Week 4: Mitosis Flashcards
An organism’s DNA, containing arrays of genes, is organized into structures called?
chromosomes
They serve as vehicles for transmitting genetic information.
Chromosomes
There are two major processes involved in the genetic continuity of nucleated cells?
mitosis and meiosis
This process leads to production of two cells with the same number of chromosomes as the parent cell.
Mitosis
This process reduces the genetic content and the number of chromosomes by half.
Meiosis
This reduction in the number of chromosomes during meiosis is important in the production of?
sex cells or gametes
True or false: Chromosomes are visible only during mitosis and meiosis.
True
When the cell is not undergoing division, the genetic material making up chromosomes unfolds and uncoils into diffuse network within the nucleus, generally referred to as?
chromatin
The chromosomes contains a constricted region called the ______, whose location establishes the general appearance of each chromosome.
centromere
True or false: Depending on the position of the centromere, different arm ratios are produced.
True
Classifications of chromosomes based on centromere location?
- metacentric
- submetacentric
- acrocentric
- telocentric
The short arm of the chromosome is called the _____, and the longer arm is called the _____.
p arm, q arm
Centromere at the middle is called?
Metacentric
Centromere between the middle and end is called?
Submetacentric
Centromere close to the end is called?
Acrocentric
Centromere at the end is called?
Telocentric
True or false: All somatic cells derived from members of the same species do not contain an identical number of chromosomes.
False. They contain an identical number of chromosomes.
All somatic cells derived from members of the same species contain an identical number of chromosomes, and this is referred to as?
diploid number (2n)
With the exception of sex chromosomes, chromosomes exist in pairs called?
homologous chromosomes
Chromosomes exist in pairs except?
sex chromosomes
True or false: The homologs do not exhibit the same length and centromere placement.
False. Homologs have the same length and centromere placement because the are homologous to one another.
Sex chromosome of males?
1 X, 1 Y chromosome
Sex chromosome of females?
2 homologous X chromosomes
Note that each chromosomes in the karyotype is clearly a double structure consisting of two parallel __________ connected by a common __________.
sister chromatids, centromere
True or false: The sister chromatids are replicas of one another and would separate into two new cells during cell division.
True
The __________ of chromosomes is equal to one-half of the diploid number.
haploid number (n)
The genetic information contained in a haploid set of chromosomes constitute the _______ of the species.
genome
Homologous chromosomes contain identical gene sites along their lengths. Each site is called a?
locus (pl. loci)
True or false: Homologous chromosomes are identical in the traits that they influence and in their genetic potential.
True
In sexually reproducing organisms, one member of each pair is derived from the mother (though the _____) and the other from the father (through the _____).
ovum, sperm
Each diploid organisms contain ________ of each gene as a consequence of biparental inheritance, or inheritance from two parents.
two copies
True or false: The members of each pair of genes, while influencing the same characteristic or trait, need to be identical.
False. They need not be identical.
In a population of members of same species, many different forms of the same gene, called _____, can exist.
alleles
In many species, one pair, consisting of the __________ chromosomes, is often not homologous in size, centromere placement, arm ratio, or genetic content.
sex-determining
These X and Y chromosomes are not strictly homologous. The __ is smaller and lacks most of the gene loci contained in the __.
Y, X
Process in which the genetic material is partitioned into daughter cells during nuclear division.
karyokinesis
Cytoplasmic division is called?
Cytokinesis
It partitions the cell volume into two parts and then encloses each new cell in a distinct plasma membrane.
Cytokinesis
The ____ is a series of events that describe the sequence of activities a cell prepares for division and then divides.
cell cycle
Stages of the Cell Cycle?
Interphase
• G1
• S phase
• G2
Mitosis
• Prophase
• Prometaphase
• Metaphase
• Anaphase
• Telophase
The ______ is devoted solely to cell’s growth and normal function. It is also when the cell replicates the DNA on each chromosome.
interphase
DNA synthesis occurs before the cell enters mitosis. This period is called the?
S phase
There are two periods during interphase in which there is no synthesis of DNA. One occurs before and one after the S phase.
G1/gap1 and G2/gap 2, respectively
During G1, S phase, and G2, what events are evident?
- intensive metabolic activity
- cell growth
- cell differentiation
By the end of ____, DNA has been replicated and the cell volume has doubled.
G2
By the end of G2, DNA has been _____ and the cell volume has _____ .
replicated,doubled
By the end of G2, the cell enters?
mitosis (M)
At a point during G1, all cell follow one of two paths?
(1) withdraw from the cycle, become quiescent, and enter the G0 stage, or
(2) become committed to proceed through G1 and complete the cycle
True or false: Cells that enter the G0 remain viable and metabolically active and can proliferate.
False. They remain viable and metabolically active but are not proliferative.
True or false: The chromosomes are not visible during the interphase.
True
This is the stage in the cell cycle in which the nucleus is filled with chromatin fibers formed from the uncoiling and dispersal of the chromosomes after the previous mitosis.
Interphase
The stage of the cell cycle in which the centrioles migrate to opposite ends of the cell.
Prophase
The stage of the cell cycle in which the centrosomes are responsible for organizing cytoplasmic microtubules into spindle fibers that run between the poles.
Prophase
The stage of the cell cycle in which the nuclear envelope break down and disappear, and the nucleolus disintegrates.
Prophase
The stage of the cell cycle in which the diffuse chromatin fibers condenses, and the chromosomes become visible.
Prophase
The stage of the cell cycle in which the chromosomes appear as a double structure split longitudinally except at a single point of constriction, the centromere.
Prophase
The sister chromatids are held together by protein complexes called?
cohesin
True or false: Even though one cannot see the chromatids in the interphase because the chromatin is uncoiled and dispersed in the nucleus, the chromosomes are already double structures, which becomes apparent in late prophase.
True
During prometaphase and metaphase, the chromosomes migrate to the?
equatorial plane (also called the metaphase plate)
The _________ is the midline region of the cell, a plane that lies perpendicular to the axis established by the spindle fiber.
metaphase plate
______ refers to the period of chromosome movement.
Prometaphase
______ is the chromosome configuration following migration.
Metaphase
Migration during prometaphase is made possible by the binding of spindle fibers to the chromosome’s _______, an assemble of multilayered plates of proteins associated with the centromere.
kinetochore
At the completion of ______, each centromere is aligned at the metaphase plate with the chromosome arms extending outward in a random array.
metaphase
The shortest stage of mitosis, the _________, whose events are critical to the chromosome distribution during mitosis.
anaphase
During this phase, the sister chromatids of each chromosome separate from one another and pulled to opposite ends of the cell.
Anaphase
The event in which the sister chromatids of each chromosome separate from one another is called?
disjunction
As the events proceed in anaphase, each migrating chromatid is now referred to as a?
daughter chromosome
At the _________, two complete sets of chromosomes are present, one on each pole.
beginning of telophase
The stage of the cell cycle in which cytokinesis occur, partitioning the cytoplasm in order to produce two new cells from one.
Telophase
During telophase in animal cells, they undergo constriction of the cytoplasm, producing the _________ that is characteristic of newly divided cells.
cell furrow
During ________, in each new cell, the chromosomes begin to uncoil and become diffuse chromatin once again.
Telophase
The stage of the cell cycle in which the nuclear envelope reforms, the spindle fibers disappear, and the nucleolus re-forms and become visible.
Telophase
At the completion of telophase, the cell enters the?
Interphase
