AP Biology : AP Biology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #311 : Cellular Biology

During what phase of mitosis do sister chromatids line up in the middle of the cell, equidistant from both poles of the cell?

Possible Answers:

Prophase

Metaphase

Interphase

Anaphase

Telophase

Correct answer:

Metaphase

Explanation:

At metaphase the spindle microtubules that are attached to the kinetochores of the chromosomes move them to the metaphase plate, an imaginary structure at the midway point between the two poles of the cell.

Example Question #316 : Cellular Biology

In mitosis, which is the first phase in which chromatin coils and forms chromosomes and the nuclear membrane breaks down?

Possible Answers:

Metaphase

Telophase

Prophase

Anaphase

Correct answer:

Prophase

Explanation:

Prophase is the first phase of mitosis in which chromatin coils and forms chromosomes, the spindle apparatus begins to form, and the nuclear membrane breaks down. The second, third, and fourth phases are metaphase, anaphase, and telophase, respectively.

Example Question #51 : Understanding Mitosis

In mitosis, which is the second phase in which spindle fibers move the chromosomes to the center of the cell where they are aligned?

Possible Answers:

Telophase

Prophase

Anaphase

Metaphase

Correct answer:

Metaphase

Explanation:

Metaphase is the second phase of mitosis in which spindle fibers move the chromosomes to the center of the cell where they are aligned. Prophase is the first phase of mitosis, anaphase is the third phase, and telophase is the fourth and final phase.

Example Question #51 : Understanding Mitosis

In mitosis, which is the third phase in which sister chromatids of chromosomes move toward the opposite poles of the cell?

Possible Answers:

Metaphase

Prophase

Anaphase

Telophase

Correct answer:

Anaphase

Explanation:

Anaphase is the third phase of mitosis in which each sister chromatids of each chromosome toward the opposite poles of the cell. Prophase is the first phase of mitosis, metaphase is the second phase, and telophase is the fourth and final phase.

Example Question #91 : Cellular Division

In mitosis, what is the fourth phase in which the chromatids unwind and become elongated and the nuclear membrane starts to form around the DNA?

Possible Answers:

Anaphase

Telophase

Prophase

Metaphase

Correct answer:

Telophase

Explanation:

Telophase is the fourth and final phase of mitosis in which the new chromatids unwind, the spindle apparatus breaks down, the cells becomes elongated, and a nuclear membrane starts to form around the decondensed DNA (chromatin). Prophase is the first phase of mitosis, metaphase is the second phase, and anaphase is the third phase.

Example Question #320 : Cellular Biology

What is the correct order of the stages of mitosis?

Possible Answers:

Anaphase, prophase, prometaphase, metaphase, telophase, cytokinesis.

Prophase, prometaphase, metaphase, telophase, anaphase, cytokinesis.

Prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.

Cytokinesis, prophase, prometaphase, metaphase, anaphase, telophase.

Anaphase, cytokinesis, metaphase, prophase, telophase, prometaphase.

Correct answer:

Prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.

Explanation:

Mitosis is in the order of this anagram: PMAT.

1. Prophase (chromosomes condense, mitotic spindle begins to form)

2. Prometaphase (some classes don't classify this as a separate stage from prophase but if your class does know that the nuclear envelope disintegrates in this stage).

3. Metaphase (the mitotic spindle attaches to the chromosomes and aligns them to the middle of the cell, crossing-over occurs here as well as elongation of the cell)

4. Anaphase (the mitotic spindle pulls apart the chromosomes and an equal amount of chromosomes are at each end of the cell)

5. Telophase (two nuclear envelopes reform around the chromosomes of each side and the mitotic spindle breaks down)

6. Cytokinesis (again, many classes put this in telophase but some classify it as a separate stage. This is the moment when the cell divides is cytoplasm into two, forming two different cells. In the body it occurs within seconds which is another reason why many classes integrate it into telophase.)

Example Question #321 : Cellular Biology

What does "n" mean when one says that cells are "2n" or "n"?

Possible Answers:

"n" refers to the amount of nitrogen in the DNA of cells.

"n" refers to the amount of nuclei in the cell.

"n" refers to the number of daughter cells a cell can produce.

"n" refers to the amount of chromosomes in a cell.

"n" refers to the amount of chromosome copies in a cell. 

Correct answer:

"n" refers to the amount of chromosome copies in a cell. 

Explanation:

It's important to know that "n" means how many sets or copies of chromosomes rather than how many chromosomes in general. If the latter were true, then "2n" would mean a cell has twice as many chromosomes as a cell that is "n." In reality, all cells have all chromosomes, including gamates.

So an organism usually has "2n" cells because its parents donated one copy each to make the organism. But the organisms' gamates are "n" cells so that when they fuse to create a new organism it will be "2n" as well. 

You can also remember this by knowing that mitosis goes from 2n to 2n and that meiosis goes from 2n to 2n to n.

Example Question #322 : Cellular Biology

What stage of mitosis involves the lining up of chromosomes at the equatorial plane of the cell?

Possible Answers:

Interphase

Anaphase

Cytokinesis

Telophase

Metaphase

Correct answer:

Metaphase

Explanation:

The correct answer is metaphase because this is the stage of mitosis where the chromosomes come together and line up in the middle forming the metaphase plate. These chromosomes then get pulled to either side in the anaphase stage.

Example Question #93 : Cellular Division

Which of the following is the first phase of mitosis?

Possible Answers:

Metaphase

Prometaphase

Prophase

Anaphase

Telophase

Correct answer:

Prophase

Explanation:

The order of mitosis is the following:

  1. Prophase
  2. Prometaphase
  3. Metaphase
  4. Anaphase
  5. Telophase

Example Question #1 : Understanding Meiosis

A scientist is interested in studying the event of crossing over (recombination) in mouse gametes. She wants to label some of the mouse DNA with fluorescent dyes to better visualize it. During what phase of the cell cycle should she look at these fluorescent DNA strands in order to most effectively study recombination?

Possible Answers:

Metaphase II

Anaphase I

Anaphase II

Telophase I

Prophase I

Correct answer:

Prophase I

Explanation:

Recombination or crossing over happens primarily in Prophase I. In anaphase and telophase, the DNA strands are separated and cannot recombine. In metaphase, homologous chromosomes line up with each other, but do not recombine.

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