Mini Lecture on Carbohydrates Flashcards
What are carbohydrates used for?
energy
structure
cell identifcation
Two major forms of monosaccharides
aldehydes and ketones
What conformation are sugars generally in?
D-conformation
Epimers
carbohydrates have the same chemical formula but are different from each other because of the arrangment of functional groups
Examples of epimers
D-glucose versus D-galactose versus D-Mannose
How is ring structure formed?
an oxygen from an -OH group interacts with a carbonyl group
Alpha rings
the hydroxyl group in down from the carbonyl group
Beta rings
the hydroxyl group is up from the carbonyl group
Anomeric relationship
relationship between alpha and beta monosaccharides
Hemiacetal group
formed when the ring structure is created
have the ability to linearize and be a reducing agent
Acetal
formed when another sugar is added to make a glycosidic bond
does not have the ability to linearize and be a reducing agent
Hemiacetal chemical structure
Carbon connected to an -OR, -OH, H, and -R group
What type of chemicals are linear monosaccharides?
reducing agents
Oxidation of monosaccharides
have to be linear
a metal like copper is reduced and monosaccharide is oxidized (loses electrons)
we add oxygen to the sugar to oxidize it
How do you form a glycosidic bond?
condensation
remove water
How do you break a glycosidic bond?
hydrolysis
add water
Energy levels of two monosaccharides versus disaccharide
Disaccharide is higher in free energy because there was a decrease in entropy
Disaccharide is unfavored
How does the creation of a glycosidic bond occur?
need to use energy coupling with ATP to make occur
Is ring forming spontaneous?
yes
for sugars with more than 5 carbons
What type of reaction is the creation of a glycosidic bond?
endergonic
Homopolysaccharide
has the same type of sugar repeated
Heteropolysaccharide
uses different types of sugars
Why is it advantageous for animals to have highly branched polysaccharides?
this branched structures can condense which is good for animals that move
Example of branched polysaccharides found in animals
glycogen
Where are the links in glycogen?
1-6 links allow for branching
1-4 links allow for linear polymerize
What is cellulose held together by?
beta 1-4 glycosidic bonds
Why is the beta form significant in cellulose?
animals cannot break down these bonds and use cellulose as an energy source
How do animals use cellulose?
bacteria and fungi in the gut breakdown cellulose
Example of cellulose that animals cannot break down
fiber
Two forms of cellulose
alpha glycosidic linkage: helical strand
beta glycosidic linkage: linear strand
Beta form of cellulose
allows for hydrogen bonding between the strands and tight packing
Peptidoglycan structure
have peptide chains crosslinking carbohydrate chains
accomplished by transpeptidase
Blood types and sugar
specific chains of sugars are attached to ceramide
chain of sugars determines blood type
Ceramide
a type of sphingosine
Do you have antigens for A if you are type A blood?
No!
We lose the antigens that would bind and recognize our blood type
What clumps to type A blood?
Anti-A antibodies
What clumps to type B blood?
Anti-B antibodies
What clumps to type O blood?
neither since both antigens are present
What clumps to type AB blood?
both since neither antigen is present
What converts alpa to beta sugars?
mutarotation
Is sucrose a reducing sugar?
no
Is glucose a carboxlyic acid?
no
What is D-gluconate a product of?
oxidation-reduction reaction between D-glucose
Are starch and glycogen found in cell walls?
no
What are polymers of alpha-D-glucose?
starch and glycogen
Where is the carbonyl group in a ketose?
anywhere
Where is the carbonyl group in an aldose?
at the end of the carbon chain
How many carbons does ribose ring have?
5
it is a pentose
Is fructose an aldose?
no
What is the reference compound for naming D and L isomers?
glyceraldehyde
The basic structure of a proteoglycan consists of a core protein and a:
glycosaminoglycan
is the secondary structure of heparan sulfate completely random?
no
lipopolysaccharides
a dominant feature of the outer cell wall of bacterial cells in gram negative bacteria
The biochemical property of lectins that is the basis for most of their biological effects is their ability to bind to:
specific oligosaccharides
What are sialic acid residues removed by?
neuraminidases
It is useful to analyze hemoglobin glycation to determine a(n):
average blood glucose level over days or weeks.
In beta groups where does the hydroxyl point?
upwards
In alpha groups where does the hydroxyl point?
downwards
What type of polysaccharide is cellulose?
homopolysaccharide
Chitin is most chemically similar to
cellulose
alpha-amylase
breaks down glycogen and starch
hyaluronan
glycosaminoglycan found in joints
Globoside
can be used to determine human blood type
What is maltose?
a disaccharide composed of 2 glucoses linked 1-4
maltose is a reducing sugar
What is sucrose?
a disaccharide composed of glucose and fructose
found in plants
sucrose is nonreducing
good for energy storage since resists oxidation
What is lactose?
a disaccharide composed of glucose and galactose
lactose is a reducing sugar
Glycans
another name for polysaccharides
What are the two energy storage polysaccharides?
glycogen (animals) and starch (plants)
What are the two structural polysaccharides?
cellulose (cell walls) and chitin (exoskeletons of anthropods)
Is cellulose linear or branched?
linear
Which amino acids attach carbs to glycoproteins?
asparginine, serine, and threonine
How is a hemiacetal formed?
when a ketose or aldose condenses with an alcohol
