cell structure and function Flashcards
cells
the basic structural and functional units of every organism
all cells…
are bound by a plasma membrane
contain cytosol
contain chromosomes
contain ribosomes
two types of cells
prokaryotes and eukaryotes
prokaryotes
domains bacteria and archaea
DNA is in the nucleoid region
generally smaller in size than eukaryotes
eukaryotes
protists, fungi, animals, and plants
DNA is in the nucleus
contain membrane bound organelles
organelles
membrane bound structures in eukaryotes
two classifications of organelles
endomembrane organelles and energy organelles
endomembrane organelles
nuclear envelope
endoplasmic reticulum
golgi complex
lysosomes
vesicles/vacuoles
plasma membrane
energy organelles
mitochondria
chloroplasts
compartmentalization
in organelles allows for different metabolic reactions to occur in different locations
compartmentalization functions
increases surface area for reactions to occur
prevents interfering reactions from occurring in the same location
unique cell components
plants
chloroplasts
central vacuole
cell wall
plasmodesmata
unique cell components
animals
lysosomes
centrosomes
flagella
nucleus
contains chromosomes
enclosed by the nuclear envelope (double membrane)
has pores
contains a nucleolus
chromosomes
genetic information
pores (in the nucleus)
regulate entry and exit of materials from the cell
nucleolus
dense region of the nucleus where ribosomal RNA (rRNA) is synthesized
what do rRNA and proteins combine to form?
large and small subunits of ribosomes
subunits exit via nuclear pores; assemble into ribosomes
ribosomes function
synthesize proteins
translate messages found on mRNA into the primary structure of polypeptides
ribosomes comprisition
ribosomal RNA and protein
two locations where ribosomes can be found
cytosol
bound to the endoplasmic reticulum or nuclear envelope
cytosol
proteins produced here generally function only within the cytosol (ie enzymes)
known as free ribosomes
bound to the endoplasmic reticulum or nuclear envelope
proteins produced here can be secreted from the cell
leave via transport vesicles
endoplasmic reticulum
a network of membranous sacs and tubes
endoplasmic reticulum functions
synthesized membranes
compartmentalizations the cell to keep proteins formed in the ER separate from those of free ribosomes
two types of endoplasmic reticulum
rough and smooth
rough ER
contains ribosomes bound to the ER membrane
smooth ER
contains no ribosomes
synthesized lipids, metabolizes carbohydrates, and detoxifies the cell
golgi complex
contains flattened membranous sacs called cisternae
cisternae
separate the sacs from the cytosol
each cisternae is not connected
has directionality (cis face and trans face)
cis face in golgi complex
receives vesicles from the ER
trans face in golgi complex
sends vesicles back out into cytosol to other locations or to the plasma membrane for secretion
golgi complex functions
receives transport vesicles with materials from the ER
modifies the materials
sorts the materials
adds molecular tags
packages material into new transport vesicles that exit the membrane via exocytosis
lysosomes
membranous sac with hydrolytic enzyme
lysosomes functions
hydrolyzes macromolecules in animal cells
autophagy
autophagy
lysosomes can recycle their own cell’s organic materials
allow the cell to renew itself
peroxisomes
similar to lysosomes
membrane bound metabolic compartment. catalyze reactions that produce H2O2; enzymes in peroxisomes then break down H2O2 to water
vacuoles
large vesicles that stem from the ER and golgi
types of vacuoles
food vacuole
contractile vacuole
central vacuole
food vacuole
form via phagocytosis (cell eating) and then ate digested by lysosomes
contractile vacuole
maintain water levels in cells
central vacuole
found in plants
contains inorganic ions and water
important for turgor pressure
endosymbiont theory
the theory that explains the similarities mitochondria and chloroplasts have to a prokaryote
theory states that an early eukaryotic cell engulfed a prokaryotic cell; prokaryotic became and endosymbiont (cell that lives in another cell), became one functional organism
endosymbiont theory evidence
double membrane
ribosomes
circular DNA
capable of functioning on their own
mitochndria
site of cellular respiration
structure of the double membrane in mitochondria
outer membrane is smooth
inner membrane has folds called cristae; divides the mitochondria into two internal compartments and increases the surface area
mitochondria types
intermembrane and mitochondrial matrix
intermembrane mitochondria
space between inner and outer membrane
mitochondrial matrix mitochondria
enclosed by inner member
location for the krebs cycle
contains: enzymes that catalyze cellular respiration and produce ATP, mitochondrial DNA, and ribosomes
what does the number of mitochondria in a cell correlate with?
metabolic activity
do cells with high metabolic activity have more mitochondria?
yes
chloroplast
specialized organelles in photsynthetic organisms
thylakoids (inside the double membrane of chloroplasts)
membranous sacs that can organize into stacks called grana
stroma
fluid around thylakoids
location for the calvin cycle
contains: chloroplast DNA, ribosomes, enzymes
cytoskeleton
a network of fibers throughout the cytoplasm
give structural support and mechanical support
cytoskeleton functions
anchor organelles
allow for movement of vesicles and organelles and/or the whole cell
what does the cytoskeleton have to interact with for movement to occur?
motor proteins
three types of fibers in the cytoskeleton
microtubules
microfilaments
intermediate filaments
microtubules
hollow rod-like structures made of the protein tubulin
grow from the centrosome (assist in microtubule assembly)
microtubules functions
serve as structural support (think: tracks) for the movement of organelles that are interacting in motor proteins
assist in the separation of chromosomes during cell division
cell motility (ie cilia and flagella)
microfilaments
thin solid rods made of the protein actin
microfilaments functions
maintain cell shape
assist in muscle contraction and cell motility
division of animal cells
intermediate filaments
fibrous proteins made up of varying subunits
permanent structural elements of cells
intermediate filaments functions
maintain cell shape
anchor nucleus and organelles
form the nuclear laminate (lines the nuclear envelope)
