Lecture 7 Basics: Organelles
Large cell organelles:
Quick Protein Synthesis
Nucleus
Contains:
Nuclear envelope:
Nuclear pores
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Nuclear import and export tags
(to think about – what molecules would need to enter the nucleus? What would
need to exit?)
Chromatin:
Chromosomes:
Nucleolus:
(to think about: Ribosomes are assembled from ribosomal RNA and small proteins.
How do small proteins get into the nucleus for the assembly?)
Endoplasmic reticulum:
Definition of “factory functions:”
Definition of “pocket functions:”
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Smooth endoplasmic reticulum:
Factory:
Pocket:
Rough endoplasmic reticulum:
Factory:
Pocket:
Ribosomes:
Made of:
Assembled in:
Found:
Golgi apparatus:
Made of:
Function:
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The endomembrane system:
Lysosomes:
Protein localization:
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The signal peptide and signal recognition particle
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Class Notes:
Nuclear import and export tags:
Molecule
Tag type (import,
export, none)
Explanation
DNA polymer
Individual ribonucleic
acids
mRNA of a ribosomal
protein
Ribosomal protein
Completed ribosomal
subunit
Video – Life of a Cell
Free vs Bound ribosomes:
1. Actin subunit
2. Sodiumpotassium pump
3. Chloride channel
4. Dynein
5. Ribosomal
protein
6. Insulin
7. Collagen
8. Myosin
9. Histone
10. LDL receptor
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When a cell increases synthesis of aquaporin channels by tenfold, the number of
free ribosomes is likely to:
A. Increase
B. Decrease
C. Remain the same
A free ribosome that binds to an mRNA molecule coding for a proton pump in the
lysosome membrane will:
A. Synthesize this protein in the cytosol and transport it to the lysosome
B. Synthesize this protein in the cytosol and package it into vesicles for
transport to the lysosome
C. Bind to the ER and synthesize the protein directly into rER membrane
D. Bind to the ER and simultaneously synthesize and translocate protein into
the rER lumen
E. Cleave off the signal peptide region before starting protein synthesis
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