4-oxopteridin-6-ylmethylamino) benzoic acid (pteroic
acid) and conjugated with one or more L-glutamate
units. Folate derivatives are important in DNA synthe-
sis and erythrocyte formation. Folate deficiency leads
toANEMIA.
folivore An animal whose primary source of food is
foliage. For example, the larvae of the buck moth
(Hemileuca maia[Drury]) eats only the leaves of oak,
favoring scrub, live, blackjack, and post oaks; the
Karner blue butterfly (Lycaeides melissa samuelis) lar-
vae feed only on the leaves of wild blue lupine (Lupi-
nus perennis).
See alsoHERBIVORE.
follicle Any enclosing cluster or jacket of cells, or a
small sac or pore, that protects and nourishes within it
a cell or structure. A fluid-filled follicle in the ovary
harbors the developing egg cell. When the follicle rup-
tures (ovulation), an egg is released. A hair follicle
envelops the root of hair.
Food and Drug Administration(FDA) A U.S. fed-
eral agency responsible for regulating the development,
use, and safety of drugs, medical devices, food, cosmet-
ics, and related products.
The U.S. Food and Drug Administration is a scien-
tific, regulatory, and public health agency that oversees
items accounting for 25 cents of every dollar spent by
consumers. Its jurisdiction encompasses most food
products (other than meat and poultry); human and
animal drugs; therapeutic agents of biological origin;
medical devices; radiation-emitting products for con-
sumer, medical, and occupational use; cosmetics; and
animal feed. The agency grew from a single chemist in
the U.S. Department of Agriculture in 1862 to a staff of
approximately 9,100 employees and a budget of
$1.294 billion in 2001, comprising chemists, pharma-
cologists, physicians, microbiologists, veterinarians,
pharmacists, lawyers, and many others. About one-
third of the agency’s employees are stationed outside of
the Washington, D.C., area, staffing over 150 field
offices and laboratories, including five regional offices
and 20 district offices. Agency scientists evaluate appli-
cations for new human drugs and biologics, complex
medical devices, food and color additives, infant for-
mulas, and animal drugs. Also, the FDA monitors the
manufacture, import, transport, storage, and sale of
about $1 trillion worth of products annually at a cost
totaxpayers of about $3 per person. Investigators and
inspectors visit more than 16,000 facilities a year and
arrange with state governments to help increase the
number of facilities checked.food chain The energy path in a community by way
of food from those who produce it to those that feed
on them. For example, plants are eaten by herbivores
that are eaten by carnivores. Food chains that are inter-
connected are called food webs.forensics The use of social and physical sciences to
combat crime, e.g., the science of using DNA for iden-
tification. It has been used to identify victims; estab-
lish paternity in child-support cases; and prove the
presence of a suspect at a crime scene. Forensic sci-
ence can be used for issues from burglary to environ-
mental protection.formation constant SeeSTABILITY CONSTANT.formula An exact representation of the structure of a
molecule, ion, or compound showing the proportion of
atoms that compose the material, e.g., H^2 O.Forssmann, Werner Theodor Otto (1904–1979)
German Surgeon Werner Theodor Otto Forssmann
was born in Berlin on August 29, 1904, to Julius Forss-
mann and Emmy Hindenberg. He was educated at the
Askanische Gymnasium (secondary grammar school) in
Berlin. In 1922 he went to the University of Berlin to
study medicine, passing his state examination in 1929.
For his clinical training he attended the University
Medical Clinic and in 1929 went to the August Victo-
ria Home at Eberswalde near Berlin.
He developed the first technique for the catheteri-
zation of the heart by inserting a cannula into his own
antecubital vein, through which he passed a catheter
for 65 cm. He then walked into the X-ray departmentForssmann, Werner Theodor Otto 133