B2.2 Organelles and Compartmentalization Flashcards
Prokaryote
usually unicellular, nucleoid, no membrane bound nucleus, has cell wall different from cell wall some animals have (peptidoglycan)
Eukaryote
single or multicellular, nucleus, membrane bound nucleus and other organelles, larger than prokaryotic, more complex, variety of internal membranous structures called organelles
Archaebacteria
autotrophs and heterotrophs, unicellular, prokaryotic, live in extreme environments such as volcanic hot springs, many live in absence of oxygen, cell wall lacks peptidoglycan, cell membrane contains unusual lipids not found in other organisms
Mitochondrion
1) Double membrane - (inner phospholipid membrane contains many proteins which act as electron carriers, they accept e and pump H+ ions from matrix to intermembrane space)
2) Folded inner membrane (cristae) - increase surface area for electron transportation chain
3) Matrix - contains fluid filled space where Krebs cycle occurs, contains enzymes that help to oxidize CoA
4) Intermembrane space - site of H+ ion accumulation, creating a proton gradient for chemiosmosis
5) Ribosomes - produce proteins required within mitochondrion
4) Site of ATP production
5) Fat hydrolysis if it is used as energy in a cell
Chloroplast
1) stroma - contains enzymes for light independent reactions
2) thylakoid membrane - separates H+ in stromal space from thylakoid lumen space, creates large SA since arranged in grana, contains specialized pigments
3) thylakoid space - small space so it is easy to create a concentration gradient, high to low conc to provide energy for ATP synthesis
Nucleus
1) nuclear envelope - pores in high numbers [when double membrane, pore sizes are bigger] allows transfer of materials from nucleus to cytoplasm
2) double membrane
- in continuation with golgi apparatus and ER (one membrane folds over the other)
- double membrane is one membrane folded to form double structure
- continuous membrane across inner and outer surfaces of the nuclear envelope. Forms network
- during mitosis and meiosis, nuclear breaks down to allow chromosomes to be moved to poles of cell
- discontinuous double membrane allows for this as disintegration into vesicles lets spindle fibers attach to chromosomes
Golgi Apparatus
- series of flattened sacs called cisternae, stacked one on top of the other
- cis-side receives products, trans side transports/discharges products
- most of these are packaged into vesicles for secretion through plasma membrane
- processes, collects, packages, distributed polypeptides that arrive from the ER
- some proteins are then transported via vesicle to plasma membrane and secreted
- transition vesicles transport between ER and golgi
Vesicles
- single or double membrane depending on what organelle they pinch off of
- transports hormones, enzymes membrane proteins, etc
Clathrin - 3 legged protein that supports the fusion of membranes when a vesicle is made - adjacent clathrin molecules bind to each other to form a coat - helps structural stability of vesicle - helps membrane to become indented and detach the vesicles
