Lecture 2 - Carbohydrates Flashcards
(23 cards)
What are macromolecules
- large highly organized molecules that form cellular structures and carry out the activities of cells
- most are short lived, except DNA, and are continually broken down and replaced
what are the 4 major categories of macromolecules
- proteins
- nucleic acids
- polysaccharides
- lipids
Which 3 macromolecules are made up of repeating units of monomers making them polymers?
- proteins
- nucleic acids
- polysaccharides
What roles do carbohydrates have
- energy (storage and immediate)
- metabolic intermediates (can be precursors for other molecules)
- structural components of RNA and DNA
- structural components of cell walls of bacteria and plants
- glycoproteins and glycolipids
what type of sugar is it if the carbonyl group is located at an internal position
ketose
what molecule is it if the carbonyl is located at one end
aldose
what affect do hydroxyl groups have on sugars
highly water soluble
formula for stereoisomers
2^n
n=chiral centers
- half are D form and other half are L form
which form are most naturally occurring sugars in
d-form
what is the anomeric carbon
carbon derived from the carbonyl carbon of the open chain form of the carbohydrate molecule
different types of pyranose (alpha and beta)
alpha - OH projection below the plane of ring
- less steric hindrance
- 64%
beta - OH projection upward
- 36%
What happens when A1C is high
- excess glucose binds non-enzymatically to proteins, lipids, and nucleic acid
- this creates AGEs which damage blood vessels, nerves, and organs by
- promoting inflammation
- increasing oxidative stress
- causing loss of protein function
how are monosaccharides connected
- glycosidic bonds
- glycosidic bonds connect anomeric carbon to hydroxyl group
what is the structural difference between maltose and cellubiose
- nature of glycosidic bond
- alpha 1-4
why do sucrose and lactose differ in glycosidic bonds
- due to bond orientation on anomeric carbon
- sucrose alpha 1-4
- lactose beta 1-4
what are storage polysaccharides and their role
glucose
- starch in plants - two forms amylose and amylopectin
- glycogen in animals
what distinguishes amylose from amylopectin
amylose - unbranched
amylopectin - branched
what are the two major sites of storage for glycogen
liver and skeletal muscle
explain structural polysaccharides
- most abundant organic material on earth
- cant be digested by humans but provides dietary fiber
-cellulose - plant product made of unbranched polymers - chitin
what is chitin
- component of invertebrate exoskeleton
- found in fungi cell walls, mollusk, shells and fish scales
what affect can different bonds types have on the structure of the polysaccharide
- alpha glycosidic bonds allow for the spontaneous formation of helical shapes
- both starch and glycogen can form these loose coils
- branching disrupts this structure
- beta glycosidic bonds form rigid linear rods
- these rods aggregate into microfibrils
what is the difference between starch and glycogen
starch
- Found in plants
- Used for long-term energy storage
- Made of amylose (unbranched) and amylopectin (branched)
- Has α(1→4) and some α(1→6) glycosidic bonds
- Moderately branched
- Less soluble in water
- Digested more slowly
glycogen
- Found in animals (especially liver and muscle cells)
- Used for quick energy release
- Made of glucose units only
- Has α(1→4) and many α(1→6) glycosidic bonds
- Highly branched (more than amylopectin)
- More soluble in water
- Digested quickly due to high branching
what are glycomics
- systematic characterization of all of the carbohydrate components of a cell or tissue
