Glossary ❮ 323filtration Capillaries allow small particles through
the pores of their endothelial linings, but large
molecules such as proteins, platelets, and blood
cells tend to remain in the vessel.
fixed-action patternAn innate behavior that seems
to be a programmed response to some stimulus.
florigenHormone thought to assist in the blooming
of flowers.
fluid mosaic model Model that states that the mem-
brane is made of a phospholipid bilayer with pro-
teins of various lengths and sizes, interspersed with
cholesterol.
fluke Parasitic flatworm that alternates between
sexual and asexual reproductive cycles.
follicle-stimulating hormone (FSH)A gonadotropin
that stimulates activities of the testes and ovaries. In
females, it induces the development of the ovarian
follicle, leading to the production and secretion of
estrogen, and in males it stimulates the production
of sperm.
food chainA hierarchical list of who snacks on who.
For example, bugs are eaten by spiders, who are
eaten by birds, who are eaten by cats.
food web Can be regarded as overlapping food
chains that show all the various dietary relation-
ships in an environment.
foraging The behavior of actively searching for and
eating a particular food resource.
fossil record The physical manifestation of species
that have gone extinct (e.g., bones and imprints).
F-plasmidPlasmid that contains the genes necessary
for the production of a sex pillus.
frameshift mutations Deletion or addition of DNA
nucleotides that does not add or remove a multi-
ple of three nucleotides. Usually produces a non-
functional protein unless it occurs late in protein
production.
frequency-dependent selectionAlleles are selected
for or against depending on their relative fre-
quency in a population.
FSHSeefollicle-stimulating hormone.
functional groupsThe groups responsible for the
chemical properties of organic compounds.
G 1 phase The first growth phase of the cell cycle,
which produces all the necessary raw materials for
DNA synthesis.
G 2 phase The second growth phase of the cell cycle,
which produces all the necessary raw materials for
mitosis.
gametangiaProtective covering that provides a safe
haven for the fertilization of the gametes and the
development of the zygote in bryophytes, ferns,
and some gymnosperms.
gametesSex cells produced during meiosis in the
human life cycle.
gametophyte A haploid multicellular organism.
gastrulation Cells separate into three primary layers
calledgerm layers,which eventually give rise to the
different tissues of an adult.
gene flow The change in frequencies of alleles as
genes from one population are incorporated into
those from another.
generalized transduction Transduction caused by
the accidental placement of host DNA into a
phage instead of viral DNA during viral reproduc-
tion. This host DNA may find its way into another
cell where crossover could occur.
generation time Time needed for individuals to
reach reproductive maturity.
genetic codeCode that translates codons found on
mRNA strands into amino acids.
genetic drift A change in allele frequencies that is
due to chance events.
genotypeAn organism’s genetic makeup for a given
trait. A simple example of this could involve eye
color, where B represents the allele for brown and
b represents the allele for blue. The possible geno-
types include homozygous brown (BB), heterozy-
gous brown (Bb), and homozygous blue (bb).
genusTaxonomic group to which a species belongs.
gibberellinPlant hormone that assists in stem elon-
gation and induces growth in dormant seeds, buds,
and flowers.
glomerular capillariesThe early portion of the
nephron where the filtration process begins.
glucagon Hormone that stimulates conversion of
glycogen into glucose.
glycerolThree-carbon molecule that combines with
fatty acids to produce a variety of lipids.
glycogen Storage polysaccharide made of glucose
molecules used by animals.
glycolysisOccurs in the cytoplasm of cells and is the
beginning pathway for both aerobic and anaerobic
respiration. During glycolysis, a glucose molecule
is broken down through a series of reactions into
two molecules of ATP, NADH, and pyruvate.
glycoproteinProtein that has been modified by the
addition of a sugar.http://www.ebook3000.com