16 Questions
What is the primary function of cytoplasmic microtubules in a cell?
Maintaining axons
In which cell structures are axonemal microtubules organized and stable?
Cilia and flagella
What is the axoneme?
Highly ordered bundle of microtubules in a cilium or flagellum
What are the two types of microtubules involved in various cell functions?
Cytoplasmic microtubules and axonemal microtubules
What is the function of axonemal microtubules in eukaryotic flagella?
Formation of the central shaft of a cilium or flagellum
Which of the following is NOT a function of cytoplasmic microtubules?
Synthesizing ATP for cellular energy
What is the basic subunit of a protofilament in a microtubule?
Heterodimer of tubulin
What is the inherent polarity of protofilaments in microtubules?
The two ends differ both chemically and structurally
What type of microtubules contain one 13-protofilament tubule and one or two additional incomplete rings?
Doublet microtubules
Which process is called nucleation in microtubule assembly?
The aggregation of dimers into oligomers
What balances the assembly of microtubules when the mass reaches a point where the amount of free tubulin is diminished?
Disassembly
What type of domain does each alpha and beta tubulin have?
GTP binding domain
What are the tubulin heterodimers made of?
One alpha-tubulin and one beta-tubulin
What do protofilaments in microtubules consist of?
Longitudinal arrays of polymers
What serves as 'nuclei' from which new microtubules grow during assembly?
Dimers aggregation into oligomers
What does the plateau phase of microtubule assembly represent?
A balanced state between assembly and disassembly
Study Notes
Microtubules
- The primary function of cytoplasmic microtubules in a cell is to provide structural support, shape, and movement.
Axonemal Microtubules
- Axonemal microtubules are organized and stable in cilia and flagella.
- The axoneme is the internal structure of cilia and flagella, composed of microtubules.
- Axonemal microtubules in eukaryotic flagella are responsible for movement and motility.
Types of Microtubules
- There are two types of microtubules involved in various cell functions: cytoplasmic microtubules and axonemal microtubules.
- Cytoplasmic microtubules are not involved in cell motility.
Microtubule Structure
- The basic subunit of a protofilament in a microtubule is a dimer of α-tubulin and β-tubulin.
- Protofilaments in microtubules have an inherent polarity.
- Cilia and flagella contain 13-protofilament microtubules with one complete tubule and one or two incomplete rings.
Microtubule Assembly
- Nucleation is the process of microtubule assembly.
- The dynamic equilibrium between assembly and disassembly balances the growth of microtubules when the mass reaches a point where the amount of free tubulin is diminished.
- Microtubule-associated proteins (MAPs) and microtubule-organizing centers (MTOCs) serve as 'nuclei' from which new microtubules grow during assembly.
- The plateau phase of microtubule assembly represents a state of dynamic equilibrium.
Tubulin
- Each α-tubulin and β-tubulin has a globular domain.
- Tubulin heterodimers are made of one α-tubulin and one β-tubulin molecule.
- Protofilaments in microtubules consist of tubulin heterodimers arranged head-to-tail.
Test your knowledge on the first part of the lecture series by Kathleen Fitzpatrick at Simon Fraser University, covering the topic of microtubules as a component of the cytoskeletal system.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
