biomolecules Flashcards
what are the functions of carbohydrates
energy storage
fuel molecules
structural support
molecular recognition
what features are carbohydrates classified by?
- number or carbon atoms
2. nature of carbonyl group (ketoses vs aldoses)
which diagram best shows the stereochemistry of carbohydrates
Fischer projections
what is the most important isomer of glyceraldehyde
D isomer
where is the OH group located on Beta isomers of glucose
above the ring
where is the OH group located on Alpha isomers of glucose
below the ring
where is the anomeric carbon in a ring?
to the right of the -o- (ester)
which glucose anomer is favoured
beta, less steric hindrance
isomers
have the same molecular formula but different arrangement of atoms and thus different physical and chemical properties
what is a chiral carbon atom
asymmetric carbon atom that has 4 different substituents
how many isomers are possible if there are n chiral atoms
2 to the power of n
stereoisomers
same chemical formula but different structure
- enantiomers: mirror images
- diastereomers: not mirror images
epimers
differ in configuration at a single asymmetric carbon
anomers
configuration of OH group at anomeric carbon
how many monosaccharides make up an oligosaccharide
less than 20 monosaccharides covalently linked together
what are oligosaccharides important for
molecular recognition as parts of cell surface receptor
what is the storage polysaccharides for plants
starch forms:
- amylose
- amylopectin
what is the storage polysaccharide for animals
glycogen
- more frequent branching than amylopectin
what is the structural polysaccharide for plants
cellulose
- principal component of cell walls
- linear unbranched
what is the structural polysaccharide for invertebrates
chitin
- makes up exoskelatons
- also found in cell walls of fungi and algae
general formula for carbohydrates
(CH20)n
general lipid description
hydrophobic, water insoluble organic molecules
lipid examples
- fatty acids
- mono/di/triglycerides
- phospholipids, glycolipids
- steroids, sterols
- waxes
function of lipids
energy storage fuel molecules membrane formation communication protection of organs thermal insulation
composition of fatty acids
hydrophilic carboxyl group & unbranched hydrophobic hydrocarbon chain (amphipathic)
saturated fatty acids
no double bonds
unsaturated fatty acids
contains double bonds
features that contribute to variation in fatty acids
number of carbon atoms
if saturated/unsaturated
cis vs trans
presence of other groups
what are the head groups of phospholipids
serine, ethanol amine, choline, inositol
2 types of phospholipids
phosphoglycerides
phosphosphingolipids
which part of phospholipids are hydrophobic/hydrophilic
hydrophilic polar head
hydrophobic non-polar tails
general characteristics of steroids
rigid, planar, amphipathic
derived from cholesterol
main component of cell membranes
phospholipids, glycolipids and sterols
