molecules of life Flashcards
atoms
atoms- consist of protons, neutrons and electrons
atoms nucleus is formed by protons and neutrons
electrons move in orbital around nucleus
elements
substance that cannot be decomposed into simpler substances by ordinary chem processes
elements contain only one type of atom
atomic mass
atomic number is number of protons
atomic mass is the number of protons + neutrons
isotopes
in an element protons stay the same but neutrons is different
2 types- carbon atom and carbon isotopes
distribution of electrons
further away from nucleus, electrons are higher energy levels
periodic
elements in the same vertical column have similar chem properties
also have same number of electrons in their outermost shell
chemical bonds
-atoms combine to from molecules held together by chemical bonds
covalent bond
- forms when 2 atoms share a pair of electrons in a molecular orbital
- the sharing of electrons most generally occurs in the outermost orbital of the atoms
- molecule forms when 2 atoms share their VE with each other
polar covalent bond
-occur when electrons that are shared between 2 atoms are not equally shared
- partial neg charge and pos charge
- if a molecule has an oxygen or hydrogen it usually is a polar
non polar covalent bonds
- share electrons equally
importance of polar and non polar compounds
- if the chem is a solvent it’s polarity determines the property of the solvent: like dissolved like
- if the chem is a solute the polarity of the chem often controls it’s solubilities in polar and non polar solvents
ionic bonds
form of chemical connection in which one atom loses valence electrons and gains them from another. For both atoms involved, this exchange results in a more stable noble gas electrical state. The attractive electrostatic interactions between two ions of opposite charge form an ionic bond.
water
- 70% of total cell mass
- essential for living organisms
- maintains similarity and ph of bodily fluids
why do salts dissolve in water?
in water, partial positive charge on the hydrogen ions accommodate with the neg charge on the chloride ions, and the partial negative charge on the oxygen ions associates with the pos charge on the na
water chemistry
- polar molecule
- good solvent
- molecules can be described as hydrophilic or hydrophobic depending on how they react with water
- ph is 7 (neutral)
- ph is a measurement of the conc of protons (h+) in solution
hydrogen bonds in water: the importance of polar covalent bonds
- a hydrogen bond is an interaction of a hydrogen atom and an electronegative atom (eg. N- O)
ice and liquid water
- water is less dense when solid (frozen) than liquid
- ## water freezes at 0 degrees c and it’s density is highest at 4 degrees c
carbon : life’s chemical backbone: 4 major elements that make up human body
- carbon
- oxygen
- hydrogen
- nitrogen
- co2 and na2co3 are inorganic
major covalent bonds of carbon in organic compounds
- c-h bonds
- c-c, c=c, c-=c (triple) bonds
- c-o, c=o bonds
- c-n, c=n bonds
- c-s bonds
4 major types of bio molecules
- proteins
- nucleic acids
- carbs
- lipids make up cell membranes, store energy and are important in cell communication
proteins
(polypeptide)
-provide structural support and act as catalysts to facilitate chemical reactions
- amino acid subunits - peptide bonds
nucleic acid
-encode and transmit genetic info
- phosphodiester bond holds 2 nucleotides together
(subunit^)
carbs
- provide structural support for many organisms and a source of energy
- monosaccharides(subunit) glycosidic linkages (bond)
lipid
-make up cell membranes, store energy and are important in cell communication
-fatty acid subunits by ester bond
- insoluble and hydrophobic
chargaffs rules
A=T (apple in the tree)
C=G (car in the garage)
total purine= total pyrimidine
types of carbs
monosaccharides
polysaccharides
- one sugar molecule
-disaccharide are 2 monosaccharides
- polysaccharide contain more than 2 mono. through dehydration synthesis and bonded by glycosidic linkages
- complex carbs are long, braided chains of mono. also subgroup of poly.
van der waals forces
- hydrocarbon chains in fatty acids have non polar covalent bonds
- the longer the hydrocarbon tail the greater the strength of van der waals forces
saturated fats
- animal fats are saturated
- without double bonds causing kinks in the structure , stack closely together and are stabilized by the van forces
unsaturated fat
- decrease van forces or hydrophobic interactions between fatty acids and increase the fluidity (decrease mp)
lipid: steroids
- a cholesterol
- found in the lipid bilayer of animal cell membranes
cholesterol produces estrogen and progesterone
