High School Biology : Mitosis
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Example Questions
Example Question #2 : Understanding Structures Of Mitosis
Which term refers to the microtuble structures that move the chromatids to opposite poles of a cell during mitosis?
Centrioles
Vesicles
Microfilaments
Kinetochores
Spindle fibers
Spindle fibers
Spindle fibers are specialized microtubule structures that guide the movement of chromosomes and chromatids during mitosis. During mitosis, the spindle fibers will bind to a protein complex (known as the kinetochore) at the center of the chromosome. The kinetochore serves as an anchor, allowing the spindle fibers to retract and separate the sister chromatids. Centrioles serve as the opposite anchor point, keeping the other end of the spindle fiber attached to the pole of the cell.
Viscles are small membrane-bound sacs that can be used to transport proteins and other molecules either within the cell, or between the cell and the extracellular matrix. Microfiliments are another component of the cytoskeleton and are frequently associated with motility; the protein actin is a microfiliment.
Example Question #183 : Cell Biology
During which stage of mitosis do the chromosomes begin to move towards opposite ends of the cell?
Anaphase
Prophase
Metaphase
Telophase
Anaphase
Recall PMAT mnemonic for remembering the steps in mitosis: prophase, metaphase, anaphase, telophase. Mitosis involves the separation of the (already-duplicated) chromosomes. The chromosomes condense, the mitotic spindle begins to form, and the nuclear envelope begins to break down during prophase. During metaphase, the chromosomes line up on the metaphase plate. In anaphase, the sister chromosomes begin getting pulled to opposite ends of the cell. Telophase is the opposite of prophase, and the cell undergoes cytokinesis.
Example Question #1 : Understanding Structures Of Mitosis
In mitosis, metaphase can be distinguished from the other stages most easily due to which of the following?
Metaphase is not a stage in mitosis.
Chromosomes are at separate poles with kinetochore attachments.
Chromosomes that are being separated by the formation of the cell plate.
Chromosomes aligned in the middle of the plane by what is known as the metaphase plate.
Chromosomes entangled with one another, enveloped in the nuclear membrane.
Chromosomes aligned in the middle of the plane by what is known as the metaphase plate.
Metaphase, by definition, is the point in which the sister chromatids align themselves along the middle of the plane which is known as the metaphase plate.
The responses explain interphase (chromosomes entangled with one another, enveloped in the nuclear membrane) and anaphase (chromosomes are at separate poles with kinetochore attachments). The other two responses are not phases of mitosis.
Example Question #31 : Mitosis
What is the role of the kinetochore?
Bind sister chromatids together
Signal the cell to enter metaphase
Perform a check that sister chromatids have been copied properly and are identical
Keep chromatin coiled
Act as an attachment point for spindle fibers
Act as an attachment point for spindle fibers
Kinetochores are protein structures located near the center of chromatids during cell division. Each chromatid has its own kinetochore so that spindle fibers can attach and pull the sister chromatids to opposite ends of the dividing cell. Note that the kinetochore assembles on the centromere region.
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