AP Biology : Cell Functions

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #24 : Understanding Meiosis

Which of the following is a correct statement about the difference between meiosis and mitosis? 

Possible Answers:

Mitosis produces two identical, diploid daughter cells after one division; meiosis produces four non-identical, haploid daughter cells after two divisions

Mitosis produces four identical, diploid daughter cells after one division; meiosis produces two non-identical, haploid daughter cells after two divisions

Mitosis produces two non-identical, diploid daughter cells after one division; meiosis produces four identical, haploid daughter cells after two divisions

Mitosis produces two identical, diploid daughter cells after two divisions; meiosis produces four non-identical, haploid daughter cells after one division

Mitosis produces two identical, haploid daughter cells after one division; meiosis produces four non-identical, diploid daughter cells after two divisions

Correct answer:

Mitosis produces two identical, diploid daughter cells after one division; meiosis produces four non-identical, haploid daughter cells after two divisions

Explanation:

Mitosis is used by somatic cells throughout the body. The goal of mitosis is to replace older cells with newer, healthier cells. In order for this replacement to be effective, the daughter cells must be identical to the parent cell. Somatic cells, or "body cells," are diploid, meaning that they carry two copies of each allele. Each round of mitosis produces two daughter cells after one division.

Meiosis only takes place in the gonads and is used to produce gametes. Gametes fuse to form a diploid zygote, but each individual gamete carries only half of the genetic information to form this zygote; as such, all gametes are haploid and carry only one copy of each allele. Gametes are not identical to the parent cell for this reason (the parent cell is diploid). Genetic variation (crossing over) can also occur during meiosis to enhance genetic diversity. Each round of meiosis produces four daughter cells after two divisions.

Example Question #22 : Understanding Meiosis

During what phase of meiosis do tetrads align along the equatorial plate?

Possible Answers:

Prophase II

Metaphase I

Prophase I

Metaphase II

Correct answer:

Metaphase I

Explanation:

Meiosis involves two cell divisions. During the first division, pairs of homologous chromosomes align at the center of the cell and are separated into two daughter cells. During the second division, single chromosomes align at the cell center (as they would during mitosis) and sister chromatids are separated into the daughter cells.

When homologous chromosomes align during the first division there are a total of four chromatids in each set, forming a tetrad. The alignment of chromosomes at the equatorial plate takes place during metaphase. Since we are looking at the alignment of chromosomes during the first meiotic division, the correct answer will be metaphase I.

Example Question #26 : Understanding Meiosis

What is the name of a pair of chromosomes that contains the same genes and loci?

Possible Answers:

Locus

Allele

Gene

Haploid chromosomes

Tetrad

Correct answer:

Tetrad

Explanation:

In prophase I, a process called synapsis involves the pairing of chromosomes. Chromosome pairs are referred to as a tetrad, homologous pair, or as bivalents.

Example Question #21 : Understanding Meiosis

During which phase of meiosis does chiasmata occur?

Possible Answers:

Prophase I

Metaphase I

Anaphase II

Prophase II

Anaphase II

Correct answer:

Prophase I

Explanation:

There are two events that occur in prophase I that do not occur in any other stage: chiasmata (crossing over) and synapsis (pairing of the chromosomes). Note that chiasmata does not occur during prophase of mitosis, but synapsis does occur.

Example Question #24 : Understanding Meiosis

Which of the following occur in both mitosis and meiosis?

Possible Answers:

Metaphase II

Prophase II

Recombination between homologous chromosomes

Recombination between sister chromatids

Separation of sister chromatids 

Correct answer:

Separation of sister chromatids 

Explanation:

The separation of sister chromatids is the only item of the answer choices that occurs in both mitosis and meiosis. Prophase II and metaphase II only occur in meiosis, as does recombination between homologous chromosomes. Recombination between sister chromatids does not occur (they are identical).

Example Question #21 : Understanding Meiosis

A human cell has 44 chromosomes and two X chromosomes. It is __________.

Possible Answers:

a somatic cell from a male

an ovum

a gamete from a female

a sperm

a somatic cell from a female

Correct answer:

a somatic cell from a female

Explanation:

Since the cell has 44 autosomes and two sex chromosomes it must be a somatic cell (2n=46). Two X chromosomes corresponds to a female so it must a somatic cell from a female. Sperm, and ova are the male and female gametes, which are haploid.

Example Question #22 : Understanding Meiosis

Meiosis in animals occurs in __________.

Possible Answers:

all somatic cells

all cells in the animal's body

testes only

ovaries only

both ovaries and testes

Correct answer:

both ovaries and testes

Explanation:

Meiosis is the form of cell division that results in gametes and so meiosis takes place in both ovaries and testes, which are the primary sex organs. Somatic cells undergo mitosis for cell division, which yields identical daughter cells that are diploid.  

Example Question #241 : Cell Functions

Human gametes are produced by the process of __________.

Possible Answers:

cytokinesis

binary fission

mitosis

meiosis

fertilization

Correct answer:

meiosis

Explanation:

Gametes are haploid cells that produced via meiosis. During meiosis, diploid cells divide into four nonidentical haploid daughter cells. Mitosis produces two identical diploid somatic cells from one parent cell.  

Example Question #32 : Understanding Meiosis

Meiosis in humans results in cells that have what number of chromosomes?

Possible Answers:

Correct answer:

Explanation:

Meiosis results in cells with 23 chromosomes (22 autosomes and 1 sex chromosome). Note that these cells are haploid since n=23, and nonidentical, due to crossing over during prophase I.

Example Question #31 : Understanding Meiosis

What would happen if gametes were made by mitosis instead of meiosis?

Possible Answers:

With each generation, the number of chromosomes in each cell would double

More than one of these

Each generation of cells would have 46 chromosomes

Each generation of cells would have 44 chromosomes

Each generation of cells would have 23 chromosomes

Correct answer:

With each generation, the number of chromosomes in each cell would double

Explanation:

Gametes are made via meiosis which produces cells with n=23 instead of diploid cells. If gametes were produced instead by mitosis each gamete would be diploid not haploid. During fertilization of diploid gametes, the zygote would become 4n=92. With each new generation the number of chromosomes would double.  

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