unit one: chemistry of life

form follows function

the subcomponents of a biological molecule and their sequence determines the properties of the molecule

polarity (water molecule)

• oxygen is covalently bonded tot he 2 hydrogen atoms

  • covalent bond: electrons are shared

  • polar covalent bonds: is unequal sharing of electrons because O is electronegative

hydrogen bonding

when a hydrogen atom in a molecule makes a bond with F, O, or N in another molecule

• creates an intermolecular force between the molecules

cohesion

when 2 of the same molecules form hydrogen bonds

• ex: water x water

adhesion

when two different molecules form hydrogens bonds

• ex. water x other

capillary action and transpiration

transpiration: when water moves up plants through the stems

• leaves through the leaves as water vapor

  • the water holds together by cohesion, and clings to the xylem tubes by adhesion

surface tension

increased hydrogen bonding at the surface of the water

• ex. can let water striders walk on water

  • can allow leaves tp float on water to allow for more photosynthesis

high specific heat

if water absorbs a lot of thermal energy before it changes states, then it can resist the changes in temp

• ex. creates stable marine/land environment

• high heat of vaporization allows for evaporative cooling while sweating

s tier solvent

solvent: dissolving agent

• allows water based organisms to obtain key nutrients from enviroments

  • acts as a buffer

hydrophilic

• likes water

• polar, ions

• cellulose, sugar, salt

• blood

hydrophobic

• repels water

• nonpolar

• oils and lipids

• tails of the plasma membrane

expansion upon freezing

• water molecules slow down when the temp decreases and the bonds between water molecules are more stable and spread out

• forms a crytalline structure

• floats because ice is less dense

• creates a little blanket and traps in heat under the ice for organisms to survive

law of conservation of energy

energy cannot be created or destroyed, only transformed

diversity of carbon

• all macromolecules have it

• can be chains, ring shaped, or branched

• can have up to 4 bonding partners

carbohydrates

contain CHO

lipids

contain CHO(P)

• NO TRUE MONOMERS

proteins

contain CHON (sometimes less)

nucleic acids

contains CHONP

dehydration synthesis

• when 2 monomers link together (form covalent bonds)

• an H is lost from one and an OH is lost from another

  • loses h2o to bind the monomers together

hydrolysis

add H to one monomer and OH to another to break them apart

carbohydrates (more detail)

• monosaccharide —> disaccharide —> polysaccharide

• monosaccharides: monomer like glucose and ribose

• polysaccharides: long chain of monosaccharides like starch and cellulose

cellulose vs. starch

both are polysaccharides of carbohydrates

• starch is made with α glucose monomers

• cellulose is made with β glucose monomers

• both have OH in different places!!!

storage vs. structural polysaccharides

storage (long chains)

• plants: starch

• animals: glycogen

structural (condensed)

• cellulose and chitin for exoskeleton

lipids (detailed)

fats: triglycerides (store energy for long term) and adipose (insulation)

• triglyceride: glycerol + 3 fatty acids

• saturated, unsaturated, polyunsaturated fatty acids

steriods: cholesterol (creates plasma membrane) and hormones (chemical messengers)

phospholipids: lipid bilayer of plasma membrane

• hydrophilic head, hydrophobic tails

lipid saturation

saturated

• saturated with hydrogen

• in animals

• solid at room temp

• butter, lard, etc.

unsaturated/polysaturated

• have some double bond carbon that leads to kinks

• in plants

• liquid at room temp

• corn oil, olive oil, etc

phospholipids

contains hydrophilic head, hydrophobic tails

• has kinks in the tails

• make the phospholipid bilayer

levels of protein structure

1. primary

   • amino acid sequence turns into a polypeptide chain

   • covalent peptide bonds link the amino acids together

   • always adds to the C TERMINUS, the carboxyl end

2. secondary

   • gains a 3d shape by hydrogen bonding

   • shapes are the alpha helix and beta plated sheet

3. tertiary

   • bonding between “R” groups of amino acids

   • hydrogen bonds, ionic bonds, disulfide bridges, and van der Waal interactions are made !!

4. quaternary

   • 2+ polypeptides bond together

   • only some proteins get to this level!!!

proteins (structure and function)

• protein structure and function are sensitive to chemical and physical changes

• unfold or denatures if the pH or temperature are not optimal

enzymatic proteins

acceleration of chemical reactions

defensive proteins

protection against disease

storage proteins

storage of amino acids

transport proteins

transport of substances

hormonal proteins

coordination of an organism’s activities

receptor proteins

response of cell to chemical stimuli

contractile and motor proteins

movement

structural proteins

support

nucleic acids (detailes)

store and transmit genetic info

• purines (single ring0

  • adenine

  • guanine

• pyrimidines (double ring)

  • cytosine

  • thymine

  • uracil

purines and pyrimidines bond together using hydrogen bonds!!

• A = T/U

• C triple bonded to G

• 3 bonds = more stability

DNA directionality

antiparallel: backbones run in opposite direction and don’t intersect!!!

• build off 3’ exposed end in 5’ to 3’ direction

DNA & RNA

DNA

• usually double stranded

• AGCT

• stores hereditary info

• longer/larger

• sugar: deoxyribose

RNA

• usually single-stranded

• AGCU

• carry info from DNA to ribosomes

• tRNA, rRNA, mRNA, RNAi

• sugar: ribose