Unit 2 Test Flashcards
Which is bigger, a bacterium or a virus?
Bacterium is 100x larger
Which is bigger, an animal cell or bacterium?
An animal cell is 10x larger
How does a transmission electron microscope work?
By sending electrons through a specimen and getting a cross-sectional image of the inside
How does a scanning electron microscope work?
By beaming electrons off of the surface of a specimen to get a 3-D image
How do prokaryotic cells differ from eukaryotic cells
Instead of a nucleus, prokaryotes have a nucleiod, which is an area where the DNA is found. Also, the DNA is round, and prokaryotes have a capsule.
What are the non-membranous organelles?
Cytoskeleton, microvilli, centrioles, cilia, ribosomes, and proteasomes.
What are the membranous organelles?
The nucleus, ER, golgi, lysosomes, peroxisomes, nucleus, and mitochondria.
What are the two types of cilium and what are their purposes?
The primary cilium senses movement, and the motile cilium helps the cell to move.
What are the three proteins found in the cytoskeleton?
Microtubules, intermediate filaments, and microfilaments.
What are proteasomes for?
They contain enzymes called proteases which disassemble and recycle bad proteins.
What is the largest organelle?
The nucleus.
What is chromatin?
Loosely bundled DNA
What is the nucleoplasm?
The inside of the nucleus containing ions, enzymes, nucleotides, and RNA.
What is the ER for?
Protein, carb, and lipid synthesis, storage, transport, and detoxification.
What’s a key difference between the smooth ER and rough ER?
The smooth ER has no ribosomes embedded in it.
What is the Golgi Body for?
The transport of proteins through vesicles.
What are the two “sides” of the Golgi body?
The cis side, which faces the nucleus, and the trans side, which faces away.
What are lysosomes for?
Breaking down substances within a cell?
What are the three “types” of lysosomes and what do they do?
The primary lysosomes are inactive, the secondary lysosomes fuse with different organelles to kill them and are active, and the autolysis lysosomes kill the entire cell.
What are Peroxisomes and what do they do?
They are vesicles containing enzymes which catalyze the production of H2O and O2.
What is epithelial tissue?
Tissue connecting organelles and cells.
What are the three main types of epithelial tissue?
Tight junctions, gap junctions, and demosomes.
What are tight junctions?
A type of epithelial tissue connecting two plasma membranes, preventing the passage of water or other solutes.
What are gap junctions?
A type of epithelial tissue holding two tissues together with channel proteins, allowing rapid communication and ion passage.
What are desmosomes?
A type of epithelial tissue tying two cells together, allowing for twisting and bending (found primarily in epithelial cells).
What are different ways that a cell might move?
With motile cilia, flagellum, phili, or cytoskeletal movement.
How does flagellum differ in bacteria versus eukaryotes?
In bacteria, it works like a rotor and is powered by a proton gradient, whereas in eukaryotes, it works like a whip and is powered by ATP.
What are the two dependent contractions that result in cytoskeletal movement?
Actin and myosin.
What is a microfilament and what is it made of?
A microfilament is two actin filaments wrapped around each other.
What is a microtubule and what is it made of?
One coiled strand of tubulin with a hollow center.
What are some characteristics of a microtubule?
25 nm diameter, maintains shape by resisting compression, moves chromosomes in replication, acts as a “track” for organelle movement.
What are kenesin and dynein?
Two proteins found along the “track” of a microtubule. Kenesin brings organelles to the “+” end, dynein brings organelles to the “-“ end.
Where can microtubules be found?
In the flagellum and cilia.
What does dynamic instability mean?
The constant polymerization and depolymerization of a polymer.
In a microtubule, what is the difference between the “+” and “-“ ends?
The “+” end is where all polymerization and depolymerization takes place, whereas the “-“ end experiences no change.
What are some characteristics of microfilaments?
7-8 nm, resists tension and shearing, helps cells split during mitosis, involved in muscle contraction, conducts cytoplasmic streaming
What are microfilaments made from?
G-actin and F-actin (which is basically just bundled up G-actin)
What is cytoplasmic streaming?
The movement of organelles in a plant cell.
Where are microfilaments found?
Around the perimeter of a cell, and in the microvilli of the small intestine.
What are microvilli?
Tiny projections off of a cell that increase surface area.
What is the difference between the “+” and “-“ ends of a microfilament?
The “+” end faces the cell membrane and polymerizes, while the “-“ side faces away from the membrane and depolymerizes.
How do microfilaments effect cell movement?
When myosin within the microfilaments contracts, it propels the cytoplasm forwards.
What are the characteristics of an intermediate filament?
Made from many proteins, 8-12 nm, permanent structure, keeps organelles in place, bonds cells to each other.