[BIO 111] CH 5 - Biological Molecules

4 classes of biological molecules

carbohydrates, lipids, proteins, and nucleic acids

Macromolecules

large, complex molecules that have unique properties due to their arrangement of atoms

Polymers

long chains of monomers

Monomers

building blocks that make up polymers 

Enzymes

specialized proteins that speed up reactions

Dehydration reaction

two monomers bond through the loss of water

Hydrolysis

water molecules break down large molecules into smaller units

Carbohydrates 

simple sugars and polymers of sugars

Carbohydrate monomer

monosaccharides

Carbohydrate polymer

polysaccharides

Monosaccharides

molecules that follow the general formula CH2

What is the most common monosaccharide?

glucose C6H12O6

How are monosaccharides classified?

location of carbonyl group and number of carbons in skeleton

Aldose

molecules with a carbonyl group attached at the end of carbon skeleton

Ketose 

molecules with carbonyl group attached within of carbon skeleton 

What do monosaccharides serve as?

major fuel source for cells and raw building blocks for molecules

Disaccharide

two monomers joined together by glycosidic linkages

Glycosidic linkage

covalent bonds between 2 monosaccharides

What role do polysaccharides serve? 

serve as storage and structural roles 

4 types of polysaccharides

starch, glycogen, cellulose, and chitin

Starch

primary carb in plants composed of glucose monomers

Where are starches stored in plants?

Chloroplast granules

What is the simplest starch? 

amylose 

Glycogen

primary carb in animals

Where is glycogen stored in animals?

Liver and muscles

Cellulose

primary carb in plants that makes up cell walls

Chitin

primary carb found in fungi and exoskeletons of arthropods

Lipids

fatty compounds

What is largest and most diverse class of biological molecules?

lipids

What are lipids considered? 

hydrophobic and nonpolar

Polymer of lipids

none

Fats

large molecules made up of glycerol group and 3 fatty acid chains

Glycerol

3 carbon alcohol with 3 hydroxyl groups attached to each carbon

Fatty acid

long carbon chain with carboxyl group attached at the end 

What is the major function of fats?

energy storage

Triglyceride

3 fatty acids chains attached to glycerol

Saturated fatty acid

fatty acid with no double bonds present

Unsaturated fatty acid 

fatty acid with one or more doubles bonds that cause a kink/bend to form 

Which type of fat is solid at room temperature and is found in most animal fats?

Saturated fats

Which type of fat is liquid at room temperature and is found in most plant and fish fats?

unsaturated fats

Trans fats

hydrogenated veggie oils with trans double bonds

Phospholipids

2 fatty acids chains and phosphate attached to a glycerol group 

What do phospholipids do in water?

self assemble in bilayers with hydrophobic tails pointing inward

Steroid

lipids characterized by carbon skeleton consisting of 4 fused rings

Cholesterol 

type of steroid that is the base of all other steroids

Hormonal proteins

coordinate organisms activities

Storage proteins

storage of amino acids

Catalyst

something that speeds up chemical reactions

Proteins 

biological molecules made up of amino acid chains 

Monomer of proteins

amino acids

Polymers of proteins

polypeptides 

Amino acids

organic molecules made up of a carboxyl and amino group

Peptide bonds

covalent bonds between amino acids that hold polypeptide chains together

How is a protein’s function determined?

unique shape given by its folding, twisting, and coiling

What are the 4 levels of structure of proteins? 

Primary, secondary, tertiary, and quaternary 

Primary structure

unique sequence of amino acids

Secondary structure

coils and folds in polypeptide chains

What are the coils called in a protein’s secondary structure?

alpha helix

What are the folds called in a protein’s secondary structure?

beta pleated sheets

Tertiary structure

loops and folds that give proteins its 3D shape that occur from the interactions between R groups within its chains

Quaternary structure

two or more polypeptide chains form a protein

Denaturation

a protein’s loss of its native structure which makes it inert

What causes denaturation? 

extreme changes in pH, salt [], temp, or other enviro factors

Gene

amino acid sequence of a polypeptide

Nucleic acids

molecules composed of nucleotides

Monomers of nucleic acids

nucleotides

Polymers of nucleic acids

polynucleotides 

Gene expression

DNA directs synthesis of mRNA which controls protein synthesis

DNA —> RNA

transcription

RNA —> protein

translation

What are nucleotides consist of? 

phosphate group, pentose sugar, and nitrogenous base 

Pyrimidines

cytosine, thymine, uracil — single 6 sided ring

Purines

adenine and guanine — 6 sided ring fused to 5 sided ring

How are nucleotides held together? 

phosphodiester linkages 

Phosphodiester linkages

phosphate group covalently bonds pentose sugars in nucleotides

How are nitrogenous bases paired in RNA?

thymine with uracil and guanine with cytosine