Lecture #1:
Introduction & Review of Chemistry of Life
I. INTRODUCTION (syllabus, exams, class notes)
How to be
successful in this course: 50% = study habits; 30% = note-taking ability;
20%=preexisting knowledge (And, learning "the language of biology".)
1. What is a
living (biological) system? What is a system?
2. What is the
difference between a living and a dead system? (flux)
3. An ecologist
studies the flow of energy through ecosystems.
4. A
physiologist studies the mechanisms by which a living organism maintains a
steady flow of energy through its metabolic machinery.
5. This state of
metabolic consistency, or steady state of metabolism, is homeostasis.
6. Thus, homeostasis
is the relatively stable state of energy flow through the biochemical
conglomerate that we call a living organism.
7. Organismic biology (or physiology) is
the study of how the different organ systems of a living organism function to
maintain homeostasis.
8. The ecosystem gets its energy from the sun.
9. Individual
plants and animals get their original source of energy from the previous
generation through the process of reproduction.
10. In its primitive form, the momentum for metabolism
is enormous. We now know, for example, that human gametes and embryos can
be frozen and then reheated, and if placed in a proper environment, there is
still the momentum to function.
11. Chemistry allows us to make sense of the inorganic
& organic diversity around us.
12. Biochemistry allows us to make molecular sense of the
biological systems that surround us and of which we ourselves are composed.
13. Organic compounds are based on skeletons of carbon
atoms. (CHON SP) (Fig
4.4)
a. vitalism = the belief in a life force outside of
physical and chemical laws.
b. mechanism = the belief that all life is governed by
physical and chemical laws.
(1) in 1828, Friedrich Wohler made urea, an organic
compound.
(2) in 1953, Stanley Miller synthesized organics from H2O,
H2, NH3, and CH4.
14. Functional groups are small groups of atoms
involved in chemical reactions.(Table 4.1)
(Note that OH groups make organic compounds water
soluble.)
15. Slight differences in functional groups can make a
big difference (E2 vs T) (Fig. 4.8)
16. Macromolecules are polymers of monomers
like glucose, or amino acids (Fig 5.2)
17. Monomers are linked by condensation, or
dehydration, reactions. (letters)
18. Polymers are split by hydrolysis, or
hydration. [to break (lyse) by water (hydro)] (words)
II. CARBOHYDRATES
(C H O)
A. MONOSACCHARIDES
(Fig 5.3)
1. Glucose is the primary product of
photosynthesis in plants. (Fig 5.4)
2. Therefore, glucose (actually CO2) is
the original source of all organic carbon.
3. Energy stored in the covalent bonds between carbon
atoms is directly, or indirectly, the source of the energy that powers living
cells.
B. DISACCHARIDES
(sucrose, maltose, lactose) (Fig 5.5)
C. POLYSACCHARIDES
("many" saccharides) (polymers)
1. Storage Polysaccharides (mainly for energy
storage) (one major function)
a. starch is the principal carbohydrate storage
product of higher plants. (Fig 5.6)
b. glycogen ("animal starch") is the principal
storage product of animals.
2. Structural Polysaccharides (mainly for strength
and protection) (other function)
a. cellulose (i.e., fiber) is a polymer of
glucose, and most abundant organic. (Fig. 5.8)
b. chitin, an amino sugar, is used for exoskeleton
of insects, spiders, crustaceans. (page 58)
(It becomes hard when encrusted with calcium carbonate.)
III. LIPIDS (C
H O + P + N) (compounds that do not readily mix with water)
A. FATS
(energy-storage molecules with 2.5X the energy of carbohydrates/gram)
1. Consist of glycerol plus 3 fatty acids (triglyceride)
(Fig 5.10)
2. Saturated vs unsaturated fatty acids (saturated
ones cause atherosclerosis) (Fig. 5.11)
3. Fat functions:
a. long-term energy storage (evolutionary
advantage) (Fig. 4.5)
b. insulation, cushioning, and protection of
various body parts.
B. PHOSPHOLIPIDS
1. Consist of glycerol + 2 fatty acids + a phosphate
group with NH3. (Fig 5.12)
2. Fatty acid tails are insoluble, but phosphate group is
soluble.
3. Function as a major part of the cell membrane, which
is selectively permeable. (Fig 5.13)
C. STEROIDS
(classified with lipids because of their solubility characteristics)
1. Complex structures consisting of four fused rings.
2. Cholesterol is an important steroid component
of the membrane of animal cells. (Fig. 5.14)
(Also, it is a precursor for steroid hormones, but
promotes atherosclerosis.)
3. Function as hormones, parts of vitamins, and
components of cell membrane.