Bio 366: Biological Chemistry 2 Lecture 1: Course Introduction
and Review of Carbohydrate Structure Instructor: Dr. Caro-Beth
Stewart Teaching Assistant: None Course URLs:
http://www.albany.edu/faculty/cs812/bio366/bio366_2002.html or
http://www.albany.edu/biology/courses/index.html Look at the online
syllabus regularly for reading list updates and any changes to the
course schedule!
Slide 2
These notes will be posted online after the class. Last years
notes are available through the link to the 2001 web site. Examples
of exams from previous years are also available on the 2001 web
site for ABio366. Please note, however, that the format for the
exams this year will be quite different. Required (or at least
strongly recommended!) readings will be posted on the 2002 web
site, and PDF of selected journal articles will also be made
available to you.
Slide 3
Notice that students will be required to give classroom
presentations to the class during the last three class sessions.
These presentations will cover recent, important advances in a
biochemical topic of the students choice. More information about
this will be given throughout the term. Do not panic! Students from
previous years (nearly) unanimously claim that the experience is
both highly educational and fun.
Slide 4
Review of Metabolism (various places in text) &
Carbohydrate structure (mostly from Chapter 8)
Slide 5
METABOLISM--- the biosynthesis (anabolism) and degradation
(catabolism) of complex metabolites. We'll focus on metabolism of
"food" in humans over the next few weeks: 1. Carbohydrates (sugars)
2. Lipids (fats) 3. Amino acids (proteins) 4. Nucleic acids (DNA
and RNAnot used for major nutritional purposes in humans, but are
metabolized for energy purposes by some animals such as
ruminants)
Slide 6
Fig. 13.2 OVERVIEW OF CATABOLISM: Glycolysis, TCA (citric acid)
cycle, Oxidative-phosphorylation Sugars, proteins & fats all
feed into these cycles.
Slide 7
CARBOHYDRATE metabolism GLYCOGEN metabolism. To understand this
material, you must first learn (review) some basic SUGAR structures
(especially GLUCOSE). Most of this material comes from Chapter 8 of
Voet, Voet and Pratt (VVP).
Slide 8
Slide 9
You're expected to know: Carbohydrate and sugar nomenclature,
especially pertaining to GLUCOSE monomers and polysaccharides. The
numbering system of glucose (and, later, ribose) The reducing end
of sugars Storage polysaccharide structures ( -amylose and
amylopectin) The structural polysaccharides, cellulose and chitin.
The peptidoglycan wall of bacteria
Slide 10
Carbohydrates or saccharides are the most abundant biological
molecules, and are composed of (see figures in Chapter 8 for
structures): Simple sugars: monosaccharides have single unit
disaccharides have two units sucrose = "sugar" legally! You must
know the numbering system of glucose (see next slide, Fig. 8-4), as
it helps make sense of the bond names.
Slide 11
-D-glucopyranoseD-glucose-D-glucopyranose (linear form)
(pyranose = sugar with a six-membered ring)
Slide 12
GLUCOSE is a major metabolic fuel source in living organisms
which is degraded via glycolysis to produce ATP. Higher organisms
protect themselves from potential fuel shortages by storing glucose
by polymerizing it into high molecular mass GLUCANS, or glucose
polysaccharides complex carbohydrates with monosaccharides held
together by "glycosidic" bonds (the bond connecting the anomeric
carbon to the acetyl oxygen) between neighboring units. Enzymes
that hydrolyze glycosidic bonds are referred to as
glycosidases.
Slide 13
In PLANTS: The major glucose storage substance is STARCH, which
is a mixture of... -amylose, an (1 4)-linked glucan, usually
several thousand glucose units long amylopectin, like amylose, but
has (1 6) branches every 24-30 residues on average; up to 10 6
glucose units/molecule These are stored in the cytoplasm of plant
cells. &
Slide 14
Fig. 8-10: -Amylose -Amylose is a regularly repeating polymer
that form a left-handed helix.
Slide 15
Compare -amylose: To cellulose: The major structural component
of plant cell walls. Is a linear polymer of up to 15,000 D -glucose
residues. WHATS THE DIFFERENCE?
Slide 16
-amylose: Compare Figure 8-10 ( - amylose structure).
Cellulose: to Figure 8-9 (cellulose structure) to see the
structural consequences of these different linkages (1 4) linkage
(1 4) linkage
Slide 17
In ANIMALS: The storage glycan of animals is GLYCOGEN, which
differs from amylopectin only in that the branches occur every 8-12
residues. Glycogen occurs in granules of about 100-400 diameter in
cytoplasm of cells that use it most. For example: Muscle has a
maximum of 1-2% of its weight in glycogen. Liver has a maximum of
10% by weight. Combined, this is about a 12 hour energy supply for
the body (about 1 day). ["Carbohydrate loading" fills these
glygogen stores.]
Slide 18
Fig. 8-11: a beautiful micrograph of a liver cell showing
stored glycogen: Glycogen granules also contain the enzymes that
catalyze glycogen synthesis and degradation, as well as some
regulatory enzymes.
Slide 19
Chitin is the major structural component of the exoskeletons of
crustaceans, insects, and spiders. It is also present in the cell
walls of most fungi and many algae.
Slide 20
PEPTIDOGLYCAN is the major structural component of the cell
walls of gram-positive bacteria. It is digested by the enzyme
LYSOZYME, causing the cells to lyse (break open).