Lecture 3 biological molecules

Organic compounds

any carbon containing liquid, solid, or gas (C bonded to C or H)

Why is carbon so important

it is the fundamental component for all macromolecules

“Backbone”

can form 4 bonds (covalent) with different atoms, forming complex molecules

Hydrocarbons

Only carbon and hydrogen

usually, fuels since their many covalent bonds store great amounts of energy

Nonpolar

hydrophobic

uncharged (unionic)

When the H is replaced with a functional group (like oh) → properties change

Functional groups

Group of atoms attached to C, replaces H

Changes complexity, shape, and properties of molecules

Key to molecular function

Exp: estradiol and testosterone sim structures but slight differences create big changes

6 groups of functional groups

Hydroxyl

Carbonyl

Carboxyl

Amino

Phosphate

Methyl

Hydroxyl group

-OH → covalently bonded

Polar

Hydrophilic

Neutrally charged

Found in alcohols

Carbonyl group

C=O - covalently bonded

Polar (but less than OH)

Hydrophilic

Neutrally charged

Found in sugars

Carboxyl group

-COOH or OH-C=O - both covalently bonded

Polar

hydrophilic

acidic

neutrally or neg charged depending on what it is bonded to

Can release H+

found in amino acids and fatty acids

Amino group

NH2 -covalently bonded

Highly polar

hydrophilic

Basic

alone it is neutrally charged but in the environment, ph contributes to how it is charged

can accept H+

found in amino acids

Phosphate group

PO4 covalently bonded

Polar

hydrophilic

acidic

-3 charge

found in phospholipids, nucleic acids, ATP, etc.

Methyl group

CH3 covalently bonded

Nonpolar

hydrophobic

neutrally charged

found in dna methylation and play major role in gene expression

macromolecules

large molecules with 1000s of atoms

necessary for life

polymers

macromolecules made of chains of monomers

monomers

identical or similar repairing building blocks of a polymer

combine with each other using covalentt bonds

dehydration synthesis

reaction that building larger molecules

when monomers combine with covalent bonds, they release water molecules as byproducts

“to put together while losing water”

hydrolysis

reaction that breaks larger molecules (polymers) into smaller molecules (monomers) by interesting a water molecule to break covalent bonds

1 monomer will gain an h while one will gain an oh hence the breaking

4 classes of biological macromolecules

carbs, m lipids, proteins, nucleic acids

LIPIDS ARE NOT POLYMERS

Carbohydrates

polymers of sugar made of CH2O

Used for fuel and structure

short to medium term energy sources

monosaccarides

monomers of carbohydrates, usually 3-6 c

exp: glucose, fructose, galactose

polysaccarides

polymer of hundreds to thousands of monosaccharides

monomers are connected with glycosidic linkages

Two main functions:

storage: starch, glycogen

Structure: cellulose, chitin

Lipids

Diverse hydrophobic macromolecules, not polymers

hydrocarbons

not water soluble

used for storage, structure, and signaling

utilize ester bonds to build (dehydration rxn)

3 types:

fats,phospholipids,steroids

fats

glycerol + fatty acid tails (3)

most abundant lipid

used for long term energy storage

phospholipids

Glycerol+ fatty acids+ phosphate group (2 fa tails)

Amphipathic- has hydrophobic and hydrophilic regions

steroids

ring structure

3 6 c rings

1 5 c ring

used for membrane structure and signaling (steroid hormones)

proteins

polymers of amino acids

amino acids are the monomers

parts of amino acids- central c, h, carboxyl group, amino group, r group, side chain

20 amino acids in cellular life

connected vis peptide bonds which result in polypeptides 100+ aa

formed via dehydration

responsible for structure, signaling, communication, enzymes, defense, transport, everything but heredity

Levels of protein structure

primary- linear

secondary- local folding, amino acids are close tgther in sequence , short distances

hydrogen bonds between the backbone carbonyl oxygen

tertiary-three-dimensional shape of a single polypeptide chain, interactions between side chains

• Hydrophobic interactions

• Hydrogen bonds

• Ionic bonds

quaternary- 2 or more polypeptide chains held together (hemoglobin)

any kind of interaction

denaturation

if protein is subject to changes in temp, ph, or exposure to chemicalcs, the protein structure may change, losing it shape w/o losing its protein sequence→ polypeptide chain is fine

nucleic acids

monomer- nucleotide

polymer- polynucleotide

found in dna and rna

store and transmit genetic info