Quizzam 2 - Mitosis

DNA is organized into _____

chromosomes

Centrioles

microtubules that organize spindle fibers. they aid in cell division.

What do an organism’s chromosomes differ in?

content and shape

Non-homologs

copies of different chromosomes with different DNA

Homologs

copies of the same chromosome with same DNA

One copy of each _____ is inherited from each parent

homolog

Mitosis

the division of one cell into two exact duplicates

Mitosis: Starts with one cell that is 2N —>

End with two cells that are each 2N

Mitosis

used for growth or asexual reproduction

Mitosis SIX phases

1. Interphase

2. Prophase

3. Prometaphase

4. Metaphase

5. Anaphase

6. Telophase

What is the cell in before the start of mitosis? What does it look like?

• Interphase:

  • there is a single centrosome.

  • chromosomes reside with the nuclear envelope.

  • chromosomes are uncondensed.

When does chromosome replication occur?

during a subphase, S-phase

What occurs during Interphase?

• the chromosome duplicates to form four centrioles

• the chromosomes replicate but remain uncondensed

• I —> X

What occurs during Prophase?

• the chromosomes condense

  • the two centrioles move to opposite sides of the cell, forming mitotic spindle fibers

  • the nuclear envelop begins to break down

  • chromosomes condense. each one now has two sister chromatids bound via the kinetochore

What does the kinetochore consist of?

proteins associated with the centromere and spindle fibers

What occurs during Prometaphase?

• the spindle fibers bind each chromosome

• mitotic spindle fibers from the centrioles bind each chromosome’s kinetochore.

• the chromosomes migrate towards the middle of the cell

What occurs during Metaphase?

• the chromosomes reach the cell’s center

• the spindle fibers align the chromosomes along a central metaphase plate.

What occurs during Anaphase?

• sister chromatids separate

• mitotic spindle fibers pull the chromosomes to opposite ends of the cell

• sister chromatids separate, forming two daughter chromosomes

What occurs in Telophase?

• the cell prepares to divide

• two new nuclear envelopes form

• the new chromosomes begin to uncoil.

What occurs during cytokinesis?

• the cell splits into two daughter cells

• the cell undergoes cytokinesis, dividing the cell in two

• each cell inherits one 2N complement of chromosomes and one centrosome with two centrioles

What is cancer?

Unregulated mitosis caused by errors in the cell cycle.