Tour of the Cell Flashcards
3 tenets of cell theory
1) cell are the fundamental units of life
2) all living organisms are composed of cells
3) all cells come from preexisting cells
Magnification
increase size of an object
resolution
clarity of an image
contrast
visible difference in brightness in parts of the sample
LM uses _____ and EM uses
Light beams; magnets + electron beam
Bright field unstained LM
minimal contrast + detail
Bright field stained LM
helps enhance contrast
Phase-contrast LM
more enhancement of light in dark regions
Differential interference contrast LM
gives impression of shadow within the cell
Fluorescence LM
using dyes and light beams to visualize specific cellular material
Deconvolution LM
applied to confocal microscopy to improve contrast + resolution
Confocal
uses fluorescence + focuses emitted light so a single pain of cell can be seen
Scanning electron microscopy SEM
visualize a 3D surface of an object
- cannot be used for living cells
Transmission electron microscopy TEM
beam of electrons is focused on object, if the beam passes through they are detected on a fluorescent screen
Cell Fractionation is
taking cells apart + separating major components from one another
The steps in cell fractionation
1) Aquire tissue sample
2) Homogenization
3) Homogenate
4) Centrifugation
Differential centrifugation is
the ability to study the structure + function of different organelles
Main features of prokaryotic cells
- absence of membrane bound nucleus
- still has DNA present in the form of a nucleotide
- Has cytosol, plasma membrane, ribosomes
- some mechanism for local motion ex- flagella
main features of eukaryotic cells
- DNA is organized differently
- has membrane bound organelles
- uses internal membranes to compartmentalize functions that take place in the cell
- larger
Compartmentalization benefits
- chemical reactions can be partitioned from one another ->
1) chemical reactions will be more efficient
2) able to maintain in higher concentrations
3) groups enzymes to increase efficiency
P + E cell have a ______ that serves as a
plasma membrane; selective barrier
the _____ of a cell is related to…
volume; chemical reactions
Cells whose role is _____ will have adaptations to increase _____
exchange; surface area
The E cell’s genetic instructions are housed in _____ and carried out by
nucleus; ribosomes
The _______ contains chromosomes and is the site for events like
Nucleolus; transcription +replication
The nuclear envelope has a _____ membrane and a ______ membrane
inner; outer
The nuclear envelope has ____ that allow for the _______ of contents in and out of the cell
pores; regulation
Ribosomes job is to ______ and are involved in ____
manufacture proteins; polypeptide synthesis
Ribosomes do not have a
meembrane
The two locations of ribosomes
1) scattered in the cytoplasm
2) bound to membranes
Cytoplasm ribosomes are considered
free ribosomes
Proteins from free ribosomes will _______ in the _______ or be transfered to specific _____
remain; cytoplasm; organelles
Ribosomes consist of a
1) large subunit
2) small subunit
The ribosomes subunits participate in _______ and are stabilized through
polypeptide synthesis; non-covalent bonding
The endomembrane system consists of
1) Nuclear envelope
2) Endoplasmic reticulum
3) Golgi apparatus
4) Lysosomes
5) Vesicles
6) Plasma membrane
7) SECRETION
The components of the endomembrane system are either _____ or connected vis transfer by _____
continuous; vesicles
the ER is continuous with the
nuclear envelope
The smooth er lacks
ribosomes
the smooth er contains _____ involved in the formation or breakdown of _____
enzymes; lipids
Smooth er is a site of
phospholipid production
Smooth er serves a role in ______ + stores ____
detoxification; intracellular calcium
the smooth er benefits from
compartmentalization
the rough er has
ribosomes
The ribosomes in the rough er will generate ____
polypeptides
The interior of he rough er is called
lumen
The lumen is the sit of
protein folding and modification
Proteins can be modified through ______ which is the addition of a ___
glycosilation; carbohydrate
The ration of rough er to smooth er is based on
the function of the cell
The testes have more ______ which means they will have more
lipid synthesis; smooth er
cell that have more ____ scretion will have more
protein; rough er
Golgi are where
proteins are processed, sorted, and shipped
the Golgi has flattened sacks called
cisternae
The Golgi cis face
receives vesicles that have products from the ER
The Golgi trans face
receives products + ships to other organelles or cell surface
The Golgi can also have ______ to assist with movement
membrane bound vesicles
Lysosomes are_____ sacks of ______ capable of _____
membraneous; enzymes; hydrolysis
lysosomes main goals are
digesting and recycling
______ will actively move protons into the lumen of the lysosome
protein pumps
the ____ after _________ are exported from the lysosome through _____
subunits; lysomal degradation; transfer proteins
Lysosomes have ______ which work optimally in a _____ ph environment
acid hydrolase; acid
Acid hydrolase + membranes are synthized by the
ER
Proteins processed by the ____ are shipped to the ____
golgi; lysosome
Phagocytes will ______ other cells to form a _____
engulf; vesicle
Autophagy are used to
recycle lare structures + organelles
Vacuoles replace the _____ in the _____ cell
lysosomes; plant
Vacuoles store
pigments; proteins; toxins
The overall purpose of the endomembrane system is to
move proteins to different areas of the cell
The mitochondria is a significant
ATP producer
The outer membrane of the mitochondria
defines the surface
The inner membrane of the mitochondria
folding of sack like structures called cristae
The Cristae increases _______ + allows for ______
surface area; compartmentalization
The mitochondria is integral for _____ + takes place along the _____ + within the ____
cellular respiration; membrane; foldings
Cells that have higher concentration of Mitochondria have
ex?
higher dependence of ATP
-muscle cells
Mitochondria contain
mitochondrial DNA
Most proteins in the mitochondria are produced from
free ribosomes
Chloroplasts contain…
1) chlorophyl
enzymes + other molecules that function in photosynthesis
Chloroplast have a ________ + no
double membrane; cristae
The third membrane of chloroplast is made up of _______ and _____
thylakoids; granum
The similarities between mitochondria and chloroplast
- both have double membrane
- both have free ribosomes
- both have circular DNA organization
- grow +reproduce independently within a cell
The evolutionary origins of mitochondria explain
ancestor of E cell engulfed prokaryote which became a mitochondria
Example of reactions that can take place in peroxisomes
ethanol oxidation-> alcoholic beverages
Peroxisomes are where ______ and _____ take place
oxidation + redox recations
Redox reactions
allow for the transfer of electrons between atoms + molecules
The product of redox reactions are ______ which is ________ + can cause ____ to components of the cell
hydrogen peroxide; chemically reactive; damage
______ detoxifies hydrogen peroxide into ____ and _____
Enzymer; hydrogen; oxygen
Peroxisomes are another example of
compartmentalization
The cytoskeleton is composed of _____ that _____ + ____ organelles
fibers; structure; anchor
The cytoskeleton can ____ + ___ to accomidate movement in the cell
move + change
The three types of molecular structures in the cytoskelton are
1) Microtubules
2) microfilaments
3) Intermediate filaments
Microtubules are the ____ cytoskeletal component
largest
Microtubules are assembeled from ____ whose subunits are ____ and ____
Tubulin; alpha tubulin; beta tubulin
The tubulin are ______ which allow for
Non-covalently bonded;
;the building and breaking with less energy expenditure
The tubulin polymers have ___
polarity
Overall microtubules
1) provide structural integrity
2) important in cell division
In animal cells microtubules will center from
centrisomes
The cytoskeleton helps support the movement of _____ through the interaction of ____
cargo; motor proteins
Motor proteins
depend on energy to walk there way through a microtubule
The motor protein has three regions
1) Head
2) Tail
3) stalk
The head of the motor protein binds to the ____ and the tail binds to the ____
microtubule; transport vesicle
The movement of the motor protein is ______ and goes towards the ___
directional; positive
Microfilaments are _____ with _____ subunits
twisted chains; actin
Actin subunits are polymerized through
non-covalent bonds
Microfilaments have
polarity
Microfilaments are under the _____ and help _____ and are involved in ____
plasma membrane; define shape of the cell; movement
Microfilaments can also function in cellualr motility through the interaction of ___ and ____
action; myosin
The interaction between myosin and actin is what allows for
muscle contraction
Cell crawling is accomplished through
actin filaments as they grow and create protrusions in the plasma membrane
Cytoplasmic streaming in plants is the
directional flow of cytosol in plant cells
Cytoplasmic streaming occurs along _____ and is powered by ____
actin; myosin
Intermediate filaments do not exhibit _____ and their role is exclusively
polarity; structural
Intermediate filaments form the ______ which helps define the shape of the
nuclear lamina; nucleus
If there is an inability to maintain shape it is due to
intermediate filaments
cells interact with the
extracellular matrix
In the ECM collagen purpose is
strength + flexibility
In the ECM Integrins
- bind to extracellular matrix components
- link ECM to cytoskeleton
Adhesive glycoproteins
allow cells to attach to the ECM
Protein polysacrides in the proteoglycan complex
provide the matrix in which structural proteins are embedded
The cell wall is the _____ in plant cells
ECM
Cell walls
provide barriers to substances
protect cells from physical damage
Parts of the cell wall + description
Primary cell wall- composed of cellulose microfibrils
Middle lamella - holds adjacent cells together
secondary wall- will occur in some plants after maturation
Cell junctions are
ways cells can interact + communicate through protein based iintercations
Tight junctions are
cell-cell attachments that pull cells close together and creates a tight seal
Tight junctions are beneficial in
intestines + stomach to prevent contents from leaking
Desmosomes are
proteins in the membrane that form bridges between anchoring proteins inside the cell
Desmosomes provide ____ between adjacent cells which allows for them to ____ and resist _____
adhesion sites; to work together; mechanical stress
Desmosomes are most abundant in the
- heart muscles
- skin
- uterus
With the loss of desmosomes comes
- heart failure
- skin defects
Desmosomes are enforced by
intermediate filaments
Gap junctions are a mechnaism for
cell communication
Gap junctions allow for cells to rapidly ___ to fluctuation in _________ or other molecules
respond; concentration of ions
Gap junctions are essential for _______ in the ______
muscle contractions; heart
The plasmodesmata is the ____ of ____ cells
cell junction; plant
