Membrane Bound Organelles Flashcards
What is cytosol
Intracellular fluid (minus the organelles)
What is the cytoplasm
Contents of the cell except the nucleus
Cytoplasm contains the organelles
What is the nucleus
-Key evolutionary event for eukaryotes
- Protects genome so can become bigger and more complex ->regulators can also become more complex
- outer leaflet of the nuclear envelope is continuous with the endoplasmic reticulum
Held together with intermediate filament-based basket =lamina
Nuclear pores-dynamic -> number of pores can increase/decrease ->controls what goes in and out of nucleus
What is the endoplasmic reticulum
Can be 50% of a cells membrane
Net of flattened tubes and sacs throughout cytoplasm
Rough ER -> protein modification/ synthesis -> has ribosomes but they aren’t permanently on the ER
Smooth ER -> lipid synthesis, calcium storage which can be released as a signal, carbohydrate metabolism -> there’s lots of sER in muscles
What is the role of the rough ER
Proteins folded here
Enzymes will sense whether protein is being folded correctly and will then send them to be destroyed if they aren’t folded correctly-> quality control
Glycosylation starts in ER and finishes in the Golgi
Proteins pinched off into a vesicles from the ER
Signal info sources on the proteins in the vesicles-> displays where the protein needs to go
Vesicles can drift or be guided with a microtubule
What is meant by the fact that the ER is dynamic
It’s supported by microtubules of the cytoskeleton
Can grow/shrink
Can be moved around the cell as necessary
If ER needs to grow-> microtubules would grow in length to spread the ER and versa
What is the the Golgi apparatus and what is its role
Proteins come in from the ER to the cis face of the golgi
Proteins will go through the cis face and exit through the trans face
What are lysosomes and what is their role
Cells can detect periods of starvation
Lysosomes breaks down dysfunctional organelles -> improve cell health
What are endosomes and what is their role
Are a type of vesicle
Membrane bound sac
What is the mitochondria and what is its role (and chloroplasts in plants)
Has its own genome -> come from mother
Has a membrane -> large SA
Generate ATP -> cells can store and and synthesise too
Prokaryotic origin (theory of endosymbiosis)
What are peroxisomes and what is their characteristics
In lumen of peroxisome = enzymes
How are peroxisomes made from the ER
- Can be made from the ER-> couple of peroxisomal proteins that are modified and accumulate in the ER membrane
This encourages other peroxisomal proteins to accumulate there as well
A bit of the ER membrane pinches off and can become a peroxisome
What are the two ways in which peroxisomes can be made
Can be made from the ER
By growing and splitting
How can peroxisomes be made from growing and splitting
Existing peroxisome gets bigger and splits in half
What is the main function of peroxisomes
Breakdown long chain fatty acids
Oxidation of amino acids or fatty acids
Uses O2 to remove H atoms (oxidise) from organic substrates to produce hydrogen peroxide
Catalase uses H2O2 to oxidise phenols, Formic acid, formaldehyde and alcohol
Give the general equations for the series of reactions in which catalase uses H2O2 to oxidise phenols etc
What other peroxisome functions are there
What diseases can occur due to mutations involving the peroxisomes
