Lecture 5 Flashcards
Nuclear envelope
The double membrane surrounding the nucleus
Nuclear pores
Nuclear pores and their associated nuclear pore complex
Determines what does in and out of the nucleus
Chromatin
DNA plus associated proteins
Nucleolus
The site of ribosome subunit assembly
Nucleoplasm
Cytoplasm of the nucleus
Anucleate
Some cells as they mature they lose their nucleus
They are anucleate
Example. Red blood cells
Multinucleate
Some cells particularly in the kingdom protista are multinucleate
Ex. Amoeba have multiple nucleus
Endomembrane system and membrane trafficking
Parts
-nuclear envelope
- Endoplasmic Reticulum
- golgi
-vesicles
-lysosomes
- vacuoles
-plasma mebrane
Endomembrane system and membrane trafficking major concepts
Compartmentalization
Control internal surface areas
Highly interdependent
Compartmentalization in terms of Endomembrane system
Compartmentalization of metabolic activities creates specialized conditions for specific processes
Ex. Lysosomes are acidic bc their enzymes only work in acidic conditions
Controlling internal surface areas in terms of Endomembrane system
Changing their membrane surface areas influences the degree of these metabolic activities
Ex. Increasing amount of smooth ER for increased lipid synthesis
Highly interdependent in terms of Endomembrane system
Different Endomembrane compartments are highly interdependent because they exchange contents
Ex. Movement of proteins from ER to golgi like an assembly line
Fusion of vesicle with target membrane
Vesicle contents released
Vesicle membrane incorporated into target membrane
Vesicle membrane proteins incorporated into target membrane
Exocytosis
When the vesicle goes into the plasma membrane
Endocytosis
The opposite of exocytosis
When the vesicle breaks away from plasma membrane
Nuclear envelope is an extension of what and why?
Extension of the ER
allows transfer of substances between the 2
Rough ER
Protein translation
Folding
Modification
Smooth ER
Lipid synthesis
Detoxification
Rough ER vs Smooth ER in terms of of looks
Rough -
studded with ribosomes
Flattened cisternae
Smooth-
No ribosomes
Tubular cisternae
Translation of protein into lumen of the rough ER
mRNA goes to ribosomes. Turned into protein. Protein enters ER lumen and starts folding or go back into the membrane to become a transmembrane protein
From here the proteins can stay in the ER (do their job there) or the can be packaged into vesicles to send to the Golgi (to do their job elsewhere)
Smooth ER
-synthesize lipids, phospholipids, and steroids
- not abundant in most cells
- highly abundant in cells that secrete the above molecules
- also abundant in cells that detoxify drugs and alcohol
ER to Golgi transport
ER:
ribosomes translate protein into ER lumen or ER membrane
ER Membrane:
Protein folds and matures
Golgi complex:
Protein is modified and sorted for destination
Golgi complex functions
- receives vesicles from the ER and other locations
-adds the final “touchups” to proteins (additions of small molecules like sugars and lipids) - like a post office: sorts/ labels/ packages items for delivery to different parts of the cell in vesicles
