The Eukaryotic Cell Flashcards
Describe Nuclear Envelope (membrane)
- double phospholipid bilayer that surrounds the nucleus
RNA exits the nucleus through what?
- nuclear pores
- DNA is trapped in the nucleus
What is the nucleolus
- part of the nucleus where rRNA is transcribed and ribosomal subunits are assembled.
Describe various types of Endocytosis…
- Phagocytosis (to eat)
- Pinocytosis (to drink)
- Receptor mediated Endocytosis
Describe Phagocytosis:
(to eat)
- cell membrane protrudes outward to envelope and engulf particulate matter.
- binding of proteins on the particulate matter to protein receptors on the phagocytotic cell.
Describe Pinocytosis:
- to drink
- extracellular fluid is engulfed by small invaginations of the cell membrane.
- nonselective process
Describe Receptor Mediated Endocytosis:
- specific uptake of macromolecules such as hormones and nutrients.
- ligand binds to a receptor protein on the plasma membrane and then is moved into the clathrin coated pit.
The reverse of endocytosis is_________?
Exocytosis
What is clathrin?
- protein that forms a polymer adding structure to the underside of the coated pit.
- absorbs ligands
- becomes a coated vesicle
Describe Rough Endoplasmic Reticulum
- contiguous with the cell membrane and nuclear membrane in many places
- has ribosomes attached to the cytosol side
- synthesizes almost all proteins not used in the cytosol
- proteins are pushed into the ER lumen as they are created, and then sent to the Golgi
Describe the Smooth Endoplasmic Reticulum
- site of lipid synthesis including steroids
- also helps detoxify some drugs(pesticides, toxins, pollutants)
- triglycerides are produced here and stored as fat droplets
Describe the Golgi apparatus
- modifies and packages proteins
- flattened, membrane-bound sacs
- releases protein filled vesicles or lysosomes
Describe Lysosomes
- contain hydrolytic enzymes to digest substances taken in by endocytosis
- come from the Golgi
- generally interior pH of 5
- material not degraded is ejected from cell
Describe Secretory Vesicles
- protein filled vesicles released from Golgi to be expelled from cell.
- may contain enzymes, growth factors, or extracellular matrix components
- supply membrane with its integral proteins and lipids
What is autolysis
- can occur when a lysosome ruptures releasing contents into the cytosol killing the cell.
- useful in the formation of certain organs and tissues ( webs fingers and toes of fetus)
Describe Peroxisomes
- production and breakdown of Hydrogen Peroxide
- vesicles in the cytosol
- grow by incorporating lipids and proteins from the cytosol
- inactivate toxic substances
- regulate O2 concentration
- play role in synthesis and breakdown of lipids
- metabolism of nitrogenous bases and carbohydrates
- self replicate
Desccribe the Cytoskeleton
Fx: cell shape, organelle movement, motility
- anchors some membrane proteins and other cellular components, moves components within the cell, moves the cell itself
- Intermediate filaments = mechanical strength
- Microtubules(tubulin) = LARGE= determine organell position and direct intracell transport
- Microfilaments ( actin) = small = cell shape and locomotion.
Describe Intermediate Filaments
- Mechanocal Strength
- tough ( can survive cell death…hair, fur, nails, claw, skin)
- controls breakdown and reassemble of nuclear envelope in Mitosis
Describe Microtubles
- Large - determine organelle position & direct intracell transport
- flagella & cilia formation
- spindle apparatus
- made from tubulin
- (-) end is anchored to MTOC (+)end grows and shrinks
Describe Microfilaments
- Actin
- Small
- cell Shape and Locomotion
- contractile force in microvilli and muscle
- squeez membrane in phagocytosis and cytokinesis.
Microtubles are made of the protein ____?
Tublin
- a globular protein that can polymerise into a straight filament.
Describe Flagella and Cilia
- 9+2 ( 9 pairs plus 2 single in the center of Microtubules)
The only cell in the in the body with flagella is _____.
Sperm
In the human body ciliated cells are only found in ____ and ______.
- Fallopian tube and Respiratory tract.
my balls your mouth =>cilia like Sx found in testes, and cilia in trachea
What is Dynein
- protein that makes cross bridges connecting MTs
- slides MTs past each other using ATP casing it to bend = whiplike movement
Whats the difference between eukaryotic flagella and prokaryotic flagella?
Eukaryotic
- 9+2 MT
- whip like motion
Prokaryotic
- single thin strand of protein Flagellin
- Flagellin rotates
What is the significance of the MTOC?
- Microtubule Organizing Center (aka centrosome)
- the MT grows away from the MTOC at is + end
- GTP bound = growth
- GDP bound = shrinkage
Describe Basal Bodies
- 9 triplets of MTs in a circle
- Anchor flagella and cilia
What are the three types of culluar jumctions ni eularyotes?
- Tight Junctions
- Desmosomes
- Gap Junctions
Describe Tight Junctions:
- Fluid Barrier around cell
- ex: Epithelial tissue like bladder, intestines, kidney –> prevents waste from leaking
- prevent protein movement between apical and basolateral serface.
What the difference between basolateral and apical surface.
Apical- part of cell facing the lumen ofa cavity
Basolateral- the opposite side of the cell
Describe Desmosomes
- holds cells together at a single point
- attach directly to cytoskeleton
- normally found in tissues that experience stress( skin, intestinal epithelium)
Describe Gap Junctions:
- Tunnels between cells allowing small molecules and ions to pass through
- In cardiac muscle , allows for spread of action potential
Describe Mitondria
- Powerhouse of the cell
- (she get it from her mamma)
