High School Biology : Meiosis

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #1 : Meiosis

Which event takes place during anaphase II?

Possible Answers:

Sister chromatids are separated 

Homologous chromosomes are separated

Sister chromatids line up in the center of the cell

Homologous chromosomes line up in the center of the cell

Correct answer:

Sister chromatids are separated 

Explanation:

During prophase I, homologous chromosomes form tetrads along the center of the cell. Full chromosomes are pulled to each pole during anaphase I, resulting in two haploid cells at the end of meiosis I. During prophase II, sister chromatids align at the center of the cell in singular chromosome structures. These sister chromatids are separated during anaphase II, resulting in a total of four haploid cells.

Example Question #2 : Meiosis

What is the first stage of meiosis during which a cell is considered haploid?

Possible Answers:

Anaphase I

Telophase II

Prophase II

Metaphase I

Correct answer:

Prophase II

Explanation:

A diploid cell will have two copies of each chromosome, known as a homologous pair. A haploid cell will only have one copy of each chromosome, though the chromosome may consist of two sister chromatids.

Diploid cell: (XX)

Haploid cell: (X)

During meiosis I, the cell is diploid because the homologous chromosomes are still located within the same cell membrane. Only after the first cytokinesis, when the daughter cells of meiosis I are fully separated, are the cells considered haploid. Following this first division, the cell begins meiosis II with prophase II, making this the first haploid meiotic stage.

Example Question #3 : Meiosis

What occurs during the S phase of the cell cycle?

Possible Answers:

DNA is replicated, resulting in two identical sister chromatids attached at the centromere

The cell grows in size, prepares mRNA and proteins, and prepares to divide

The cytoplasm splits and forms two diploid daughter nuclei

The cell's chromatin condenses and forms chromosomes

The cell enters a state in which it neither divides, nor is preparing to divide

Correct answer:

DNA is replicated, resulting in two identical sister chromatids attached at the centromere

Explanation:

The S phase occurs between the G1 and G2 phases and is the stage during which DNA is replicated, and then checked for defects. Depending on the level of nutrients and energy available, the cell will either enter the G0 phase or the M phase.

During the G1 phase, the cell replicates organelles and grows in size. During the G2 phase, DNA is checked for damage and the cell prepares to divide. The M phase refers to mitosis, while the G0 phase refers to quiescence—a period during which the cell is not preparing for division.

Example Question #3 : Understanding Stages Of Meiosis

During which phase of meiosis does DNA begin to condense?

Possible Answers:

Anaphase I

Metaphase I

Prophase I

Metaphase II

Telophase I

Correct answer:

Prophase I

Explanation:

Mitosis is also known as "karyokinesis." "Karyo-" refers to the nucleus. (Remember that eu-KARY-ote means true ("eu-") nucleus, and pro-KARY-ote means before ("pro-") nucleus.) The "-kinesis" part of "karyokinesis" comes from the same roots as "kinetic" and refers to movement. Thus, mitosis is the movement of the nucleus. Packing of the DNA occurs in prophase of mitosis so that it's easier to move rather than having to move the loose chromatin. Think of moving forty-six strands of hundreds of yards of yarn—we would want it to be tightly coiled to make it manageable.

Example Question #1 : Understanding Stages Of Meiosis

Meiosis is the process by which a ___________ cell is formed from a ___________ cell.

Possible Answers:

haploid . . . haploid

haploid . . . diploid

diploid . . . diploid

diploid . . . haploid

Correct answer:

haploid . . . diploid

Explanation:

Meiosis is the process by which a haploid cell is formed from a diploid cell. The difference between haploid cells and diploid cells is that haploid cells contain one complete set of chromosomes, whereas diploid cells contain two complete sets of chromosomes. Meiosis involves the division of a diploid (2n) parent cell. The chromosomes are duplicated, but carry out two consecutive divisions. The result is four haploid (n) cells, each with half the number of chromosomes as the parent cell due to the separation of homologous pairs in meiosis I.

In contrast, mitosis is the process by which a diploid parent cell produces two diploid daughter cells.

Example Question #2 : Meiosis

Which three events most accurately describes what occurs in meiosis I?

Possible Answers:

Sister chromatids pair, cross over, then separate

Homologous chromosomes are duplicated, pair, then separate

Homologous chromosomes pair, cross over, then separate

None of these occur in meiosis I

Sister chromatids are duplicated, pair, then cross over

Correct answer:

Homologous chromosomes pair, cross over, then separate

Explanation:

In meiosis I, the homologous chromosomes have already been duplicated in S phase of interphase. The sister chromatids are identical at this stage. Homologous chromosomes pair in prophase I, forming tetrads. The tetrads then cross over, exchanging genetic material. Then, the genetically-mixed tetrads line up on the metaphase plate and are separated in anaphase I. Note that after the first meiotic division, the two daughter cells are nonidentical and are haploid.

Example Question #4 : Understanding Stages Of Meiosis

Meiosis produces __________ daughter cells. 

Possible Answers:

three

two

one

four

Correct answer:

four

Explanation:

Meiosis involves two divisions and results in four unique daughter cells called gametes. Meiosis begins with one parent cell, after the first division there are two daughter cells, and then those each split, resulting in a total of four daughter cells.   

Example Question #2 : Meiosis

Homologous chromosomes pair up in which stage of meiosis?  

Possible Answers:

Metaphase II

Prophase I

Metaphase I

Prophase II

Correct answer:

Prophase I

Explanation:

In prophase I chromosomes become compact and homologous chromosomes pair up. Also during prophase I, the nuclear membrane begins to break down and the spindle apparatus begins to form.

Example Question #3 : Meiosis

Homologous chromosomes line up along the cell's equator in which stage? 

Possible Answers:

Anaphase II

Metaphase I

Anaphase I 

Metaphase II

Correct answer:

Metaphase I

Explanation:

In metaphase I, homologous chromosomes line up along the center of the cell in order to be pulled apart. Recall that during meiosis I, homologous chromosomes pair, cross over, and separate. Meiosis II is when the sister chromatids are separated.

Example Question #4 : Meiosis

Sister chromatids separate in which stage of meiosis?                   

Possible Answers:

Anaphase II

Telophase I

Telophase II

Anaphase I

Correct answer:

Anaphase II

Explanation:

Chromatid disjunction occurs in anaphase II after the chromosomes line up along the equator during metaphase II. The chromosomes are then pulled apart, with one chromatid moving north, and one moving south. The next steps are telophase, and cytokinesis, which upon completion, will result in genetically distinct haploid gametes.

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