AP Biology : Understanding Meiosis

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #61 : Understanding Meiosis

Which of the following is not a function of mitosis? 

Possible Answers:

Mitosis allows for organisms to grow

Mitosis contributes to genetic diversity in sexual organisms 

Mitosis allows for repair of damaged tissues 

All of these are functions of mitosis

Mitosis is the process by which asexual organisms reproduce

Correct answer:

Mitosis contributes to genetic diversity in sexual organisms 

Explanation:

For homogenous or identical cells of a particular tissue, mitosis allows for the restoration of lost or damaged tissue by resulting in identical daughter cells which can replace lost cells. The same is true for an asexual population. The process of mitosis has several checkpoints to ensure fidelity with each round of copied cells. Meiosis, on the other hand, tries to ensure evolutionary fitness of a sexually reproducing population by introducing a variety of genetic alleles per gamete which will result in fertilization to create a unique individual. Therefore, mitosis allows for growth, restoration of damaged tissue, asexual reproduction (for example, bacteria!) and does not result in genetic variety.

Example Question #62 : Understanding Meiosis

Which of the following contribute to genetic diversity?

Possible Answers:

Mitosis, independent assortment of homologous chromosomes, and chromosomal crossover

Meiosis, nondisjunction, and chromosomal crossover

Meiosis, independent assortment of homologous chromosomes, and chromosomal crossover

Meiosis, independent assortment of sister chromatids, and chromosomal crossover 

Mitosis, nondisjunction, and chromosomal crossover

Correct answer:

Meiosis, independent assortment of homologous chromosomes, and chromosomal crossover

Explanation:

Meiosis, which includes independent assortment of homologous chromosomes and chromosomal crossover, contributes to genetic diversity. Independent assortment of chromosomes is the random distribution of one chromosome per homologous chromosomal pair to each daughter cell during anaphase I. Chromosomal crossover, which begins in prophase I, results in genetic recombination between each tetrad (homologous chromosomes). Nondisjunction is not a correct option as this typically results in large scale genetic abnormalities and infertility which subsequently does not contribute to a population's long-term genetic diversity. 

Example Question #277 : Cell Functions

Select the answer choice with the correct terms. 

In human female gametogenesis __________ occurs which results in only one functional gamete called a(n) __________ due to __________.

Possible Answers:

mitosis . . . ovum . . . unequal division of cytoplasm

meiosis . . . ovum . . . unequal division of cytoplasm

meiosis . . . sperm . . . unequal division of cytoplasm

meiosis . . . ovum . . . nondisjunction 

meiosis . . . sperm . . . nondisjunction

Correct answer:

meiosis . . . ovum . . . unequal division of cytoplasm

Explanation:

Human female gametogenesis occurs through meiosis and results in three non-functional daughter cells known as polar bodies and one functional and much larger daughter cell called an ovum. Unequal division of cytoplasm during meiosis I and meiosis II towards only one of the daughter cells results in the ovum. Non-disjunction is the unequal assortment of chromosomes, not cytoplasm. Human female gametogenesis results in ovum while human male gametogenesis results in sperm. Mitosis does not result in gamete daughter cells but identical daughter cells as mitosis occurs in somatic (body or non-germ cells) cells. 

Example Question #281 : Cell Functions

Which of the following cells will undergo meiosis? 

Possible Answers:

All of these

Amoebae

Heart cells

Germ cells

Unicellular organisms

Correct answer:

Germ cells

Explanation:

Germ cells give rise to gametes through meiosis. All of the other organisms listed are asexually reproducing organisms and therefore only undergo mitosis. 

Example Question #61 : Understanding Meiosis

In which two phases can nondisjunction occur?

Possible Answers:

Metaphase I and anaphase II

Anaphase I and anaphase II

Anaphase I and metaphase II

Metaphase I and metaphase II 

Telophase I and telophase II

Correct answer:

Anaphase I and anaphase II

Explanation:

Nondisjunction of homologous chromosomes may occur in anaphase I and nondisjunction of sister chromatids may occur in anaphase II. 

Example Question #161 : Cellular Division

Which of the following is the basis for independent assortment of homologous chromosomes?

Possible Answers:

Recombination occurs in telophase I 

Spindles align chromosomes randomly in anaphase  I 

Homologous chromosomes undergo crossover in prophase I 

Homologous chromosomes line up randomly at the metaphase plate in metaphase I 

Chromosomes are paired into tetrads in prophase I 

Correct answer:

Homologous chromosomes line up randomly at the metaphase plate in metaphase I 

Explanation:

Independent assortment depends upon random alignment of homologous chromosomes in metaphase I which will result in randomly assorted chromosomes into two daughter cells at the end of meiosis I. Crossover, or recombination, occurs in prophase I which contributes to genetic diversity, but does not affect random alignment of homologous chromosomes. Spindles align chromosomes randomly in metaphase I, not anaphase I during which they are already "aligned" and are moving towards opposite poles of the cell.

Example Question #61 : Understanding Meiosis

In the process of meiosis, what is the correct description of the gametes?

Possible Answers:

The gametes are haploid, with half the number of chromosomes compared to the parent cell

The gametes are polyploid

The gametes are diploid, with half the number of chromosomes compared to the parent cell

The gametes are diploid, with twice the number of chromosomes compared to the parent cell

Correct answer:

The gametes are haploid, with half the number of chromosomes compared to the parent cell

Explanation:

In meiosis, the gametes are haploid having half the number of chromosomes of a diploid cell.  The gametes are the egg or sperm cells that combine in sexual reproduction.

Example Question #163 : Cellular Division

Homologous pairs of chromosomes separate depending on the random way they line up on the metaphase plate during metaphase I. What is this process called?

Possible Answers:

Independent assortment

G1 phase

Glycolysis

Cytokinesis

Mitosis

Correct answer:

Independent assortment

Explanation:

Random rearranging of alleles on chromosomes that occurs as a result of homologous pairs lining up during metaphase is known as independent assortment and is a factor in genetic diversity. Cytokinesis is the physical process for cell division. Glycolysis is the process of breaking down sugars to generate ATP. G1 phase is the first of four phases of the cell cycle that takes place in eukaryotic cell division. Mitosis only has one metaphase, since the question stem indicates metaphase I, we know that the overall process is meiosis, during which there are two cell divisions.

Example Question #165 : Cellular Division

Which process produces four genetically different haploid cells?

Possible Answers:

Transcription

Meiosis

Mitosis

Translation

Correct answer:

Meiosis

Explanation:

Meiosis produces four genetically different haploid cells, which have half the chromosomes of diploid cells. Diploid cells are produced by mitosis. Transcription produces messenger RNA, and translation produces a chain of amino acids that is protein.

Example Question #164 : Cellular Division

What is not a similarity between mitosis and meiosis?

Possible Answers:

They both result in daughter cells with half of the number of copied chromosomes of the parent cells.

DNA is replicated and later separated into two daughter cells.

Microtubules are used in forming the mitotic spindle.

Problems can occur in both processes, such as nondisjunction.

They are both forms of cellular division.

Correct answer:

They both result in daughter cells with half of the number of copied chromosomes of the parent cells.

Explanation:

Only meiosis produces daughter cells that have half the number of copied chromosomes as the parent cells. This occurs in meiosis II and the importance of having daughter cells that are haploid is that fusion of those cells during sexual reproduction will create a cell with a normal amount of copied chromosomes (diploid), not more or less. Since mitosis deals with asexual reproduction there is no need to make haploid daughter cells.

Mitosis and meiosis, then, are two forms of cellular division and like all processes they can have problems.

DNA is both replicated (interphase) and pulled apart (anaphase) in both processes. Meiosis just goes through the cycle an additional time.

Finally, microtubules are the main component in the mitotic spindle for both meiosis and mitosis.

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