Chapter 7- Polysaccharides and Glycoconjugates Flashcards
most carbs occur as polysaccharides, aka ____
glycans
What is a homopolysaccharide?
contain only 1 kind of monosaccharide unit
what is a heteropolysaccharide?
contain 2 or more monosaccharides
2 types of polysaccharides
- storage polysaccharides
- Structural polysaccharides
Types of storage polysaccharides
- starch
- glycogen
Types of structural polysaccharides
- cellulose
- agarose
- glycosaminoglycans
Starch is a mixture of ____ and ______
alpha amylose
amylopectin
alpha amylose causes the starch chain to ____
turn
starch forms a _______ stabilized by H-bonds
left-handed helix
Glycogen is similar to ____
amylopectin
Why is glucose not stored in its monomeric form?
- high degree of branching
- Insoluble glycogen contributes to osmolarity
- glycogen decreases the concentration gradient
Glucose’s high degree of branching causes ____
rapid release of monosaccharide units (multiple enzymes can work at many spots simultaneously)
glucose’s insoluble glycogen causes contributes____
little to osmolarity which would cause cells to burst from water entry
glucose’s glycogen decreasing the concentration gradient causes ____
glucose to uptake in cells
Cellulose is a linear polymer of ____
D-glucose
Cellulose possesses _______
Extended conformation
Strength of cellulose comes from ____
extensive H-bonding
Cellulose strands line up into sheets which leads to:
- Sheets stack on each other (added strength)
- inter-sheet H-bonding
- Hydrophobic molecule
it is ____ to break down cellulose
hard
Degradation of cellulose is ____ due to _____
very slow
tight packing and H bonding
what is agar?
a complex mixture of sulfated heteropolysaccharides
What is agarose?
polymer of disaccharide agarobiose
When agarose and water is heated and cooled down:
it forms a double helix that traps water in the central cavity, causing the structures to form a 3D matrix/ Gel
what are glycoconjugates?
sugars that are conjugated to proteins and lipids
Functions of glycoconjugates
- contribute to cell type uniqueness
- regular cell-cel recognition and interaction
- label proteins for localization/destruction
All bacterial cell walls possess a strong protective polysaccharide layer called ____
peptidoglycan
Lipopolysaccharide coats the outer membrane of ____
Gram-negative bacteria
The composition of Lipopolysaccharide determines _____
the antigenicity of the bacteria
LPS antigen structures play a role in ____
cell recognition evasion of the host immune system
Gram staining interacts with the ____
peptidoglycan
What is gram staining used for?
used as a stain to distinguish bacteria based on their cell wall composition
Gram-positive bacteria characteristics
- thick layer of peptidoglycan
- one membrane
- retains gram stain
gram-negative bacteria characteristics
- thinner peptidoglycan (between membranes)
- two membranes
- does not retain gram stain
