Eukaryotic Cell Components Flashcards
Components of Eukaryotic cells?
1) endomembrane system
- Plasma membrane, ER, Golgi, vesicles, nuclear env
2) nucleus
- chromatin, nucleolus
3) cytoplasm
- cytotsol, cytoskeleton, organelles
4) organelles
- mitochondria
Theory for how eukaryotic organisms came to be?
- endosymbiotic event
- mitochondria first thing to show up, had bacteria enfold archaeology and end up with organelle within the bacteria
- evidence: there is internal lining of cells that resemble bacterial genome…and outer liner closer to archae genome
endomembrane system? components?
- primary center for protein & lipid synthesis in the cell
- plasma membrane, Rough/Smooth ER, Golgi, lysosomes/peroxisomes, nuclear envelope
plasma membrane
- gives cell integrity, is selectively permeable
- composed of phospholipid bilayer
- regulate cell-cell interaction
- transport system
- transduces external signals
what are membrane junctions? (x3)
- how neighbor cells communicate
1) occluding=tight junction
2) communicating= gap junction
3) adhering= desmosome
occluding membrane junctions?
- tight junctions
- prevent molecules from passing between epithelial cells
communicating membrane junctions?
- gap junctions
- lets small molecules move between neighboring cells
adhering membrane junctions?
- desmosome
- provides connection between intermediate filaments of the cell & cytoskeletons of adjacent cells
- gives strength to tissues
what are glycorporteins?
- have carbohydrates, can participate in cell to cell communication & interaction
endocytosis? three types?
- uptake of fluid and macromolecules surrounded by PM
1) pinocytosis
2) receptor mediated endocytosis
3) phagocytosis
1) pinocytosis
2) receptor mediated endocytosis
3) phagocytosis
1) ingestion of fluid & small protein molecules by vesicles
2) allows entry of specific vesicles via receptors
3) consumption of large vesicles by specialized cells
exocytosis?
reverse of endocytosis, the expulsion of cellular components from cell–> extracellular env via vesicles that bud off from PM
Endoplasmic reticulum?
- system of membrane channels continuous w/ outer membrane of nuclear envelope
- rough ER= has ribosomes
- smooth ER= no ribosomes
rough ER vs smooth?
Rough:
1) ribosomes
2) makes proteins, lipids, and membrane proteins
3) few post translation modifications
Smooth:
1) no ribosomes, enzymes that help build molecules
2) makes lipids, carbs & steroids
3) detoxification & storage
4) membrane formation& recycling
ribosomes
- FACTORIES of protein synthesis
- attached to ER or free floating
- can link together (poly ribosome)
- mRNA typically bound by 2 or more ribosomes
ribosome composition?
- two subunits synthesized separately in the nucleolus
how know whether ribosome goes to ER or remain in cytosol?
- when mRNA contains a signal recognition particle (SRP) it marks it as a transmembrane protein or a secretory protein
- this SRP particle causes mRNA + ribosome to go to the ER
Golgi apparatus?
PROCESSING
- has flattened membranous sacs (cisternae)
- receives products from rough ER & processes them
- protein modification, lipid transport, produce lysosomes, secretory vesicles & PM
- sends finished products to cell surface
Movement of proteins through Golgi?
Cis–> trans
-each section has diff enzymes w/ diff properties
endosomes
- formed at trans Golgi
- transient structures (from endocytosis) or stable cytoplasmic organelles
- can communicate w/ ER & golgi
how make endosomes/ potential of endoscopes?
-early endosomes made at face of the PM, can nature into progressively more acidic structures OR become lysosomes
lysosomes
- membrane bound vesicles
- made by golgi
- have digestive enzymes to destroy proteins, recycle cell material & digest compounds form endocystosis
- highly acidic
defects in lysosomal enzymes?
-lead to genetic neurodegenerative diseases like tay Sachs
peroxisomes?
- organelles derived from ER
- perform oxidative rxt (remove electrons)
- peroxisomal enzymes break down long FA–> smaller molecules
- destroy toxins (alc)
nuclear envelope
what separates nucleus from cytoplasm
- double layer membrane
- continuous w/ ER
how shit get from nucleus –> cytoplasm?
- nuclear pores allow exchange between nucleoplasm & cytoplasm
the nucleus
- command center, deals w/ genetic material
- shape maintained by nuclear lamina, composed of protein
- contains nucleolus
Nucleolus
-found in nucleus
-forms around chromosomal regions
-composed of proteins & RNA
Function= transcribe rRNA & combine w/ proteins to make ribosomes
cytoplasm
- made of viscous fluid (cytosol) with interconnected filaments & fibers
- where organelles are located
Cytoskeleton & macromolecular fibers (3)?
- maintains cell shape
- assist in movement of cells & organelles
- has 3 macromolecular fibers
1) actin (microfilaments)
2) microtubules
3) intermediate filaments
actin filaments (microfilaments)
- (8nm) extremely thin, help maintain cell shape by composing a dense web below the PM
- important for muscle contraction
microtubules
- (25nm) hollow cylinder made of 2 globular proteins (alpha and beta tubulin)
- alpha & beta form dimers than arrange into spirals of 13 dimers
- cause movement by working w/ kinesis & dynein
intermediate filaments
- (10nm) intermediate in size
- rope like assembly
- support nuclear envelope
centrosome & centrioles
1) Centrosome: composed of 2 centrioles; function as main microtubule organizing center (MTOC); regulates cell-cycle
2) Centrioles: short, hollow cylinders composed of 27 microtubules
- oriented at right angles to eachother
- separate during mitosis…determining plane of division
proteasome
- mutli-subunit protein complex
- destruction of malformed & ubiquitin tagged proteins
- ubiquitin molecule is released back into the cytosolic pool
- important for immune response
mitochondria
- have own DNA (13 proteins, 22 tRNAs, 2 rRNAs)
- maternal inheritance
- double membrane, folds of inner membrane = CRISTAE
- ATP energy production
-NOT PRESENT in RBC
Cilia & Flagella general
- hair like organelles that extend from cell surface
- for cell motility
- have a central pair of microtubules, then surrounded by 9 other pairs
1) Cilia used for?
2) Flagella used for?
1) short and in large numbers, used to move substances outside the cell
2) long, found on sperm; whip like extensions used to move cells
