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Bio 121 Chapter 7 - Quiz

Terms in this set (39)

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.
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.
A single cell grows into a multicellular organism by the process of
mitosis.
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
Biologists believe the process of mitosis evolved from binary fission. What are the similarities between these two processes?
Both processes include DNA segregation.
The goal of mitosis is to
form two equal daughter nuclei.
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
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.
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.
Cell division, which is the climax of the cell cycle, consists of
cytokinesis plus mitosis or meiosis.
During the S phase, the cell
duplicates its DNA.
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.
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.
An unduplicated chromosome contains
a single molecule of double-stranded DNA combined with a large number of proteins.
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.
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
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.
At the completion of mitosis, the nucleus of a human somatic cell has ________ chromosomes.
46
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
The mitotic spindle is made of
microtubules.
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.
The completion of the physical division of the parent cell cytoplasm that usually occurs during the last stage of mitosis is known as
cytokinesis.
In animals, only meiosis can lead to the production of new ________.
sperm
The successful union of one male gamete and one female gamete forms a new single cell known as a
zygote.
Which of the following foods is most likely to contain a haploid cell or cells?
one or more chicken eggs
After a single cell undergoes meiosis in a male, how many sperm cells will be produced?
four
If a plant has a karyotype of 18 chromosomes, how many chromosomes would each of its gametes have?
nine
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.
Meiosis I is called a reduction division because
the number of chromosomes goes from diploid to haploid
Compared with the amount of genetic material in a generalized body cell, gametes contain
half the amount.
By the time a cell enters meiosis II, it has
become haploid.
During anaphase I of meiosis, which of the following things happens?
Each member of a bivalent moves toward a different pole.
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
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
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.
How many sister chromatids are in a bivalent?
four
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.
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.
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.
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