Ch 14 part 2 Flashcards
cell division, a cell divides to produce two new cells that are genetically identical to the original
mitotic
In preparation for division, the ___________ become very condensed and can easily be viewed with a microscope.
chromosomes, chromatids,
sister chromatids
Name the region where the two sister chromatids are tightly associated.
Centromere
The mitotic spindle is made up of which of the following?
Microtubules
Astral, polar, and kinetochore microtubules are the three types of
spindle microtubules
Mitotic cell division is:
cell division that results in two genetically identical daughter cells
When a cell prepares to divide, what structures become highly compacted and readily visible under a microscope?
Sister chromatids
Transmission of chromosomes during every cell___ is critical because all cells have to inherit the right number of chromosomes
division
In a replicated chromosome, the two sister chromatids are bound closely at a region known as the
centromere
Mitosis occurs as a continuum of phases that proceed in the following order:___________ , prometaphase, metaphase,__________ , _________and lastly .
prophase, anaphase, telophase
In what phase of mitosis does the fragmentation of the nuclear envelope begin?
Prophase
Identify the three types of spindle microtubules.
astral
polar
kinetochore
Identify the phase in which the nuclear envelope completely fragments into small vesicles.
prometaphase
The precise transmission of ____ during every cell division is critical so that all cells receive the correct amount of genetic material.
chromosomes
The pairs of sister chromatids align themselves in a single row along a plane half-way between the poles during which of the following phases of mitosis?
Metaphase
At anaphase of mitosis, ___ ___ separate from one another and begin to move toward the poles of the cell.
sister chromatids
list the phases of mitosis in the correct order. start with the earliest on top.
prophase prometaphase metaphase anaphase telophase
Identify the phase of mitosis where each group of chromosomes reaches a pole of the cell and decondenses.
Telophase
The nucleolus is no longer visible in the
prophase stage
Which of the following events occur during prometaphase of mitosis?
- Spindle fibers interact with the sister chromatids Nuclear envelope
- completely fragments into small vesicles
- The mitotic spindle is fully formed
- Centrosomes move apart and demarcate the two poles
In plant cells, cytokinesis occurs through the formation of a
cell plate
during ___ the chromosomes are aligned midway between the spindle poles.
metaphase
When two haploid gametes unite, they create a diploid cell called a
zygote
During ______ of mitosis, the kinetochore microtubules shorten, pulling the chromosomes toward the pole to which they are attached.
anaphase
Meiosis is the process by which ____ cells are produced from a cell that was originally diploid.
haploid
During this phase the chromosomes have reached their respective poles and decondense.
Telophase
Meiosis I sorting separates which of these?
Homologous chromosomes
In what phase of mitosis does the fragmentation of the nuclear envelope begin?
Prophase
The formation of bivalents and subsequent crossing over occur in what phase of meiosis?
Prophase I
In what cells does cytokinesis involve the formation of a cleavage furrow?
Animal cells
Synapsis is the process of forming a(n)
bivalent
A zygote is created when two haploid cells, called ___ fuse
gametes
Crossing over is best described as which of these?
It involves a physical exchange of chromosome segments in the tetrad.
A diploid cell divides by a process called _____ to produce haploid cells.
meiosis
In mitosis, a pair of sister chromatids is attached to both poles while in meiosis I a pair of sister chromatids is attached to just one pole via kinetochore microtubules. What phase is described here?
Prometaphase
The sorting that occurs during ______ separates homologues from each other.
meiosis I
Because meiosis I produces two haploid nuclei, it is called:
reduction division
In _________________ I of meiosis, the replicated chromosomes condense, the homologous chromosomes form bivalents, and crossing over occurs.
prophase
prophase
The sister chromatids are separated during
anaphase II of meiosis.
Pairs of homologous chromosomes are joined during meiosis by a process termed
synapsis
Bivalent formation and crossing over are two key events that typically occur at the beginning of which of these?
Meiosis
What process involves a physical exchange between chromosome segments of the bivalent?
Crossing over
Which of the following is the end result of mitosis in a diploid organism?
Two daughter cells that are diploid
In prometaphase, there is a key difference between mitosis and meiosis I. In mitosis, a pair of sister chromatids is attached to both poles. In meiosis I a pair of sister chromatids is attached to just one pole via ___________ microtubules.
kinetochore
The life cycle of sexually reproducing organisms involves
an alternation between haploid and diploid stages.
The end result of _____ I is that two nuclei are produced, each with full pairs of sister chromatids; this is called a reduction division.
meiosis
Put the events of an animal life cycle in the correct order, beginning with the production of gametes
- Meiosis occurs in cells within testes and ovaries to produce haploid gametes
- During fertilization, sperm and egg unite to create a diploid zygote
- Repeated mitotic cell divisions produce a diploid multicellular organism
During anaphase II of meiosis ______ are separated.
sister chromatids
Which of these are typically haploid-dominant species?
Protists
Fungi
Which two key events occur at the beginning of meiosis but not mitosis?
Formation of bivalents
Crossing over
The diploid multicellular organism in species that exhibit alternation of generations is known as a(n
sporophyte
Following cytokinesis, meiosis II produces:
four daughter cells that are haploid
What chromosomal variations have major effects on the characteristics of an organism?
number
structure
True or False: All sexually reproducing species produce haploid and diploid cells at different stages in their life cycle
True
In a particular species, the composition of chromosomes remains relatively
constant.
During the life cycle of a diploid animal, what process produces haploid gametes?
meiosis
Which of the following are variations that exist among different eukaryotic chromosomes?
chromosome size
location of centromere
banding pattern
In which two ways is the banding pattern of eukaryotic chromosomes useful?
- to detect changes in chromosome structure due to mutation
* individual chromosomes can be distinguished from each other
In species that exhibit alternation of generations, the diploid multicellular organism is called the
sporophyte
What are the main types chromosomal mutations?
inversions
duplications
translocations
deletions
The study of chromosomal variation is important because these variations in chromosome structure and number can have major effects on the characteristics of an organism. Also, these changes have been an important force in the ___________ of new species.
evolution
Organisms possessing chromosomes that occur in one or more complete sets are termed
euploid
True or false: Chromosome composition within a given species is variable.
False
Aneuploidy refers to an alteration in the number of particular _______
Chromosomes
In nature, chromosomes are found to vary in:
size, centromere location, number, and banding pattern
The banding pattern of eukaryotic chromosomes is useful in two ways. First, individual chromosomes can be distinguished from each other. Also, the patterns are used to detect changes in chromosome structure due to _____.
Mutation
Nondisjunction events can happen in:
both meiosis I and meiosis II
Chromosomal mutations are of four main types:
Deletions, Translocations, Duplications and Inversions
Polyploidy is generally a lethal condition in
mammals
Which of these terms best describes organisms that have complete sets of chromosomes?
Euploid
