AP Biology : Understanding Meiosis

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #51 : Understanding Meiosis

How many chromosomes are there in a gamete produced during meiosis in humans?

Possible Answers:

Correct answer:

Explanation:

Meiosis produces four daughter cells that are haploid, meaning that they contain half the number of chromosomes as the parent cell. Human parent somatic cells have 46 chromosomes, or 23 chromosome pairs, meaning that gametes produced during meiosis have 23 chromosomes.

Example Question #52 : Understanding Meiosis

Synapsis allows which of the following to occur?

Possible Answers:

Crossing over

The shortening of the mitotic spindles

Chromosome condensation

Nuclear membrane dissolution

Correct answer:

Crossing over

Explanation:

Synapsis is the pairing of homologous chromosomes during prophase I of meiosis. Due to synapsis, pairs of homologous chromosomes are arranged in a way that allows for crossing over to occur, which leads to genetic recombination, and genetic diversity.

 

Example Question #53 : Understanding Meiosis

What are the resulting cells of meiosis I?

Possible Answers:

Two haploid cells

Four haploid cells

Four diploid cells

Two diploid cells

Correct answer:

Two haploid cells

Explanation:

Meiosis I is the first cell division of the entire meiosis process. Following segregation of homologous chromosome pairs, or tetrads, the two resulting daughter cells have half the number of chromosomes as the parent cell. These chromosomes have two sister chromatids per chromosome, which are nonidentical due to crossing over.

Example Question #54 : Understanding Meiosis

What cellular features are duplicated during prophase II of meiosis?

Possible Answers:

Centrioles

Genetic material

Plasma membrane

Centrosomes

Correct answer:

Centrioles

Explanation:

Prophase II marks the beginning of the second cell division of meiosis, called meiosis II. Unlike prophase I, the chromosomes are not duplicated prior to the start of prophase II. However, during prophase II, the centrioles replicate, resulting in two pairs of centrioles per cell. The two centriole pairs separate to opposite cell poles. Other features of prophase II are chromosome condensation, the degradation of the nuclear membrane, and meiotic spindle formation.

Example Question #55 : Understanding Meiosis

What happens during metaphase II of meiosis?

Possible Answers:

Homologous tetrads line up at the metaphase plate

Chromosomes segregate to opposite poles

The nuclear membrane forms 

Sister chromatids line up at the metaphase plate

Correct answer:

Sister chromatids line up at the metaphase plate

Explanation:

During metaphase II, sister chromosomes line up at the metaphase plate, like during the metaphase of mitosis. Mitotic spindles are attached to the kinetochores during this stage. Homologous chromosomes have already been separated during anaphase I.

Example Question #56 : Understanding Meiosis

Which of the following is not true of human gametes?

Possible Answers:

Gametes are produced during meiosis

They are haploid

Male and female gametes fuse during fertilization

They arise from somatic cell lines

Correct answer:

They arise from somatic cell lines

Explanation:

Gametes are haploid sex cells produced from germ line cells during mitosis. During human fertilization, male and female haploid gametes fuse to form a diploid zygote. 

Example Question #57 : Understanding Meiosis

Which of the following best represents a difference between mitosis and meiosis?

Possible Answers:

The process of cytokinesis

Nuclear membrane reformation

The resulting number of chromosomes per cell

Chromosome condensation

Correct answer:

The resulting number of chromosomes per cell

Explanation:

The processes of mitosis and meiosis have many characteristics in common (i.e. cytokinesis, chromosome condensation, and nuclear membrane reformation); however, there are key differences that distinguish the processes from one another. One of these differences is the cell type that result from each respective process. Mitosis results in two daughter cells with the same number of chromosomes as the parent cell. Meiosis, on the other hand, yields four daughter cells with half of the number of chromosomes as the parent cell—“haploid” cells.

Example Question #58 : Understanding Meiosis

When does crossing over happen in meiosis? 

Possible Answers:

Metaphase II

Metaphase I

Prophase II

Prophase I

Anaphase I

Correct answer:

Prophase I

Explanation:

The exchange of genetic material happens during the prophase I of meiosis. We know that since meiosis I involves the pairing, crossing over, and separation of homologous chromosomes, our answer must be in meiosis I. During metaphase I, the tetrads line up along the metaphase plate, and during anaphase they begin to be pulled to opposite sides of the cell by spindle fibers.

Example Question #59 : Understanding Meiosis

Which of the following describes when crossing over occurs during meiosis?

Possible Answers:

Metaphase II

Metaphase I

Anaphase I

Prophase I

Prophase II

Correct answer:

Prophase I

Explanation:

In prophase I, homologous chromosomes pair up and facilitate the exchange of genetic information through the process of crossing over.

Example Question #60 : Understanding Meiosis

In regards to DNA, how does a cell prepare for cell division?

 DNA is __________ to create two __________ per __________, which are connected at the __________.

Possible Answers:

replicated . . . sister chromosomes . . . chromatid . . . centromere

replicated . . . sister chromatids . . . chromosome . . . centromere 

replicated . . . homologous chromatids . . . chromosome . . . centriole

replicated . . . homologous chromosomes . . . chromatid . . . centromere 

replicated . . . homologous chromosome . . . chromatid . . . centriole

Correct answer:

replicated . . . sister chromatids . . . chromosome . . . centromere 

Explanation:

In preparation for cell division, DNA is copied (replicated) to create chromosomes with two identical sides (sister chromatids), which are connected at the centromere. DNA must be replicated before prophase, in S phase of interphase. Do not be confused with the terms centrioles, centrosomes, and centromere. Centrioles are located at centrosomes, which are found at opposite poles of the cell during meiosis stages of prophase, metaphase, anaphase, and telophase. The question is asking about interphase, which is prior to the meiosis/mitosis stages. 

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