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Chapter 5

BIOLOGY 1A03 Chapter Notes - Chapter 5: Amylopectin, Glycan, Dic Entertainment


Department
Biology
Course Code
BIOLOGY 1A03
Professor
Gillian Goward
Chapter
5

Page:
of 8
Structure
Function
made of (CH2O)n where n refers to
the number of carbon-hydrate
groups
contain carbonyl, several
hyrodxyl and other functional
groups with several C-H bonds
Carbohydrates based on sizes:
o Monomers called
monosaccharides --> one -
sugar/simple sugars = e.g.
sugars(see the table below)
o Polymers called
oligosaccharides --> few -
sugars
o Large polymers called
polysaccharides
Simplest called
disaccharides
Polysasccharides:
starch, glycogen,
cellulose, chitin and
peptidoglycan
Cellulose, chitin
and
peptidoglycan
are structural
polysaccharides
that have a
common
feature, that is
that they
usually exist as
sets of long,
parallel strands
that are linked
to each other.
This structure
gives them
ability to
withstand
tension and
compression
How to monomers form polymers:
o Monomers polymerize to
form polymer called
Perform a variety functions in cell
o Energy Source: glucose is rapidly metabolized
o Energy storage: starch and glycogen
o Structural support: cellulose, chitin, cartilage and
peptidoglycan
Structure: form longs strands which allows to form
H/peptide bonds between adjacent strands. These
strands further criss - cross to form a tough sheets.
Individual H bond is weak; but H+H+H bonds =
strong
Function: form fibres that give cells and organisms
strength and elasticity
Structure is resistant to decay because only a few
enzymes have active sites with correct geometry
and reactive group to break the beta 1,4 linkage
o Transport of energy source: sucrose (plants), lactose
(milk)
o Cell surface signals: cell communication and cell - cell
recognition
Glycoproteins: are protein bonded to
carbohydrates by covalent bonds (mostly to
oligosaccharides). These are key in cell- cell
recognition and cell- cell signalling.
Help to identify part of your body
Immune system cells use it to distinguish
body cells from foreign cells.
Every diff. type of cell (such as muscle or
nerve cell) displays a different set of
glycoproteins on its surface.
Identification info. Presented by these
proteins allows for cell recognition and
communication
polysaccharides (a.k.a
complex carbohydrates)
o During polymerization, a
condensation reaction
occurs between 2 hydroxyl
groups, resulting in a
covalent bond called
glycosidic linkages forms,
that links monomers
forming polymers
Carbohy
drates
Structure
Funct
ion
Significance
Linkages
+ others
Sugars
Monosaccharides
Linear (is rare form)
Ring (most exist
in this form, as
rings form in
solutions)
Differ in the position
of carbonyl group
Alpha glucose
Hydroxyl at c 1 is
below the ring
Differ in the position
of hydroxyl group
Beta glucose
Pro
vid
e
ch
em
ical
en
erg
y in
cell
s
Fur
nis
h
so
me
of
the
mo
lec
ula
Ribose
(pento
se)
Presen
t in
RNA
Deoxyr
ibose
Presen
t in
DNA
Glucos
e
(hexos
e)
Presen
t in
starch,
cellulo
se,
glycog
en
Used
by our
cells
and is
in our
bloods
The
carbons
in
monosac
charides
are
numbere
d
consecuti
vely,
starting
with the
end that
is nearest
to
carbonyl
group
They are isomers but
not optical. There are
total 16 distinct
structures with
molecular formula
C6H12O6 present.
Hydroxyl at c1 is
above the ring
r
bui
ldi
ng
blo
cks
req
uir
ed
for
the
syn
the
sis
of
lar
ger
,
mo
re
co
mp
lex
co
mp
ou
nd
s
tream
Galact
ose
Presen
t in
cartila
ge.
Galato
se to
be
used
as a
source
of
energy
has to
be first
conver
ted
into
glucos
e via
an
enzym
e
catalyz
ed
reactio
n
Disacch
arides
Polysaccharides
Alpha glucose + alpha glucose = maltose
Beta galactose + Beta Glucose = lactose (In this
glucose has to be inverted to accommodate the
bond)
Ma
lto
se
=
pre
sen
t in
be
er,
sw
eet
pot
ato
, in
ger
mi
nat
ing
Lactose related
conditions:
Lactose
Intolerance
and
Galactosemia
LACTOSE
INTOLERANCE:
Occurs in
adults that do
not produce
sufficient
amount of
lactase = an
enzyme which
splits lactose
into glucose
and galactose.
Maltos
e has
alpha
1,4
linkage
Lactos
e has
beta
1,4
linkage
(glucos
e is
flipped
to
accom
modat
e this)