B2.2 Organelles and Compartmentalization Flashcards
ultracentrifugation, advantages of compartmentalization, respiration, photosynthesis
cell components not considered to be organelles
cell wall, cytoplasm, cytoskeleton
steps to ultracentrifugation
- fractionation
- solution spun at low speeds, densest organelles forms pellet
- pellet removed, process repeated at faster speed
- 2nd-densest forms pellet, and so on
steps to fractionation
- homogenization: blending in cold, isotonic, buffered solution
- filtration
advantages of nucleus compartmentalization
DNA protected from outside reactions, transcription inside nucleus separated from translation outside (mRNA modified before entering cytoplasm), maintains conditions for transcription, membrane breaks down for cell division then fuses back together
epigenetic change
changes in chromatin resulting in different gene expression
disadvantage of no nucleus compartmentalization
prokaryotes have no nucleus; as mRNA transcribed, ribosomes attach and begin translation, no separation results in increased errors
advantages of lysosome compartmentalization
only releases enzymes when cell damaged
phagocytosis
material like food or bacteria engulfed, forming phagocytic vacuole, which fuses with lysosome, becoming phagosome, which digests bacteria
what is the function of acinar cells and what special organelle features do they have for this function?
secrete digestive enzymes in pancreas; have bigger ER, golgi, granule storage compartments
adaptations of mitochondria for efficient ATP production
- outer membrane with channels for pyruvate to enter, impermeable to protons to allow for build-up in intramembrane space
- inner membrane has proteins of electron transport chain and ATP synthase, allows chemiosmosis
- matrix has enzymes for link reaction and Krebs cycle
- cristae increase surface area for reactions during oxidative phosphorylation
ATP synthase
conversion of ADP and P to ATP
chemiosmosis
diffusion of ions across membrane (protons across mitochondria membrane during respiration/chloroplast during photosynthesis)
draw and label a mitochondria
porins, ribosomes, matrix, outer/inner membrane, intramembrane space, cristae, DNA, granule
equation for respiration
C6H12O6 + 6 O2 = 6 CO2 + 6 H2O + energy
catabolic vs anabolic
breaks down larger molecules to smaller pieces vs smaller form larger
stages of cellular respiration
- Krebs cycle
- oxidative phosphorylation
- electron transport chain
adaptations of chloroplasts for efficient glucose production
- thylakoid membrane contains chlorophyll, facilitates electron transport chain and ATP synthase, increases surface area
- stroma: has enzymes for light-independent reactions (Calvin cycle)
- space in thylakoid (lumen) allows rapid proton build-up
equation for photosynthesis
6 CO2 + 12 H2O + energy = C6H12O6 + 6 H2O + 6 O2
organism that performs photosynthesis, makes own food
autotroph
draw and label a chloroplast
thylakoid, grana, lipids, lumen, stroma, DNA, ribosomes, outer/inner membrane
structure of ribosomes
one large and one small subunit, each composed of proteins and rRNA
function of free-floating ribosomes vs attached to ER
synthesizes proteins for use in cell vs for out of cell/production of lysosome enzymes
receptor-mediated endocytosis
- clathrins line coated pits on cell exterior that anchor receptors that bind to molecules
- molecules cause pit to deepen and clathrins polymerize to form cage, forcing membrane into rounded bud
- coated vesicle formed inside cell, cage removed
clathrin
triskelion-shape protein associated with receptor-mediated endocytosis
