cell organelles Flashcards
(49 cards)
cytoskeletal filaments
provide tracts for moving organelles around and for directing traffic of vesicles between them.
motor proteins
drive the skeletal filaments movements, that use energy of ATP hydrolysis to propel the organelles and vesicles along the filaments.
organelles examples:
cytosol
cytoplasm
nucleus
endoplasmic Reticulum
Golgi Apparatus
mitochondrion
lysosome
peroxisome
vacuole
cytosol =
concentrated aqueous gel
cytoplasm
cytosol + membrane bounded organelles except nucleus
Cytoskeleton
a network of protein filaments that extend throughout the cell: actin filaments, microtubules & intermediate filaments.
The cytoskeleton allows for the movement of organelles around the cell.
nuclear lamina
Array of protein filaments, anchor-sites for chromatin
nucleolus
Prominent structure in non-dividing nucleus
Nuclear Pore
Are protein-lined channels in the nuclear envelope.
Appear as perforations on the surface of the nucleus.
Allow for passage of materials from the nucleus to the cytoplasm.
what is the nucleolus site of???
it is the site of RNA transcription and processing and ribosome assembly
Chromatin
genomic DNA + proteins
nucleosome
is a structure where DNA is tightly packed around proteins known as histones
Heterochromatin
This is the condensed form of chromatin organisation and is the inactive form of chromatin.
Euchromatin
It is the lighter region of the nucleus and is most abundant in active cells because it is the active form of chromatin.
the nucleoplasm contains substances such as :
Nucleotides (for DNA replication and transcription)
Proteins/Enzymes (for all nuclear functions)
3 Key Processes of the Nucleus
Replication
Transcription
Translation
Replication
mediates copying of DNA in the cell cycle which is essential for the development and growth of a cell.
Transcription
controls the production of messenger RNA is produced in the nucleus using DNA as a template.
Translation
mRNA is transported via the nuclear pores to the cytoplasm for the synthesis of specific proteins which in turn have specific cellular functions (e.g. regulating metabolism, initiating mitosis)
LSU and SSU
are described as Svedberg (s) units
Svedberg (s) units
which are based upon their rate of sedimentation in a centrifuge.
SMOOTH ER
Agranular ER - has no ribosomes attached
ROUGH ER
Granular ER - has ribosomes attached
Functions of ER
The general function of the ER is in the synthesis, activation and transport of macromolecules in the cell, however depending on the addition of ribosomes or not, the ER has specific functions such as:
SMOOTH ER: outer surface lacks ribosome. Contains enzymes important in synthesis of lipids and steroids, detoxification of drugs and poisons, metabolism of carbohydrates, stores CA2+, enzyme reactions.
ROUGH ER: ribosomes stud outer surface, proteins produced on ribosomes, protein and lipid transport and secretion.