Molecules of Life

Introduction

  • Carbohydrates: Essential for energy storage and providing structural support in cells.

  • Proteins: Play a crucial role in catalyzing biochemical reactions and maintaining cellular structure.

  • Lipids: Important for forming cell membranes and storing energy.

  • What are they? Carbohydrates, Lipids, Proteins, Nucleic Acid

  • -O,H,N,P - make 99% of your body
    -K,S,Mg,Cl - 1%
    -B,Cu,F,I,Fe,Zn, etc. - trace elements

  • Organic compounds are relatively large: Glucose, DNA, Lipid, Protein are considered organic compounds and they are made up of mostly Carbon based molecules, and an organic compounds properties depend not only on the size and shape of its carbon backbone but also on the atoms attached to that skeleton

  • Functions:
    Carbohydrates: Serve as a primary energy source and are essential for cellular structure.
    Lipids: Play a crucial role in energy storage, cell membrane structure, and signaling within the body.
    Proteins are vital for numerous biological functions, including catalyzing metabolic reactions as enzymes, facilitating transport of molecules across cell membranes, and providing structural support to cells and tissues.

  • Compounds with the same formula but different structural arrangements are called isomers.

  • What’s so special about Carbon?
    -Carbon can make up to 4 other bonds with itself or other molecules
    - Can form long chains: Branched, linear, circular
    -Can make single, double, or triple bonds
    -Very versatile and essential for forming complex structures that are critical to life processes.

  • Carbon skeletons - Made up Carbon, can be linear/branched/circular, in the center of the molecule

  • Functional groups: Specific groups of atoms attached to the carbon skeleton that determine the characteristics and reactivity of the molecule, influencing how it interacts with other substances. These functional groups include hydroxyl, carboxyl, amino, and phosphate groups.

  • Functional groups are hydrophilic and are soluble in water

  • Types of functional groups:

    -Hydroxyl: Characterized by the presence of an -OH group, it makes molecules polar and increases their solubility in water.

    -Carboxyl: Contains a -COOH group, it acts as an acid by donating a proton, crucial in metabolic processes.

    -Amino: Composed of -NH2, this group serves as a base and is essential in the formation of proteins.

    -Phosphate: Featuring a -PO4 group, it plays a key role in energy transfer through ATP and is vital in nucleic acids.

    -Sulfhydryl: Identified by the -SH group, it contributes to the stabilization of protein structures through disulfide bonds, influencing the overall shape and function of proteins.
    -Methyl Group: Consists of a carbon oonded to three hydrogen atoms. -CH3. Affects the expression of genes.

  • Hydrocarbons - molecules consisting of only carbon and hydrogen, they serve as a primary source of energy and are fundamental components of lipids (fats), playing a crucial role in cellular structure and function.

  • Hydrocyl group consists of a hydrogen atom bonded to an oxygen atom.

  • Carbonyl group: A carbon atom is linked by a double bond to an oxygen atom, can be loacted within or at the end of a carbon skeleton, simple sugars/monosaccharides contain a carbonyl group and several hydroxyl groups

  • Carboxyl group: Consists of a carbon double-bonded to an oxygen atom and also bonded to a hydroxyl group. Can act as an acid by contrbuting an H+ to a solution.

  • Macrmolecules: Consisting of carbohydrates, proteins, and nucleic acids are gigantic on a molecular scale.

  • Polymers: A large molecule consisting of many identical or similiar monomers linked together by covalent bonds

  • Monomers: The building block of polymers

  • Reactions of Functional Groups:

    -Dehydration reaction/synthesis: Occurs when a polymer is to be made by having a reaction that removes a molecule of water as two molecules become bonded together.

    -When you digest something you have to break down the polymers to make their monomers available to your cells. This digestion process is called hydrolysis; the addition of a water molecule. The functional groups are restored.

  • Enzymes: Enzymes are required when btoh dehydration reactions and hydrolysis occur because enzymes help to make and break bonds. Enzymes are specialized macromolecules that speed up chemical reactions.

  • Water is inorganic because it doesn’t have a water molecule.

Carbohydrates

  • Carbohydrates range from small sugar molecules (monosaccharidess) to large polysaccharides.

  • Monosaccharides: The monomers of carbohydrates; mainly consists of glucose and fructose.

    • 5-carbon sugars; pentoses. 6-carbon sugar; hexoses

  • Draw glucose and fructose and galactose

    • Molecular Formula: C6H12O6

    • glucose and fructose are isomers

  • Cells use the carbon skeletons of monosaccharides as raw material for making other kinds of organic molecules such as amino acids and fatty acids

  • Disaccharide: Two monosaccharides bonded together by going through dehydration synthesis

  • Polysaccharides are macromolecules, polymers of hundreds to thousands of monosaccharides linked together by dehydration reactions.

  • Know difference of starch, glycogen, and cellulose:
    Starch - a storage polysaccharide in plants, consists of long chains of glucose monomers, coil into a helical shape and may be unbranched, can serve as carbohydrates “banks” from which plant cells can withdraw glucose for energy or building materials. Hydrolysis breaks down starch.
    Glycogen - animals store glucose in the polysaccharide glycogen, more branched than starch, stored as granules in your liver and muscle cells which hydrolyze the glycogen to release the glucose when it is needed
    Cellulose - the most abundant organic compound on Earth, major component of the tough walls that enclose plant cells, polymer of glucose but linked together in a different orientation, arranged parallel to each other, joined by hydrogen bonds. It’s not a nutrient for huans because animals do not have enzymes that allow the glucose linkages in cellulose to hydrolyze.
    Chitin - a structural polysaccharide used by insects and crustacean to build their exoskeleton also found in the cell walls of fungi.

  • Elements: CH2O
    Functional Group: OH

    Building Blocks or MONOMERS: Monosaccharides (simple sugars)

    E.X.: Gluctose, Fructose

    Dimers/Disaccharides:
    e.g. sucrose, maltose
    Polymers: Polysacharides
    e.g glycogen, starch, cellulose

Lipids

  • Lipids: A diverse group of molecules that are classified from one thing: they are hydrophobic.

    • They differ from carbohydrates, proteins, and nucleic acids from that they are neither huge macromolecules nor polymers built from similar monomers

    • Function: they store energy for later use and provide more energy than carbs and proteins, the cell structure form the membranes of cells (like phospholipids and cholesterol), they insulate (keep the body warm) the body and protect your organs by cushioning it for damage, some lipids act as messengers like hormones and help cells communicate by giving signals

  • 3 important types of lipids: fats, phospholipids, and steroids.

  • A fat is a large lipid made from 2 kinds of smaller molecules: glycerol and fatty acids

    • Glycerol + fatty acid = triglyceride/fat (1 glycerol 3 FA)

    • Main function: Energy storage

  • Non C-H bonds in the hydrocarbon chains are the reason fats are hydrophobic

  • Unsaturated fatty acid: A fatty acid whose hydrocarbon chain contains one or more double bonds

    • The double bond causes kinks or bends in the carbon chain

    • fats of plants and fishes generally contain unsaturated fatty acids

    • Liquid at room temperature so its considered an oil

  • Saturated fatty acid: Has no double bonds in its hydrocarbon chain

    • most animals fats are saturated

    • solid at room temperature

  • Trans fat: An unsaturated fat linked to health risks that is formed artificially during hydrogenation of vegetable oils

  • Phospholipids are the major component of cell membranes.

    • Structurally similar to fats except they contain 2 fatty acids

  • Elements: C,H, O
    Functional Groups: OH, COOH

    Monomers: Fatty Acids and glycerol
    Polymers: fats, phospholipids, waxes, steroids.

  • Phospholipids contains:
    -Glycerol

    -2 fatty acids
    -1 phosphate group
    -Partly hydrophobic and partyly hydrophilic
    -make up teh cell membranes

  • Hydrophobic and hydrophilic repel each other

  • Steroids:
    -Characteristics: All have 3,6 carbon ring and 1,5 carbon ring
    -Different in the side chains

  • Functions of lipids:
    1) Tryglycerides provide long term stores of energy

    2) Cell membranes are made of phospholipids
    3) Cholesterol is important in cell membranes
    4) Some steroids are hormone
    5) Waxes provide waterproofin

Proteins

  • Elements: C,H,O,N sometimes S
    Monomers: Amino Acids
    Polymers: Polypeptides or proteins
    Function: Diversity of functions in cell. Structure of skin muscles, hair, nails. Function as hormones, enzymes, transport, protection, etc.

  • In the R group , if it has an OH/CH by itself then you know it’s hydrophilic or -O (negative charge) CH3/CH2 by itself is nonpolar.

  • Primary structure is a sequence of amino acids unique for each protein. When you change the sequence of amino acids it changes the protein type

  • Secondary structure: The folding of the primary structure due to hydrogen bonds forming between the backbone of the amino acids.

    • There are two types of secondary structures: Alpha helix and beta pleated sheet

  • Tertiary structure: folding of the secondary structure by interaction of the R groups. H bonds hold the structure and it has to look a certain to perform its job. Hydrophiliscity/hydrophibisity makes the shape.

  • Quaternary Structure: Interactions similiar to those involved in tertiary structures (H bonds and R groups interacting with each other) hold s the subunits together. Multiple tertiary structured bonded together.

  • A protein is a polymer of amino acids.

  • The proteins most important role is as enzymes in which they are chemical catalysts that speed up and regulate all chemical reactions

  • The structural protein collagen forms the long, strong fibers of connective tissues accounts for 40% of the protein in your body.

    • Some proteins are storage proteins which supply amino acids to developing embryos

  • The function of the protein depends on its shape

  • Lysozyme consists of one long polymer of amino acids and its general shape is called globular.

    • Lysozyme can destroy bacterial cells, but it first must bind to molecules on the bacterial cell surface

    • Because of the enzymes specific shape it enables it to recognize and attach to its molecular target

  • Most enzymes and many other proteins are globular, however, structural proteins such as those making up hair, tendons, and ligaments are typically long and thin and are called fibrous proteins.

  • Denaturation: When a protein unravels which loses its specific shape and also its function as a result (since shape leads to function, it would lose its function if there is no shape [or program!] to live by)

  • Given proper cellular environment, a synthesizes amino acid chain would fold into its functional shape. If a protein doesn’t fold into its proper shape then many diseases could occur (such as Alzheimers)

  • Amino Acids all have an amino group and a carboxyl group.

    • Both of the functional groups are covalently bonded together by a central carbon atom

    • Then there is a hydrogen atom bonded to the central Carbon atom and then a variable chemical group symbolized by the R

    • 20 amino acids in all and the R groups determine whether it is hydrophobic or hydrophilic

  • Hydrophobic Amino Acids: R groups have CH3/CH2 or H only. (Has 2 rings with NH then it’s hydrophobic)
    Hydrophilic Amino Acids: Has O or NH2/NH3 in the R groups as an addition

  • Cells join amino acids together in a dehydration reaction that links the carboxyl group of one amino acid to the amino

    • The linkage they form is called a peptide bond

    • The product between two amino acids (the monomers) is a dipeptide

    • A chain of amino acids is called a polypeptide

  • A long polypeptide is NOT THE SAME to a protein

  • Hydrophobic amino acids would cluster together in the center of a globular protein while hydrophilic would go outside of the protein which woudl help it to be disolved in an aqueous solution of a cell.

  • The unique sequence of the various types of amino acids in a polypeptide determines how a protein takes shape.

    ALL ENZYMES ARE PROTEINS BUT NOT ALL PROTEINS ARE ENZYMES

Enzymes

  • Energy is the ability to cause change or to do work.

    • 2 basic forms of energy: Kinetic energy and potential energy

    • Kinetic Energy: the energy of motion

    • Potential Energy: stored energy that matter possesses

    • Thermal Energy: Type of kinetic energy that associates with the movement of atoms or molecules

    • Chemical Energy: Potential energy available for release in a chemical reaction