CIBI 3031 Terms to Know Instructor: Kristin Peterson

Chapter 4: Glossary of selected key terms (términos clave selectos)

basal body / cuerpo basal

Centriole which, after giving rise to microtubules of a flagellum or cilium, stays attached to its base in cytoplasm.

cell / célula

Smallest living unit, it can survive and reproduce on its own, given its DNA, raw materials, and an energy source.

cell communication / comunicación celular

Mechanisms by which free-living cells of a species or the cells of a multicelled organism coordinate their activities; involves sending and receiving, transducing, and responding to signaling molecules.

cell cortex / corteza celular

A dynamic, crosslinked mesh of cytoskeletal elements under plasma membrane.

cell junction / union celular

Site where cells are interacting physically, functionally, or both.

cell theory / teoría celular

All organisms consist of one or more cells, the smallest units with a capacity for independent life that no longer spontaneously arise under existing conditions on Earth.

cell wall / pared celular

A semirigid, permeable structure external to the plasma membrane; helps many cells retain their shape and resist rupturing.

central vacuole / vacuola central

Fluid-filled storage organelle of plant cell; its growth enhances cell surface area.

centriole / centriolo

Structure that gives rise to microtubules of cilia and flagella.

chloroplast / cloroplasto

The organelle of photosynthesis in plants and many protistans.

chromatin / cromatina

A cell's collection of DNA and all of the proteins associated with it.

chromosome / cromosoma

Of eukaryotic cells, a DNA molecule, duplicated or unduplicated, with many associated proteins. Of prokaryotic cells, a circular DNA molecule.

cilium / cilio

Short motile or sensory structure of certain eukaryotic cells; its core is a 9 + 2 array of microtubules.

cytoplasm / citoplasma

All cell parts, particles, and semifluid substances between the plasma membrane and nucleus or nucleoid.

cytoskeleton / citoesqueleto

Inner, interconnected system of protein elements that reinforce, organize, and move the eukaryotic cell and its structures.

endomembrane system / sistema de endomembranas

Series of organelles that modify new polypeptides and make lipids.

ER (endoplasmic reticulum) / RE (retícolo endoplásmico)

Organelle that starts at nucleus and curves through cytoplasm. New polypeptides get side chains in rough ER (has ribosomes on its cytoplasmic side); smooth ER (has no ribosomes) is a site of lipid synthesis.

eukaryotic cell / célula eucarionte

Cell having a nucleus and other membrane-bound organelles.

flagellum / flagelo

A motile structure of many free-living eukaryotic cells. Its core has a 9 + 2 array of microtubules. Typically longer than cilia.

Golgi body / complejo de Golgi

Organelle of lipid assembly, polypeptide chain modification, and packaging of both in vesicles for export or for transport to locations in cytoplasm.

intermediate filament / filamento intermedio

Cytoskeletal element; mechanically strengthens some animal cells.

lipid bilayer / bicapa de lípidos

Phospholipids, mostly, arranged in two layers; the structural basis of all cell membranes. Hydrophobic tails are sandwiched between the hydrophilic heads; the heads are dissolved in intracellular or extracellular fluid.

lysosome / lisosoma

Important organelle of intracellular digestion.

microfilament / microfilamento

Cytoskeletal element of two thin, helically twisted polypeptide chains; functions in movement, cell shape.

micrograph / microfotografía

Photograph of an image brought into view with the aid of a microscope.

microtubule / microtúbulo

Cylinder of tubulin subunits; cytoskeletal element with roles in most eukaryotic cell movements.

mitochondrion / mitocondria

Double-membrane organelle of ATP formation. Only site of aerobic respiration's second and third stages. May have endosymbiotic origins.

motor protein / proteína motora

Type of protein (e.g., myosin) attached to microfilaments and microtubules; used in cell movements (e.g., contraction).

nuclear envelope / cubierta nuclear

Outermost portion of the cell nucleus; consists of a double membrane (two lipid bilayers and associated proteins).

nucleoid / nucleoide

Portion of bacterial cell interior in which the DNA is physically organized but not enclosed by a membrane.

nucleolus / nucléolo

In a nondividing cell nucleus, a site for assembling protein and RNA subunits that will later join up as ribosomes in the cytoplasm.

nucleus / núcleo

Of atoms, a central core of one or more protons and (in all but hydrogen atoms) neutrons. In a eukaryotic cell, the organelle that physically separates DNA from cytoplasmic machinery.

organelle / organelo

Membrane-bound sac or compartment in the cytoplasm having one or more specialized metabolic functions. Most eukaryotic cells have a profusion of them.

peroxisome / peroxisoma

A vesicle; its enzymes digest fatty acids and amino acids to hydrogen peroxide, which is then converted to harmless products.

plasma membrane / membrana plasmática

Outermost cell membrane; structural and functional boundary between cytoplasm and the fluid outside the cell.

primary wall / pared primaria

A thin, flexible plant cell wall of cellulose, polysaccharides, and glycoproteins; allows growing cells to divide or change shape.

prokaryotic cell / célula procarionte

Archaebacterium or eubacterium; single-celled organism, most often walled; lacks the profusion of membranebound organelles observed in eukaryotic cells.

pseudopod / pseudópodo

A dynamically extending lobe of cytoplasm used for motility or engulfment.

ribosome / ribosoma

Two subunits of rRNA and proteins briefly joined together as a structure on which mRNA is translated into polypeptide chains.

secondary wall / pared secundaria

Of older plant cells no longer growing but in need of structural support, a wall on the inner surface of the primary wall. Contains lignin in older cells of woody plants.

surface-to-volume ratio / proporción entre superficie y volumen

Mathematical relation in which the volume of an object expands in three dimensions (e.g., length, width, depth) but its surface area are expands in only two dimensions; a constraint on cell size and shape.

vesicle / vesícula

One of various small, membrane-bound sacs in cytoplasm that function in the transport, storage, or digestion of substances.

wavelength / longitud de onda

A wavelike form of energy in motion. The horizontal distance between the crests of every two successive waves.