Chapter 6 Flashcards
cytosol
jellylike substance in which sub cellular components are suspended inside all cells
eukaryotic cell
most DNA is in the nucleus bounded by a double membrane
prokaryotic cell
DNA is concentrated in a region that is not membrane-enclosed called the nucleoid
cytoplasm
the interior of all cells/the region between the nucleus and the plasma membrane
plasma membrane
at the boundary of every cell, functions as a selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell
nucleus
contains most of the genes in a eukaryotic cell
nuclear envelope
encloses the nucleus, separating its contents from the cytoplasm
nuclear lamina
lines the nuclear side of the envelope, a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope
chromosomes
discrete units where DNA is organized
chromatin
the complex of DNA and proteins making up chromosomes
nucleolus
structure in the nucleus consisting of chromosomal regions containing rRNA genes and ribosomal proteins imported from the cytoplasm; site of rRNA synthesis and ribosomal subunit assembly
ribosomes
made of ribosomal RNAs and proteins, carry out protein synthesis
end-membrane system
includes the nuclear envelope, the ER, the Golgi apparatus, lysosomes, vesicles and vacuoles, and the plasma membrane
vesicles
a membrane-bound sac in or outside a cell, helps transport
endoplasmic reticulum (ER)
extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome free (smooth) regions
smooth ER
outer surface lacks ribosomes, synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, and stores calcium ions
rough ER
studded with ribosomes on the outer surface, makes secretory proteins like glycoproteins (proteins with carbohydrates covalently bonded to them)
transport vesicles
transports things from one part of the cell to another
Golgi apparatus
consists of a group of associated, flattened, membranous sacs; a warehouse for receiving, sorting, shipping, and some manufacturing; cis face is the receiving side; trans face is the shipping side
lysosomes
membranous sac of hydrolytic enzymes that many eukaryotic cells use to digest macromolecules
phagocytosis
cell eating by engulfing smaller organisms or food particles
vacuoles
large vesicles derived from the ER and Golgi apparatus
food vacuoles
formed by phagocytosis of microorganisms or particles to be used as food by the cell
contractile vacuoles
pump excess water out of the cell
central vacuole
in a mature plant cell, a large membranous sac with diverse roles in growth, storage, and sequestration of toxic substances
mitochondria
sites of cellular respiration, the metabolic process that uses oxygen to drive the generation of ATP by extracting energy from sugars, fats, and other fuels
chloroplasts
found in plants and algae, are the sites of photosynthesis, the process of converting solar energy to chemical energy
endosymbiont theory
the theory that states that an early ancestor of eukaryotic cells (a host cell) engulfed an oxygen using nonphotosynthetic prokaryotic cell. eventually, the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an endosymbiont (a cell living within another cell). indeed, over the course of evolution, the host cell and its endosymbiont merged into a single organism, a eukaryotic cell with the endosymbiont having become a mitochondrion. at least one of these cells may have then taken up a photosynthetic prokaryote, becoming the ancestor of eukaryotic cells that contain chloroplasts
cristae
the inner membrane infoldings, gives the inner mitochondrial membrane a large surface area, thus enhancing the productivity of cellular respiration
mitochondrial matrix
contains many different enzymes as well as mitochondrial DNA and ribosomes
chloroplasts
contain the green pigment chlorophyll along with enzymes and other molecules that function in the photosynthetic production of sugar
thylakoids
membranous system in the form of flattened, interconnected sacs
granum
each stack of thylakoids in chloroplasts
stroma
fluid outside the thylakoids, which contains the chloroplast DNA, ribosomes, and many enzymes
peroxisome
an organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading hydrogen peroxide
cytoskeleton
a network of fibers extending throughout the cytoplasm
motor protein
interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell
mictrotubules
hollow rods constructed from globular proteins called tubulins that shape and support the cell, in all eukaryotic cells
centrosome
in animal cells where microtubules grow out from
centrioles
a pair within the centrosome, each composed of nine sets of triplet microtubules arranged in a ring
flagella and cilia
in some eukaryotic cells, cellular extensions that contain microtubules to help the cell move
basal body
in eukaryotic cells, organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole
dynein
in cilia and flagella, a large motor protein extending from one microtubule doublet to the adjacent doublet. ATP hydrolysis drives chance in dynein shape that lead to the bending of cilia and flagella.
microfilaments
thin solid rods built from molecules of actin (a globular protein), can form structural networks when certain proteins bind along the side of such a filament and allow a new filament to extend as a branch
cortex
outer region of cytoplasm in a eukaryotic cell lying just under the plasma membrane that as a more gel-like consistency than the inner regions due to the presence of multiple microfilaments
myosin
a type of motor protein that associates into filaments that interact with actin filaments to cause cell contraction
pseudopodia
a cellular extension of amoeboid cells used in moving and feeding
cytoplasmic streaming
a circular flow of cytoplasm, involving interactions of myosin and acting filaments, that speeds up the distribution of materials within cells
intermediate filaments
a component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments
cell wall
extracellular structure of plant cells, protects the plant cell, maintains its shape, and prevents excessive uptake of water
primary cell wall
in plants, a relatively thin and flexible layer that surrounds the plasma membrane of a young cell
middle lamella
in plants, a thin layer of adhesive extracellular material, primarily pectins, found between the primary walls of adjacent young cells
secondary plant wall
in plant cells, a strong and durable matrix that is often deposited in several laminated layers around the plasma membrane and provides protection and support
extracellular matrix (ECM)
the meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by cells
collagen
a glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone, the most abundant protein in the animal kingdom
proteoglycan
a large molecule consisting of a small core protein with many carbohydrate chains attached. found in the extracellular matrix of animal cells, may consist of up to 95% carbohydrate
fibronectin
an extracellular glycoprotein secreted by animal cells that helps them attach to the extracellular matrix
integrin
in animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular matrix and the cytoskeleton
plasmodesma
an open channel through the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, and some larger molecules to pass between the cells
