Non Membranous Organelles Flashcards
Location of cilia
It is found on the free surfaces of the epithelium lining of the respiratory system and parts of female and male genital tract
Cilia under L.M
- Each cilium has basal body shaft and rootlet —> formed of a single centrioles —> which migrate to surface of the cell to form the basal body of the cilium
- the basal body of the cilium is formed of 27 microtubules —> 9 bundles —> each bundle is formed of 3 microtubules ( triple tubule )
- the shaft of the cilium ( axoneme ) —> contain 2 single microtubules
- rootlet of the cilium —> formed of minute rootlet fibers —> extend underneath the basal body into the cytoplasm to fix the basal body to underlying cytoplasm
Function of cilia
- pushing fluids or small bodies in one direction over the surface of the ciliated cells , the movement of the cilia is initiated by energy which is released from ATP
- each rod and cone in the retina of the eye is covered by a single modified cilium which acts as a photoreceptors
Structure of flagella
- Similar in structure to the cilium , but it is rather longer , and present in a single form
- in man the only cell with a single flagellum is the spermatozoon
Function of centrioles during cell division
- The two centrioles develop another two daughter centrioles
- each pair of centrioles migrates to both sides of the dividing cell
- then each pair becomes surrounded by an area of cytoplasm rich in protein called —> micro-tubular organizer centre - MTOC -
Function of centrioles in relation to cilia and flagella
Each centriole divided into procentrioles which can form cilia and flagella
Centrioles under E.L
- each centriole is a hollow cylinder ; its wall is formed of 27 microtubules embedded in a protein matrix
- it is arranged in the wall of the cylinder in the form of 9 bundles
- each bundle is formed of 3 microtubules called triplets
Centrioles under L.M
- small dark body surrounded by a clear zone known as microcentrum , followed by dense zone called centrospheres
Staining of centrioles
Stained with iron hematoxylin
Location of centrioles
Centrioles are not present in erythrocytes and mature nerve cells
Structure if centrioles
The pair of centrioles is tubular structures ; each centriole is a hollow cylinder , closed at one end while the other end is opened
Centrioles
Centrioles it is a zone of cytoplasm present near the nucleus in an area called centrioles , it is contains a pair of centrioles
Function of ribosomes
- Synthesis protein —> which used for building up the cells
- as hemoglobin of RBCs
- this protein is secreted by the cells as a secretory products in the form of hormones or enzymes
Ribosomes under E.M
- composed of 2 subunits , one is large while the other is small
- the large one is formed of 2 parts , between these two parts there is a polypeptide chain
- the polypeptide chain segregate the protein which is formed or synthesized by ribosomes
Which type of ribosomes are responsible for the basophilia of the cytoplasm
Free ribosomes “ which scattered freely in the cytoplasm “
Their number may increase in growing cells , secretory cells , cancer cells and during normal cell division, what is it ?
The free ribosome
Location of free ribosomes
Find in all kinds of cells except in mature RbCs
Position of free ribosomes
- Scattered freely in the cytoplasm so they are not attached to membrane
- arranged in groups usually of 5 ribosomes
The attached ribosomes are called
Ribosomal RNA
Function of attached ribosomes
They are responsible for protein synthesis
Location of attached ribosomes in the cytoplasm
They are attached to outer surface of R.E.R
Types of ribosomes
1 - ribosomes in form of small fragments “ are rich glucose 6 phosphate enzyme “ “ are called microsomes “
2 - ribosomes attached to each other “ forming spiral - shaped structure or rosette shaped structure “ “ are called polysomes “
3 - ribosomes with R.E.R “ form isolated bodies in nerve cells” and “ are called nissls granules “
4 - attached ribosomes
5 - free ribosomes
Staining if ribosomes
- Basophilic in staining due to their content of r - RNA
- stain “ hematoxylin , toluidin blue , and methylene blue .
Ribosomes Site of formation
They are formed at nucleolus
Shape of ribosomes
They are rounded or oval cytoplasmic bodies
Structure of ribosomes
Ribosomes are formed of ribo-nucleoprotein
The pathway of ribosomes after formation in the nucleolus
They pass through the nuclear pores to reach the cytoplasm
