Unit 3

Biomolecules (macromolecules)

• Carbohydrates *

• Lipids 

• Proteins *

• Nucleic Acids *

* Polymers: chemicals made up of many repeating units called monomers 

Dehydration RXN (condensation)

Short polymer with and H and monomer with OH connect to form a polymer with H2O

Hydrolysis RXN

Large polymer with H2O breaks into short polymer with and H and monomer with OH

Enzymes: proteins that allow rxns to take place

Hydrolytic enzymes: enzymes that use water to break down polymers 

Carbohydrates 

Empirical formula: CH2O 

Monomers of carbohydrates are called Monosaccharides. 

Functions:

• Provide energy for all organisms 

• Structure of plant fungi and bacteria 

• Communication for cells 

Glucose 

Structure of Glucose

If a B glu and B glu connect one of them has to flip. 

Polysaccharide 

1. Starch 

   1. Very long chains of A-Glu (1000>)

   2. Amylose - short chain 

   3. Amylopein - branch 

   4. Storage of energy for pants 

2. Glycogen 

   1. Very long branched chains of A-Glu (1000>)

   2. Highly branched 

   3. Storage of energy in liver/muscle cells

3. Chitin (CH2ON)

   1. Exoskeleton of insects 

   2. Makes up cell wall of fungi 

   3. Straight chain 

4. Cellulose 

   1. Only made up of B-Glu 

   2. Makes up the cell wall for plants 

   3. Made up of straight chains 

What makes cells strong and rigid?

H bonds between cellulose molecules 

Microfibril: a group of cellulose molecules holding onto each other 

When many are stacked, they form the cell wall

Adaptive tissue: fat tissue 

Our body stores sugar as glucose and excess sugar is stored as body fat 

Proteins 

All functions in the body are carried out by proteins

Protein could be used as energy once all other sources run out, this state is called starvation

Components 

20 different types of amino acids 

1. Nonpolar (hydrophobic)

2. Polar (hydrophilic) 

3. Electrically charged (ionic) 

Examples:

Nonpolar: Methionine 

Polar: All polar amino have O or N at it’s end 

Except for Cysteine, helps for 3D structure of proteins 

The basic structure of an amino acid:

Elements found in all proteins 

• Carbon 

• Oxygen 

• Nitrogen 

• Hydrogen 

• Sulfur

Structure level of proteins 

Primary structure 1°

1. Tells the number of amino acids 

2. Types of amino acids 

3. Sequence of amino acids 

Secondary structure 2°

1. Folding of the 1° structure using H-Bonds 

   1. α Helix (spiral)

• Exp: collagen, holds cells together 

2. β pleated sheets 

• Exp: keratin, for hair and nails 

Fibrous Protein

Proteins that have up to the 2° structure and they are insoluble in water, nonpolar, hydrophobic 

Tertiary structure 3°

1. Further folding and twisting of previous structures by using Intra molecular forces such as: 

• H Bonds

• LDF

• Ionic bonds

• Dip Dip

• Disulfide bridges 

2. Exp: hemoglobin or insulin 

Globalor proteins: 

They have 3° structure or higher, and they are soluble in water 

Quateunary structure 4°

1. Found in proteins that have 2 or more polypeptide chains held together by intra-MF

• Exp: 

  • Hemoglobin: 4 polypeptide 

  • Indulin: 2 polypeptide 

Denaturation

loss of protein structure leading to loss of functions 

Caused by:

• pH 

• Temperature 

• Pressure 

• Salt → have charged when dissolved in H2O, disrupts ionic bonds 

↑ maybe reversible or irreversible 

Structure of protein 

Defence → antibodies → protects from bacteria and viruses 

Enzymes → Alpha amylase → breaks down starch 

Structure → collagen → molecules have 2° fibers have 4° 

Communication → insulin (dec glucose) glucagon (inc glucose)

Storage → ferritin → stores iron 

Transport→ calcium pump → moves Ca^2+ across membrane

      HDL → lipids around body 

      Hemoglobin → transports O2 in blood 

Contractile proteins → myosin and actin → contract & move muscles 

Receptors → insulin receptor → detect hormones 

Nucleic Acid 

Central dogma: All life depends on DNA

DNA: 

• deoxyribonucleic acid 

• Double helix 

• It has 2 strands with H-Bonds in the middle.

RNA: ribonucleic acid 

• 1 strange with different types 

• mRNA (message) - carries the info from the nucleus to the cytoplasm 

• tRNA (transfer) - brings the correct amino acid during protein synthesis 

• rRNA (ribosomal) - needed in structure for ribosomes 

call structure that builds proteins 

• miRNA (micro) - regulates gene expression 

DNA → RNA → PROTEINS 

from DNA to RNA: Transcription                

from RNA to protein: Translation 

Transcription:

It happens in the nucleus 

Type of chemical remains the same but the structure changes 

Translation:

Happens in the cytoplasm 

Type of chemical changes and so does the structure 

Monomers of nucleic acids: nucleotides 

Made up of:

• Nitrogenous base ↓H⁺ attached to C1

• Pentose sugar      C5H10O5

• Phosphate group Always attached to C5

Lipids 

Fats

• Animal sources

• Solid at room temp 

• Saturated 
  
  

Oils

• Plant source 

• Liquid at room temp

• Unsaturated 

Basic functions of lipids

• Energy storage

• Insulation 

• Cell membranes (make new cells)

• Communication for hormones 

• Defence 

Triglycerides 

Used for energy storage

Made up of

• 1 glycerol

• 3 fatty acids 

  • Fatty: hydrocarbon 

  • Acid: carboxyl 

Structure 

Esterification: the process of creating an ester bond rxn between alcohol and fatty acid

Types of triglycerides 

Saturated triglycerides  

• All three fatty acids must have single bonds ONLY 

Monounsaturated  

• One and only one  

• double bond must be present, causing one of the fatty acids to move downwards, allowing it to be liquid at room temp. Because it leaves space for it to move and become a liquid  

Polyunsaturated  

• Has two or more double bonds present. It can be on the same fatty acid  

Vitamins

V. are special chemicals needed for proper metabolism  

Nonpolar are stored in adopost tissue 

Polar ones cannot be stored 

Retinol: V A1 alcohol nonpolar 

Retinal: V A aldehyde nonpolar 

VD: nonpolar cholesterol-based forms on skin 

Phospholipids 

Create the cell membranes. 

Made up of:

• Glycerol 

• 2 fatty acids

• Phosphate group 

Steroids 

• Creation of hormones 

• Membrane stability (flexibility) 

• Regulates fluidity 

  • More cholesterol more rigid 

Components

• Cholesterol 

Cholesterol Rings 

Waxes

For defence 

Made up of:

• Long chained alcohol 

• Long chained fatty acid