Cell Division and Cytoskeleton Functions

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the diameter of microtubules in a cell?

  • 8 nanometers
  • 25 nanometers (correct)
  • 40 nanometers
  • 10 nanometers

Which type of filament is exclusively found in animal cells?

  • Microtubules
  • Microfilaments
  • Intermediate filaments (correct)
  • Contractile fibers

What are the two primary components of tubulin?

  • Microfilaments and actin
  • Alpha and beta tubulin (correct)
  • Intermediate filaments and keratins
  • Centrioles and centrosomes

What function does the cytoskeleton serve in cellular movement?

<p>Maintaining cell's shape (C)</p> Signup and view all the answers

What is the primary microtubule organizing center in a cell?

<p>Centrosome (A)</p> Signup and view all the answers

How many protofilaments typically form a single microtubule in mammalian cells?

<p>10 to 15 (B)</p> Signup and view all the answers

Which of the following is a characteristic of microfilaments?

<p>Diameter of approximately 8 nanometers (D)</p> Signup and view all the answers

What role do centrioles play in the organization of microtubules?

<p>Organizing pericentriolar material to produce microtubules (A)</p> Signup and view all the answers

What is the primary role of the cytoskeleton in a cell?

<p>To assist in cell division and maintain cell shape. (A)</p> Signup and view all the answers

Which filamentous structure is responsible for rapidly growing and shrinking?

<p>Microtubules (B)</p> Signup and view all the answers

How many different protein subunits compose intermediate filaments in humans?

<p>70 (D)</p> Signup and view all the answers

What structural feature characterizes microtubules?

<p>A hollow cylinder (A)</p> Signup and view all the answers

What is the composition of centrioles?

<p>Microtubules (B)</p> Signup and view all the answers

What diameter do microfilaments share?

<p>8 nm (D)</p> Signup and view all the answers

What is the function of microtubule organizing centers (MTOCs) in cells?

<p>To generate microtubules and organize them. (C)</p> Signup and view all the answers

What type of filaments are associated with muscle cells?

<p>Desmin filaments (B)</p> Signup and view all the answers

What happens to the nuclear membrane during prophase?

<p>It breaks down into small vesicles. (A)</p> Signup and view all the answers

Which role do kinetochore microtubules play in anaphase?

<p>They shorten to draw chromosomes toward spindle poles. (A)</p> Signup and view all the answers

During which phase do chromosomes migrate to the equatorial plane?

<p>Metaphase (D)</p> Signup and view all the answers

What key process is observed during anaphase?

<p>Separation of sister chromatids. (D)</p> Signup and view all the answers

What is the function of the mitotic spindle checkpoint?

<p>To assess spindle assembly correctness. (B)</p> Signup and view all the answers

Which complexes contribute to the exit from metaphase?

<p>APC/C complex and cyclins A and B (A)</p> Signup and view all the answers

What characterizes telophase in the cell cycle?

<p>Chromosomes arrive at cell poles. (B)</p> Signup and view all the answers

Which type of microtubule is responsible for positioning the spindle apparatus during mitosis?

<p>Astral microtubules (D)</p> Signup and view all the answers

What is the primary purpose of somatic cell division in eukaryotes?

<p>To ensure tissue growth and regeneration (D)</p> Signup and view all the answers

Which phase directly follows karyokinesis during mitosis?

<p>Cytokinesis (B)</p> Signup and view all the answers

Which of the following accurately describes cyclin-dependent kinases (CDKs)?

<p>They require cyclin proteins for kinase activity. (C)</p> Signup and view all the answers

What occurs during the prophase phase of mitosis?

<p>Chromosomes condense into compact structures. (D)</p> Signup and view all the answers

Which kinase is primarily responsible for phosphorylating H1 histone during prophase?

<p>Cdk1 (C)</p> Signup and view all the answers

Which phase of mitosis is characterized as the separation phase?

<p>Anaphase (C)</p> Signup and view all the answers

What role do Polo-like kinases and Aurora kinases play in mitosis?

<p>They regulate phosphorylation and centrosome function. (B)</p> Signup and view all the answers

How are sister chromatids held together during prophase?

<p>By cohesin proteins (B)</p> Signup and view all the answers

Flashcards

Cytoskeleton

A network of protein filaments that maintain cell shape, position organelles, resist deformation, and transport intracellular cargo. It's like scaffolding inside a cell, giving it structure and helping things move.

Microtubules

The largest cytoskeletal filaments, formed from tubulin proteins. They are hollow cylinders, important for cell division and transportation.

Microfilaments

The smallest cytoskeletal filaments, made of actin proteins, crucial for cell movement and muscle contraction.

Intermediate Filaments

Filaments in between microtubules and microfilaments in size, with diverse protein subunits, important for supporting specific cell types.

Signup and view all the flashcards

Centrosome

The main microtubule organizing center (MTOC) in animal cells, containing centrioles.

Signup and view all the flashcards

Centrioles

Cylindrical organelles within the centrosome, composed of microtubules, and play a role in organizing those microtubules.

Signup and view all the flashcards

Tubulin

A protein that makes up microtubules, composed of alpha and beta tubulin subunits.

Signup and view all the flashcards

Cytoskeleton function

Maintains cell shape and enables movement, positions organelles, resists deformation, and transports materials within the cell.

Signup and view all the flashcards

Microtubule type

The largest filamentous component of the cytoskeleton, made of tubulin.

Signup and view all the flashcards

Microtubule subunits

Tubulin protein subunits (alpha and beta) combine to form the microtubule structure.

Signup and view all the flashcards

Microtubule structure

Microtubules are hollow cylinders formed by the assembly of 13+ protofilaments wound together.

Signup and view all the flashcards

Centrosome function

The main microtubule organizing center (MTOC) in animal cells, anchoring microtubule minus ends.

Signup and view all the flashcards

Centrosome components

The centrosome contains centrioles and pericentriolar material (PCM).

Signup and view all the flashcards

Centrioles function

Centrioles organize the pericentriolar material (PCM) and microtubules within animal cells.

Signup and view all the flashcards

Intermediate filaments function

Strengthens and supports specific cell types with different protein structures.

Signup and view all the flashcards

Microfilament composition

The smallest cytoskeletal filament, composed of actin protein.

Signup and view all the flashcards

Somatic cell division

A type of cell division in eukaryotes that creates two genetically identical daughter cells.

Signup and view all the flashcards

Mitosis

The process of nuclear division during cell division, creating two identical nuclei.

Signup and view all the flashcards

Cytokinesis

The division of the cytoplasm to form two separate daughter cells.

Signup and view all the flashcards

Cell cycle regulation

The control of cell cycle progression, ensuring accurate duplication and division.

Signup and view all the flashcards

Cyclin-dependent kinases (CDKs)

Key cell cycle regulation proteins that control progression through the cycle, particularly mitosis.

Signup and view all the flashcards

Prophase

The first phase of mitosis, where chromosomes condense.

Signup and view all the flashcards

Prophase

The first phase of mitosis, where the nuclear membrane dissolves and chromosomes condense.

Signup and view all the flashcards

Prometaphase

Chromosomes attach to spindle fibers during this phase of mitosis.

Signup and view all the flashcards

Metaphase

Chromosomes align at the center of the cell in this stage of mitosis.

Signup and view all the flashcards

Anaphase

Sister chromatids separate and move to opposite poles during this stage of mitosis.

Signup and view all the flashcards

Telophase

The final stages of mitosis: New nuclei form around separated chromosomes.

Signup and view all the flashcards

Mitotic Spindle

The structure that separates chromosomes during cell division.

Signup and view all the flashcards

Sister Chromatids

Identical copies of a chromosome joined together.

Signup and view all the flashcards

Daughter Chromosomes

The separated copies of a chromosome.

Signup and view all the flashcards

Kinetochore Microtubules

Attach to the kinetochore of chromosomes, pulling them to the poles.

Signup and view all the flashcards

Interpolar Microtubules

Extend across the equator in the cell, pulling chromosomes apart.

Signup and view all the flashcards

Study Notes

Cell Division - Cytoskeleton

  • The cytoskeleton is composed of three filamentous structures: microtubules, microfilaments (actin filaments), and intermediate filaments.

Cytoskeleton - Functions

  • Maintains cell shape and changes shape during movement (e.g., cell division, organelle migration, cell migration).
  • Positions organelles.
  • Resists deformation.
  • Transports intracellular cargo (e.g., vesicles) and assists in the transport of communication signals between cells.

Microtubules

  • The largest type of filament, composed of tubulin protein.
  • Diameter is approximately 25 nanometers.
  • Tubulin is composed of α-tubulin and β-tubulin subunits assembled into linear protofilaments.
  • Microtubules can rapidly grow or shrink in size through polymerization and depolymerization, respectively.
  • The size depends on the number of tubulin molecules they contain.
  • A single microtubule contains 10 to 15 protofilaments (13 in mammalian cells).
  • They wind together to form a 24 nm wide hollow cylinder.

Centrosome

  • In cells, the minus ends of microtubules are anchored in structures called microtubule-organizing centers (MTOCs).
  • The primary MTOC in a cell is the centrosome.
  • The centrosome consists of two centrioles.
  • The centrosome is duplicated during the S phase of the cell cycle.

Centrioles

  • Occur as paired cylindrical organelles together with pericentriolar material (PCM) containing more than 100 different proteins.
  • Constructed of microtubules.
  • Organize the PCM to produce microtubules, including mitotic spindle fibers.

Intermediate Filaments

  • Composed of different protein subunits (~70 in humans).
  • Diameter is approximately 10 nanometers.
  • Found only in animal cells.
  • Associated with specific cell types: neurofilaments in neurons, desmin filaments in muscle cells, and keratins in epithelial cells.

Microfilaments

  • The smallest type of filament composed of the contractile protein actin.
  • Diameter is approximately 8 nanometers.
  • Particularly prevalent in muscle cells.

Motor Proteins

  • Use energy derived from ATP hydrolysis to generate movement and force.
  • Involved in cell movement:
    • Kinesin moves along microtubules to pull organelles towards the cell membrane.
    • Dynein pulls cellular components inward (toward the nucleus) and works to slide microtubules.
    • Myosin interacts with actin to perform muscle contractions, and is involved in cytokinesis, endocytosis, and exocytosis.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Lecture 7: Cytoskeleton PDF
Lecture 7_II_Mitosis PDF

More Like This

Microtubules: Structure and Functions
21 questions
Cytoskeleton Overview and Functions
10 questions
Cell Biology: Cytoskeleton Functions and Filaments
18 questions
Cytoskeleton Components and Functions
48 questions
Use Quizgecko on...
Browser
Browser