Chapter 2: Cells and Organelles Flashcards
cell membranes hold cellular contents and are composed of ___ and ___, with small amounts of ___
phospholipids, proteins, cholesterol
phospholipids are made up of a ___ backbone, one ___ group, and ___ fatty acid tails
glycerol, phosphate. 2
phospholipids are ___ because the molecules have both polar and non polar parts
amphipathic
being amphipathic allows phospholipids to form a ___ in an aqueous environment
lipid bilayer
cholesterol has four ___ ___ rings and is a precursor to ___ hormones
fused hydrocarbon, steroid
similar to phospholipids, cholesterol is ___
amphipathic
cholesterol can also help to regulate ___ ___
membrane fluidity
the membrane proteins in cells membranes are either ___ or ___ membrane proteins
integral, peripheral
___ (transmembrane) proteins traverse the entire bilayer, so they must be ___
integral, amphipathic
integral proteins ___ parts lie in the middle of the bilayer while their ___ ends extend out into the aqueous environment
non polar, polar
integral proteins usually assist in cell ___ or ___
signaling, transport
peripheral membrane proteins are found on the ___ of the ___, and they are generally hydro___
outside, bilayer, philic
like integral proteins, peripheral membrane proteins also function as ___
receptors
peripheral receptors trigger ___ ___ within the cell for ___
secondary responses, signaling
if a receptor transmits a ___ all the way through the ___ ___, it is considered an ___ protein
signal, lipid bilayer, integral
drugs that bind to receptors can either be ___ or ___
agonist, antagonist
___ are ligands that bind to receptors and functionally activate a target
agonists
___ are ligands that bind and prevent other molecules from ___, inhibiting production of a response
antagonists, binding
adhesion ___ cells to other things and act as ___ for the cytoskeleton
attaches, anchors
cellular ___ proteins: proteins that have carbohydrate chains (___) and are used by cells to ___ other cells
recognition, glycoproteins, recognize
the ___ ___ model describes how the components that make up the cell ___ can move ___ within the membrane (“fluid”)
fluid mosaic, membrane, freely
the cell membrane contains many different kinds of ___ (“mosaic”)
structures
the fluidity of the cell membrane is affected by ___, ___, and degrees of ___
temperature, cholesterol, unsaturation
of the two unsaturated fatty acids, the ___ fatty acids have a more severe kink
cis-unsaturated
the 3 types of transport across cell membranes are simple ___, ___ transport, and ___ transport
diffusion, facilitated, active
simple diffusion is the flow of small, un___, ___ substances across the cell membrane
uncharged, non polar
in simple diffusion, substances go ___ their concentration gradient ___ using energy
down, without
osmosis is a type of ___ ___ that involves ___ molecules
simple diffusion, water (water is polar but is small enough to cross the membrane)
in facilitated transport, ___ proteins allow ___, hydro___ molecules to cross cell membrane
integral, larger, philic
the three integral proteins are ___, ___, or ___
uniporters, symporters, antiporters
uniporter proteins are ___ substances, ___ direction
single, single
symporter proteins are ___ substances, ___ direction
two, same
antiporter proteins are ___ substances, ___ direction
two, opposite
integral membrane proteins can also be classified as ___ proteins and ___ proteins
channel, carrier
channel proteins open ___ that face ___ sides of bilayer
tunnels, both
carrier proteins ___ to a molecule on one side and change ___ to bring it to the other side
bind, shape
passive diffusion is a type of ___ transport that is performed by ___ proteins, bringing molecules ___ their concentration gradient without energy use
facilitated, channel, down
passive diffusion is similar to ___ diffusion, except a ___ channel is used
simple, protein
porins are channel proteins used for ___ molecules
hydrophilic
___ channel proteins are used for ions
ion
in active transport, substances travel ___ their concentration gradient and require the consumption of ___ by ___ proteins
against, energy, carrier
___ active transport uses ___ hydrolysis to pump molecules against their concentration gradient
primary, ATP
an example of primary active transport is the ___-___ pump, which establishes membrane ___
sodium potassium, potential
___ active transport uses ___ energy released when other molecules flow down their concentration gradient to ___ the molecule of interest ___ the membrane
secondary, free, pump, across
cytosis refers to the ___ transport of large, hydro___ molecules across the cell membrane and requires ___
bulk, hydrophilic, energy
cytosis is an ___ ___ mechanism
active transport
endocytosis involves the cell membrane ___ around an ___ substance, internalizing it into the cell via __
wrapping, extracellular, vesicle/vacuole
the different forms of endocytosis are ___cytosis, ___cytosis, ___ ___ endocytosis
phagocytosis, pinocytosis, receptor-mediated
phagocytosis is cellular ___ around solid objects
eating
pinocytosis is cellular ___ around dissolved materials
drinking
receptor-mediated endocytosis requires the ___ of dissolved molecules to peripheral ___ ___ proteins
binding, membrane receptor
peripheral membrane receptor proteins initiates ___
endocytosis
clathrin is a ___ that aids in receptor mediated ___ by forming a ___ in the membrane that pinches off as a ___ ___
protein, endocytosis, pit, coated vesicle (process aka clathrin mediated endocytosis
___ is the opposite of endocytosis, in which material is ___ to the extracellular environment through ___ secretion
exocytosis, released, vesicle
organelles are cellular ___ enclosed by ___ ___
compartments, phospholipid bilayers
organelles are located within the ___ and help make up the ___
cytosol, cytoplasm
cytosol is the ___ intracellular fluid
aqueous
cytoplasm is made up of the ___ and ___
cytosol, organelles
only ___ cells contain membrane-bound organelles
eukaryotic
prokaryotes keep their ___ material in a region called the nucleoid
genetic
the nucleus primarily functions to ___ and ___ DNA
protect, house
DNA ___ and ___ occur in the nucleus
replication, transcription (DNA–>mRNA)
the nucleoplasm is the ___ of the nucleus
cytoplasm
the nuclear envelope is the ___ of the nucleus
membrane
the nuclear envelope contains two ___ bilayers with a ___ space in the middle
lipid, perinuclear
nuclear pores are holes in the ___ ___ that allow molecules to travel ___ and ___ of the nucleus
nuclear envelope, in, out
the nuclear lamina provides ___ support to the nucleus, as well as regulating ___ and cell ___
structural, DNA, division
the nucleolus is a ___ area that is responsible for making ___ and producing ___ subunits
dense, rRNA, ribosomal
___ are not considered to be organelles
ribosomes
ribosomes work as small factories that carry out ___ (mRNA–>protein)
translation
Eukaryotic ribosomal subunits (___S and ___S) assemble in the ___
60, 40, nucleoplasm
after assembling, eukaryotic subunits are then exported from the ___ to form complete ribosome in the ___ (___S)
nucleus, cytosol, 80
S refers to ___ characteristics
sedimentation
prokaryotic ribosomal subunits (___S and ___S) assemble in the ___
50, 30, nucleoid
prokaryotic ribosomal subunits form the complete ribosome in the ___ (___S)
cytosol, 70
___ ___ ribosomes make proteins that function in the cytosol
free floating
