biological molecules

Key molecules

  • Carbohydrates

  • Proteins

  • Lipids

    • Fats

  • DNA

 

Composition of carbohydrates, proteins and lipids

  • Made up of elements

    • Carbon, hydrogen + Oxygen

      • These molecules are also classified as organic molecules

        • Organic chemistry the study of carbon

        • Due to them containing carbon

      • These elements make up those molecules

      • All these molecules are macromolecules

        • Large and complex

      • There are made up of smaller sub-units called monomers

 

Examples of key macromolecules and their monomers

  • Starch

    • Made up the monomer glucose

    • A storage compound in plants

  • Glycogen

    • Storage compounds in animals

      • Animal starch

  • Cellulose

    • Monomer is glucose

    • Compound making up cell wall

    • Gives strength and support to plant cells

  • Protein

    • Monomer is amino acid

  • Lipids

    • Monomer are fatty acids and glycerol

 

 

Chapter 4

 

Carbohydrates, fats and proteins                                                                                                                                    

Carbohydrates

  • Substances that include sugars, starch, and cellulose; they contain carbon, hydrogen and oxygen

  • Starch

  • Cellulose

  • Sugar

    • Simplest type

    • Tastes sweet

    • Smallest one

    • Glucose

      • A sugar that is used in respiration to release energy

      • Made of six carbon, twelve hydrogen, six oxygen

        • C6H12O6

      • Way  it is transported around the body

      • Dissolves in blood plasma

      • Delivers to every cell

        • Needed for energy

      • Link together in chains

        • Form larger molecules

        • In animals, formed into glycogen

          • A carbohydrate that is used as an energy store in animal cells

      • Dissolved in blood plasma

        • Plasma is a liquid

        • Delivers to every cell

          • They need energy

  • Made of three elements

    • Carbon, hydrogen, oxygen.

 

Fats and oils

  • Also known as lipids

  • At room temperature

    • Fat is solid

    • Lipids are liquid

      • Insoluble in water

      • Used as energy storage

  • Contain Carbon, Hydrogen and Oxygen

    • Contains less oxygen than carbohydrates

  • Two kinds of smaller molecules

    • Glycerol

    • Fatty acids

 

  • Make cell membranes

  • Energy storage

  • In mammals

    • Fat droplets beneath the skin

      • Layered

      • Heat insulation layer

      • Fat-containing tissue

      • Energy storage

  • Do not dissolve in water

  • Dissolve in ethanol

    • Used to detect presence of fat in foods

      • Food shaken with ethanol

      • Fats dissolve in ethanol

      • Ethanol with fat dissolved in it poured into a cleat test tube of water

      • Tiny droplets form in water

      • Emulsion happens

        • Milky appearance

        • Liquid containing two substances that do not fully mix; one of them forms tiny droplets dispersed throughout the other

 

Proteins

  • Contain four elements

    • Carbon, Hydrogen, Oxygen and Nitrogen

    • Some contain Sulfur

  • Long chain of smaller molecules

    • Amino acids

      • 20 different kinds

    • Linked in a specific order

      • If the order they are in were changed even by one switch, then it would be a new/different protein

        • Infinite number of proteins

  • Many different functions

    • All enzymes are proteins

    • Antibodies

      • Protect body against pathogens

      • Secreted by white blood cells, which bind to pathogens and help destroy them

    • Pathogens

      • Microorganisms that cause diseases, such as bacteria

    • Haemoglobin

      • Transports oxygen in mammalian blood

      • Contains iron

        • Helps hold the oxygen molecules

    • Form cell membranes

    • Keratin

      • Protein that forms hair

      • Found in fingernails as well

  • To test for it

    • Use Biuret reagent

      • A blue solution that turns purple when mixed with amino acids or proteins

  • Cut pieces up or have a solution

  • Put into the test tube with Biuret reagent

  • Mix/shake together

 

DCPIP

  • A purple liquid that becomes colour less when mixed with vitamin C

  • Use a dropper pipette to add lemon juice to the DCPIP

  • The DCPIP should have a loss of colour 

    • The soonest site of loss of colour  is what you should look at, especially in exams

 

The structure of DNA                                                                                                                                                  

  • Deoxyribonucleic acid

    • Dee-ox-E-rye-bow-nucleic acid

  • Makes up genes and chromosomes

    • Each nucleus contains DNA

  • Inherited from our parents

  • Carries a code

    • Instructs the cell which amino acids should link together

  • Determines almost everything in the body's structure

  • Made of smaller molecules

    • Nucleotides

      • Contain bases

        • A, C, G, T,

          • Car in the garage

      • Two coil around one another