Structure of cell Flashcards
What is on top of Phosphate grp in phospholipid
Nitrogenous part
By what forces are the phospholipids held together
Hydrophobic interaction
What is the word describing solubility of phospholipid
Amphipathic
Name another component in cell membrane that helps stabilize. And It’s orientation
Cholesterol. It’s -OH group points towards the phosphate , the side chain is pointing at the fatty acids
Name 3 actions that phospholipid can take
Diffuse laterally, flip flop (rare), Rotate
Name the science model used to describe the orientation of different components in cell membrane
Fluid Mosaic Model
Name 4 factors that will make the fluidity rises
Shorter FA, Higher temp, less cholesterol, more C=C
Where are the ribosomes in Rough ER
On cytosolic surface
Describe the shape of Rough ER
Flattened sheet of membranes and tubules
What is the membrane and lumen of Rough ER
Membrane is attached to Outer membrane of nuclear envelope, while lumen is continuous with that of nuclear envelope
Compare the shape of Rough ER and Smooth Er
SMooth ER is more tubular
Name 4 possible functions of Smooth ER
Make steroid
Lipid
Detoxification
Calcium storage and release
Describe the pathway of protein/lipid into and out of Golgi Apparatus
Cis-Golgi network –> lumen –> Trans-golgi Network (as vesicle)
What is lysosome for. What doees it contain. Under what circumstances are the content activated
Degrading protein and phagocytosis. Enzymes to degrade phagocytosed material and organelles. It is activated under acidic, ie pH=4.4-5.5
What is the size, function and common site for Peroxisomes
Smaller than lysosome.
For degradation of long FA and amino acids
In liver
What is the function of nuclear pores
It allows passive diffusion of small molecules and actively import of protein and actively export RNA and protein
What is the inside of nuclear envelope called
Nucleolus and nucleoplasm
What is the function of nucleolus
To make rRNA from the gene for encoding it in chromosome 13,14,15,21,22.
To process and assemble ribosomal subunits (NOT YET FULLY ASSMEBLED)
Where is the product assembled to form a fully functional ribosome
In cytoplasm
What are the 3 subparts of nucleolus and their function
Fibrillar centre: depot of inactivated RNA genes
Dense fibrillar centre:Pre rRNA synthesis and early processing
Granular component: Contains ribosomal subunits of different stages
What is nucleoplasm containing
DNA, nucleoproteins and protein
What is a chromatin. What can chromatin be classified into
DNA complexed with histones. It can be divided into
heterochromatin
(less active in transcription) and
euchromatin (active in transcription)
What are the functions of cytoskeleton
Maintains cell shape, involve in cytokinesis, guide intercellular traffic, for whole cell locomotion and provide mechanical support
What is the major component of polymer microfilament
F-Actin
What is the component of gobular monomer
G-Actin
Arrange the size of filaments in ascending order
Microfilament < Intermediate filament < Microtubules
What are the 2 possible confrontmation of microfilament and the arrangement of actin
Bundle (parallel)
Network (crossing)
How does the actin shows different arrangement
By interacting with different cross-linking proteins
What is inside a microvilli
Actin bundles, ie fimbrin
What are the filament connected to
Actin network,filamin
What does a dimer of intermediate filament made of
2 rod-like proteins twisting in a parallel manner to form a dimer
How does a tetramer of intermediate filament form
It is formed by 2 dimers twisting in an anti-parallel direction
What does tetramer form then
end to end to form protofilament
Name 3 types of cytoplasmic intermediate filament
Keratin (in epithelial cell)
Vimentin (connective tissue,smooth muscle cell)
neurofilament (Nerve cell)
Name 1 type of intermediate filament in nucleus
Nuclear lamina (inside nucleus to form nuclear lamina in the inner membrane)
What is the problem of lacking keratin in cell
Cell being fragile and prone to rupture hence skin blistering
What is the building unit of microtubule
Tublin dimer made of Alpha and Beta tublin
What does microtubule builds to
Protofilament when arranged in longtidinal row
What does protofilament form.
13 to form a hollow centre
Where does microtubule lengthen and shorten respectively
+ end and - end
What is the origin of all microtubules. Name another function of it. What is that in human
MTOC (microTubill Organising Centre)
As the anchor of 1 end
Centrosome (with centriole as centre) in human
Basal body (to push out extensions like fragella and cilia)
What can microtubules do
- Separating chromosomes during mitosis (Mitotis spindle)
- Intracellular transport of organelles)
Axonal transport - Cell locomotion
Cilia and fragella movement
What stops elongation of microtubule
colchicine
What stops depolymerization of microtubule
taxol
Name 1 process possibily affected by the taxol
Mitotic cell division
