Lecture 4 - Eukaryotic Cell Flashcards
What are two ways that Eukaryotic cells came about?
- Membrane infolding: created organelles like a nucleus. The cell folds and encompasses organelles.
- Endosymbiotic theory: some eukaryotic cell organelles, such as mitochondria and plasmids, evolved from free-living prokaryotes. A pre-eukaryotic cell engulfed respiring (living and breathing) bacteria to form mitochondria and photosynthetic bacteria to form a chloroplast. It ate all the bacteria that become organelles.
(organelles such as chloroplasts and mitochondria were once free-living prokaryotes that eventually lived symbiotically within larger cells, forming modern-day eukaryotes.)
who was Lynn Margulis?
She first proposed that the energy-converting organelles of eukaryotic cells (mitochondria and chloroplasts) evolved as a result of endosymbiosis.
what is endosymbiosis etymology?
inside + living together
what is the size of a eukaryote?
5-50 um
what are the components of eukaryotes?
-Plasma membrane
-Cell wall (+/-)
-Flagella and cilia (+/-)
-Cytoplasm with cytosol, cytoskeleton, ribosomes, and membrane-bound organelles including nucleus.
plasma membrane:
what is the structure?
-Has a phospholipid bilayer
-Has proteins
-Has sterols (some have some don’t)
plasma membrane:
what is the function of the sterols within the plasma membrane? how about the other two things the plasma membrane does?
-to maintain the membrane in a state of fluidity adequate for function.
-protection, controls traffic in and out of cell, and also has active and passive transport.
plasma membrane:
how does the cell membrane get its resistance, functionality, and flexibility?
by combining a variety of floating components called a fluid mosaic.
plasma membrane:
what is the primary component of the fluid mosaic?
A phospholipid with a hydrophilic head and hydrophobic tail.
plasma membrane:
what is the phospholipid bilayer?
consists of a hydrophilic head facing the aqueous water environment on the outside and inside of the cell. it also has a hydrophobic tail that is tucked inside.
plasma membrane:
what other molecules does the plasma membrane have?
proteins, carbohydrates, cholesterol
plasma membrane:
T/F: cells capture and release proteins
True
plasma membrane:
what are the membrane proteins fucntions?
-Enzymes
-Recognition
-junction
-Transport
-Structural
-Receptors
plasma membrane:
what is the consistency of the fluid mosaic model? why?
fluid or oil-like so that the components can move freely; it is a mosaic of lipids, proteins, and carbohydrates
plasma membrane:
what are the functions?
-to protect and form a border
-is semipermeable
-senses the environment
-transports (similar to prokaryotes)
plasma membrane:
what are the types of transport?
-Passive: down the gradient w/out energy.
-Active: against the gradient w/ energy; Within active: Bulk transport: for molecules too big to go through membrane proteins
plasma membrane:
what is bulk transport? examples?
it is active transport and needs energy from the whole membrane, not just a protein. consists of:
-Exocytosis: stuff exiting the cell
-Endocytosis: stuff coming into the cell
plasma membrane:
Within endocytosis; what are the two subtypes of this type of transport?
- Pinocytosis: “Cell drinking” for dissolved material.
- Phagocytosis: “Cell eating” for particulate material
how is the plasma membrane in eukaryotes different from those in prokaryotes?
Eukaryotic plasma membrane has sterols, but prokaryotic doesn’t.
Eukaryotic cells have bulk transport whereas prokaryotic cells don’t.
cell wall:
what are the structure and functions of the cell wall?
-Located in algae, plants, and fungi.
-Provides support for the cell.
-Not made of Peptidoglycan (PG)
How is the cell wall in eukaryotes different form those of prokaryotes?
Eukaryotic cell wall doesn’t have peptidoglycan. Prokaryotic cells can be Gram-positive and negative, not the Eukaryotic cell.
flagella and cilia:
what are the structures? what are they made of?
-Flagella: long and few
-Cilia: short and numerous
They are both made of protein filaments called microtubules, which are covered by the plasma membrane.
flagella and cilia:
what is the function? what are they powered by?
-They allow the cells to swim using whiplash
-They are powered by ATP
how are flagella and cilia in eukaryotic cells different from those of prokaryotic cells?
The eukaryotic cell doesn’t have the basal body, hook, or filament, whereas the prokaryotic cells do.
Prokaryotic cells have flagellin protein; Eukaryotic cells have microtubules
cytoplasm:
where is it located? what does it contain?
-The region inside the plasma membrane and just outside the nucleus.
-Contains the cytosol, cytoskeleton (protein filaments forming the cell’s infrastructure), ribosomes, and membrane-bound organelles.
ribosomes:
what are they made of?
-They are made of proteins and rRNA (ribosomal RNA)
ribosomes:
what are the subunit numbers?
80s = 60s + 40s