cell division and differentiation

• What structures are depicted in the images?

  The mitotic spindle and the contractile ring during cell progression through the M phase.

  
• What phase of the cell cycle is shown in the progression?

  M phase

  
• What is the role of the mitotic spindle during M phase?

  It separates chromosomes to ensure equal distribution between daughter cells.

  
• What is the function of the contractile ring in M phase?

  It contracts to divide the cytoplasm into two daughter cells during cytokinesis.

  
• What are the key differences between the mitotic spindle and the contractile ring?

  • Mitriotic Spindle:
  • Composed of microtubules
  • Separates chromosomes during mitosis
  • Contractile Ring:
  • Composed of actin and myosin filaments
  • Divides cytoplasm during cytokinesis

  
• What filaments form the contractile ring during cell division?

  Actin and myosin filaments

  
• What is the role of the contractile ring in cell division?

  • To constrict the cell membrane
  • To separate the two daughter cells

  
• What are the two main filaments that comprise the contractile ring?

  Actin and myosin

  
• How do actin and myosin filaments contribute to the function of the contractile ring?

  • Actin provides structural support
  • Myosin provides motor function for contraction

  
• What are the four main phases of the cell cycle?

  • $G_1$ phase
  • $S$ phase
  • $G_2$ phase
  • $M$ phase

  
• What are the checkpoints in the cell cycle?

  • $G_1$ checkpoint
  • Intra $S-phase$ checkpoint
  • $G_2$/M</latex> checkpoint
  • Spindle assembly checkpoint

  
• What are the main factors checked at the $G_1$ checkpoint?


  Cell size, nutrients, DNA damage, and growth factors

  
• What are the primary criteria assessed during the $G_2$/M</latex> checkpoint?


  Cell size and DNA replication

  
• What is checked at the spindle assembly checkpoint?

  Chromosome attachment to the spindle

  
• What factors are monitored at the intra $S-phase$ checkpoint?


  DNA damage and DNA replication

  
• What cyclin and CDK are associated with the $G_1$ phase?


  • Cyclin D
  • $CDK_4$ and $CDK_6$

  
• Which cyclin and CDK are primarily active during the $S$ phase?


  • Cyclin E
  • $CDK_2$

  
• Which cyclin and CDK regulate the $G_2$ and $M$ phases?


  • Cyclin A
  • $CDK_1$
  • Cyclin B
  • $CDK_1$

  
• How do cyclin-dependent kinases (CDKs) contribute to the progression of the cell cycle?

  • CDKs are enzymes that regulate the cell cycle by phosphorylating target proteins.
  • They are activated by binding to cyclins, which vary in concentration throughout the cell cycle.

  
• What is the main role of cyclins in the cell cycle?

  To activate cyclin-dependent kinases (CDKs)

  
• What are the key structures and their functions involved in cell division?

  • Chromosomes: Carry genetic information
  • Centromere: Attaches sister chromatids
  • Sister chromatids: Identical copies of chromosomes
  • Spindle fibers: Help move chromosomes
  • Centrosomes: Organize spindle fibers

  
• What is the primary function of chromosomes?

  Carry genetic information

  
• What structure holds sister chromatids together?

  Centromere

  
• What are sister chromatids?

  Identical copies of chromosomes

  
• What is the role of spindle fibers in cell division?

  Help move chromosomes

  
• What organizes spindle fibers during cell division?

  Centrosomes

  
• What occurs during the G1 phase of the cell cycle?

  Cell growth and metabolism

  
• What are the main phases of the cell cycle and their primary events?

  1. Interphase:

  • G1: Cell growth and metabolism
  • S: DNA replication
  • G2: Cell prepares for mitosis

  
  

  1. Mitotic phase:

  • Prophase: Chromosomes condense, spindle fibers form
  • Metaphase: Chromosomes align at the metaphase plate
  • Anaphase: Sister chromatids separate
  • Telophase: Chromosomes reach opposite poles, nuclear envelope reforms

  
  

  1. Cytokinesis: Division of the cytoplasm

  
• When does DNA replication occur in the cell cycle?

  S phase

  
• What happens during the G2 phase of the cell cycle?

  The cell prepares for mitosis

  
• What is the first phase of mitosis?

  Prophase

  
• In which phase of mitosis do sister chromatids separate?

  Anaphase

  
• What is the division of the cytoplasm called?

  Cytokinesis

  
• When do chromosomes align at the metaphase plate during mitosis?

  Metaphase

  
• What reforms during telophase of mitosis?

  Nuclear envelope

  
• What structure holds sister chromatids together?

  Centromere

  
• What organizes spindle fibers during cell division?

  Centrosomes

  
• When does DNA replication occur in the cell cycle?

  S phase

  
• When do chromosomes align at the metaphase plate during mitosis?

  Metaphase

  
• What is the division of the cytoplasm called?

  Cytokinesis