Ch. 2 - Cells Flashcards
Phospholipid membrane permeability – ______ (polar can only if ___) and hydrophobic molecules can ___ across the membrane. Everything else requires ___ (large, polar, charged molecules).
___
small, uncharged, nonpolar molecules
small and uncharged
freely pass
transporter
peripheral membrane proteins are generally ___; held in place by H-bonding and electrostatic interaction. Disrupt/detach by changing ___ or ___ to disrupt these interactions.
Integral proteins are ___; use ___ to destroy membrane and expose these proteins
hydrophilic
salt conc.
pH
hydrophobic
detergent
- Channel proteins: provide passageway through membrane for ___ (water-soluble) substances (polar, and charged).
**- Recognition proteins: such as major-histocompatibility complex on macrophage to distinguish between self and foreign; they are ___ due to oligosaccharides attached.
hydrophilic
glycoproteins
- Ion channels: passage of ions across membrane. Called gated channels in nerve and muscle cells, respond to stimuli. Note that these can be ___ (respond to difference in membrane potential), ___ (chemical binds and opens channel), or ___ (respond to pressure, vibration, temperature, etc).
**- Porins: allow passage of certain ions + small polar molecules. ___ increase rate of H2O passing (___). These tend not to be specific, they’re just large passages, if you can fit you’d go through.
voltage-gated
ligand-gated
mechanically-gated
aquaporins
kidney and plant root cells
- Carrier proteins: bind to ___, protein changes shape, molecule passed across. E.g. ___ into cell.(this is a type of transport protein). Carrier seems to be specific to movement across membrane via integral membrane protein.
specific molecules
glucose
- Transport proteins: can use ATP to transport materials across (___ ). Active transport. E.g. Na+-K+ pump to maintain gradients. ___ as well. Transport protein is a broad category that encompasses many of the above.
**- Adhesion proteins: attach cells to ___ , provide ___ for internal filaments and tubules (stability)
- Receptor proteins: binding site for ___ + other trigger molecules
not all transport use ATP
facilitated diffusion
neighboring cells
anchors
hormones
- Cholesterol: adds ___ to membrane of ___ under normal conditions (but at low temperatures it ___); sterols provide similar function in ___. Prokaryotes do not have cholesterol in their membranes (use ___ instead)
rigidity
an animal cell
maintains its fluidity
plant cells
hopanoids
**- Glycocalyx: a ___ coat that covers ___ of some bacteria and ___ (some animal cells). It consists of ___ (attached to plasma membrane) and ___ (such as recognition proteins). It may provide adhesive capabilities, a ___, or markers for cell-cell recognition.
carbohydrate
outer face of cell wall
outer face of plasma membrane
glycolipids
glycoproteins
barrier to infection
- Nucleus: ___ is the general packaging structure of DNA around proteins in eukaryotes, the tightness of the packaging varies depending on ___; ___ is tightly condensed chromatin when the cell is ready to divide; histones serve to organize DNA which coil around it into ___
chromatin
cell stage
chromosomes
bundle nucleosomes (8 histones)
___ inside the nucleus are the maker of ribosomes (rRNA). rRNA is synth’d in ___ + ribosomal proteins ___ = ribosomal subunits form; these subunits are ___ to the cytoplasm for final assembly into complete ribosome.
nucleolus
nucleolus
in the cytoplasm
exported
Nucleus bound by ___ nuclear envelope w/ nuclear pores for transport (mRNA, ribosome subunits, dNTPs, proteins like RNA polymerase + histones, etc) in/out. Note there is no “cytoplasm” in nucleus, there’s a ___ instead.
double layer
nucleoplasm
**- Nuclear Lamina: dense fibrillar network inside nucleus of ___ (___ + ___). Provides mechanical support; also helps regulate ___, ___, chromatin organization.
eukaryotic cells
intermediate filaments + membrane associated proteins
DNA replication
cell divison
- Nucleoid: irregular shaped region within the cell of ___ that contains all/most generic material
prokaryote
- Cytoplasm: this is an ___, not a ___! metabolic activity and transport occur here. ___ is streaming movement within cell. Doesn’t include ___, but does included cytosol, organelles, everything suspended w/in cytosol but nucleus
area
structure
cyclosis
nucleus
- Cytosol: difference vs cytoplasm here (cytosol doesn’t include the stuff suspended within the gel-like substance, it is ___. Think jello vs veggie stew.) (the cytosol is also known as ___)
just the gel-like stuff
cytoplasmic matrix
- Ribosomes: ___ = 80S, prokaryote (___ = 70S); the two subunits produced inside the nucloleus moved into the cytoplasm where they assembled into a single 80S ribosomes (larger S value indicates ___). Made of rRNA+protein, function to make proteins.
60S + 40S
50S + 30S
heavier molecule
**- ER: rough ER (with ribosomes) creates glycoproteins by attaching ___ to polypeptides as they are assembled by ___. In eukaryotes the rough ER is ___ with the outer nuclear membrane.
Smooth ER (no ribosomes) synthesizes ___ for export. In liver cells, smooth ER has functions in breakdown toxins, drugs, and toxic by-products from cellular rxn. Smooth and striated muscle have smooth ER’s called ___ that store and release ions, e.g. Ca 2+
polysaccharides
ribosomes
continuous
lipid and steroid hormoes
sarcoplasmic reticulum
**- Lysosomes: vesicles produced from Golgi that contain digestive enzymes (___ for function); break down nutrients/bacteria/cell debris. Any enzyme that escape from lysosomes remains ___ in the neutral pH of cytosol (other source says autolysis) (lysosomes in plant cell – maybe, but generally taught as none). Functions in ___ (releases contents into cell).
low pH
inactive
apoptosis
- Golgi: transport of various substances in vesicles (___ face is for incoming vesicles, trans face for secretory vesicles). Has flattened sacs known as ___.
cis
cisternae
