BIOCHEMISTRY 411-504
March 18, 2002
Exam II Preparation
Exam II will cover two topics: Photosynthesis and Lipid metabolism. Photosynthesis will be
divided into 3 topic areas: (1) Light reaction, (2) Dark reaction, (3) Photoefficiency. Lipid
metabolism will be divided into 4 topic areas: (1) Beta oxidation, (2) fatty acid biosynthesis, (3)
complex lipid biosynthesis, (4) cholesterol metabolism. This is your blueprint, so plan your
study strategy carefully.
Photosynthesis: Be able to USE the following concepts to solve problems. The anatomy of
chloroplasts, energy of photons as a function of wave length, basic structure of chlorophyll,
absorption spectra, the Hill reaction, photosynthetic reaction centers, light harvesting complexes,
events following photon absorption. Be able to distinguish between photosystem I and II (PS700
and PS680) with regard to the Z scheme components and functions. Know the function of:
special pair, pheophytin a, plastoquinones, cytochrome b6f, plastocyanin, water splitting enzyme,
Z. Know the components in PSI Ao, ferredoxins, ferredoxin NADP+ reductase. Know how ATP
is made, the function of Cf1Cfo complex, cyclic photophosphorylation and control of NADPH
ATP ratios. Know the Jagendorf experiment, what it meant and why it worked. Know the
relationship between photons and NADPH, ATP. Know the Calvin cycle (C3). Know the
function of Rubisco, carbon balance, reactions in the Calvin cycle, the balanced formula for
overall stoichiometry. Know the meaning of photorespiration and its biochemical cause, the
difference between C3 and C4 plants, the Hatch-Slack pathway, mesophyll vs bundle sheath cells,
the significance of pyruvate phosphate dikinase, PEP carboxylase, and malic enzyme.
Lipid Metabolism: Know all of the reactions of fatty acid oxidation (beta oxidation) and be
prepared to determine the energy yield as ATP from any given fatty acid. Know the strategies of
odd chain and unsaturated fatty acid oxidation, one of the functions of vitamin B12 and carnitine.
Know the strategy of elongation and desaturation. Know the ketone bodies and how they form
from excess acetyl-CoA. Know the order of intermediates in the fatty acid synthesis pathway,
the function of NADPH, the source of acetyl-CoA, the activation of acetyl-CoA, the role of
malonyl-CoA. Know how the cell synthesizes longer and more unsaturated fatty acids such as
arachidonic acid. Know how triacylglycerols are synthesized. Know how phospholipids are
synthesized in mammalian systems. Know what is meant by salvage. Know how cells
synthesize sphingolipids, the role of serine, the incorporation of carbohydrates into sphingolipids
and diseases that result from faulty glycolipid metabolism. Know the three facets of the
cholesterol biosynthesis pathway, the synthesis of mevalonate, isopentenyl pyrophosphate, and
eventually squalene and lanosterol. Know how cholesterol is metabolized, the role of LDL,
HDL, VLDL and chylomicrons. Know the mechanism of cholesterol transport into cells,
receptor mediated endocytosis, coated pits, endosomes, and enzymes that play a role in
metabolizing cholesterol internally.