histo chapt 2: cytoplasm Flashcards
the first zygotic cellular divisions produce cells called
blastomeres
explanted to tissue culture cells of the cell mass are called
embryonic stem cells
they predominantly express sets of genes that mediate specific cytoplasmic activities
differentiation
all animals contain ____ ____ and _____, but most ______ _____ are specialized for using these proteins to convert chemical energy into forceful contractions
actin filaments, myosins, muscle cells
envelops every eukaryotic cells consists of phospholipids, cholesterol, and proteins, with oligosaccharide chain
plasma membrane
functions as a selective barrier
plasma membrane
are amphipathix, consisting of two nonpolar long chain fatty acids linked to a charged polar head that bears a phosphate group.
membrane phospholipids
the site where materials are exchanged between the cell and its environment.
plasma membrane
transports small, nonpolar molecules directly through the lipid bilayer
diffusion
multipass proteins forming transmembrane pores through which ion or small molecules pass selectively.
channels
water molecules usually cross the plasm membrane through channel proteins
aquaporins
transmembrane proteins that bind small molecules and translocate the across the membrane via conformational changes
carriers
normally enter cells by being enclosed within folds of plasma membrane
macromolecules
three major types of endocytosis
Phagocytosis
Pinocytosis
receptor-mediated endocytosis
molecules interact like the struts of geodesic dome
clathrin
a dynamic collection on the peripheral cytoplasm of membranous tubules and vacuoles
endosomal compartment
small GTPases that bind guanin nucleotides and associated proteins
Rab proteins
movement of large molecules from inside to outside the cell usually involves vesicular transport on the process of _______
exocytosis
is used for products that are released from cells continuously
constitutive secretions
occurs in response to signals coming from the cells
regulated secretion
process of membrane movement and recycling is called
membrane traffiking
the signal molecules are carried in the blood from their sources to target cells throughout the body.
endocrine signaling
the chemical ligan diffuses in extracellular fluid but rapidly metabolized so that its effect is only local on target cells near its source
paracrine signaling
a special kind of paracrine interaction, neurotransmitters act on adjacent cell through special contact are called ______
synaptic signaling, synapses
signal bind receptors on the same cells that produce the messenger molecule
autocrine signaling
bind surface receptors of the target cell when two cells make direct physical contact
juxtacrine signaling
three important functional classes of such receptors
Channel-linked receptors
enzymatic receptors
G-protein-coupled receptors
bind guanine nucleotide GTP, and are release to activate other cytoplasmic proteins
G-protein-coupled-receptors
open associated channels upon ligand binding to promote transfer of molecules or ions across the membrane
Channel-linked receptors
ligand binding catalytic activity on associated peripheral proteins
enzymatic receptors
in a cell membrane can be considered first messengers
ligands binding
assemble polypeptides from amino acids on molecules of transfer RNA
Ribosomes
the cytoplasm of most cells contain a convoluted membranous network
endoplasmic reticulum
a major site for vital cellular activities
Endoplasmic reticulum
prominent in cells specialized for protein secretion
rough endoplasmic reticulum
inhibits further polypeptide elongation
signal-recognition particle
has a highly regulated system to precent nonfunctional proteins being forwarded to the pathway for secretion or the other organelles.
RER
regions of ____ lack bound polyribosomes
SER
not basophilic and is best seen with the TEM
SER
allows detoxification of potentially harmful exogenous molecules
Cytochrome P450
modifies, packages, and sorts materials that arrive from the ER in transport vehicle
Golgi apparatus
transport cellular material
vesicles
digest microbes or materials
lysosomes
detoxify specific harmful substances either produced by the cell or taken into the cell
peroxisomes
synthesize most ATP during aerobic cellular respiration
mitochondria
engage in protein synthesis
ribosomes
maintains intracellular structural support and organization of cells
cytoskeleton
maintain cell shape, support microvilli
microfilaments
provide structural support; stabilize junctions between cells
intermediate filaments
maintain cell shape and rigidity; organize and move organelles
microtubules
organize microtubules; participates in mitotic spindle formation during cell division
centrosome
degrade and digest damaged or unneeded proteins; unsure quality of exported proteins
proteasomes
serves as temporary storage for these molecules
inclusions
the command center of the cell
nucleus
forms a selectively permeable barrier between the nuclear and cytoplasmic compartments
nuclear envelop
closely associated with the inner nuclear membrane is a highly organized meshwork of proteins
nuclear lamina
bind to membrane proteins and associate with chromatin in nondividing cells
lamins
display eightfold symmetry around a lumen
nucleo porins
consists of DNA and all of the associated proteins involved in the organization and function of DNA
chromatin
DNA associating with sets of small basic proteins called
histones
the structural unit of DNA and histones is called the
nucleosome
visible as finely dispersed granular material in the electron microscope and as lightly stained basophilic areas in the microscope
Euchromatin
appears as coarse, electron-dense material in the electron microscope and as intensely basophilic clumps in the light microscope``
Heterchromatin
