HL BIO Unit 1

Molecules and Water 

• origins of life were in water and water is a medium for life 

• electron configuration determines the chemical behaviour of an atom, which depends on the # of electrons in the outermost shell 

• all atoms with incomplete valence shells are chemically reactive 

1. London Forces - exists in all molecules 

2. Dipole-dipole forces - exist between polar moles. Attraction between a partial positive and partial negative 

3. Hydrogen bonds - forms between molecules containing H-F, H-O, H-N bonds. Much stronger

   1. these intermolecular forces give water many unique properties 

4. Ion-dipole interactions - form between ion and polar mole. (full charge with smt like water)

Cohesion and Surface 

• it sticks to each other and forms droplets, it sticks to something else (polar) 

• It allows things like insects to sit on top. 

Adhesion (ex capillary action) 

• ex plants, water is pulled up  roots/stem 

hydrophilic - water loving 

• polar or charged molecules 

hydrophobic - water fearing 

• non polar 

Blood Plasma: 

• polar dissolves, like the polar amino acid molecule is small and will dissolve in blood 

• but the non-polar does not dissolve, these are instead trsnported by hemoglobin which is O2 

  • HEMOGLOBIN: oxygen comes from lungs, then oxygen bonds to hemoglobin and oxygen is released thru tissue

• Lipoproteins - have phospholipids which can be polar and non-polar

Physical properties:

• Buoyancy is the living things that have overall density similar to water

• Viscosity - hydrogen bonds in water increase the viscosity to many organic solvent, more dissolved solutes

Specific Heat Capacity → amount of energy required to increase the temp by 1 degree Celsius.

• water has a high thermal conductivity - conducts heat quickly. Opposite, fats and oils conduct heat much slower and better insulators

The goldilocks zone → there is a perfect state of theu universe for all the living things on earth

Carbohydrates:

Carbs → simple sugars → carbon, hydrogen and oxygen → energy storage for short term

₂

Chemical Reactions in Living Organisms:

1. Dehydration → removes a water

2. Hydrolysis → add a water

3. Neutralization →

4. Redox Reactions → electrons lost from one atom and gained by another. Loses electron is oxidized and gains electrons is reduced

Carbs:

• chemically stable, good for quick and short term energy

• important in structural molecules in cells

• simple (sugars C(H2O) ) and complex (starches C₆H₁₂O₆)

• MONOSACCHARDIES (CH₂O)_n GLUCOSE

  • glucose, fructose, galactose

  • found in cyclical structures

  • hexose - 6 carbons

  • pentose - 5 carbons

  • 

• Alpha (dominating so thats why 1st is down) is OH down, down, up, down and Beta is OH up, down, up, down

  • glucose relases energy when its oxidized, so it loses electrons (respiration)

• Galactose OH is up on C4

  

isomers - same chemical formula diff properties

Glycosidic bonds → anabolic process that needs energy, its the building of larger molecules its the between C1, oxygen, C4 in maltose after dehydration

Disaccharides -

• maltose (alpha glucose- alpha glucose)

• sucrose (glucose and fructose)

• lactose (galactose-glucose)

Polysacchardies - complex carbs

• polymers are chains of the identical monomers bonded together

• examples starch (amylose and amylopectin), glycogen, cellulose

  • Amylose → alpha 1,4-glycosidic bonds

  • Amlyopectin → alpha 1-4 but sometimes 1-6 glycosidic bonds. It is more branched

• starch is storage molecule found in plants

• glycogen is storage molecule found in animals (muscles and liver)

• more ideal energy stroage than monosaccharies because large size decrease solubility

• Cellulose - structural polysaccharide found in plants (cell walls)

  • the hydrogen bond hold celluose microfibrils together to give them a HIGH TENSILE STRENGTH

  • straight chain with hydrogen bonds holding it together

• Starch is all alpha glucose when cellulose is beta-glucose, B1-4 glycosidic linkage

• Glycoproteins - short chain carbs (oligosaccharides) attached to proteins

  • component of cell membrances and important in cell recongition (example blood types)

Lipids :

• non-polar molecules made of carbon, hydrogen, and oxygen

• long term energy storage

• important for cell memberances and signalling molecules

• animals store energy

  • its more stable

  • non-polar so no water needed

  • high amount of energy per gram

  • liquid at body temp

• oils - melts below 20º

• fats - melts between 20º and 37º

• waxes - melts above 37º

• steroids

Fatty Acids:

• carbon chain (14-20 carbons) with a carboxyl (double O and OH)

• Saturated are straight chained

  • pack together

  • solid animals fats

  • less flexible

• Unsaturated - mono has kink in bend in chain, poly double bonds so more kinks

  • less than max amount of hydrogen

  • double or trips bonds between C

  • more space between molecules

  • liquids and oils

  • more flexibility in memberane

• CIS vs TRANS: carbons on same side vs carbons on opposide sides of double bond

  • trans unsaturated is elaidic acid

  • cis unsaturated is oleic acid

• OMEGA

  • omega-3 double bond on the C3

  • omega-6 double bond on the C6

Triglycerides → glycerol + 3 fatty acid chains

• bonded by ester bonds

• may be the same of different, so saturated or unsaturated

  

Phospholipids:

• glycerol bonded to two fatty acids and phosphate group

• primary component of cell membrances

• amphipathic (polar (phosphate) and non polar regions (fatty acid) )
  

  

Waxes:

• hydrocarbon chains linked to alcohols or carbon rings

• very hydrophobic, provide waterpoof proteciton for plants and animals

Steriods:

• four fused carbon rings with side groups giving molecules specific properties

• many hormones are steroids

• non polar so can pass directly through cell membrane

Proteins 

• essential for parts of living, virtually participating in every procress
  

  

• polymers composed of amino acid monomers

• Amino Acids have 20 different side groups (‘R’ Group)

  • 

  • nonpolar - C and H chains

  • polar - OH, NH2, no charge

  • charged acidic - negative charge

  • charged basic - positive charge

  • Last universal common ancestor (LUCA)

1. Primary Structure - specific sequence of amino acids joind by PEPTIDE bonds called a polypeptide

   

2. Secondary Structure - hydrogen bonding between the amino acid backbond

   1. alpha helix (spiral) and beta pleated sheets (parallel lines)

3. Tertiary structure - interactions between chains (R groups)

   • ionic bonds (charged)

   • hydrogen bonds (polar)

   • hydrophobic (nonpolar)

   • disulfide bridge (cysteine amino acid S-S)

   • hydrophilic on outisde (exposed to cytoplasm/water) and hydrophobic amino acids fold no to middle

4. Quaternary structure - two or more folded polypeptides come together to make final functional protein (not for all proteins)

   

   • polypeptides held by ionic bonds, hydrogen bonds and etc depending on R groups

   • Non-conjugated protein - only poplypetide subunits like insulin and collagen

     • collagen - fibers strong, structured

     • insulin - hormone for communcation

   • conjugated protein - includesw one or more non polypetide units in addition to polypeptides like hemoglobin contains heme group

     • hemoglobin dissolves in blood

     • compact easy to move through blood/blood vessels

     • heme is iron to bind to oxygen

       

• Proteome - all of the proteins produced by a cell, tissue or organism (each individual has their own)

• Proteomics - study of which proteins are active in a certain cell at a certain time

Nucleic Acids