Cell Structures Flashcards
9 characteristics of all living things
G- Grow and Develop
O- Organized
S - Structure
H - Homeostasis
A - Adapt and Evolve
R - Reproduce
E - Energy
D - DNA
what is cytology?
study of cells including everything from unicellular to multicellular organisms
3 domains of the classification of organisms
Archaea, Bacteria, Eukarya
what is the science of naming and organizing living things?
taxonomy
one level of classification pyramid? multiple layers?
taxon
taxa
what is the most specific level of classification?
species (sub-species)
acronym to remember the different levels of classifications
Do King Play Chess On Fine Gold Sets
levels of classification (least specific to most)
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
two distinct types of cells for every organism
prokaryote and eukaryote
what domain consists of prokaryotic cells?
Archaea and Bacteria
what type of organisms are in Eukarya domain?
eukaryotes - protists, fungi, animals, plants
what are protists?
not fungus, animal nor plant but has nucleus
what are all cells surrounded by?
selective barrier called the plasma/cell membrane
what does the plasma membrane allow for?
passage of o2, nutrients, and wastes
what is the jellylike substance inside all cells?
cytosol in which subcellular components are suspended
what is the interior of all cells called?
cytoplasm
all cells also contain DNA and ribosomes, what do ribosomes help with?
complexes that assemble primary level of a protein
what is another name for fimbriae?
attachment pili
while not present on all prokaryotes, what function do attachment pili/fimbriae serve in the prokaryotes who have them?
hold onto surfaces
starting from the inside, list the 3 layers that surround a prokaryotic cell
1) cell membrane
2) cell wall
3) capsule/slime layer
what makes up the cell walls of the Bacteria domain?
peptidoglycon
not pictured, what small circles of DNA do some prokaryotes also have?
plasmids
what is the only structure some prokaryotes use for locomotion?
flagellum
what is a common mistake student often make regarding prokaryotes?
prokaryotes DONT HAVE cilia
what does prokaryotic mean in greek?
“before kernel (nucleus)”
who evolved first? prokaryotes or eukaryotes?
prokaryotes evolved first
characteristic of DNA in prokaryotes
nucleoids are circular in shape and suspended in the cytosol
typical size of prokaryotes
1-5 um
do prokaryotes have a nucleus? what else do they not have?
no; membrane bound organelles
what does it mean to be membrane bound?
phospholipid bilayer
what does eukaryotic mean in Greek?
“true kernel”
where is the DNA in eukaryotic cells?
contained inside a membrane-bound nucleus along with other organelles bounded by double membranes
what do organelles allow for?
compartmentalization - different compartments - with permits incompatible processes to occur simultaneously inside a single cell
size of eukaryotes
bigger than prokaryotes 10-100 um
total surface area
h x w x number of boxes
total volume
h x w x l x number of boxes
what is the difference between larger and smaller organisms in terms of their cells?
the size is not different, but the quantity. larger organisms have more cells
why is there a limit on cell size?
due to metabolic requirements
if it’s too big, it’ll be too far to deliver nutrients throughout the cell and to eliminate waste efficiently
what happens to volume and surafce area when a cell increases in size?
v grows faster than its sa
what is the ratio of sa to v in smaller objects?
larger ratio of surface area to volume
what are membranes fundamental to?
organization of the cell and surround not only the cells, but also the ogranelles
most biological membranes are in what type membrane?
double layer of phospholipid with protein embedded
what organelle contains most of the genes in a eukaryotic cell?
nucleus
where are some genes also located in a eukaryotic cell?
mitochondria and chloroplasts
what is the nucleus surrounded by?
nuclear membrane/envelope - double membrane perforated by pores
what maintains the nucleus shape?
nuclear lamina - netlike array of protein filaments
how is DNA organized into within the nucleus?
chromosomes that carry genetic info for the making of proteins
what form is DNA in when the cell is not dividing?
loose form called chromatin
how many chromosomes in a human body? gametes?
46 ; 23
where is the nucleolus located?
within the nucleus of a nondividing cell
what is the role of the nucleolus?
make ribosomal RNA (rRNA)
proteins from the cytoplasm are imported into the nucleolus which combine with the rRNA and the nucleolus assembles the two into the large and small subunits of ribosomes
what are ribosomes?
complexes of rRNA and proteins
what happens on ribosomes?
amino acids are assembled into proteins (protein synthesis or central dogma)
what are the two types of ribosomes?
free ribosome - suspended in the cytosol
bound/attached ribosome - on the outside of the endoplasmic reticulum or nuclear envelope
ribosomes are smaller in prokaryotes than in eukaryotes. what are the 2 subunits referred to as in eukaryotes?
large subunit - 60s
small subunit - 40s
ribosome subunits in prokaryotes?
large - 50s
small - 30s
the S in the subunits unit is called the Svedburg unit. what does it measure?
the rate of sedimentation in a centrifuge, not size
how does the location the assembling of amino acids effect it?
if a protein is completed on a free ribosome, it usually has a function within the cytosol
bound ribosomes usually proteins destined to be inserted into membranes, into organelles, or for export from the cell
where does the assembling often start?
on a free ribosome which then may attach onto the rough ER
what is the endomembrane system?
all structures related by either direct physical contact or by the transport of membrane systems called vesicles
what are vesicles?
sacs of membrane
what does endomembrane mean?
endo = inside
membrane = surrounded by a phospholipid bilayer
what makes up the endomembrane system? (7)
- nuclear membrane/envelope
- endoplasmic reticulum
- vesicles (including transport vesicles)
- golgi apparatus
- plasma membrane
- vacuoles
- lysosome
what does endoplasmic mean?
within the cytoplasm
what does reticulum mean?
little nets
what is the er?
extensive network of membranous tubules and sacs
what are the sacs located in the ER?
cisternae - reservoir for liquid
what is the space inside the ER called?
ER lumen/ cisternal space
what does lumen mean?
open space/cavity
what is the ER continuous with?
nuclear envelope
what are the two types of ER?
smooth - lacks ribosomes
rough - studded with ribosomes
what does the smooth ER synthesize?
lipids - oils, phospholipids, steroids
cells in the gonad are rich in smooth ER since they make the steroid sex hormones
what does the smooth ER metabolize?
carbs
what does the smooth ER detoxify?
drugs and alcohol
hepatocytes are rich in smooth ER because they add OH groups to drugs to make them more soluble and easier to flush from the body
alcohol and drugs induce the liver to make more smooth ER along with detoxification enzymes and explains why higher exposure increases tolerance to drugs and alcohol
what does the rough ER create?
secretory proteins
pancreatic cells make protein insulin that is secreted into bloodstream.
where do the proteins assembled on the ER enter through? why?
cisternal space - to get folded (2 and 3 levels)
most type of secretory proteins are what type of protein?
glycoprotein - proteins with carbs covalently bonded
how do proteins leave the ER?
secretory proteins depart wrapped in transport vesicle that bud off like bubbles from a specialized region called transitional ER
what does the rough ER assemble?
membrane
joins membrane proteins together with phospholipids
pinches off pieces of the membrane in the form of transport vesicles which go to other components of the endomembrane system
diff in function between smooth and rough ER regarding membranes
rough - assembles
smooth - creates phospholipids
what do transport vesicles do after leaving ER?
fuse with the Golgi
what does the Golgi apparatus?
receieving, manufacturing, sorting,shipping, proteins sent to other destination
what are the membranous sacs in the golgi?
cisternae - looks like stacks of pita
what are the two sides of the golgi?
cis face - receiving end
trans face - shipping end
what does the golgi body do?
modifies its products with a team of enzymes before shipping them elsewhere in transport vesicles
example of golgi function
alters sugar monomers from glycoproteins to finishing quaternary level of a protein creating polysaccharides
transport vesicles are given molecular ID tag (phosphate group) that aid in shipping to the correct location along with molecules on their membrane surfaces to recognize specific “docking sites”
what are lysosomes?
membranous sacs with hydrolytic enzymes with acidic interior (ph 5) that animals use to digest macromolecules
where are lysosomes made?
made by rough ER, finished in Gogli
roles of lysosomes (3)
- phagocytosis
- macrophage
- autopagy
lysosomes in phagocytosis?
fuses with food vacuole to digest contents and provide nutrients for organism
lysosome with macrophages?
white blood cell, macrophage, engulfs and destroys pathogens with help of lysosomes
lysosomes in autophagy?
damaged organelles use lysosomes to recycle their materials through autophagy
Tays-Sechs
lysosomal storage disease when people lack the hydrolytic enzymes in lysosomes to break down lipids
causes lysosomes to become engorged with indigestible lipids especially in the brain
what are vacuoles
are like vesicles but contain mostly water
where are vacuoles derived from?
from the ER and Golgi and come in a variety of type
types of vacuoles (5)
- food vacuoles
- contractile vacuoles - found in freshwater protists that pump excess water out of the cell
- hydrolytic vacuoles - in plants, similar to lysosomes in animals
- storage vacuoles - seeds contain many filled with proteins, others with poisons/unpalatable substances to animals
- central vacuoles - generally large in plants and is filled with a solution mostly water and ions
what is the Endosymbiont Theory/Endosymbiosis?
theory states that a prokaryote engulfed another prokaryotic cell and instead of digesting it, the two formed a symbiosis becoming an endosymbiont and this evolved into a eukaryotic cell
what organelles led to the endosymbiont theory? how?
mitochondria and chloroplast display similarities with bacteria
what is an endosymbiont?
a cell living with another cell
what support is there for the endosymbiosis theory? (5)
- mitochondria and chloroplast both have 2 membranes surrounding them (chloroplast have additional internal membranous sacs)
- have their own ribosomes
- have their own circular DNA
- are the same size as bacteria
- are autonomous organelles that grow and reproduce within the cell (asexual binary fission)
how is protein synthesis done in mitochondria and chloroplast?
protein synthesis is done on their own
what does the mitochondria do?
site of cellular respiration, the process that uses O2 to generate ATP by extracting energy from biomolecules
how many membranes does the mitochondria have?
inner and outer membrane each comprised of phospholipid bilayers embedded with proteins and separated by a space
what are the two membranes of the mitochondria separated by?
intermembrane space - first compartment
characteristic of the inner membrane of the mitochondria
convoluted/ has infoldings to increase surface area called cristae
what is the second compartment in the mitochondria?
enclosed by the inner membrane and called the mitochondrial matrix
what are chloroplasts?
found in plant and algae
site of photosynthesis
converting solar energy into chemical energy by synthesizing organic compounds such as sugars from co2 and water
contain green pigment chlorophyll
how are chloroplasts similar to mitochondria?
have an inner and outer membrane with intermembrane space serving as one of the 3 compartments
second compartment of cholorplast?
inside inner membrane filled with fluid called stromae
what are thylakoid?
flattened interconnected sacs stacked inside chloroplasts
what are grana?
stacks of thylakoids
third compartment of chloroplasts
located inside each thylakoid called the thylakoid space
lumen of the thylakoid
third compartment of chloroplast
what are plastids?
a general term for an organelle found only in plants
chloroplasts are specialized version of these organelles
types of plastids
amyloplast - colorless organelle that stores starch in roots and tubers
chromaplast - gives fruits and flowers their yellow and orange hues
what type of membrane are peroxisomes bounded by?
bounded by a single membrane
what do peroxisomes contain?
enzymes that remove hydrogen atoms from substrates and combine them with oxygen producing the by-product hydrogen peroxide
how do peroxisomes use oxygen?
some use it to break down fatty acids to then be used as fuel as mitochondria
what do peroxisomes do in the liver?
detoxify alcohol similar to smooth ER
what does the body do to the toxic H2O2 that is produced by peroxisomes?
enzyme catalase converts it into O2 and H2O
what is the cytoskeleton?
network of protein fibers extending throughout the cytoplasm
what three types of protein fibers make up the cytoskeleton
mircotubules
mircofilaments (actin filaments)
intermediate filaments
function of the cytoskeleton (3)
give support and shape to cell
provide anchorage for organelles and cytosolic enzymes
can be quickly dismantled in one part of the cell and reassembled in a new location changing its shape
how does motility occur with the cytoskeleton?
due to the interactions with motor proteins
examples of motor proteins interacting with cytoskeleton
vesicles and other organelles using motor protein “feet” to “walk” to their destinations along a track provided by the cytoskeleton
circular streaming of cytoplasm within large plant cells is movement brought by the cytoskeleton’s microfilaments interactions with motor proteins
microtubule characteristics
thickest
hollow, rigid, coiled rods made of the globular protein tubulin
functions of microtubules (3)
- tracks for organelles with motor proteins to move along
- make up centrioles (only in animal cells)
- separate replicated DNA in cell division (make up the spindle apparatus)
microfilaments characteristic
thinnest
solid, flexible, coiled rods make of the globular protein actin
functions of microfilaments (3)
1.support the cell’s shape by bearing tension (pulling forces)
2. gives the outer layer of the cytoplasm (cortex)
3. forms a cleavage furrow which enables animal cells to divide into two cells and works with another protein myosin
how do microfilaments and myosin work together? (3)
- enable muscle cells to contract
- allows for amoeboid movement
- cytoplasmic streaming in the interior sol-gel
diff between cortex and sol
cortex is a semisolid gel-like consistency in contract to the more fluid sol interior cytoplasm
what is amoeboid movement?
cell crawl along with cellular extensions called pseudopods (false feet)
ex. amoeba, WBC
what does cytoplasmic streaming allow for?
speeds up the distribution of materials throughout the cell
intermediate filaments characteristics (3)
- diameter in middle range
- solid, coil rods make of fibrous protein keratin
- more permanent than other two types
intermediate filament functions (3)
- support cell’s shape by bearing tension
- anchors the position of certain organelles in place like nucleus
- makes up nuclear lamina
what still exists after skin cells full of intermediate filaments due?
keratin proteins still exist
what makes up flagella and cilia in eukaryotes?
microtubules containing extensions
how does the bacterial flagella differ from eukaryote flagella?
make of completely different structures
how do cilia and flagella act as?
locomotor appendages
function of cilia and flagella
propel through water
sperm of animals to swim to an eff
ciliate lining of the trachea to sweep mucus contain trapped debris out of the lungs
cilia characteristics
short
can occur in large numbers on the cell surface
work like ors with alternating power and recovery strokes
flagella characteristics
longer
limited to one or a few per cell
use an undulating motion
what is each cilium and flagellum sheathed in?
an extension of the plasma membrane
structure of cilia and flagella
9 doublets of microtubules are arranged in a ring (9+2 arrangement along with two central microtubules)
anchored in the cell by basal body
what connects the outer the outer doublets to each other and the central microtubles?
flexible cross-linking proteins
what is dynein?
motor proteins responsible for the bending movements of cilia and flagella
how does dynein function?
changes shape with ATP providing energy
resembles walking with each dynein protein having two “feet” that “walk” along the microtubules of the adjacent doublet causing the doublets to curve which bends the cilium or flagellum
where are cell walls found
organism and component
plants - contains cellulose
fungi - contains chitin
bacteria - domain bacteria contain peptidoglycan
some protists - containing diff substances like silica, cellulose calcium carbonate
cell wall function
protects the plant cell
provides shape
hold plant up against the force of gravity
structure of cell wall
primary cell wall
middle lamella
secondary cell wall
when does a plant have its primary well?
young plant first secretes this
what is the middle lamella?
between adjacent primary cell walls
rich in sticky polysaccharides, pectin, thickening agent in jams and jellies, that glues the cells together
when is the secondary cell wall made
after plant matures, strong cell wall between plasma membrane and the primary cell wall is created
how are plant cells perforated?
by channels between adjacent cells called plasmodesmata
what is the ECM
elaborate extracellular matrix located in animal cells
mostly made up of proteins (collagen abundant)
what does collagen do in the ECM?
forms strong fibers outside the cell
embedded in a proteoglycan complex
what is a proteoglycan complex?
made up single central polysaccharides with some protein, but mostly carb branches
what do integrins do in the ECM? (4)
span across the cell membrane
attach to microfilaments of the cytoskeleton
transmits signals from the extracellular environment to the interior of the cell
alter the cells function
how can integrins change cell function?
can coordinate chemical pathways like turning on genes
how is the ECM attached to integrins?
fibronectin - fasteners
what is a plamsodesmata?
cell junction
plasmodesmata function
allows cytosol to flow between adjacent plant cells
unify most of the plant
water and solute pass freely
three types of junctions in animal cells
tight junctions
desmosomes/anchoring functions
gap/communicating junctions (most like plasmodesmata)
tight junction function
seal cells together and prevent leakage between cells
desmosome junction function
together with intermediate filaments rivet cells together
gap junction function
provide cytoplasmic channels from one cell to the next
necessary for communication between cells
ex of tight junction
skin cells are watertight/do not leak between each other
ex of desmosome junction
attach to muscle cells to each other and muscle tears involve rupture of these
ex of gap junction
between cells of cardiac tissue
what can pass through animal cell junction? (4)
ions, small sugars, amino acids, and other small molecules
what structures are found in plants cells, but not animal cells? (4)
cell wall, all the plastids, majority of vacuoles, plasmodesmata
which structures are found in animal cells, nut not plant? (4)
lysosome, 3 junctions, ECM, centrioles
