Cells and Orgnellels Flashcards
Cell membrane holds Cellular contents and are composed of what?
phospholipids, proteins, and cholesterol
What are phospholipids composed of?
glycerol backbone, one phosphate group, and two fatty acid tails
Phospholipids are _________ because they have polar and nonpolar parts, allowing then to form a lipid bilayer in an aqueous environment.
amphipathic
What is cholesterol composed of?
four hydrocarbon rings
Cholesterol is the precursor to ______ ______.
steroid hormomes
Cholesterols are ____ and regulate ____ ____
amphipathic; membrane fluidity
What are the two types of membrane proteins?
integral(transmemebrane protien), peripheral(surface protien)
Integral protiens transverse the entire membrane bilayer and so they must be ____?
Amphipathic
Integral protein ____ parts lie in the middle of the bilayer while the _____ parts extend out into the aqueous environment outside and inside the cell membrane.
nonpolar;polar
Function of membrane protiens
signaling and transport
Where are peripheral proteins found?
outside of the cell membrane
Peripheral proteins are generally ____
hydrophilic (water loving)
What are the functions of peripheral proteins?
receptor,signaling, adhesion
Protein receptors trigger ____ within the cell for signaling. However, if the protein receptor transmits a signal through the lipid bilayer it is considered an _____ protein.
secondary; integral protien
Drugs that bind to receptors can be considered either __ or __.
agonists; antagonists
Agonists
they are like party people they bind to receptors to activate a target
Antagonists
They are like Karens they bind to a receptior to prevent other molecules from binding and inhibits target activation
Adhesion
attaches cells to other things
Cellular Recognition
proteins that have carbohydrate(glycoprotiens) chains used to recognize other cells (sugar intenas)
What does the fluid mosaic model descibe
FLUID-how components that make up the cell membrane can move freely.
MOSAIC-how many structures the membrane contains
What affects the fluidity of a memebrane
Temp,cholesterol,degrees of saturation
how does temp affect membrane fluidity
high temperatures increase fluidity
low temperatures decrease fluidity
How does cholesterol affect membrane fluidity?
high temp cholesterol make membrande more rigid to prevent it from becoming too fluid.
low temp cholesterol makes the membrane more fluid to prevent it from becoming too ridgid and shattering
How do degrees of saturation affect membrane fluidity?
saturated fatty acids pack tight because they lack double bonds and thus are solid a room temp. unsaturated fatty acids have double bonds that doesnt allow tight packing and makes them fluid at room temp
Why are Trans-unsaturated fatty acids considered bad?
they raise bad cholesterol and lowers good cholesterol
trans-unsaturated fatty acids pack tighter than____. Why?
cis-unsaturated; becuase cis-unstaturated has more kinks and cant back tight
Cells must regulate….
substances that travel through the cell membrane
What are the three types of transport?
Simple, Facilitated, Active
Define Simple diffusion
flow of small, uncharged, non-polar substances across the membrane down their concentration gradient without using energy
Osmosis is apart of which type of transport?
passive
Define Osmosis
is the type of simple diffusion that involves a water molecule
Water is small/large and polar/nonpolar
polar/small
Define facilitated transport
integral proteins allows, larger, hydrophilic molecules to cross the membrane
Facilitated Transport can be one of three directional type of proteins
uniporters,symporters,antiporters
define a uniporter,symporter and antiporter
uniporter-single substance,single direction
symporter-2 substances same direction
antiporter- 2 substances different direction
two types of transport protiens
channel and carrier
define channel proteins
tunnels open face on both sides of the bilayer
define carrier proteins
bind to a molecule on one side and change shape to bring the substance to the other side
Passive diffusion is only done with what
facilitated transport, bring molecules down their concentration gradient without energy
Examples of channels proteins
channels for ions and porins for hydrophilic molecules
Define Active Transport
substance travel against their concertation gradient and require the consumption of energy by carrier proteins
What are types of active transport
primary and secondary
define primary active transport
uses ATP hydrolysis to pump molecules against their concentration gradient
secondary active transport (freeloeaders)
uses free energy released when other molecules flow down their concentration gradient to pump the molecule of interest across the membrane
cytosis (just a generic name for a type of active transport mechanism)
refers to bulk transport of large, hydrophilic molecules across the cell membrane and requires energy
Endocytosis
involves the cell membrane wrapping around an extracellular substance internalizing it into the cell via vesicle and vacuole
What are the different types of endocytosis
phagocytosis, pinocytosis, receptor-mediated cytosis
Define phagocytosis
cellular eating solid objects
define pinocytosis
cellular drinking of dissolved molecules
Receptor-medicated endocytosis
requires the binding dissolved molecule to peripheral membrane receptor proteins that initiated endocytosis
Clathrin
forming a pit in the membrane that pinches off as a clathrin coated vesicle
Exocytosis
material is released from in the cell to out the cell via vesicle secretion
what are organelles
cellular compartments enclosed by phospholipid bilayer they are locatede in the cytosol and make up the cytoplasm which is (cytosol and organells)
Eukaryotic cell have ___ organells
membrane bound
Prokaryotes do not have ___ but do have adaptation like ___ where they store their genetic informetion
membrane bound organelles;nucleoid
Nucleus
Primarily function to protect and house DNA
Where does DNA replication and transcription occur
nucleus
Nuclear envelope
is the membrane of the nucleus
describe the nuclear envelope
two phospholipid bilayer with a perinuclear space
Nuclear pores
holes in the nuclear envelope that allows molecules to travel in and out nucleus
Nuclear lamina
provides structure and support as well as regulating DNA cell division
Nucleolus
is the dense area that is reposible for producing rRNA and assembling ribosomal subunits RNA+Proteins
Ribosomes
non-organelles; they work as small factories that carry out translation. They are composed of ribosomal subunits
Eukaryotic ribosomal subunit
60S and 40S; assemble in the nucleoplasm and are exported from the nucleus to make complete ribosomes in the cytosol (80)
Who is your have puppy
BUBBA
What does the S in 80S stand for?
Sedimentation
Prokaryotic ribosomal subunit
50S AND 30S complete 70S forms in cytosol
Free-floating ribsomes
make protiens that function in the cell
Endoplasmic reticulum ribosomes
make protiens that will be sent out of the cell
Rough ER
Proteins synthesized by the embedded ribosomes are sent into the lumen for modifications
Smooth ER
is an extension of the rough ER. its function is to synthesize lipids, produce steroid hormones, detoxify cells
Golgi apparatus
stores,modifies, exports protiens that will be secreted from the cell
cisternae
flattened sacs that modify and package substances
cis face of golgi
closest to the ER
trans face
closest to the membrane
Lysosomes
break down substances through hydrolysis taken in through endocytosis
Lysosomes contain
acidic digestive enzymes that function at low pH
Autophagy
breakdown the cells own machinery for apoptosis
Proteasomes
protein based complexes that breakdown unwanted or damages proteins, and have ubiquitin and proteins for degradation
Vacuole types
transport, food, central, tonoplast,storage, contractile
trasport vacuole
transport materials between organelles
food vacuole
temporarily holds endocytosed food and later fuses with lysosomes
central vacuole
large in plants function in storage and breakdown
what are tonoplasts
large membrane in central vacuole thazt maintains rigidity by exerting tugor
storage vacuole
stores starch,pigment, and toxic substances
contractile vacuole
found in single celled organsisms and works to pump out excess water
endomembrane system
it is the group of organelles that work together to modify package and transport proteins and lipids entering or exiting the cell
What are the components of the endomemebrane system?
nucleus, rough ER, Golgi lysosomes, vacuoles, and cell membrane
Peroxisomes
perform hydrolysis and break down stored fatty acids and help detoxification
Detoxification can generate what and why is this dangerous?
can produce hydrogen peroxide which is toxisc and can be reactive oxygen speicies that damages cells via fre radicals but peroxosomes have catalase that breaks hydrogen peroxide into water and oxygen
mitochandria
power house of the cel produces ATP in cellular respiration
you get mitochandrial DNA from your mother
Chloroplasts
found in plants and some protists and carry out photosynthesis
Plasmids
double membraned organelles found in plants and algae that function in photosynthesis and storage of metabolites
centrioles
found in animal cells and act as microtubule organizing centers during cell division
Cytoskeleton
provides structure and function to the cytoplasm
microfiliments
smallest structure of the cytoskeleton and are composed of a double helix made of two actin filaments
function of microfiliments
involved cell movement and can quickly assemble and disassemble
cleavage furrow
cyclosis
muscle contraction
cleavage furrow
during cell division myosin motors and actin filiments form contractile rings and split the cell
cyclosis
the flow of cytoplasm inside the cell it is driven by the forces of actin and myocin in a manner similar to muscle contraction
muscle contraction
actin have directionaloty allowing myosin motor protiens to pull on them for muscle contraction
intermediate filaments
are between microfilaments and microtubule and function as structural support
intermedate filaments are more stable than microtubules or microfilaments?
microfilaments
keratin
intermediate filament in the skin hair and nails
lamins
intermeidate filaments function in making up nuclar lamina lamina a network of fiborus intermediate filaments that support the nucleus
microtubules
lagest in side and gives structural integrity to the cells
structure of microtubules
hollow and have walls of tubulin protien dimers aqnd fucntion in cell division, cillia, and flagella
Kinesin and dynein
are motor protiens that transport cargo along microtubules
microtubule organizing centers
are present in eukaryotic cells and help organize microtuble extension
centriole characterisitcs
hollow cylinders made of 9 triplets of microtubules 9x3 array
centrosomes
contain a pair of centrioles orient in 90 degree angles to one another
A pair of centirole (centrosomes)
replicate during the S phase of the cell cycle so that each daughter cell after cell dividion has one centrosome (pair of centroles)
cillia
small hair like projections found only in eukaryotes they line outside of the cell or fluid and function in locomotion
2 types of cillia
motile cillia- help cell or fluid move
non-motile cillia- act as cellular antennas that receive signals from neighbors an enviornment
cillia characteristics
cillia have 9 doublets of microtubule made of tubulin with two singles in the center forming and 9+2 array they are produced by the basal body which is fomred by the mother centriole which is an older centiole after S phase replication
Flagella
hairl like structures found in both prokaryotes and eukaryokes function in locomotion of cell and fluids
eukaryote flagella structure
composed of polymers of of tubulin in 9+2 array
prokaryote flagella
polymers of flagellin and DO NOT have a 9+2 array they do not have micro tubules
eukaryotic move in a ____ motion while prokaryotic flagella move in a ____ motion
bending;rotary
Extracellular matrix (EMC)
provides extracellular mechanical support of cells
extracellular matrix
proteoglycan,collagen,integrin,fibronectin,laminin,basal lamina
proteoglycan
a type of glycoprotien that has a high propotion of carbohydrates
collagen
the most common structure protien organzied by collagen fibrils (fibers of glycoilated collagen secreted by fibroblasts
Integrin
a transmembrane protein that faciliated ECM adheasion and signals cells how to respond to EMC growth apoptosis
Fibronectin
a protin that connects to integrin to emc and helps signal transduction
Laminin
behaves similary to fibroactin it functions in cell differentiation, adheasion, and movement, it is a major compenent of the basal lamina
cell walls
carbohydrate based structures that act like a subtitute EMC because they provide structural support to cells that either do not have EMC or have minimal EMC.
Where are cell walls found
plants-cellulose
fungi-chatin
bacteria-peptidiglycan
archaea
Peptidoglycan
is a poly sacharride with peptide chains and is the primary componet of bacterial cell walls
Archaea
made up of polysacharrides and don not contain peptidoglycan
Glucocalyx
glycolipid/glycoprotien coat found mainly on bacteria and animal epithelial cells it helps with adheasion, protection adn recognisition
Cell matrix junstions
connect EMC to cytoskeleton
focal adheasions
emc connects to acting microfiliments via integrins
Hemidesomsomes
EMC connects to intermediate fillament inside the celln via integrins
Cell to cell jusntions
connects cells to other cells
tight juction
form water tight seal between cells so substances pass through them and not between them
desmosomes
provide support against mechanical stress connects neigboring cells via intermedite fillaments
Adhearens
structural support against mechanical stress it just uses actin fillaments
Gap junction
allows passage of ions between cells formed by transmemebrane connexins and are only present in animal cells
middle lamella-plants junctions
sticky cement similar to tight junctions
plasmodesmata- plant cell
tunnels between plant cell allows cytosol fluids to freely travel between plant cells
isotonic solution
same solute concentration as the cell placed in them
hypertonic solution
higher solute than the cell placed in them
hypotonic
less solute then the cell place in them
turgid
swollen plant
plasmolysis
when plant cell shrinks away from its wall
cell undergo a range of adaptations that will ensure survival due to changes of enviormental conditions these changes include
atrophy, hypertrophy, hyperplasia,metaplasia,dysplasia
Atrophy
decrease in cell size due to reduced metabolism
Hypertrophy
increase in cell size due to increased metobolic activty
Hyperplasia
increase in the number of cells in an organ or tissue that appear normal under microscope often seen in the beginning of cancer
Metaplasia
a somatic cell undergoing transformation into another specialized type of somatic cell
Dysplasia
development of phenotypically abnormal cells in a tissue that can lead to cancerous growth
epithelial tissue
tissues are coheasive sheets of cells that line internal organs and cover the body
connective tissue
tissues that support the structure of organism sparse connective tissues cells are scattered within the an extracellular matrix
examples of connective tissues
cartliage,bone,blood,adipose
muscle tissue
tissue responsible for body movement and come in smooth skeletal and cardiac muscles
nervous tissue
tissues process and transmit information within the body. Nervous tissue is composed of neurons to send info and support cells to glial cells
Dynein
motor protiens transport cargo along microtubules
Trypsin
pancreatic protease, breakdown /digust protien
Isomerase
is an enzymes used in second step of glycolysis modifies glucose6phophase
Lamins
intermediate filament helps make up nuclear lamina, a network of fibrous intermediate filaments that support the nucleus
Peroxidase
is an enzyme that catalyzes the oxidation of reactive oxygen species
