Chapter 8: Carbohydrates Flashcards
are aldehyde or ketone derivatives of straight-chain polyhydroxy alcohols
containing at least three carbon atoms.
Monosaccharides
Monosaccharides are linked together by what?
glycosidic bonds
Sugars that differ only by the configuration around one C atom are known as what of
one another.
epimers
The most common ketoses are
dihydroxyacetone, ribulose, and fructose
When a monosaccharide cyclizes, the carbonyl carbon, called the what?
anomeric carbon
is a component of flavin coenzymes
Ribitol
is a sweetener that is used in “sugarless” gum and candies
Xylitol
are important lipid components
glycerol and myoinositol
Saccharides bearing anomeric carbons that have not
formed glycosides are termed
reducing sugars
consist of monosaccharides linked together by glycosidic bonds
Polysaccharides (glycans)
Lactose intolerance is a painful digestive upset which is caused by low levels of what which allows bacteria in digestive tract to convert lactose into large quantities of CO2, H2, and irritating organic acids
β-galactosidase (or lactase)
the primary structural component of plant cell walls, accounts for over half of the carbon in the biosphere
Cellulose
is the principal energy reserve of plants and is deposited in the chloroplasts as insoluble granules composed of α-amylose and amylopectin
Starch
The digestion of starch is
done by
amylase and debranching enzyme
is the storage polysaccharide of animals and is present in all cells but is most prevalent in skeletal muscle and in liver.
Glycogen
In the cell, glycogen is degraded for metabolic use by
glycogen phosphorylase and
glycogen debranching enzyme
The extracellular spaces, particularly those of connective tissues such as cartilage, tendon, skin, and blood vessel walls, contain collagen and other proteins embedded in a gel-like
matrix that is composed largely of
glycosaminoglycans
is an important glycosaminogly can component of connective tissue.
Hyaluronic acid
is a sulfated glycosaminoglycans, which makes it the most highly charged polymer in mammalian tissues. It inhibits the clotting of blood and is therefore in wide clinical use to inhibit blood clotting
Heparin
are major components of cell walls and made of heterogeneous polysaccharides with a core of α(1→4) linked galacturonate residues interspersed with the hexose rhamnose.
Pectins
are enzymatically generated and covalently linked to the polypeptide.
glycoproteins
Penicillin specifically binds to and inactivates enzymes that
cross-link the peptidoglycan strands of bacterial cell walls.
invade their target tissues by first binding to cell-surface carbohydrates.
viruses, bacteria, and eukaryotic parasites
O-Linked Oligosaccharides Are
Attached to
Serine or Threonine.
N-Linked Oligosaccharides Are
Attached to
Asparagine
can shield a protein’s surface, possibly modifying its
activity or protecting it from proteolysis.
oligosaccharide
are oligosaccharide components of glycoproteins and glycolipids on the surfaces of an individual’s cells (not just red blood cells).
ABO blood group antigens
Individuals with type A cells
have what?
A antigens on their cell
surfaces and carry
anti-B antibodies in their blood
Individuals with type B cells
have what?
which bear B
antigens, carry anti-A antibodies;
Individuals with type AB cells
have what?
which have both A and B antigens, carry neither anti-A nor anti-B antibodies
Individuals with type O cells
have what?
whose cells bear
neither antigen, carry both anti-A and anti-B antibodies.
