(iii.) biological molecules

gen bio 01:119:115

organic compounds

chemical substances that contain C atoms bonded to H, O, and H

carbon

tetravalent: 4 e- in the valence shell

carbon chains

strucutral chains that are the backbones of organic molecules

interchanged based off location and function

length, double bond position, bracing, presence of rings

hydrocarbon

organic molecules of only C and H

hydrophobic (nonpolar), uncharged (nonionic)

may contain functional groups, replace one or more H

can be added to any hydrocarbon

functional groups

specific type of atoms in a molecule that can alter its chemical properties, often can dictate function

chemical groups that replace H in hydrocarbons

structure is key to molecular function

ex: estradiol vs. testosterone

hydroxyl

(-OH) one oxygen atom covalently bound to one hydrogen atom

polar, hydrophilic

acidity neutral

found in alcohols (end in “-ol)

carbonyl

(-CHO) one carbon atom double bonded to an oxygen atom

polar, hydrophilic

acidity: neutral

found in sugars

carboxyl

(R-COOH) one carbon atom that is double bonded to an oxygen atom and single bonded to a hydroxyl group

polar, hydrophilic

acidity: acidic

found in amino acids and fatty acids

amine group

(R-NH2) one nitrogen atom bound to two hydrogen atoms

polar, hydrophilic

acidity: basic

found in amino acids

phosphate

(R-PO4H2) one central phosphorus atom bonded to four oxygen atoms

polar, hydrophilic

contributes a negative charge

acidity: acidic

found in phospholipids, ATP, nucleic acids

methyl

(R-CH3) one carbon atom bonded to three hydrogen atoms

nonpolar, hydrophobic

acidity: neutral

important role in DNA methylation

DNA methylation

an epigenetic mechanism that adds a methyl group to cytosine bases in DNA, altering gene expression without changing the underlying genetic sequence

macromolecules

large molecules made up of thousands of atoms, built from smaller repeating subunits called monomers

monomers

identical or similar building blocks

polymers

produced by linking monomers

all polymers are macromolecules NOT all macromolecules are polymers

dehydration synthesis

removes a water molecule, forming a new bond

synthesizes a new polymer and results in longer polymers

enzyme: dehydrogenase

hydrolysis

adds a water molecule, breaking a bond

breaks a polymer and results in making monomers

enzyme: hydrolase

carbohydrates

(C6H12O6) made up of carbon, hydrogen, and oxygen

primary source of oxygen

ex: sugars, tend to end with “-ose” (glucose, fructose, lactose)

monosaccharides

monomer of carbohydrates, usually 2-6C

determines sweetness and whether it could be dissolved

ex: single sugars (glucose and ribose)

polysaccharides

polymer of hundreds of thousands of monosaccharides

monomers connected with glycosidic linkage

ex: sucrose (storage: starch, glycogen

structure: cellulose, chitin)

lipids

organic compounds that are insoluble in water (hydrophobic)

primarily made up of hydrocarbons, nonpolar and glycerol+fatty acids

not polymers, only macromolecule not considered a monomer

function: energy storage, structure, and signaling

families: fats, phospholipids, steroids

lipid bond

covalent bond: ester linkages (COO)

fats

most abundant lipid

energy storage: contains 9 cal/gram

structure: glycerol and fatty acids

fatty acids

unbranched hydrocarbon, 14-22 C, carboxyl group

3 ester bonds per glycerol

phospholipids

glycerol + 2 fatty acids + phosphate group

3 ester bonds per glycerol

phospholipids

glycerol + 2 fatty acids + phosphate group

amphipathic

contains membrane structure

amphipathic

has both hydrophilic and hydrophobic regions

membrane structure

phosphate:head hydrophilic

fatty acid: tail hydrophobic

steroids

a large group of organic compounds with a specific ring structure

3 six C rings

ring structure

function: membrane structure and signaling

ex: cholesterol, estradiol, testosterone

how to count C-

each corner/point is a carbon

proteins

large group of organic compounds that account for 50% of the dry cell mass

monomer: amino acids

bond: peptide bonds, results in polypeptide

basic structure contains amino group, r chain, hydrogen atom, carboxyl group, central (alpha) carbon

r group - side chain - variable

function: digestion, supporting muscles/hereditary materials, transportation of nutrients, regulation and expression of dna/rna (structure, signaling/communication, enzymes, defense, transport)

protein primary structure

long polypeptide chain with amino acids

protein secondary structure

helix with hydrogen bonds and Beta strand (can become alpha helix that curls up or forms Beta bleated sheets)

protein tertiary structure

transthyretin polypeptide chain, 3d structure formed by R groups, creates multiple bonds (no restrictions)

protein quaternary structure

polypeptide chains that fold and form transthyretin protein (multiple tertiary structure)

how many amino acids in cellular life

20 amino acids

nonpolar: hydrogen side chain

polar: hydroxyl group

amino acid

central C, H, carboxyl group, amino group, R group/side chain

joined together by peptide bond

peptide bond

form between carboxyl and amino groups via dehydration synthesis, must move in a linear sequence

polypeptide

many amino acids joined together by peptide bonds in a linear sequence

not a protein until correct shape → shape determines function

side chains, backbone, amino end (N-terminus), peptide bond, carboxyl end C-terminus

denature

loss of protein’s native structure, bonds being broken and change in structure

loss of structure = loss of function

→ caused by pH, temperature, salt concentration

renaturation

folding back into protein

nucleic acids

monomer: nucleotides

structure: phosphate, ribose (sugar), nitrogenous base

function: store and transmit genetic information

two types: deoxyribonucleic acid and ribonucleic acid