Organelle DSA Flashcards
Golgi Apparatus
- Structure
- Function
- Stacks of dislike compartments
2. Post translational changes in proteins and lipids, Trafficking
Mitochondria
- Structure
- Function
- Have outer and inner matrix
2. Make ATP, signaling, cell differentiation, and cell death
Lysosomes
- Structure
- Function
- Contain digestive enzymes
2. Degrade organelles and biomolecules
Peroxisome
- Structure
- Function
- Small vesicular compartment that contains enzymes
2. Oxidation reactions
Three topological categories
- Nucleus and cytosol—communicate through nuclear pore)
- ER, Golgi, endosome, lysosome—involved in secretory pathways and communicate through vesicles.
- Mitochondria
Cell that make secreted proteins have many…..
RER! (Ribosomes on the endoplasmic reticulum.
Rough Endoplasmic Reticulum
- Structure
- Function
- Parallel sacks of flat elongated cisternae studded with ribosomes
- Protein modification and assembly, segregation of proteins for internal and external use, export from the cell.
Smooth Endoplasmic Reticulum
- Structure
- Function
- Contiguous with RER, but lacks ribosomes and has tubular cisternae.
- Glycogen metabolism, lipid synthesis, phospholipid synthesis, detox, steroidogenesis, calcium regulation
SER is abundant in cells that do what?
Make steroids or lipids
Golgi apparatus has two ends…
Entry—CIS, is adjacent to the endoplasmic reticulum.
Exit—TRANS, faces the plasma membrane or the nucleus
These types of vesicles transport products from the Golgi apparatus to the lysosome or from the exterior of the cell to the lysosome. The end game here is to get stuff to the lysosome.
Clathrin-coated vesicles
This type of vesicle transports products between stacks of the Golgi.
COPI-coated vesicles (COat Protein)
This type of vesicle transports products from the endoplasmic reticulum to the Golgi
COPII-coated vesicles
Clathrin is used in two pathways
- Exocytosis/SECRETORY
2. Endocytosis (to the lysosome)
What protein is used to “pinch” the vesicle from the membrane
Dynamin
What protein allows clathrin to bind to the vesicle membrane?
Adaptin.
Clathrin does not bind directly to the membrane.
Clathrin binds to adaptin which binds to receptor molecules which have bound to cargo on the outside of the cell that need to be brought in.
How do lysosomes maintain an acidic enviornment?
ATP-depended H+ pump
There are two different kinds of lysosomes. What are they and what is the difference?
- Primary lysosomes—storage site of lysosomal hydrolases. There are NO digestive enzymes, the contents are HOMOGENOUS, and the enzymes are INACTIVE. (Think about them like they have been freshly made and have not been used yet.)
- Secondary lysosomes are engaged in a catalytic process. They have ACTIVE DIGESTIVE enzymes and have HETEROGENEOUS contents.
What are the 3 pathways for intracellular degradation?
- Phagocytosis—large particles, such as another cell, are brought into the cell; “eaten”
- Autophagy—cell components are degraded within the same cell.
- Receptor mediated endocytosis—larger molecules are brought into the cell via receptors.
When are lysosomes formed?
Lysosomes are formed via
Fusion of transport vesicle with endosome.
Early endosomes mature into late endosomes which are precursors to secondary endosomes.
Key step in endosome maturation»>lowering of internal pH to 5.5
Is clathrin digested in the lysosome after it has brought molecules into the cell?
No, clathrin is recycled back to the cell membrane.
Familiar Hypercholesterolemia
- Disfunction
- Possible consequences of Disfunction
- Clinical marker
- Mutation in gene that encodes the LDL receptor.
- receptor is unable to bind LDL
- receptor binds at reduced capacity
- receptor binds normally, but is incapable of internalization.
- Characterized by elevation of LDL which can lead to atherosclerotic plaques
Functions of Peroxisomes (also called Microbodies)
- synthesize and degrade hydrogen peroxide.
- beta-oxidation of long-chain fatty aids
- synthesize bile acid and cholesterol
- detoxifies alcohol
Zellweger Spectrum Disorder
Peroxisome assembly disorder
12 genes involved with the proper assembly of peroxisomes—a mutation in any one can cause disorders of the zellweger spectrum
Most serious=Zellweger syndrome—absence or reduced number of peroxisomes in the cell.
Congenital, no cure, death within first year of life.
What organelle evolved from bacteria
Mitochondria <3
They even evolved to retain their own DNA
Mitochondria make up ____% of the cytoplasmic volume and are often associated with ________.
20% of the cytoplasmic volume
Associated with microtubular cytoskeleton
In high energy cells, mitochondria are…
More fixed, less dynamic.
Can pack tightly between myofibrils and around flagellum of sperm cells.
Mitochondrial DNA diseases are caused by….
- Mutations in the mitochondrial DNA that affect the mitochondrial function
- Mutations of the nuclear DNA whose gene products are imported as mitochondrial proteins.
