Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The centrosome is an organelle usually containing two cylindrical structures called centrioles, which are surrounded by amorphous pericentriolar materials.
Both the centrioles in a centrosome lie perpendicular to each other, exhibiting an organization like a cartwheel.
Centrioles are made up of nine evenly spaced peripheral fibrils of tubulin protein. Each of the peripheral fibrils is a triplet ( microtubules).
The central part of the proximal region of the centriole is also proteinaceous and called the hub, which is connected with tubules of the peripheral triplets by radial spokes made of protein.
The microtubule organization in a centriole is referred to as the arrangement because it lacks central microtubules, unlike the arrangement seen in cilia and flagella.
Centrioles form the basal body of cilia or flagella and spindle fibers that give rise to the spindle apparatus during cell division in animal cells.
📐Formulae
💡Examples
Problem 1:
Contrast the microtubule arrangement of a centriole with that of a eukaryotic flagellum.
Solution:
Centriole: arrangement; Flagellum: arrangement.
Explanation:
In a centriole, there are peripheral triplets and microtubules in the center. In a eukaryotic flagellum, there are peripheral doublets and central microtubules.
Problem 2:
Calculate the total number of microtubules present in the peripheral fibrils of a single centriole.
Solution:
Total microtubules = .
Explanation:
Since there are peripheral fibrils and each fibril is composed of a triplet ( microtubules), the total number is calculated as .