Carbohydrate Structure & Function (Chapter 13) Flashcards
______ is the study of glycan structure and function.
Glycobiology
What are the three major groups of carbohydrates?
Simple sugars, polysaccharides, glycoconjugates
______ consist of monosaccharides, disaccharides, and oligosaccharides, which often function as metabolic intermediates in energy conversion pathways.
Simple sugars
______ consist of either glucose homopolymers, such as cellulose, or disaccharide heteropolymers, such as chitin or heparan sulfate, in which one of the two sugars is a hexosamine – a monosaccharide containing an amino group.
Polysaccharides
______ are proteins or lipids with covalently attached glycans, which play a critical role in cellular communication.
Glycoconjuagtes
Glucose, galactose and mannose are examples of?
Monosacchrdies
Sucrose, lactose and lactose are examples of?
Disaccharides
Raffinose is an example of?
Oligosaccahrides
Cellulose, starch and glycogen are examples of?
Glucose homopolymers
Chitin and keratan sulfate are examples of?
Disaccharide heteropolymers
Antibodies and viral coat proteins are examples of?
Glycoproteins
Aggrecan, syndecan, glypican are examples of?
Proetoglycans
Blood antigens and membrane anchors are known as?
Glycolipids
Glycoconjugates are ______ attached to proteins and lipids as branched and unbranched structures.
Covalently
What are the four core principles of glycobiology?
Glycan biochemistry
Glycan biosynthesis
Glycan diversity
Glycan recognition
Glycan chains arc branched or linear carbohydrate structures consisting of modified and unmodified monosaccharides, which are covalently linked by ______ bonds in either of two conformations (α or β).
Glycosidic
True or False: Monosaccharides are scavenged from the environment or synthesized de novo in the cell.
True
True or False: Specific binding proteins recognize and bind to glycans to elicit a biological response.
True
True or False: Only a few of the more than 100 oligosaccharides detected in breast milk have been biochemically characterized.
True
True or False: Lactose-derived oligosaccharides are the third most abundant component in human milk, after free lactose and neutral lipids.
True
Studies suggest that ______ provides a probiotic growth advantage to bifidobacteria, which contain the glycosidases required to metabolize this oligosaccharide.
lacto-N-tetraose
True or False: Some milk oligosaccharides may function as soluble decoys that inhibit pathogenic bacteria from invading intestinal epithelial cells by providing a large number of competing glycan binding sites.
True
______ is found in fungal cell walls and invertebrate exoskeletons.
Chitin
Cellulose, hemicellulose and pectin are found in?
Plant cell walls
Plants store glucose in the form of ______.
Startch
Starch is a mixture of 15-20% ______ and 80-85% ______.
amylose, amylopectin
Animals and fungi store glucose in the form of ______.
Glycogen
Cellulose provides strength to a plant’s cell wall. This is due to which intermolecular force?
Hydrogen bonding
Plant cell walls consist of ______ fibrils hydrogen bonded to the polysaccharides ______ and ______
cellulose, fibrils and pectin
Chitin is formed from repeating ______ units,
GlcNAc
______ is a linear homopolymer of glucose with six glucose residues per turn
Amylose
The amylose polymer forms a ______handed helix stabilized by intrastrand ______ bonds
left, hydrogen
______ and ______ are branched forms of glucose homopolymers with α-1,6 linkages connecting linear strands of α-1,4–linked glucose units
Amylopectin, glycogen
True or False: Amylopectin has more branching and more glucose units than glycogen.
False, glycogen more than amylopectin
______ has a single reducing end (red) and α-1,6 branch points about once every ______ glucose residues
Amylopectin, 15-30
______ has branch points about once every ______ glucose residues and a glycogenin homodimeric core protein (red) with two glucose molecules at the center.
Glycogen, 8-12
______ glycoconjugate interactions occur within and between cells of the host organism and ______ glycoconjugate interactions occur between host cells and pathogen cells.
Intrinsic, extrinsic
True or False: Immune cells communicate with each other by cell–cell interactions between glycoproteins and glycan binding proteins on the cell surface (intrinsic recognition)
True
The _______ glycan groups are attached to asparagine residues in the protein using a GlcNAc monosaccharide, whereas _______ glycan groups are attached to serine or threonine residues using a GalNAc monosaccharide.
N-linked, O-linked
______ glycan groups have a core structure of GlcNAc2Man3 (outlined), and ______ glycan groups are GalNAc (outlined),
N-linked, O-linked
Type ______ blood does not contain functional GTA and GTB enzymes.
O
Type ______ blood contain neither anti-A or anti-B antibodies.
Type AB
Type ______ blood contains both A and B antigens.
Type AB
The universal blood donor type is?
Type O
True or False: Proteoglycans primarily function in the extracellular space.
True
What two ways can glycoproteins be biochemically synthesized?
analysis using lectin array and identification by mass spectrometry
______ glycan groups are removed from purified glycoproteins using enzymatic cleavage with the enzyme PNGaseF. ______ glycans are released using chemical cleavage with NaOH and NaBH4 (a β-elimination reaction).
N-linked, O-linked
