Chapter 5- The structure and Function of Large Biological Molecules

Biomolecules

The organic molecules that are essential to living organisms

The 4 primary classes of biomolecules

1) Carbohydrates

2) Proteins

3) Nucleic Acids

4) Lipids

Monomers

Single, individual building blocks that can be repetitively linked together to form polymers

Monomers vary?

Depending on the type of biomolecule polymer

Consistent and not consistent monomers

Carbohydrates, Proteins and nucleic acids use consistent monomers to form polymers, but lipids do NOT

Dehydration Synthesis

Forms covalent bonds to link individual monomers and build a polymer

Hydrolisis

Breaks covalent bond to break down a polymer

Carbohydrates

Carbon-based-molecules hydrated with many hydroxyl groups (-OH)

What is carbohydrates referred to

Saccharides

Simple Carbohydrates

Fit Cn(H2O)n formula exactly

Complex Carbohydrates

Can differ slightly from Cn(H2O)n and can have P,N or S atoms

Monosaccharide

A single carbohydrate unit or monomers

Oligosaccharide

2 to 20 covalently linked monosaccharides

Polysaccharides

More than 20 covalently linked monosaccharides (polymer)

Glycosidic Bonds

Covalent bonds that link monosaccharides together

Hydrolysis

Breaks down polysaccharides into individual monosaccharides

What are the two main functions of a carbohydrate

Storage Support: Helps build

Energy Storage: Used for short-term energy-storage

Cellulose

Most abundant carbohydrate found in plant-cells

Starch

Storage form of glucose in plants

Chitlin

Found in the exoskeleton of a insect or crustaceans

Glycogen

Storage form of glucose in animals

Proteins

A class of biomolecule polymers made of amino acid monomers

Peptide Bonds

Covalent bonds linking adjacent amino acids together

Proteins polymers have directionality

N-terminal and C-terminal Ends

Amino Acids

The monomers of proteins

Amino Acids: Nonpolar Side Chains; Hydrophobic

Glycine, Alanine, Valine, Leucine, Isoleucine, Methionine, Phenylalanine, Tryptophan, Proline (9)

Amino Acids: Electrically charge side chains; hydrophilic

Serine, Threonine, Cysteine, Tyrosine, Asparagine, Glutamine (6)

Amino Acids: (Negatively Charged)

Aspartic Acid, Glutamic acid

Amino Acids: (positively charged)

Lysine, Arginine, Histidine

1st protein related term

Amino Acids: A single protein unit or monomer

2nd protein-related terms

Oligo peptide: 2 to 20 covalently linked amino acids

3rd Protein related terms

Peptide: Less than 50 covalently linked amino acids

4th Protein-related terms

Polypeptide: Greater than 50 covalently linked amino acids

5th Protein-related terms

Protein: One or multiple polypeptide chains in their folded/functional forms

Primary Protein Structure

Types, quantity, and order of amino acids. Determines all other levels of structure

Secondary Protein structure

Formation of either alpha-helics or Beta-sheets in the protein backbone

Tertiary protein structure

Overall 3D-shape of a polypeptide chain

Quaternary Protein structure

Multiple polypeptide chains associate to form a single, functional protein

Why is a proteins structure and shape critical

Its critical for its proper function

Denatured Protein

A non-functional protein that has altered its shape

What causes a denatured protein

pH, Temp, or salt concentration

Chaperone Proteins

Chaperone Proteins

Proteins that help other proteins can re-form their shape (or renature)

Nucleic acids

A class of biomolecule polymers that store/ encode genetic information

Directionality of the nucleic acid polymer

5’ and 3’ ends

Nucleotide monomers consist of 3 components

1) Phosphate Group

2) Pentose Sugar

3) Nitrogenous base

Nitrogenous Basses: Pyrimidines

Single-ringed molecules

Cytosine, Thymine, Uracil

Nitrogenous Bases: Purines

Double Ringed Molecules

Adenine, Guanine

Nitrogenous bases on different DNA strands pair together

A with T and C with G

Phosphodiester Bonds

The covalent bonds that link nucleotides together

Results in the sugar-phosphate “Backbone”

Directionality of 5’ phosphate end to 3’ hydroxyl end

Deoxyribonucleic acid (DNA)

Stores genetic/hereditary information in the cell.

Forms a double-helix 2 anit-parallel strands connected by base-pair hydrogen bonds

Ribonucleic acid (RNA)

Has a variety of functions including acting as a template for synthesizing proteins

Usually forms a single-stranded nucleotide chain

Lipids

Hydrophobic biomolecules insoluble in water that are highly diverse in their structure and function

Can be amphipathic: Having both hydrophobic and hydrophilic group

Do not form polymers

Lipids include

Fats, oils, phospholipids, steroids, and waxes

Fats and oils

Long term energy storage in animals and plants

Phospholipids

Major component of cell membranes

Steroids

Component of plasma membrane and hormones

Waxes

Protection and prevention of water loss

Fatty acids

Hydrocarbon chains of varying length with a carboxylic acid

Saturated Fatty acids

Fully saturated with hydrogens (only contains C-C single bonds)

Solids at room temp

Unsaturated Fatty acids

Not fully saturated with hydrogens due to presence of more than 1 C=C double bond

-Double bond creates a bend in the chain making them liquids at room temp

Trans-fat

Artificial unsaturated fatty acids that are NOT bent (linear)

Triglycerides

A lipid with 3 fatty acid chains covalently linked to a single glycerol molecule

Fatty acids linked to glycerol results in

Dehydration synthesis reactions

Phospholipids

Large class of lipids that contain a phosphate group

Major component of all cell membranes

Amphipathic molecules with a hydrophilic head and hydrophobic tails

Steroids

Lipids that are made of 4 fused carbon ring structures

Cholesterol

Common steroid important for the structure of animal cell membranes

Waxes

Another class of lipid that can be used for protection and prevention of water loss