chapter 3.1 macromolecules Flashcards
chemical composition of the cell
- dry weight of e.coli: 2.8 x 10^-13 grams
- total weight (70% water): 9.5 x 10^-13 grams
chemical composition protein
50% dry weight
(there are 2000 different types of proteins)
FUNCTIONAL GROUPS
MEMORIZE
covalent bonds
bonds in which electrons are shared between atoms (these don’t break even when H bonds are broken by boiling conditions
hydrogen bonds (weak)
hydrogen bonds form between H and other electronegative elements (O or N)
other weak bonds
van der waals and hydrophobic interactions
GCAT
- takes more energy to separate CG than AT
- AT is 2 bonds
- CG is 3 bonds
four classes of macromolecules
- polysaccharides
- lipids (fats)
- nucleic acids
- proteins
carbohydrates
CH2O (1:2:1 ratio)
- most relevant carbs contains 4,5,6,7, carbon atoms
- most relevant carbs are D-form sugars
- optically active (chirality)
- OH group of next to last carbon determines chirality of molecule
D sugars
- right rotating
- most natural sugars are D
- our enzymes only work with D, not L
- D glucose will have more OH groups on the right, L on left
polysaccharides
- high molecular weight carbs containing monomeric units
- can be linked to proteins or lipid molecules to form glycoproteins and glycoproteins
polysaccharides
α-glycosidic bond
- right side up H
- carbon and energy reserves in bacteria, plants, and animals
polysaccharides
β-glycosidic bond
- right side down H
often used as structural components of cells (cellulose)
lipids
- fatty acids bound to glycerol
- contain hydrophobic and hydrophilic components
- principle component of membranes
lipids - bonds
- every C attached to a H is saturated (single bonds outside of func group)
- if H is removed, double bond will form (unsaturated)
- more than one double bond is polyunsaturated
lipid structure
bacteria is same as eukarya, but different for archaea
phospholipid membrane
- one molecule
- proteins mobile in hydrophobic region of phospholipid membrane, BUT do not leave that area
nucleic acid polymers
- DNA is a polymer of deoxyribonucleic acid
- RNA is polymer of ribonucleic acid
nucleic acid structure
- ribose or deoxyribose sugar
- nitrogenous base
- phosphate group
bases of nucleic acids
- purine or pyrimidine
- purines have two rings (A and G)
- pyrimidines have one ring (C, T, U)
nucleic acid configuration
3’ to 5’ configuration via phosphodiester linkage, results in primary structure of nucleic acid
nucleic acid base bonds
H bond to one another in a specific manner
- A to T, or U
- G to C
secondary structure in RNA
when H bonds form between bases within the chain
ribose vs deoxyribose (OH/H)
- ribose has OH on 2’
- deoxyribose has no OH, just H on 2’
3 rules of biochemistry
- biochemistry is backwards
- biochemistry does not happen in the absence of water
- biochemistry is STUPID
amino acids
- monomeric units of protein and polypeptides
- joined to each other in a peptide linkage
- 21 commonly occurring amino acids
- optically active
- L-form commonly used
proteins (primary and secondary structure)
- juxtaposition of α-carbon R groups dictates the primary structure of a protein (the amino acid sequence)
- twists and folds in the linear sequence caused by H bonding determine the Secondary Structure of the protein
secondary structure of protein
α- helix
β- pleated sheet
we sequence the DNA that codes the protein
not the actual protein itself
primary struc
coded in the DNA
secondary struc
interaction within a change between amino acids
all proteins are peptide, not all peptides are proteins
- may need more than one peptide
- 1 gene (amino acid chain) = 1 peptide (single stranded)
- protein is the finished product (1 protein = 1 OR more peptides)
tertiary structure of a protein
results from further folding of secondary structure and is “cemented” by the covalent bridging of different sections of the chain by disulfide linkages
quaternary structure
results when one or more peptide chains interact via strong or weak molecular bonds
denaturation of proteins
occur when bonds conferring secondary, tertiary, or quaternary structure are broken either chemically or by heat or radiation
