biology 4.5-4.7
what is the secondary cell wall? (in some cells)
added between the plasma membrane and the primary cell wall
plasmodesmata are channels between what?
adjacent plant cells
what are microfilaments?
also called actin filaments, are the thinnest components
what is the endosymbiont theory?
an early ancestor of eukaryotic cells engulfed a nonphotosynthetic prokaryotic cell, the host cell and endosymbiont merged into single organism a eukaryotic cell with mitochondrion, now one of these cells may have taken up a photosynthetic prokaryote, becoming the ancestor cells that contain chloroplasts
what is the cell wall?
an extracellular structure that distinguishes plant cells from animal cells
what are intermediate filaments?
are fibers with diameters in a middle range
what is the cristae?
are infoldings of the inner membrane which increase its surface area
what are peroxisomes?
are specialized metabolic compartments bounded by a single membrane; oxidative organelles
what is mitochondria?
are the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP
how does cilia and flagella differ?
by their beating patterns
what does mitochondria and chloroplast have similarites with bacteria
enveloped by a double membrane, contain free ribosomes and circular DNA molecules, grow and reproduce somewhat independently in cells
what is the structure of intermediate filaments?
fibrous protein
what is chloroplast?
found in plants and algae, are the sites of photosynthesis
what is ECM made up of?
glycoproteins such as collagen, proteoglycans, and fibronectin
how does cytoskeleton help?
helps to support the cell and maintain its shape
what is the function of intermediate filaments?
support cell shape and fix organelles in place are more permanent cytoskeleton elements that the other two classes
what does microtubules control?
the beating of cilia and flagella
what does the cytoskeleton organize?
the cell's structures and activities, anchoring many organelles
what does chloroplasts contain?
the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis
what is extracellular matrix (ECM)
the meshwork surrounding animal cells, consisting of glycoproteins , polysaccharides, and proteoglycans synthesized and secreted by the cells.
what does the cell wall protect?
the plant cell maintains its shape and prevents excessive uptake of water
what are microtubules?
the thickest of the three components of the cytoskeleton
what is the middle lamella?
thin layer between primary walls of adjacent cells
what are the three cell junctions in animal tissues?
tight junctions, desmosomes, gap junctions
flagella are limited...
to one or a few per cell, while cilia occur in large numbers on cell surfaces
what is the structure of microtubules?
tubulin molecules
through plasmodesmata what happens?
water and small solutes (and sometimes proteins and RNA) can pass from cell to cell
how many layers does the cell wall have?
3
what is centrosome?
a region that is often located near the nucleus and is considered a "microtubule-organizing center"
what are tight junctions?
a type of intercellular junction between animal cells that prevents the leakage of material through the space between cells
what are desmosomes?
a type of intercellular junction in animal cells that functions as a rivet, fastening cells together
what are gap junctions?
a type of intercellular junction in animal cells, consisting of proteins surrounding a pore that allows the passage of materials between cells
what are the types of intercellular junctions?
plasmodesmata, tight junctions, desmosomes, gap junctions
what else had cell walls?
prokaryotes, fungi, and some protists
what does peroxisomes perform?
reactions with many different functions
what does ECM protein bind to?
receptor proteins in the plasma membrane called integrins
what is the primary cell wall?
relatively thin and flexible
what do cilia and flagella share?
a core of microtubules sheathed by the plasma membrane, a basal body that anchors the cilium or flagellum, a motor protein called dynein, which drives the bending movements of a cilium or flagellum
what is the cytoskeleton?
a network of fibers extending throughout the cytoplasm
what is centrioles?
a pair of centrosome composed of nine sets of triplets microtubules arranged in a ring
what is motor proteins?
a protein that interacts with cytoskeleton elements and other cell components, producing movement of the whole cell or parts of the cell
what does peroxisomes produce?
hydrogen peroxide and convert it to water
where are chloroplasts found in?
in leaves and other green organs of plants and in algae
what is the structure of microfilaments?
intertwined actin
what are plant cell walls made up of?
made of cellulose fibers embedded in other polysaccharides and protein
what is the function of microfilaments?
maintain cell shape and changes in cell shape, muscle contraction, division of animal cells, cytoplasmic streaming plants
what is the function of microtubules?
maintain cell shape and motility, chromosome movements in cell division organelle movements
what are the main type of fivers the make up the cytoskeleton?
microtubules, microfilaments, intermediate filaments
