Cell Biology and Epithelia Flashcards
Role of Lamins
Attach Chromatin to the inner membrane of nuclear envelope and participate in the breakdown and reformation of the nuclear envelope during the cell cycle
What initiates nuclear disassembly into small vesicles during prophase
Phosphorylation of the lamina by lamin kinase
What is responsible for rRNA synthesis and assembly
Nucleolus
3 zones of nucleolus
- Granular Zone: found in periphery containing ribosomal precursor particles
- Fibrillar Zone: Central contains ribonuclear protein fibrils
- Fibrillar Center: Contains DNA not being transcribed
Histones enriched with
Positively charged Arginine and Lysine
Heterochromatin
Highly condensed inactive chromosome
Euchromatin
More extended transcriptionally active chromosome.
Ribosomes move on mRNA
Start from 5’ and move towards 3’
RER synthesizes proteins designated for
- Golgi apparatus
- Secretion
- Plasma membrane
- Lysosomes
SER contains enzymes responsbile for
Biosynthesis of phospholipids, TG, and sterols
Function of Golgi
- site of post-translational modification and sorting of newly synthesized proteins and lipids
- Further modification of carbohydrate moiety of glycoproteins produces complex and hybrid oligosaccharide chains
I-Cell disease deficiency
N-acetylglucosamine-phophotransferase
I-Cell disease charaterized by
- Huge inclusion bodies in cells due to accumulation of undergraded glycoconjugates in lysosomes
- Skeletal abnormalities
- Coarse features
- Restricted joint movement
- Psychomotor retardation
Lysosomes contain what enzymes
- Nucleases
- Lipases
- Gycosidases
- Proteases
- Peptidases
- Phophatases
Deficient breakdown of sphingolipids by lysosomes causes
- Gaucher
- Niemann-Pick
- Tay-Sachs
Peroxisome function
- Synthesis and degradation of hydrogen peroxide
- β-oxidation of very long chain FA
- Phospholipid exchange
- Bile acid synthesis