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
ribosomes:
what are the functions?
-They make proteins
what are the two types of ribosomes within eukaryotic cells?
-Free: makes proteins that remain in the cytosol.
-Bound: make proteins that are inserted in membranes or secreted outside the cell
(some ribosomes are free and some are bound)
T/F: All ribosomes (ribosomes in bacteria, archaea, and eukarya) are made up of proteins and rRNA. BUT the type of proteins and rRNA differ.
True
how are ribosomes of eukaryotic cells different from those of prokaryotic cells?
Eukaryotic cells: 80s = 60s + 40s.
Prokaryotic Cells: 70s = 50s + 30s
nucleus:
what does the nucleus contain?
it contains DNA; which is the blueprint of the cell
nucleus:
what are the shapes of the chromosomes within the nucleus?
linear chromosomes
nucleus:
what is the nuclear envelope?
it is a double membrane that surrounds the nucleus
nucleus:
what are nuclear pores?
they are pores that allow for transport of mRNA
nucleus:
what is the nucleolus?
the site of assembly of the ribosome subunits
how is the nucleus of the eukaryotic cell different from those of prokaryotic cells?
Eukaryotic cell: linear chromosome DNA.
Prokaryotic cell: circular chromosome DNA.
No nucleus in prokaryotic cells; just nucleoid
mitochondria:
does the mitochondria have a double membrane? what does it consist of?
yes, it consists of two things:
-Cristae: the infoldings in the inner membrane to increase the surface are so you can stuff more proteins and make more ATP.
-Matrix: the fluid inside the inner membrane that contains DNA, RNA, 80s ribosomes, and proteins.
mitochondria:
why does the matrix of the double membrane contain DNA, RNA, 70s ribosomes, and proteins?
Because the mitochondria was once it’s own cell/bacteria before it was engulfed.
When the prokaryotic cell engulfs the free bacteria, that then became a mitochondria. This is also why there is a double membrane because the mitochondria has its own membrane when it was a free bacteria.
mitochondria:
why is it the cell’s powerhouse?
Because it converts the chemical energy of food into ATP that can be used to power all cellular activities.
how are the mitochondria in eukaryotic cells different from those of prokaryotic cells?
No mitochondria in prokaryotic cells.
endoplasmic reticulum:
what is the ER? what are the two types of ER?
it is a series of flattened, hollow, interconnecting sacs.
the two types are rough ER and smooth ER
endoplasmic reticulum:
what is the rough ER (RER)?
it has ribosomes and receives, transports, and stores proteins
endoplasmic reticulum:
what is the smooth ER (SER)?
it synthesizes, transports, and stores lipids. it has no ribosomes.
the RER and SER make the proteins and lipids and send them where?
to the golgi apparatus
how is the ER different in eukaryotic cells from prokaryotic cells?
No RER or SER in prokaryotic cells.
Golgi Apparatus:
what is the Golgi Apparatus?
it is a series of sacs that are independent of the ER
Golgi Apparatus:
what does the Golgi Apparatus do?
it assembles raw materials and routes end products
Golgi Apparatus:
what is the vesicle transport?
the vesicles assist in the transport of proteins and lipids from the ER to the Golgi Apparatus.
afterward, the Golgi Apparatus send them to the final destination (which is in the cell, outside the cell, or in the plasma membrane).
how is the golgi in eukaryotic cells different from those in the prokaryotic cells?
No golgi apparatus in prokaryotic cells.
what are the steps of the endomembrane system?
- Transport vesicle buds from the smooth or rough ER. They leave the ER by exocytosis.
- The transport vesicles fuse with the Golgi Apparatus, dumping the contents inside.
- The Golgi Apparatus modifies the molecules as they move through it.
- The modified molecules bud off from the Golgi Apparatus in a transport vesicle.
- Vesicles may fuse with the plasma membrane, dumping contents outside the cell for delivery elsewhere in the organism.
Lysosomes:
what are Lysosomes?
they are floating garbage disposals
Lysosomes:
what type of vesicles are they?
they are vesicles with digestive enzymes (from RER) that bud off from the golgi
Lysosomes:
what do they do?
they digest foreign invaders and old organelles.
Lysosomes:
what are there lots of in lysosomes?
phagocytes
how are lysosomes in eukaryotic cells different from those in prokaryotic cells?
No lysosomes in prokaryotic cells.
what happens in phagocytosis?
-Phagocytes attach to the area of invasion and attach to the microorganism.
-The microorganism is then engulfed by the phagocyte. It is engulfed into a vesicle known as a phagosome.
-Vesicles in the cytoplasm called lysosomes fused with the phagosome, which then releases digestive enzymes such as lysozyme into the phagosome.
-The structure resulting in this fusion is a phagolysosome.
-Inside the phagolysosome, microorganisms and killed and digested.
-Finally, the digested contents of the phagolysosome are eliminated from the phagocyte by exocytosis.
which organelle is thought to have originated as a bacterial cell, and what is its function?
mitochondria: produce energy
The plasma membranes of animal cells and mycoplasmal bacteria contain which of the following:
1. Contain peptidoglycan
2. Are rigid and static
3. Contain sterols for support
4. Are bound by cell walls
5. Contain lipopolysaccharide (LPS
- They contain sterols for support
Which eukaryotic structures can move substances along the surface of a series of cells?
cilia
The Golgi complex (apparatus) functions to:
Assemble raw materials and route end-products
Eukaryotic cells are what of the following:
1. Are larger than prokaryotic cells
2. Have a single circular strand of DNA
3. Contain peptidoglycan in the cell wall
4. Have the same cytoplasmic ribosomes as prokaryotes
5. Are members of the Domains Bacteria and Archaea
- Are larger than prokaryotic cells
Which of the following is NOT true about mitochondria?
1. They are found in all living organisms
2. They contain their own DNA
3. They have 70S ribosomes
4. They are thought to be derived from a bacterial ancestor
5. They generate ATP
- They are found in all living organisms (not true)
Phagocytes are white blood cells that attack and destroy foreign invaders in a process called phagocytosis. Certain bacteria, however, produce chemicals that help them evade phagocytosis. These chemicals kill the phagocyte by stimulating the release of the phagocyte’s own lysosomal enzymes into its cytoplasm. Describe the structure and function of lysosomes in eukaryotic cells, and explain why the release of lysosomal enzymes kills the phagocyte.
Lysosomes are membrane-bound vesicles that contain digestive enzymes. They digest foreign invaders and old organelles. Lysosomal enzymes, if released into the cytoplasm of the phagocyte, would digest the phagocyte itself (thus killing it)
The site of energy generation is __________ in bacteria and __________ in protozoa.
Plasma membrane in bacteria and mitochondria in protozoa (since it is a eukaryote)
In a hypotonic solution, while an animal cell will __________, an algal cell will __________.
lyse; become turgid.
Just like bacteria, mitochondria have all of the following except:
-cell wall
-plasma membrane
-70s ribosome
-circular chromosome
Cell wall
What is the route that antibodies (proteins) take from production to secretion outside the cell?
Ribosomes to RER to Golgi to Outside
How would you classify a cell that is resistant to penicillin, and has a nucleoid with one circular chromosome and ribosomes?
Prokaryote
