Prokaryotes (more primitive, pro ! early, organisms) are singlecelled organisms which have many cellular commonalities with the
eukaryotes, which include humans. These prokaryotes lack a defined
nucleus. The genetic ma
nucleus of the cell and the cell membrane in an orderly fashion. This
organization facilitates the delivery of certain protein and lipid products to the Golgi apparatus. Transport vesicles fuse with the cis face
of the Golgi apparatus and e
The substrate/velocity curve produced by the Michaelis-Menton equation can be seen to have two nearly linear portions. The first is at very
low substrate concentrations ([S] ! KM), where the velocity is essentially equal to:
APPLICATION BOX 2.1
Self-Assembly in Biology and Technology
The amphipathic character of the phospholipid molecules (see Figs. 1.19 and
1.20) allow for the property of self-assembly. If individual phospholipid
molecules are dropped into
If we multiply through on the numerator and then multiply both sides
by [ES], we get the following equation.
KM[ES] 5 [S][E]0 2 [ES][S]
Bringing [ES][S] to the left-hand side and grouping terms gives us the
Nanoparticles bioengineered from customized combinations of phospholipids with one or two fatty acid substituents, cholesterol, and other polyols
are known as micelles, vesicles, or liposomes depending upon the geometry
of the structure for
dehydrogenases (see Clinical Box 1), where the first substrate to bind,
the coenzyme molecule NAD!, induces a conformational change in
the enzyme that actually creates the binding site for B. In many
enzymes, the binding of B to the free
Goblet cell (secretes mucin)
Layer of mucus
Figure 2.10 (a) Cilia and (b) flagella. These are common cell surface modifications
composed of microtubules. Cilia often move extracellular material al
kinetic expressions become more complex since more than one ES complex is formed during the reaction cycle and the reaction velocity is
dependent on the concentration of both substrates. There are a myriad
of substrate/product combinati
The cell is a fantastic representation of biology. It literally encapsulates
life in its elemental form. By understanding the components of a cell,
we are able to discern and decipher many of the complexities of living
organisms. Each compo
[I] = 4 mM
[I] = 2 mM
[I] = 1 mM
[I] = 0 mM
Competitive inhibition plot. The double reciprocal
plot shows the effect that different fixed concentrations of a
competitive inhibitor, I, have on the observed velocity of an
work of Henri (1903) 10 years earlier and provided algebraic solutions to
the equations he derived. It was understood by this time that a binding
site on the surface of the enzyme existed and that this site was saturable.
It was also know
APPLICATION BOX 2.2
The Muscle Machine
Hugh E. Huxley elegantly described in 1969 what has been come to be
known as the Sliding Filament Theory of muscle contraction. The theory
describes the movement of a series of proteins in conjunction
Fats and oils
Fats and oils are fatty acid triesters of the 3-carbon molecule glycerol
and are often known as triglycerides or just glycerides. The formation
and structure of a triglyceride is outlined in Fig. 1.15. Hexanoate,
Peroxisome Free ribosomes
Peroxisome. These organelles contain oxidative enzymes and resemble lysosomes. Peroxisomes are
responsible for detoxification of harmful substances from
the cell such as peroxides and hydrogen
In pharmaceutical applications, customized lipid formulations are dispersed in aqueous solutions containing a drug or diagnostic compound and
liposome formation proceeds with the interior aqueous compartment trapping a few nanoliters of dr
The statin class of drugs inhibits HMG-CoA synthase in the pathway
of cholesterol synthesis (see Clinical Box 3.2), and various antibiotics are
inhibitors of cell wall synthesis or of bacterial protein synthesis. There
are three basic t
Longitudinal section of centriole
Centrosome. The centrosome includes the two perpendicularly oriented centrioles and the space immed
the outside environment. The chemical soup enclosed by the cell membrane is regulated by the membrane and its components allowing some
substances into and out of the cell. This differential permeability is
a hallmark of a cell membrane.
the flat surface area, and there by more energy can be produced. The folds
of the inner membrane form compartments called cristae. Cristae are
ultramicroscopic features of mitochondria. The energy produced is in the
form of a molecule calle
Asexual reproduction: Process in which an organism produces a copy of itself
without the involvement of another individual.
Basement membrane: Extracellular thin membrane underlying epithelial cells.
Binary fission: Method by which bacteria r
Ground tissue: One of three types of plant tissues, being present in leaves,
roots, and stems.
Homeostasis: See Chap. 1.
Horizontal gene transfer: Transmission and incorporation of DNA from one
species to another.
Lipid raft: Cell membrane mi
Death receptor: See Chap. 4.
Diploid: See Chap. 7.
Dorsal blastopore lip: Area of cells that are migrating inward toward the animal
pole during early gastrulation and will become the dorsal mesoderm.
Dorsal: Near the back or upper side of a s
S phase: Cell cycle phase during interphase when DNA is replicated.
Senescence: Process of aging.
Somatic cell nuclear transfer (SCNT): Scientific term for cloning in which an
egg without a nucleus is combined with the nucleus of a somatic ce