L2 - molecules of life Flashcards
general formula of carbohydrates
nCH2O
functional groups in carbohydrates
carbonyl (CHO) and hydroxyl (OH)
properties of carbohydrates
hydrophilic
polar
water soluable
what are the two classifications of monosaccharides
aldoses and ketoses
aldehyde group or ketone group
how do sugars form ring structures
spontaneously
the ketone/aldehyde group reacts with hydroxyl group forming 5/6 membered ring
What are D and L isomers?
non superimposable mirror images (optical isomers)
how can a D sugar be determined from a L sugar
L isomer - OH group on the left of chiral centre
D isomer - OH group on the right of chiral centre
what OH group determines whether glucose is D or L? (in straight formula)
Carbon 5 (away from functional group)
define epimer
stereoisomers that differ in configuration of a single chiral C
what are structural isomers? (examples)
ketose and aldoses
eg glucose and fructose
define anomers
sterioisomers that differ in configuration of the anomeric carbon
what is the anomeric carbon in glucose
C1
examples of anomers
a and B glucose (D form)
what is the positioning of the hydroxyl groups on a and B glucose
a - hydroxyl is below C1
B - hydroxyl is above C1 (then rest of OH alternate)
what are the types of glyosidic bond?
a 1-4
B 1-4
aB’ 1-2
a 1-6 (in glycogen branches)
what are the polymers of glucose in plants
starch (amylose and amylopectin)
what is the polymer of glucose in animals
glycogen
compare glycogen and amylopectin structure
similar but glucose has more branches
functions of carbohydrates
- metabolism
2. recognition molecules (glycoproteins/glycolipids)
function of TAGs? where are they stored?
energy storage
lipid droplets in cells
describe structure of glycerophospholipids
a TG but one FA is replaced with a phosphate group bound to an amino alcohol (Hphilic) via ester bonds
amphipathic (form bilayer)
what is steroid template?
fused alkly rings which form the basis of all steroid hormones - they just have add ons
describe cholesterol structure and function
Hphilic head and Hphobic tail
rigid
can insert into membrane to modualate fluidity
describe nucleic acid general structure
pentose sugar + nitrogenous base + phosphate group
what are pyrimidines? and give examples
single ring structure nitrogenous base
Cytosine
Thymine
Uracil
what are purines? and give examples
double ring structure nitrogenous base
Adenine
Guanine
what determines protein folding?
the charged / polar / uncharged side chains of AAs
hphilic on outside hphobic on inside
polar& charged Hphilic (water soluble)
uncharged = H phobic (lipid soluble)
properties of AAs
charged at pH 7 (NH+ , COO-)
water soluble
what is special about histidine at pH 7?
can easily gain or lose a H+
