Biology- Chapter 8 The Cellular Basis of Reproduction and Inheritance
TRUE OR FALSE (OF CELL DIVISION): Cell division can reproduce an entire organism.
True
TRUE OR FALSE (OF CELL DIVISION): Cell division is necessary for development to occur.
True
TRUE OR FALSE (OF CELL DIVISION): Cell division is the basis of both sexual and asexual reproduction.
True
TRUE OR FALSE: A zygote is a fertilized egg.
True
TRUE OR FALSE: Gametes are haploid cells.
True
TRUE OR FALSE: Two haploid cells fuse during fertilization.
True
In comparing a frog cell in metaphase of mitosis with one in metaphase I of meiosis, how would tell you which was which?
Unlike mitosis, in meiosis each chromosome would be opposite its homolog.
What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells?
all of the above are differences between prokaryotic and eukaryotic DNA. which is > - the amount of DNA present - whether the DNA is housed in a nucleus or not - whether the DNA is linear or circular
Crossing over is important because it __________.
allows the exchange of different versions of genes between homologous chromosomes
Centromeres divide and sister chromatids become full-fledged chromosomes during _____.
anaphase
Homologous chromosomes migrate to opposite poles during _____.
anaphase I
During _____ sister chromatids separate.
anaphase II
In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____.
are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
Mature human neuron (nerve) cells and muscle cells
are permanently in a state of nondivision
A cell replicates its entire chromosomal DNA only __________.
before it is about to divide
Bacteria divide by
binary fission
During _____ chromosomes align single file along the equator of a haploid cell.
metaphase II
During _____ a spindle forms in a haploid cell.
prophase II
The exchange of parts between nonhomologous chromosomes is called _____.
reciprocal translocation
One version of a gene may encode __________, whereas a different version of the same gene may encode __________.
red eyes; white eyes
In meiosis II, _____.
sister chromatids are separated
Crossing over of chromosomes during meiosis shuffles parental chromosomes, resulting in a genetically unique child.
- During prophase I of meiosis I, homologous paternal and maternal chromosomes pair up and undergo crossing over. - During meiosis II, sister chromatids separate into four different gametes. - A hybrid chromosome that has crossed over will contain pieces of both the maternal and paternal chromosomes
Which processes lead to most genetic variation in sexually reproducing organisms?
- crossing over - independent orientation of chromosomes in meiosis -random fertilization
Which of the following events have not yet occurred?
- separation of sister chromatids into distinct cells - production of four haploid gametes
Places the events of meiosis in the proper order. Rank from the first event to the last event left to right.
1. homologous chromosomes pair up 2. nonsister chromatids form chiasmata 3. crossing over occurs 4. homologous chromosomes separate 5. sister chromatids separate 6. four haploid gametes are produced
Asexual reproduction requires ________ individual(s), whereas sexual reproduction requires _______ individual(s).
1;2
How many pairs of autosomes do humans have?
22
A human somatic cell contains __________ chromosomes.
46
In a cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing __________ chromosomes.
5
A human bone marrow cell in the prophase stage of mitosis contains 46 chromosomes. Therefore, there are a total of __________ sister chromatids in this cell.
92
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
Anaphase
The stage of mitosis during which the chromosomes move toward separate poles of the cell is _____.
Anaphase
The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called
Asexual reproduction
During meiosis I, homologous chromosomes form a tetrad and crossing over occurs. What is the outcome of crossing over?
Crossing over creates new combinations of genes present on a single chromosome.
At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.
Cytokinesis (Cytokinesis is the division of the cytoplasm that occurs in conjunction with telophase, the last phase in mitosis)
Which of the following statements correctly describes the timing of DNA synthesis?
DNA is synthesized in the S phase of interphase.
The first step of bacterial replication is _____.
DNA replication
Which of these phases encompasses all of the stages of mitosis?
E
TRUE OR FALSE (OF CELL DIVISION): Cell division is common in eukaryotes but rare in prokaryotes.
False
TRUE OR FALSE: An X chromosome is an autosome
False
Immune system cells enter a resting phase after undergoing mitosis. When activated—for example, by an infection—they can reenter the sequence of events in the cell cycle that leads to cell division. What would be the correct cell cycle sequence of events for these reactivated cells?
G1, S, G2, M (After reactivation, these cells move into G1. Here they grow in preparation for DNA replication (S phase). Once complete, the cells move into G2 and make the final preparations for mitosis.)
Eukaryotic cells spend most of their cell cycle in which phase?
Interphase
During binary fission, each copy of the duplicating chromosome moves to opposite ends of the cell. What does this achieve?
It ensures that each daughter cell receives one copy of the chromosome.
The chromosomes line up in the center of the cell during which phase of mitosis?
Metaphase
Which of the following statements regarding the function of mitosis is false? -Mitosis promotes genetic diversity -Mitosis is necessary for asexual reproduction in eukaryotes -Mitosis promotes repair tissues -Mitosis allows organisms to grow.
Mitosis promotes genetic diversity.
Many cancer drugs known as "antimitotics" target microtubules. What is the first stage of mitosis at which these drugs are likely to have an effect?
Prophase
The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?
Prophase
Synapsis occurs during _____.
Prophase I
Which of the following statements regarding mitosis and meiosis is true?
Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis.
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
Telophase
What must happen before a cell can begin mitosis?
The chromosomes must be duplicated (Before mitosis can begin, the chromosomes, or genetic material, must be copied, which occurs during interphase)
What would be the immediate consequence of destroying a cell's centrosomes?
The mitotic spindle would not form.
Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?
The sequences are identical. (Except for the occurrence of rare mutations, this is always the case. Both sister chromatids come from replication of a single DNA molecule, which is present in the one chromatid before replication.)
You are observing a single cell under a microscope. You go home for the night, and the next day you see four cells. The four cells look similar, and when you stain them with a dye that binds to DNA they all appear to contain the same amount of DNA as the original cell. What likely happened overnight?
The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by asexual reproduction.
Which of the following represents a chromosomally normal human female?
XX
Meiosis differs from mitosis in that _____ only occurs in meiosis.
crossing over
A cleavage furrow forms in an animal cell during ____.
cytokinesis
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called
cytokinesis.
When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of
density-dependent inhibition.
The diploid phase of the human life cycle begins with _____
fertilization
Which of the following types of organisms commonly demonstrates polyploidy?
flowering plants
Which of the following is a feature of plant cell division that distinguishes it from animal cell division?
formation of a cell plate
Meiosis II typically produces _____ cells, each of which is _____.
four ... haploid
The function of meiosis is to make __________.
four cells with a haploid number of chromosomes
What is the typical result when a diploid cell undergoes meiosis?
four haploid cells
At the conclusion of meiosis I, the daughter cells are _____.
haploid and the sister chromatids are joined
Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are
homologous chromosomes
Synapsis occurs during _____.
prophase I
In anaphase I, __________.
homologous chromosomes move toward opposite poles
During anaphase I, __________.
homologous chromosomes separate and migrate toward opposite poles
During _____ the cell grows and replicates both its organelles and its chromosomes.
interphase
Nucleoli are present during _____.
interphase
Both mitosis and meiosis are preceded by
interphase.
A fragment of chromosome 21 reattaches to chromosome 21, but in the reverse direction. What is the name given to this change?
inversion
If a chromosome fragment breaks off and then reattaches to the original chromosome but in the reverse direction, the resulting chromosomal abnormality is called a(n)
inversion.
When we say that an organism is haploid, we mean that _____
its cells each have one set of chromosomes
Sister chromatids are
joined together at a centromere.
Which of the following is a correct representation of an event that occurs in mitosis?
metaphase—chromosomes line up on the equatorial plane.
After fertilization, the resulting zygote begins to divide by __________.
mitosis
If the four cells shown resulted from cell division of a single cell with diploid chromosome number 2n = 4, what best describes what just occurred?
nondisjunction
Spindle fibers attach to kinetochores during _____.
prometaphase
Chromosomes become visible during _____.
prophase
In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____.
prophase (During prophase we observe the formation of the spindle, the condensation of chromatin, and the disappearance of the nucleolus, which are the opposite events to those occurring during telophase.)
During anaphase II, __________.
sister chromatids separate and migrate toward opposite poles
The kinetochores are __________.
sites at which microtubules attach to chromosomes
An example of a cell that is 2n is a __________.
somatic cell (Somatic is a word used to refer to the "body." These body cells are diploid and have two homologous copies of each chromosome.)
Cytokinesis often, but not always, accompanies _____.
telophase
During which phase of mitosis does the nuclear envelope re-form?
telophase
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.
telophase I
At the end of _____ and cytokinesis there are four haploid cells.
telophase II
During _____ both the contents of the nucleus and the cytoplasm are divided.
the mitotic phase
During mitosis, the chromosomes move because _____.
they attach to a dynamic, precisely regulated mitotic spindle
Meiosis I produces _____ cells, each of which is _____.
two ... haploid
During prophase a homologous pair of chromosomes consists of _____.
two chromosomes and four chromatids
Mitosis and cytokinesis result in the formation of __________; meiosis and cytokinesis result in the formation of __________.
two diploid cells : four haploid cells
Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! You realize that this cell is
undergoing cytokinesis.
Homologous chromosomes possess the same genes arranged in the same order but may possess different __________ of some of these genes.
versions