Chapter 5 Flashcards
technique for producing visible images of objects that are too small to be seen by the human eye
microscopy
instrument of microscopy with different magnifications and resolutions of specimens
microscope
microscope that uses light to illuminate the specimen
light microscopes
microscope that uses electrons to illuminate the specimen
electron microscopes
the ration of an object as viewed to its real size
magnification
the minimum distance 2 points in a specimen can be separated and still be seen as 2 points
resolution
the outer limit of the cytoplasm responsible for the regulation of substances moving into and out of cells
plasma membrane
all the parts of the cell that surround the central nucleus (eukaryotes) or nucleoid region (prokaryotes)
cytoplasm
the nucleus and other specialized internal structures and compartments of eukaryotic cells
-“little organs”
organelles
aqueous solution in the cytoplasm containing ions and various organic molecules
cytosol
the interconnected system of protein fibers and tubes that extend throughout the cytoplasm of a eukaryotic cell
cytoskeleton
organism in which the DNA is suspended in the cell interior without separation from other cellular components by a discrete membrane
prokaryotes
the central region of a prokaryotic cell with no boundary membrane separating it from the cytoplasm, where DNA replicates and RNA transcription occur
nucleoid
organisms in which the DNA is enclosed in a nucleus
eukaryotes
the central region of eukaryotic cells, separated by membranes from the surrounding cytoplasm, where DNA replication and messenger RNA transcription occur. it is a concentration of nerve cells within the central nervous system that have related functions
nucleus
what is the plasma membrane, and what are its main functions?
the plasma membrane is a bilayer of lipid and suspended protein molecules that bounds the cytoplasm of a cell. The lipid bilayer is hydrophobic; therefore, it is a barrier to the passage of water-soluble substances. The membrane has protein channels through which selected water-soluble substances are able to pass
The genetic material of prokaryotes in most cases a single, circular DNA molecule
prokaryotic chromosome
a ribonucleoprotein particle that carries out protein synthesis by translating mRNA into chains of amino acids
ribosomes
a rigid external layer of material surrounding the plasma membrane of cells in plants, fungi, bacteria, and some protists, providing cell protection and support
cell wall
A carbohydrate coat covering the cell surface
glycocalyx
a coat typically composed of polysaccharides that is loosely associated with bacterial cells
slime layer
an external layer of sticky or slimy polysaccharides coating the cell wall in many prokaryotes
capsule
a long threadlike cellular appendage responsible for movement; found in both prokaryotes and eukaryotes but with different structures and modes of locomotion
flagella
a hair or hairlike appendage on the surface of a prokaryote
pili
in eukaryotes, membranes separating the nucleus from the cytoplasm
nuclear envelope
a large octagonally symmetrical cylindrical structure that functions to exchange molecules between the nucleus and cytoplasm and prevents the transport of material not meant to cross the nuclear membrane. a nuclear pore- a channel through the complex- is the path for the exchange of molecules
nuclear pore complex
a short amino acid sequence in a protein that directs the protein to the nucleus
nuclear localization signal
the liquid or semiliquid substance within the nucleus
nucleplasm
an assemblage of eukaryotic nuclear DNA molecules and their associated proteins
chromatin
a DNA molecule, with its associated proteins, in the nucleus of a eukaryotic cell
eukaryotic chromosome
the nuclear site of rRNA transcription, processing, and ribosome assembly in eukaryotes
nucleoli
in eukaryotes, a collection of interrelated internal membranous sacs that divide a cell into functional and structural compartments
endomembrane system
1) all organisms are composed of 1 or more cells
2) cell is basic structural and functional unit of all living organisms
3) cell arise only from the division of preexisting cells
cell theory
a small, membrane-bound compartment that transfersx substances between parts of the endomembrane system
vesicles
in eukaryotes, an extensive interconnected network of cisternae that is responsible for the synthesis transport, and initial modification of proteins and lipids
endoplasmic reticulum
membranous channels and vesicles that make up the endoplasmic reticulum
cisternae
ER lumen
the enclosed space surrounded by a cisterna
endoplasmic reticulum with many ribosomes studding its outer surface
rough ER
endoplasmic reticulum with no ribosomes attached to its membrane surfaces. has various functions, including synthesis of lipid that becomes part of cell membranes
smooth ER
in eukaryotes, the organelle responsible for the final modification, sorting, and distribution of proteins and lipids
golgi complex
vesicle that transports proteins to the plasma membrane
secretory vesicles
in eukaryotes, the process by which a secretory vesicle fuses with the plasma membrane and releases the vesicle contents to the exterior
exocytosis
in eukaryotes, the process by which molecules are brought into the cell from the exterior involving a bulging in of the plasma membrane that pinches off to form an endocytic vesicle
enocytosis
vesicle that carries proteins and other molecules from the plasma membrane to destinations within the cell
endocytic vesicle
membrane-bound vesicle containing hydrolytic enzymes for the digestion of many complex molecules
lysosomes
process in which some types of cells engulf bacteria or other cellular debris to break them down
phagocytosis
membrane-bound organelle responsible for synthesis of most of the ATP in eukaryotic cells
mitochondria
the smooth membrane covering the outside of a mitochondrion
outer mitochondrial membrane
membrane surrounding the mitochondrial matrix
inner mitochondrial membrane
the innermost compartment of the mitochondrion
mitochondrial matrix
fold that expands the surface area of the inner mitochondrial membrane
crista
small, membrane-bound organelle that carries out vital reactions linking metabolic pathways
microbodies
microbody that produces hydrogen peroxide as a by-product
peroxisomes
a cytoskeletal component formed by the polymerization of tubulin into rigid, hollow rods about 25 nm in diameter
microtubules
the main microtubule organizing center of a cell, which organizes the microtubule cytoskeleton during interphase and positions many of the cytoplasmic organelles
centrosome
a cylindrical structure consisting of 9 triplets of microtubules in the centrosomes of most animal cells
centrioles
a cytoskeletal filament about 10 nm in diameter that provides mechanical strength to cells in tissues
intermediate filaments
a cytoskeletal filament of actin
microfilaments
structure that anchors cilia and flagella to the surface of a cell
basal body
the site of photosynthesis in plant cells
chloroplasts
a family of plant organelles that includes chloroplasts, amyloplasts, and chromoplasts
plastids
colorless plastid that stores starch in plants
amyloplasts
plastid containing red and yellow pigments
chromoplasts
a smooth membrane that surrounds a chloroplast, enclosing the stroma
outer boundary membrane
membrane lying just inside the outer boundary membrane of a chloroplast, enclosing the stroma
inner boundary membrane
structure in the chloroplasts of higher plants formed by thylakoids stacked one on top of another
grana
a large, water-filled organelle in plant cells that maintains the turgor of the cell and controls movement of molecules between the cytosol and sap
central vacuoles
The membrane that surrounds the central vacuole in a plant cell
tonoplast
the initial cell wall laid down by a plant cell
primary cell wall
a layer added to the cell wall of plants that is more rigid and may become many times thicker than the primary cell wall
secondary cell wall
layer of gel-like polysaccharides that holds together walls of adjacent plant cells
middle lamella
a minute channel that perforates a cell wall and contains extensions of the cytoplasm that directly connect adjacent plant cells
plasmodesmata
a cell surface protein responsible for selectively binding cells together
cell adhesion molecules
junction that seals the spaces between cells and provides direct communication between cells
cell junctions
cell junction that forms belts that run entirely around cells, “welding” adjacent cells together
anchoring junction
anchoring junction for which microfilaments anchor the junction in hte underlying cytoplasm
desmosomes
animal cell junction in which intermediate filaments are hte anchoring cytoskeletal component
adherens junctions
region of tight connection between membranes of adjacent cells
tight junctions
junction that opens direct channels allowing ions and small molecules to pass directly from one cell to another
gap junctions
