A Glossary of Terms from Lab 3:
cell
membrane
The outer boundary of cells, the structure of which is visible only under the
electron microscope.
cell
wall
Unique to plant cells, a wall formed of cellulose fibers embedded in a polysaccharide-protein
matrix. The primary cell wall is thin and flexible, whereas the secondary cell
wall is stronger and more rigid and the primary constituent of wood.
centriole
One of two structures in the center of animal cells, composed of cylinders of
nine triplet microtubules in a ring. Centrioles help organize microtubule assembly
during cell division
centromere
The centralized region joining two sister chromatids.
chloroplast
A subcellular organelle which contains chlorophyll and enzymes necessary to
perform photosynthesis. Has an inner and outer membrane, as well as a third
membrane bound sac, the thylakoid. Stacks of thylakoids are called grana, where
the Light Reaction occurs. The cytoplasm of the chlorplast is called the stroma,
and the Light Independant Reaction (carbon fixation) occurs here.
chromatid
One of a pair of duplicated chromosomes produced during the S phase of the cell
cycle, which are joined together at the centromere.
chromatin
The aggregate mass of dispersed genetic material formed of DNA and protein and
observed between period of cell division in eukaryotic cells.
crista (plural, cristae)
An infolding of the inner membrane of a mitochondrion that houses the electron
transport chain and the enzymes catalyzing the synthesis of ATP.
cytokinesis
The division of the cytoplasm to form two separate daughter cells immediately
after mitosis.
cytoplasm
The entire contents of the cell, exclusive of the nucleus, and bounded by the
plasma membrane.
differentiation
Divergence in structure and function of cells as they become specialized during
a multicellular organism's development; depends on the control of gene expression
(cell differentiation).
diploid
Refers to a cell nucleus containing two of each type of chromosome. Refers to
an organism in the main life stage having cell nuclei having two of each type
of chromosome, written as 2N.
endoplasmic
reticulum
A series of interconnected, flattened cavities lined with a membrane about 4
nm thick, which is continuous with the nuclear membrane.
epidermis
(1) the dermal tissue system in plants. (2) the outer covering of animals.
golgi
apparatus
An organelle in eukaryotic cells consisting of stacks of membranes that modify,
store, and route products to the endoplasmic reticulum.
granum (plural, grana)
A stacked portion of the thylakoid membrane in the chloroplast. Grana function
in the light reactions of photosynthesis.
haploid
Referring to a cell nucleus it contains one of each type of chromosome. Referring
to an organism it is one in which the main life stage has cell nuclei with one
of each type of chromosome, written as n.
interphase
A stage of growth in the cell cycle in which metabolism occurs without visible
evidence of nuclear division. Interphase is the phase between divisions (meiosis
and mitosis).
karyokinesis
The division of the cell nucleus.
lumen
Any cavity enclosed within a cell or structure, such as the lumen of the gut.
lysosome
A membrane-enclosed bag of hydrolytic enzymes found in the cytoplasm of
eukaryotic cells.
meiosis
A type of nuclear division associated with sexual reproduction, producing four
haploid cells from a single diploid cell, the process involving two cycles of
division.
metaphase
A stage of nuclear division in eukaryote cells, occurring once in mitosis and
twice in meiosis. This phase begins when all of the centromeres line up at the
equatorial plane.
microvillus
(plural, microvilli)
Collectively, fine, finger-like projections of the epithelial cells in the lumen
of the small intestine that increase its surface area.
mitochondrion
(plural, mitochondria)
An organelle in eukaryotic cells that serves as the site of cellular respiration.
mitosis
A process of cell division in eukaryotic cells conventionally divided into the
growth period (interphase) and four stages: prophase, metaphase, anaphase, and
telophase. The stages conserve chromosome number by equally allocating replicated
chromosomes to each of the daughter cells.
muscularis
The fleshy part of any animal that consists of tissue made up of highly contractile
cells serving to move parts of the body relative to each other.
nucleus
An organelle of eukaryotic cells that is bounded by a nuclear membrane and
contains the chromosomes whose genes control the structure of proteins
within the cell.
nucleolus
(plural, nucleoli)
A specialized structure in the nucleus, formed from various chromosomes
and active in the synthesis of ribosomes.
organ
Any multicellular structural or functional unit of an animal of plant,
often composed of different tissues that perform specific roles, such as the
liver and leaf.
plasmalemma
The cell membrane that also lines the connecting plamsodesmata between living
cells.
rough
endoplasmic reticulum
Endoplasmic reticulum when it is covered with ribosomes is referred to as
rough ER.
smooth endoplasmic reticulum
Endoplasmic reticulum that is not covered with ribosomes and gives rise to the
Golgi Apparatus.
stroma
The fluid of the chloroplast surrounding the thylakoid membrane; involved in
the synthesis of organic molecules from carbon dioxide and water.
tissue
A large group of cells of similar structure in plants or animals that
performs a specific function. (ex. muscle, phloem, etc.)
vacuole
A membrane-enclosed sac taking up most of the interior of a mature plant cell
and containing a variety of substances important in plant reproduction,
growth, and development.
vascular system
1. in animals the blood circulatory system and the water vascular system in
echinoderms that manipulate the tube feet. 2. in plants the tissue that serves
to conduct water throughout plants.