240 terms

DAT Bootcamp - Cells and Organelles

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what are the 3 main things in a cell membrane?
phospholipids; cholesterol; proteins
what are the 2 types of membrane proteins?
integral; peripheral
_____ membranes are embedded in the core of the plasma membrane
integral
many integral proteins are _____ proteins, meaning they extend all the way through the membrane
transmembrane
transmembrane proteins are _____
amphipathic
integral/transmembrane proteins may function in cell _____, but most tend to transport _____ molecules across the cell membrane
signaling; large, polar (hydrophilic)
_____ membrane proteins do not extend through the entire bilayer
peripheral
_____ membrane proteins may or may not be amphipathic
peripheral
what are 3 common types of peripheral membrane proteins?
receptors; adhesion proteins; recognition proteins
_____ (peripheral) receive chemical signals from the extracellular environment
receptor proteins
_____ (peripheral) attach adjacent cells, and also act as anchors for the cytoskeleton
adhesion proteins
_____ (peripheral) give cells a way to identify each other when they come in contact
recognition proteins
recognition proteins are also known as _____
glycoproteins
what is a common example of a recognition peripheral protein?
major-histocompatibility complexes (MHC molecules)
cell membranes follow a _____ model
fluid-mosaic
what are the 3 main factors that affect membrane fluidity?
temperature; cholesterol; the degree of phospholipid tail unsaturation
cells would _____ if they were completely isolated from the outside
die
_____ particles can travel directly across the phospholipid bilayer via simple diffusion
small, uncharged, non-polar (hydrophobic)
simple diffusion is the flow of substances _____ their concentration gradient in a _____ consuming process
down; non-energy
_____ does not utilize proteins to help particles across the membrane
simple diffusion
osmosis is a type of _____
simple diffusion
_____ molecules cannot travel directly across the bilayer
large, hydrophilic
_____ describes how large, hydrophilic molecules travel across the bilayer by transmembrane proteins
facilitated transport
what are the three main types of facilitated transport (direction)?
uniport; synport; antiport
_____ move 1 molecule in 1 direction
uniporters
_____ move 2 molecules in the same (1) direction
synporters
_____ move 2 molecules in opposite (2) directions
antiporters
what are the two classes of transmembrane proteins involved with facilitated transport?
channel; carrier
_____ proteins face the extracellular and intracellular environments of the cell at the same time
channel
channel proteins are like tunnels for many _____
small, polar molecules and ions
carrier proteins _____ face extracellular and intracellular environments at the same time
do not
_____ diffusion describes a type of facilitated transport of particles down their concentration gradient through a _____ protein
passive; channel
porins and ion channels are common examples of _____ diffusion
passive
_____ change their shape to facilitate the movement of molecules through the protein.
carrier proteins
_____ occurs when particles travel against their concentration gradient, which requires an energy input
active transport
active transport tends to rely upon _____ proteins
carrier
what are the 2 types of active transport?
primary; secondary
_____ active transport uses the energy released from ATP hydrolysis
primary
the Na+/K+ pump is a form of _____ active transport
primary
the Na+/K+ pump moves _____ out of the cell and _____ into the cell with the hydrolysis of 1 ATP
3 Na+; 2 K+
secondary active transport depends on _____ to generate free energy in the form of a concentration gradient
primary active transport
_____ active transport uses free energy to pump other molecules against their concentration gradient
secondary
_____ is bulk transport of large, polar (hydrophilic) molecules
cytosis
what are the 2 directions of cytosis?
endocytosis (in the cell) and exocytosis (out of the cell)
cytosis mechanisms are _____ transport mechanisms, meaning they require energy
active
_____ is a type of endocytosis where a cell engulfs undissolved materials
phagocytosis

(cellular eating)
during phagocytosis, the cell membrane will project _____ to wrap around the solid
outward
phagocytosis forms _____
vacuoles (phagosomes)
_____ is a type of endocytosis where a cell engulfs dissolved materials
pinocytosis

(cellular drinking)
during pinocytosis, the cell membrane will _____ around the liquid
invaginate
pinocytosis forms _____
vesicles
certain non-steroidal hormones target cells via which pinocytosis mechanism?
receptor-mediated endocytosis
receptor-mediated endocytosis is pinocytosis, so it forms _____
vesicles
organelles are enclosed by a _____
phospholipid bilayer
membrane-bound organelles are predominately associated with which cell type?
eukaryotes
the _____ is the aqueous intracellular fluid
cytosol
the _____ is everything within the cell (fluid and organelles)
cytoplasm
what is the nucleus?
a membrane-enclosed organelle that contains most of a eukaryotic cell's genetic material
do prokaryotes have a nucleus?
no - they have a nucleoid
the nucleus contains an aqueous _____
nucleoplasm
the nucleus has an inner and outer membrane, called the _____
nuclear envelope
what is the space between the inner and outer nuclear membranes?
perinuclear space
the _____ is a dense and fibrous network of proteins associated with the inner membrane of the nuclear envelope
nuclear lamina
the nuclear lamina is made of _____
intermediate filaments
the _____ functions to provide structural support to the nucleus; regulate DNA organization, DNA replication, and cell division
nuclear lamina
the nuclear envelope has holes called _____
nuclear pores
the _____ is a dense region in the nucleus, associated with ribosomal subunit assembly
nucleolus
is the nucleolus an organelle?
no - it is not membrane bound
ribosomal subunits contain _____ and _____
ribosomal ribonucleic acid (rRNA); proteins
ribosomes are macromolecules that _____ contain a membrane, so they are _____
do not; not organelles
do prokaryotes and eukaryotes have organelles?
yes - they are not membrane bound organelles
prokaryotic _____ are made and assembled in the cytosol
ribosomal subunits
eukaryotic _____ are made in the nucleus and assembled in the cytosol
ribosomal subunits
what do ribosomes do?
function in the synthesis of proteins

(translation)
what is the structure of a eukaryotic ribosome?
60S + 40S = 80S
what is the structure of a prokaryotic ribosome?
50S + 30S = 70S
where are ribosomes found?
freely in the cytosol or attached to the rough ER
_____ ribosomes tend to make proteins that function within the cytosol of the cell
free
ribosomes that bind to the rough ER will synthesize proteins _____
into the rough ER lumen
the rough ER is continuous with the _____, which means the ER lumen is continuous with the _____
outer nuclear membrane; perinuclear space
what happens to proteins inside the rough ER?
they are manipulated
what is a common manipulation for proteins in the rough ER?
glycosylation to make glycoproteins
what are the 2 fates of proteins that enter the lumen of the rough ER?
become a part of the cell membrane; exocytosis
the _____ synthesizes lipids and steroid hormones for export
smooth ER
in some cells (ex: liver), the _____ functions in the breakdown of toxins, and drugs
smooth ER
what is the name of the smooth ER of muscle cells that stores and releases Ca2+ ions?
sarcoplasmic reticulum
the _____ ER is not covered by ribosomes
smooth
the smooth ER is usually not attached to the _____
outer nuclear membrane
the lumen of the smooth ER is usually not continuous with the _____
perinuclear space
ERs send vesicles to the _____
cis-face of the Golgi
vesicles travel from the _____ to _____ of the Golgi, and the vesicle contents are manipulated along the way
cis-face; trans-face
the main function of the Golgi is to..?
direct molecules to their correct locations
which organelles break down nutrients/bacteria/cell debris?
lysosomes
lysosomes receive vesicles containing digestive enzymes from the _____
Golgi
lysosomes have a _____ pH, so their enzymes can only function inside them
low (~5)

(cytosol pH = ~7)
intracellular breakdown of unneeded/defective cellular components is called _____
autophagy
lysosomes function in _____ when they release their contents into the cell
apoptosis
which cells have vacuoles?
all plants and fungus; some animal, protist, bacteria
what are the types of vacuoles?
transport; food; central; storage; contractile
_____ vacuoles move materials from organelle to organelle or from organelles to the plasma membrane
transport
_____ vacuoles are temporary food holders that eventually merge with lysosomes fro digestion
food
central vacuoles have a _____ and exert _____ when filled to maintain plant cell rigidity
tonoplast; turgor
_____ vacuoles (in plants) act similarly to lysosomes and storage vacuoles
central
_____ vacuoles tend to store starches, pigments, and toxic substances
storage
_____ vacuoles collect and pump excess water out of single-celled organisms
contractile
contractile vacuoles prevent _____ in _____ environments
lysis; hypotonic
contractile vacuole use _____ transport
active
what is the endomembrane system?
group of organelles/membranes that work together to modify, package, and transport proteins and lipids that are entering/exiting a cell
what are the components of the endomembrane system?
nucleus/nuclear envelope, rough and smooth ERs, Golgi apparatus, lysosomes, vacuoles, and cell membrane
_____ break down fatty acids and some amino acids; also involved with detoxification
peroxisomes
alcohol detoxification occurs in the _____ of liver cells
peroxisomes
are peroxisomes part of the endomembrane system?
no
peroxisomes _____ vesicles from the Golgi apparatus
do not receive
peroxisomes generate _____, which can produce reactive oxygen species (dangerous)
hydrogen peroxide
reactive oxygen species can create _____
free radicals
peroxisomes contain an enzyme called_____, which converts dangerous hydrogen peroxide radicals into harmless water
catalase
in plant cells, _____ modify the by-products of photorespiration
peroxisomes
what are the specialized peroxisomes that provide energy for a developing plant embryo?
glyoxysomes
_____ make ATP in all eukaryotes
mitochondria
_____ carry out photosynthesis in select eukaryotes
chloroplasts
the centrosome is an organelle found near the _____ of animal cells
nucleus
a centrosome contains a pair of _____, which work together to serve as _____ during cell division in animal cells
centrioles; microtubule organizing centers (MTOCs)
the _____ aids in cell structure, function, and movement in prokaryotes and eukaryotes
cytoskeleton
the cytoskeleton is found within the _____ of prokaryotes/eukaryotes
cytoplasm
what are the 3 components of eukaryotic cytoskeletons?
microfilaments; intermediate filaments; microtubules
_____ have the smallest diameter out of the three cytoskeletal components
microfilaments
microfilaments are made of a double helix of two _____ filaments
actin
the actin monomers of a microfilament have _____, so the microfilaments do too
directionality
actin can undergo rapid _____, which makes microfilaments useful for cell movement
assembly/disassembly
what are some examples of cellular processes that rely upon microfilaments?
amoeboid movement; cyclosis; cleavage furrow formation; muscle contraction
intermediate filaments have a diameter _____ the other two cytoskeletal components
between (intermediate to)
_____ filaments provide cytoskeletal support for maintaining cell shape, and they are also found in the nuclear lamina
intermediate
intermediate filaments can contain many different types of proteins - what is one of the most common?
keratin
keratin is a protein that concentrates in _____
skin, hair, and nails
intermediate filaments do not undergo _____, so they are longer lasting
rapid assembly/disassembly
_____ have the largest diameter out of the three cytoskeletal components
microtubules
microtubules are a hollow tube, where the walls of the tube are a helical polymer of _____
tubulin protein dimers
microtubules are similar to microfilaments in the sense that they can grow and shrink _____
rapidly
_____ have directionality, so microtubules do too
tubulin dimers
what are some of the main functions of microtubules?
structural support; cell division; cilia/flagella
microtubule organizing enters (MTOCs) are in _____ cells
eukaryotic
what do MTOCs develop that is crucial to cell division?
the spindle apparatus
the spindle apparatus guides chromosomes to opposite ends of the cell during _____
karyokinesis (nuclear division)
what are the 3 main types of spindle apparatus microtubules?
kinetochore; polar; astral
_____ attach to a chromosome's kinetochore
kinetochore microtubules (K-fibers)
_____ microtubules connect to push the MTOC to opposite ends of the cell during division
polar
_____ microtubules extend to the cell membrane and are involved with spindle apparatus orientation
astral
a centrosome is a type of MTOC in _____ cells
animal
fungi and most plant cells do not contain a _____ as their MTOC
centrosome
_____ are near an animal cell's nucleus
centrosomes
_____ are specialized cylinders of microtubules that inhabit the centrosome
centrioles
each centrosome has a mother and daughter centriole, oriented at a _____
ninety-degree angle
each centriole is a hollow cylinder made of _____
nine triplets of microtubules

(9x3 array)
there is usually _____ centrosome in a non-dividing cell
1
the centrosome will replicate during _____ to prepare fro cell division
S phase of interphase
the _____ can form a basal body by attaching to the cell membrane
mother centriole
basal bodies are found at the base of each _____
flagellum and cilium
basal bodies have a similar structure to centrioles, so they have a _____ array
9x3
cilia and flagella have a different microtubule structure than basal bodies - they have a _____ array
9+2 array
the protein building block of prokaryotic flagella is called _____
flagellin
_____ of a centrosome is a matrix of proteins that surround the centrioles
pericentriolar material
the pericentriolar material is involved with _____ and _____ to the centrosome
microtubule nucleation; securing microtubules
_____ is the process where several tubulin dimers come together to form a microtubule
microtubule nucleation
_____ determine the placement of the nucleus and organelles
centrioles
the _____ primarily functions to provide mechanical support in the area between adjacent animal cells
extracellular matrix (ECM)
_____ are a class of glycoproteins that exist in the ECM between animal cells
proteoglycans
the most common fibrous structural protein in the ECM is a protein called _____
collagen
animal cells called _____ will glycosylate collagen before secreting it
fibroblasts
glycosylated collagen will form long woven fibers called _____, a major component of the ECM
collagen fibrils
which transmembrane protein connects the ECM to cells?
integrins
_____ are transmembrane proteins that interact with the ECM and signal the cell about its extracellular environment
integrins
integrins interact with the ECM to signal for _____
growth/division/differentiation/apoptosis
_____ is a protein that connects integrins to the network of proteoglycans and collagen in the ECM
fibronectin
fibronectin connections help in the transduction of signals from..?
the ECM --> integrins
_____ is a protein that behaves similarly to fibronectin; found in the basement membrane, which integrins attach to
laminin
_____ are unique carbohydrate-based structures that lie above the cell membrane in certain types of cells that do not make collagen and therefore cannot make an ECM
cell walls
cell walls are unique carbohydrate-based structures that lie _____ in certain types of cells that do not make collagen and therefore cannot make an ECM
above the cell membrane
cell walls are unique carbohydrate-based structures that lie above the cell membrane in certain types of cells that do not make _____ and therefore cannot make an _____
collagen; ECM
which cell types have cell walls?
plants; fungi; bacteria; archea
cell walls are similar to animal cell ECMs - why?
they provide structural support, protection, and an enhanced degree of filtration
do animal cells have a cell wall?
no - they secrete collagen and make an ECM
hard, non-living structural polysaccharide that makes up the cell wall of a plant cell
cellulose
structural polysaccharide that makes up the cell walls of fungi
chitin
found in the cell walls of certain bacteria
peptidoglycans
form the cell walls in archaea
polysaccharides
the _____ is a coat of glycolipids and glycoproteins that covers the surface of bacterial cell walls; some animal cell membranes
glycocalyx
the glycocalyx can..?
provide adhesive capabilities; act as an infection barrier; act in cell-cell recognition
_____ allow the ECM to connect to the cytoskeleton at the interior of an animal cell
cell-matrix junctions
what are the 2 types of cell-matrix junctions?
focal adhesions; hemidesmosomes
_____ are cell-matrix junctions that use actin filaments in the cell
focal adhesions
_____ are cell-matrix junctions that use intermediate filaments e.g. keratin
hemidesmosomes
_____ junctions connect adjacent cells
cell-cell
what are the 4 main types of cell-cell junctions?
tight junctions; desmosomes; adherens junctions; gap junctions
tight junctions are protein junctions that provide a _____ seal between cells
water-tight
_____ junctions ensure that materials must enter the cells to pass through the tissue
tight
tight junctions are characteristic of cells lining the _____
digestive tract
in _____ (cell-cell junctions) cytoskeletal keratin filaments attach to adhesion plaques, which bind transmembrane adhesion proteins that hold adjacent cells together
desmosomes
what are the adhesion proteins used by desmosomes?
cadherins
in _____ (cell-cell junctions) cytoskeletal microfilaments attach to adhesion plaques, which bind transmembrane adhesion proteins that hold adjacent cells together
adherens junctions
what are the adhesion proteins used by adherens junctions?
cadherins
desmosomes and adherens junctions are types of _____ junctions
anchor
anchoring junctions provide _____ and hold cellular structures together
mechanical stability
where are anchoring junctions found?
skin epithelium, cervix, and uterus
gap junctions allow for the passage of _____ and small molecules between cells, but they prevent the _____ of each cell from mixing
ions; cytoplasms
what is a common example of human cells that contain gap junctions?
heart cells (cardiac muscle)
_____ are small holes in the plasma membrane of cells that make gap junctions
connexons
connexons are made up of 6 membrane proteins called _____
connexins
when a connexon of 1 cell lines up with a connexon of another cell, we have a _____
gap junction
a _____ is a sticky cement which attaches adjacent plant cell walls to each other
middle lamella
_____ are tunnels between adjacent plant cells, which consist of a narrow tube of the endoplasmic reticulum called a desmotubule
plasmodesmata
plasmodesmata are tunnels between adjacent plant cells, which consist of a narrow tube of the _____ called a desmotubule
endoplasmic reticulum
plasmodesmata are tunnels between adjacent plant cells, which consist of a narrow tube of the endoplasmic reticulum called a _____
desmotubule
material moves through plasmodesmata via the _____ that surrounds the _____
cytosol; desmotubule
_____ refers to the relative solute concentrations for 2 solutions that are separated by a semipermeable membrane
tonicity
tonicity refers to the relative solute concentrations for 2 solutions that are separated by a _____
semipermeable membrane
tonicity determines the extent and direction of solvent flow via _____
osmosis
_____ is a simple diffusion of water across a semipermeable membrane, from areas of low to high solute concentration
osmosis
osmosis is a _____ of water across a semipermeable membrane, from areas of low to high solute concentration
simple diffusion
osmosis is a simple diffusion of water across a semipermeable membrane, from areas of _____ to _____ solute concentration
low; high
a low solute concentration also means a _____ water concentration, and vice versa
high
osmosis makes the solute concentrations _____ on both sides of the membrane
equal
_____ solutions are those where the extracellular and intracellular environments have the same solute concentrations
isotonic
animal cells prefer _____ environments because they will be in water balance
isotonic
if the solute concentration outside a cell were higher, it would be called a _____ environment
hypertonic
in a _____ environment, water will leave the cell via osmosis in an attempt to reduce the solute concentration outside the cell
hypertonic
the loss of intracellular fluid in hypertonic environments causes the cell to _____
shrivel
if a cell in a hypertonic environment has a cell wall, it will experience _____
plasmolysis
if the solute concentration is lower outside the cell than it is inside the cell, the environment is _____
hypotonic
in a _____ environment, water will travel via osmosis from the external environment and into the cell
hypotonic
animal cells will _____ in hypotonic environments
swell --> lyse
plant cells prefer _____ environments because the extra water goes into the central vacuole, resulting in the normal turgid state
hypotonic
what are the 3 types of intracelular circulation?
bronian motion; cyclosis/streaming; endoplasmic reticulum
_____ is a random particle movement due to kinetic energy that spreads suspended particles through the cytoplasm
brownian motion
what is cyclosis/streaming?
circular motion of the cytoplasm around cell transport molecules
the _____ provides a channel through the cytoplasm, from the plasma to nuclear membrane
endoplasmic reticulum

(type of intracellular circulation)
what are the 2 types of extracellular circulation?
diffusion; the circulatory system
_____ can suffice for food/respiration in cells that are in close contact with the external environment
diffusion

(type of extracellular circulation)
_____ is also used for the transport of materials through interstitial fluid (between cells) in more complex animals
diffusion

(type of extracellular circulation)
complex animals with cells that are too far from the external environment require a _____
circulatory system

(extracellular circulation)
the circulatory system uses _____
vessels (vasculature)
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