smaller Building Blocks

Organic macromolecules are large polymers.

Three categories of macromolecules are Carbohydrates Proteins Nucleic acids


Short polymer Monomer

Dehydrationreaction

Longer polymera Building a polymer chain

Polymer Formation

Polymers are made by stringing together many smaller molecules called monomers.

A dehydration reaction Links two monomers together Removes a molecule of water


Breaking up Polymers

Organisms also have to break down macromolecules.

Hydrolysis Breaks bonds between monomers Adds a molecule of water Reverses the dehydration reaction


LARGE BIOLOGICAL MOLECULES

There are four categories of large molecules in cells: Carbohydrates Lipids Proteins Nucleic acids

Lipid is the only large molecule that isn’t also a macromolecule


Carbohydrates

Carbohydrates are sugars or sugar polymers. They include Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes


Monosaccharides

Monosaccharides are simple sugars that cannot be broken down by hydrolysis into smaller sugars.

Glucose and fructose are both monosaccharides

Monosaccharides are the main fuels for cellular work. In aqueous solutions, many monosaccharides form

rings.


Disaccharides

A disaccharide is A double sugar Constructed from two monosaccharides Formed by a dehydration reaction

Glucose Galactose

Lactose


Glucosemonomer

a Starch

b Glycogen

c Cellulose

Starch granules

Glycogengranules

Cellulose fibril

Cellulosemolecules

Polysaccharides

Complex carbohydrates Made of long chains of sugar units and polymers of

monosaccharides


Carbohydrates (cont.)

Monosaccharides and disaccharides dissolve readily in water.

Cellulose does not dissolve readily in water.

Almost all carbohydrates are hydrophilic, or “water-loving,” adhering water to their surface.


Oil (hydrophobic)

Vinegar (hydrophilic)

Lipids

Lipids are Neither macromolecules nor polymers, but they are

large molecules Hydrophobic, unable to

mix with water


Lipid Family

The lipid family contains of:1. Fatty acids 2. Triglycerides ( fats and oils )3. Phospholipids4. Steroids ( Cholesterol, Bile Salts, Vit. D, Adrenocortical hormones, Sex hormones )5. Eicosanoids ( prostaglandins and leukotrienes )6. Others ( Carotenes, Vit. E, Vit. K, Lipoproteins )


Fatty acid

Glycerol (a) A dehydration reaction linking a fatty acid to glycerol

(b) A fat molecule with a glycerol “head” and three energy-rich hydrocarbon fatty acid “tails”

Fats or Triglycerides

A typical triglyceride, consists of a glycerol molecule joined with three fatty acid molecules via a dehydration reaction.


Triglycerides

Triglycerides : the most plentiful lipid in your body. It consists of two types of building blocks: a single three-carbon glycerol molecule and three fatty acid molecules.

It can be either solid (fat) or liquids (oil). It's functions in the human body are for

protection, insulation, and energy storage.


Steroids

Steroids : the structure of steroids differ from triglycerides, they have four rings of carbon atoms.

Steroids are synthesized from cholesterol.

Functions :1. Cholesterol : minor component of cell membranes, precursor of other steroids2. Bile Salts : digests dietary lipid3. Adrenocortical Hormones : regulate metabolism, resistance to stress, have a role in salt and water balance4. Sex hormones : stimulate reproductive functions and sexual characteristics


Steroids

Steroids are very different from fats in structure and function. The carbon skeleton is bent to form four fused rings. Steroids vary in the functional groups attached to this

core set of rings.

– Cholesterol is• A key component of cell membranes • The “base steroid” from which your body produces

other steroids, such as estrogen and testosterone


Cholesterol

Testosterone A type of estrogen


Proteins

Are polymers constructed from amino acid monomers Perform most of the tasks the body needs to function Form enzymes, chemicals that change the rate of a

chemical reaction without being changed in the process


The Monomers of Proteins: Amino Acids

All proteins are constructed from a common set of 20 kinds of amino acids.

Each amino acid consists of a central carbon atom bonded to four covalent partners in which three of those attachment groups are common to all amino acids.

Peptide bonds link amino acids together to form proteins


Protein Structure & Function

The structure of a protein is vital to its function. Proteins differ in their arrangement of amino acids. The specific sequence of amino acids in a protein is its

primary structure.

A slight change in the primary structure of a protein affects its ability to function.


Protein

Target

Protein Structure & Function

A protein’s three-dimensional shape Recognizes and binds to another molecule Enables the protein to carry out its specific function in a

cell


Protein Shape

A functional protein consists of one or more polypeptide chains, precisely folded and coiled into a molecule of unique shape.


Nucleic Acids

Nucleic acids Are macromolecules that provide the directions for

building proteins Include DNA and RNA Are the genetic material that organisms inherit from

their parents


Nucleic Acids

DNA resides in cells in long fibers called chromosomes.

A gene is a specific stretch of DNA that programs the amino acid sequence of a polypeptide.

The chemical code of DNA must be translated from “nucleic acid language” to “protein language.”


Nitrogenous baseA, G, C, or T

Thymine T

Phosphategroup

Sugardeoxyribose

a Atomic structure

Nucleotides

Nucleic acids are polymers of nucleotides. Each nucleotide has three parts:

A five-carbon sugar A phosphate group A nitrogenous base


Nucleotides

Each DNA nucleotide has one of the following bases: Adenine (A) Guanine (G) Thymine (T) Cytosine (C)


Sugar-phosphatebackbone

NucleotideBasepair

Hydrogenbond

Bases

a DNA strandpolynucleotide

b Double helixtwo polynucleotide strands


DNA Structure

Two strands of DNA join together to form a double helix.

Bases along one DNA strand hydrogen-bond to bases along the other strand.

The functional groups hanging off the base determine which bases pair up: A only pairs with T. G can only pair with C.


Phosphategroup

Nitrogenous baseA, G, C, or U

Uracil U

Sugar ribose

RNA

RNA, ribonucleic acid, is different from DNA. RNA is usually single-stranded but

DNA usually exists as a double helix.

RNA uses the sugar ribose and the base uracil (U) instead of thymine (T).

© 2010 Pearson Education, Inc. Organic Compounds.

Documents

Transcript of © 2010 Pearson Education, Inc. Organic Compounds.