AP Biology : Cell Functions

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #53 : Understanding Meiosis

What cellular features are duplicated during prophase II of meiosis?

Possible Answers:

Centrioles

Centrosomes

Plasma membrane

Genetic material

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 #54 : Understanding Meiosis

What happens during metaphase II of meiosis?

Possible Answers:

Sister chromatids line up at the metaphase plate

The nuclear membrane forms 

Homologous tetrads line up at the metaphase plate

Chromosomes segregate to opposite poles

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 #273 : Cell Functions

Which of the following is not true of human gametes?

Possible Answers:

They are haploid

Gametes are produced during meiosis

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 #55 : Understanding Meiosis

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

Possible Answers:

The process of cytokinesis

The resulting number of chromosomes per cell

Chromosome condensation

Nuclear membrane reformation

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 #56 : Understanding Meiosis

When does crossing over happen in meiosis? 

Possible Answers:

Prophase II

Anaphase I

Prophase I

Metaphase II

Metaphase 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 #276 : Cell Functions

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

Possible Answers:

Prophase II

Prophase I

Metaphase II

Anaphase I

Metaphase I

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 #271 : Cell Functions

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 chromatids . . . chromosome . . . centromere 

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

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

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

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

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. 

Example Question #61 : Understanding Meiosis

Which of the following is not a function of mitosis? 

Possible Answers:

Mitosis contributes to genetic diversity in sexual organisms 

Mitosis allows for repair of damaged tissues 

Mitosis allows for organisms to grow

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 #61 : Understanding Meiosis

Which of the following contribute to genetic diversity?

Possible Answers:

Meiosis, nondisjunction, and chromosomal crossover

Mitosis, independent assortment of homologous chromosomes, and chromosomal crossover

Mitosis, nondisjunction, and chromosomal crossover

Meiosis, independent assortment of sister chromatids, and chromosomal crossover 

Meiosis, independent assortment of homologous chromosomes, 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 #62 : Understanding Meiosis

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 . . . unequal division of cytoplasm

meiosis . . . ovum . . . nondisjunction 

meiosis . . . sperm . . . nondisjunction

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

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. 

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