lec 2 building blocks of life Flashcards
what is an atom?
smallest unit of an element that has some chemical characteristics of that element
what are atoms made of? what are their charges? (3 particles)
protons-positive charge
electrons- negative charge
neutrons- no charge (neutral)
what orbit the nucleus? What does it mean if electron shells are completely full?
electron shells
the atom is stable
what does an atoms chemical identity (# on periodic table) depend on?
number of protons in the atom
what is a bond? what do bonds form?
chemical linkages that hold atoms together to form molecules
why and how do elements form bonds?
form bonds to become stable, they form by taking or sharing electrons from other atoms
what is a covalent bond?
forms when atoms share electrons
what are non-covalent bonds? where do they form? strength of bonds in relation to covalent?
when an atom gains/loses electrons to become more stable (NO SHARING)
form between and within molecules
weaker than covalent bonds
what are 2 main types of non-covalent bonds?
hydrogen, ionic
what type of bonds are hydrogen bonds? what kind of molecules do they form between?
non covalent bonds, form between polar molecules
what are polar molecules?
molecules with uneven pole distrubution (poles are charge of either side if molecule)
what are ions?
atoms that have lost or gained electrons
if an atom gains an electron, what charge does it have?
negative
what are ionic bonds?
bonds that form between atoms of opposite charge
what is an example of an ionic bond?
Salt in water (NaCl + H2O)
what are the 4 major classes of chemical compounds in living organisims?
- sugars
- nucleotides
- amino acids
- fatty acids
why is carbon important? what shapes can it form in?
predominant element in compounds
versatile
can form chains, branches or rings
what is monomer
what element do they contain
small carbon containing molecules, can exist as individual molecules
individual small molecule with 20 or less atoms
what is a polymer
macromolecules
made of joined monomers
give 3 examples of monomers
sugars, amino acids, nucleotides
give 3 examples of polymers
DNA, protein, polysaccharides
sugars and their polymers are called
carbohydrates
what is a monosaccharide? example?
-simplest type of sugar (monomer)
-basic unit of carbohydrates
ex. glucose
what is a monosaccharide made up of in what ratio ?
carbon, hydrogen, oxygen
1:2:1
what is a disaccharide?
what kind of reaction ?
2 monosaccharides joined by a covalent bond
dehydration
reactions in which water is added/removed? what does it do with respect to monomers?
dehydration- links monomers, water removed
hydrolysis- breaks monomers apart, water added
what is a polysaccharide and give 3 examples
thousands of joined monosaccharides
glycogen, cellulose, starch
how are polysaccharides formed?
dehydration rxn b/w monomers
What is a nucleotide ?
5 carbon sugar molecule
base molecule
a phosphate
what makes up DNA RNA
nucleotides (monomers)
DNA and RNA are..
type of molecule
polymers
thymine, cytosine _______ & ________ are in __________
guanine or adenine
DNA
RNA contains uracil, _________
guanine or adenine , cytosine
explain phosphate component. How many phosphate groups can a nucleotide have?
-phosphorous+oxygen
-nucleotide can have 1,2,3 phosphate groups bound to the sugar
what are the monomers that form protein polymers?
amino acids
what is the basic structure of amino acid
-alpha carbon
-carboxyl group
-amino group
-side chain
what is a peptide bond
amino acids are covalently linked
what is a peptide? polypeptide? what do polypeptides form?
peptide: 2+ amino acids joined by peptide bonds
polypeptide: chain of many amino acids
protein: 1+ polypeptides
long chains of amino acids held together by peptide bonds
what are the 4 protein structures? what does each one look like?
primary- amino acids linked tgt, looks like beads on necklace
secondary- either helix (spiral) or beta-pleated sheets (accordion folded strip)
tertiary- protein folds into 3d structure
quaternary- more than 1 polypeptide chain, each in own tertiary structures
What is the cause of each shape? excluding primary
secondary- hydrogen bonding of peptide backbone, AA fold in repeating pattern
tertiary- side chain interactions causes folding
quaternary- more than 1 polypeptide chain
what are lipids? polymers or not?
organic compounds made of fatty acids, insoluble in water
NOT polymers
What makes a lipid unsaturated? Where are they found?
1 or more double bonds in lipid
plants
what makes a lipid saturated? where are they found?
only single bonds in lipid
animals
What are carbohydrates made of, in what ratio?
carbon, hydrogen, oxygen
1:2:1 ratio
What does hydrophobic mean? Hydrophilic?
hydrophobic- water fearing
hydrophilic- water loving
What is a fatty acid? What is its structure?
organic molecule
-hydrophobic hydrocarbon chain
+ hydrophilic head group
what are fatty acids found in?
-phospholipids
-glycerides
-waxes
