Bio 121 Chapter 7 - Quiz

This illustration depicts a cell that has a diploid number of 8 (2n = 8). If we assume that cell division started with a diploid cell, the cell shown in the diagram is in what stage of what type of cell division?

anaphase II of meiosis

This illustration depicts a cell that has a diploid number of 4 (2n = 4). If we assume that cell division started with a diploid cell, the cell shown in the diagram is in what stage of what type of cell division?

anaphase of mitosis

Cell division, which is the climax of the cell cycle, consists of

cytokinesis plus mitosis or meiosis.

The completion of the physical division of the parent cell cytoplasm that usually occurs during the last stage of mitosis is known as

cytokinesis.

You are examining the rapidly dividing cells of an onion root tip and you see a cell whose chromosomes are visible and arranged in approximately the same shape and size as the nucleus. What stage of mitosis is this cell in?

prophase

At the completion of mitosis, the nucleus of a human somatic cell has ________ chromosomes.

46

During anaphase I of meiosis, which of the following things happens?

Each member of a bivalent moves toward a different pole.

This illustration shows a summary of the events in the human life cycle. Which of the lettered transitions or events require(s) mitosis?

A, B, and C

Which of the following statements about why multicellular organisms need cell division is generally NOT true?

As an organism matures, it needs to replace the DNA in each of its cells.

Biologists believe the process of mitosis evolved from binary fission. What are the similarities between these two processes?

Both processes include DNA segregation.

Why must DNA be packed into chromosomes before mitosis or meiosis can occur?

In their unpacked state, the DNA strands would be difficult to pull apart during cell division.

Which of the following statements about the chromosomes in a homologous pair is true?

One chromosome came from the organism's mother and the other came from the organism's father.

Sexual reproduction results in many benefits for a population, but also some inconveniences. Which of the following statements is NOT an example of an inconvenience of sexual reproduction?

Sexual reproduction with each reproductive event is more likely to result in too many offspring for the species.

In what way does a human somatic cell differ from a human gamete?

Somatic cells differentiate into at least 220 cell types, whereas there are only two types of gametes.

When appropriately prompted, diploid individuals of Ulva prolifera form spores that germinate to become haploid individuals. What is the most likely mechanism by which diploid individuals could be created to complete the life cycle?

Some of these individuals differentiate to become haploid gametes and then fuse to produce a diploid zygote.

Lily plants sometimes have twice as many chromosomes per cell as their parent plants. Which of the following statements explains how this phenomenon might have happened?

The lily's sister chromatids failed to separate during meiosis.

Parthenogenesis is a type of asexual reproduction in which embryos can be established and grow without fertilization. Essentially, this means that an embryo develops from an unfertilized egg. What is the most likely reason why the parthenogenetic whiptail lizards of the desert Southwest create no new genetic combinations during crossing-over, whereas other animals do?

The lizards have no homologous chromosomes. In this species, crossing-over takes place between genetically identical sister chromatids; therefore, no changes occur.

The bivalents of homologous chromosomes undergo crossing-over. What is the significance of this process?

The resulting gametes will have different gene combinations than those of their parent cells.

Which statement below describes one way in which the karyotype shown in this figure would be different if the chromosomes came from an egg or sperm cell?

The sex chromosomes would be represented by a single X or a single Y, rather than a pair.

If a drug that inhibits the formation of microtubules is added to a culture of cells during the G2 phase, how would the cell division be affected?

The spindle apparatus would be unable to form.

Some human cells (skeletal muscle, for example) are multinucleated and originate when uninucleated cells fuse. What cell division process alone could produce a multinucleated cell?

a cell undergoing mitosis but not cytokinesis

An unduplicated chromosome contains

a single molecule of double-stranded DNA combined with a large number of proteins.

Cancers are groups of cells that divide uncontrollably because they

are unable to respond to the negative internal or external signals that keep the cell from dividing.

By the time a cell enters meiosis II, it has

become haploid.

Some daughter cells are called clones; for this description to be accurate, the daughter cells must

contain a set of DNA that is identical to that of the parent cell.

During the S phase, the cell

duplicates its DNA.

The goal of mitosis is to

form two equal daughter nuclei.

After a single cell undergoes meiosis in a male, how many sperm cells will be produced?

four

How many sister chromatids are in a bivalent?

four

Compared with the amount of genetic material in a generalized body cell, gametes contain

half the amount.

Gametes are produced by meiosis rather than mitosis because

meiosis reduces the number of chromosomes so that the zygotes resulting from fertilization will have one full genome consisting of a diploid number of chromosomes.

The mitotic spindle is made of

microtubules.

A single cell grows into a multicellular organism by the process of

mitosis.

If a plant has a karyotype of 18 chromosomes, how many chromosomes would each of its gametes have?

nine

Which of the following foods is most likely to contain a haploid cell or cells?

one or more chicken eggs

In animals, only meiosis can lead to the production of new ________.

sperm

Which of the following things could NOT be determined from looking at a karyotype?

the height and eye color of the individual who provided the sample

Meiosis I is called a reduction division because

the number of chromosomes goes from diploid to haploid

The successful union of one male gamete and one female gamete forms a new single cell known as a

zygote.