AP Biology : AP Biology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #451 : Ap Biology

Which of the following contribute to genetic diversity?

Possible Answers:

Meiosis, independent assortment of sister chromatids, and chromosomal crossover 

Meiosis, independent assortment of homologous chromosomes, and chromosomal crossover

Mitosis, independent assortment of homologous chromosomes, and chromosomal crossover

Meiosis, nondisjunction, 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 #452 : Ap Biology

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:

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

meiosis . . . ovum . . . nondisjunction 

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

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

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 #64 : Understanding Meiosis

Which of the following cells will undergo meiosis? 

Possible Answers:

All of these

Heart cells

Amoebae

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 #161 : Cellular Division

In which two phases can nondisjunction occur?

Possible Answers:

Metaphase I and metaphase II 

Anaphase I and anaphase II

Metaphase I and anaphase II

Anaphase 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 #162 : Cellular Division

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

Possible Answers:

Spindles align chromosomes randomly in anaphase  I 

Recombination occurs in telophase I 

Chromosomes are paired into tetrads in prophase I 

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

Homologous chromosomes undergo crossover 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 #163 : Cellular Division

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

Possible Answers:

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

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

The gametes are polyploid

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:

Mitosis

G1 phase

Cytokinesis

Glycolysis

Independent assortment

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:

Microtubules are used in forming the mitotic spindle.

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

Problems can occur in both processes, such as nondisjunction.

They are both forms of cellular division.

DNA is replicated and later separated into two daughter cells.

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.

Example Question #165 : Cellular Division

What is the difference between anaphase I and anaphase II?

Possible Answers:

During anaphase I, the chromosomes line up along the metaphase plate and in anaphase II, the chromosomes separate from each other.

During anaphase I, the pair of homologous chromosomes separate from each other and then in anaphase II a different pair of homologous chromosomes separate from each other.

There are no differences between the two.

During anaphase I, the pair of homologous chromosomes separate from each other and then in anaphase II the sister chromatids separate from each other.

During anaphase I, the sister chromatids separate from each other and in anaphase II the pair of homologous chromosomes separate from each other.

Correct answer:

During anaphase I, the pair of homologous chromosomes separate from each other and then in anaphase II the sister chromatids separate from each other.

Explanation:

During anaphase I, it is just like mitosis. There is a pair of homologous chromosomes (two X's) and they separate into two daughter cells. Anaphase II is a continuation of cellular division so instead of separating a pair of homologous chromosomes it separates sister chromatids of one chromosome (one X) into two daughter cells.

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