ap bio

1. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus 2. Alignment of tetrads at the metaphase plate 3. Separation of sister chromatids 4. Separation of the homologs; no uncoupling of the centromere 5. Synapsis; chromosomes moving to the middle of the cell in pairs 41) Which of the steps takes place in both mitosis and meiosis?

3

A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following?

63 chromosomes in 21 sets of 3

Which of the following is an example of alternation of generations?

A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte).

In the human species, all somatic cells have 46 chromosomes. Which of the following can also be true?

A plant species (privet shrubs) has 46 chromosomes per cell.

Which of these statements is false?

At sexual maturity, ovaries and testes produce diploid gametes by meiosis.

If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants?

Clone the plant asexually to produce an identical one.

To view and analyze human chromosomes in a dividing cell, which of the following is/are required?

DNA stain and a light microscope

Which of the following is true of a species that has a chromosome number of 2n = 16?

Each cell has eight homologous pairs.

The somatic cells of a privet shrub each contain 46 chromosomes. To be as different as they are from human cells, which have the same number of chromosomes, which of the following must be true?

Genes of privet chromosomes are significantly different than those in humans.

Which of the following happens at the conclusion of meiosis I?

Homologous chromosomes are separated.

I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 39) Synaptonemal complexes form or are still present.

I only

I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 38) Tetrads of chromosomes are aligned at the equator of the spindle; alignment determines independent assortment.

II

Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores

II, III, and IV

Which of the following is a true statement about sexual vs. asexual reproduction?

In sexual reproduction, individuals transmit 50% of their genes to each of their offspring.

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents?

It has half the amount of DNA as the cell that began meiosis.

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?

Its gametes must have 23 chromosomes.

In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common?

Length, centromere position, staining pattern, and traits coded for by their genes.

A cell divides to produce two daughter cells that are genetically different.

The statement is true for meiosis I only.

Independent assortment of chromosomes occurs.

The statement is true for meiosis I only.

Chromatids are separated from each other.

The statement is true for mitosis and meiosis II.

How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis?

They have half the number of chromosomes and one-fourth the amount of DNA.

Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. Such molecules must have which of the following properties?

They must be removed before anaphase can occur.

I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II 40) Centromeres of sister chromatids disjoin and chromatids separate.

VII

Which of the following best describes a karyotype?

a display of each of the chromosomes of a single cell

Which of the following can utilize both mitosis and meiosis in the correct circumstances?

a plantlike protist

For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?

about 8 million

Which of the following might result in a human zygote with 45 chromosomes?

an error in either egg or sperm meiotic anaphase

The human X and Y chromosomes

are of approximately equal size and number of genes.

If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following?

at most, 2 alleles for that gene

How does the sexual life cycle increase the genetic variation in a species?

by allowing crossing over

Experiments with cohesins have found that

cohesins are protected from cleavage at the centromere during meiosis I.

The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following?

either anaphase I or II

The human genome is minimally contained in which of the following?

every human cell

Referring to a plant's sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes?

gametophyte mitosis

After telophase I of meiosis, the chromosomal makeup of each daughter cell is

haploid, and the chromosomes are each composed of two chromatids.

When does the synaptonemal complex disappear?

late prophase of meiosis I

At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?

metaphase

When we see chiasmata under a microscope, that lets us know which of the following has occurred?

prophase I

Which of the following occurs in meiosis but not in mitosis?

synapsis of chromosomes

To visualize and identify meiotic cells at metaphase with a microscope, what would you look for?

tetrads all aligned at the cell's center

Which of the following defines a genome?

the complete set of an organism's genes

A karyotype results from which of the following?

the ordering of human chromosome images

Independent assortment of chromosomes is a result of

the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.

A tetrad includes which of the following sets of DNA strands?

two sets of sister chromatids that have synapsed