BIO1011 Lecture Notes - Lecture 5: Plastid, Macromolecule, Glycosidic Bond
31 Jul 2018
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5.1-5.5
▪ macromolecule: big molecule
▪ hydrolysis: add water to let polymers change into monomers
▪ carbonhydrates: includes sugars and polymers of sugars,the simplest are the
monosaccharides
▪ monosaccharide: depending on the location of carbonyl group, a sugar is either an
aldose(glucose) or a ketose(fructose);size of the carbon skeleton, 3-7 carbon
long:i.e. six carbon sugar called hexoses, trioses and pentoses are common as
well, like to combine carbon 1-5
▪ another source of diversity is in the spatial arrangement of their parts around
asymmetric carbon(glucose and galactose,the hydroxyl group of glucose is on
the right)
▪ a disaccharide joint by a glycosidic linkage:maltose(2 glucoses),also known as malt
sugar, is an ingredient used in brewing beers; sucrose(table sugar, glucose and
fructose,plants generally transport carbonydrates from leaves to roots and other
nonphotosynthetic organs in the form of surcose) lactose(glucose joined to
galactose),in milk
▪ plants store starch,as granules within cellular structure know as plastid, which include
chloroplasts,synthesis starch enables the plant to stockpile surplus
glucose,potato tubers and grains, the fruit of wheat,corn,rice,and other grasses,
are the major sources of starch in the human diet
▪ most of the glucose monomers in starch are joint by 1-4 linkages, the simplest dorm
of starch,amylose, is unbranched,amylopectin, is branched(1-6
linkages),glycogen is more branched than amylopectin starch,human and other
vertebrates store this maily in liver and muscle cells,this store cannot sustain in
an animal for long, glycogen stores are depeted in about a day unless they are
replenished by comsumption of food
▪ in plant cell wall, the ,parallel cellulose molecule held togehther in this way are
grouped into unit called microfibres, these cablr-like microfibres are a strong
building material for plants and an important substance for human because
cellulose is the major constituent of paper and the only component of cotton
▪ enzyme that are able to hydrolyse the alpha linkage are unable to hydrolyse beta’s
because od the distinctly different shapes of these two molecule
▪ a cow harbour
▪ Canopy dwelling animal: sugar glide, emerge at night, forage for tree sap and the
nectar from flowers, hunt for insects and small animal….these allow them to eke
out a living under challenging conditions
▪ An organism’s adaptions to the environment are the result of evolution
▪ emergent properties are due to the arrangement and interactions of parts as
complexity increases(have a unique property while arrange in a correct order)
▪ reductionism-the approach of reducing complex systems to simpler components that
are more manageable to study
▪ system study-an approach that attempts to model the dynamic behaviour of whole
biological systems based on a study of the interactions among the system’s part-
