Cell Organization Flashcards
What are the ways cells move organelles and other substances in cells?
Motor proteins systems like microtubules (kinesin, dynein) and actin (myosin)
What is the purpose of the organelle structure of cells?
Increases efficiency, protects cells from harmful substances
(e.g lysosomes contain digestive enzymes that breakdown molecules , membrane bound organelle increases efficiency and protects the rest of the cell)
What is the result of a knock out in microtubules protein?
Fatal because used in axons to transport organelles to ends, so axons can’t function and you get rapid neurodegeneration
How do proteins get to mitochondria, nucleus, and peroxisomes?
signal sequences
What is an example of harm caused by changes in a signal sequence?
There was a drug fialuridine that was tested in mice for inhibiting Hep B, had a signal sequence PARS that targeted proteins to plasma membrane, in humans PARS changed to PEXN which is a signal sequence for mitochondrial membrane so damaged mitochondria, couldn’t make ATP, liver failure and death
What is unique about the transport of proteins into the nucleus?
bidirectional, can go in in a folded state
What is Zellweger syndrome and how is it caused?
Peroxisomes are involved in breaking down chemicals, fatty acids, and key lipid synthesis materials (eg lipid plasmogen which is important for the synthesis of mylein in neurons), PEX molecules move proteins into peroxisomes, mutations in PEX cause Zellwegers, can’t make mylein
How does the cell position organelles?
microtubules that extend throughout the cytoplasm help transport and anchor organelles in places that increase efficiency
What is the structure of microtubules?
heterodimers of alpha and beta tubulin that bind GTP
13 protofilaments
hollow tube
lateral contacts let them grow longer than actin by increasing stability
polarized, grow from plus ends
MTOC stabilizes minus ends
