Term
What is an organism’s
DNA, with its arrays of genes, organized into structures? |
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Definition
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Term
What are two major processesinvolved in the genetic continuity
of nucleated cells? |
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Definition
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Term
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Definition
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Term
What is the genetic
material making up chromosomes (unfolds and uncoils)
into a diffuse network within the nucleus not undergoing division? |
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Definition
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Term
What is an
outer covering that defines the cell boundary and delimits
the cell from its immediate external environment? |
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Definition
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Term
What is an outer covering whose major component is a polysaccharide
called cellulose in plant cells? |
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Definition
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Term
Animal cells have a covering over the
plasma membrane, referred to as the? |
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Definition
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Term
Molecules that act as recognition sites that transfer specific chemical signals across the cell membrane into
the cell are? |
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Definition
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Term
The presence of a nucleus and other membranous organelles
is the defining characteristic of __________. |
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Definition
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Term
What is a membrane-bound
structure that houses the genetic material, DNA, which is
complexed with an array of acidic and basic proteins into
thin fibers in eukaryotic cells? |
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Definition
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Term
What is an amorphous component where
ribosomal RNA (rRNA) is synthesized and where the initial
stages of ribosomal assembly occur? |
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Definition
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Term
What are portions of DNA
that encode rRNA are collectively referred to as the ________. |
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Definition
| nucleolus organizer region (NOR) |
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Term
| What lacks a nuclear envelope and membranous organelles? |
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Definition
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Term
What is a long, circular
DNA molecule that is compacted into an unenclosed region? |
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Definition
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Term
What is the remainder of the eukaryotic cell within the plasma
membrane that includes a variety of extranuclear cellular organelles? |
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Definition
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Term
| What is a nonparticulate, colloidal material that surrounds and encompasses the cellular organelles? |
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Definition
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Term
| What is an organelle that compartmentalizes the cytoplasm, greatly increasing the surface area available for biochemical synthesis? |
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Definition
| endoplasmic reticulum (ER) |
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Term
| What are sites where genetic information contained in messenger RNA (mRNA) is translated into proteins? |
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Definition
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Term
__________ is found in
most eukaryotes, including both animal and plant cells,
and are the sites of the oxidative phases of cell respiration.
These chemical reactions generate large amounts of
the energy-rich molecule adenosine triphosphate (ATP). |
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Definition
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Term
What is found in plants, algae, and someprotozoans,and are associated with photosynthesis, the major
energy-trapping process on Earth? |
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Definition
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Term
Animal cells and some plant cells also contain a pair
of complex structures called ________. |
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Definition
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Term
What are cytoplasmic
bodies located in a specialized region? |
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Definition
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Term
These play an important role in the movement of chromosomes
as they separate during cell division. They are composed
of arrays of microtubules consisting of polymers of
the protein tubulin. |
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Definition
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Term
What is a constricted
region, whose location establishes the
general appearance of each chromosome? |
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Definition
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Term
| What is the shorter arm above the centromere? |
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Definition
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Term
| What is the longer arm below the centromere? |
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Definition
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Term
somatic cells derived from
members of the same species contain this identical number
of chromosomes. |
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Definition
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Term
When the lengths and centromere placements of all such
chromosomes are examined with the exception of sex chromosomes, they exist in pairs with regard to these two properties, and the members
of each pair are called |
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Definition
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Term
the physical appearance of different
pairs of homologous chromosomes |
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Definition
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Term
chromosomes
is equal to one-half the diploid
number. |
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Definition
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Term
the genetic
information contained in a haploid set
of chromosomes |
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Definition
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Term
Homologous chromosomes
contain identical gene sites along their lengths called |
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Definition
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Term
| In a population of members of the same species,many different alternative forms of the same gene called |
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Definition
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Term
| single-celled fertilized eggs in a multicellular diploid organism |
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Definition
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Term
genetic material is partitioned into daughter cells
during nuclear division, |
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Definition
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Term
| Karyokinesis is followed by cytoplasmic division or _________ |
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Definition
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Term
events that occur from the completion
of one division until the completion of the next division |
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Definition
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Term
the initial stage of the cell cycle and the replication of the DNA of
each chromosome. |
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Definition
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Term
| This period, during which DNA is synthesized,occurs before the cell enters mitosis |
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Definition
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Term
Investigations of this nature demonstrate two periods
during interphase when no DNA synthesis occurs, one before and one after the S phase.During both of these intervals, as
well as during S, intensive metabolic activity, cell growth, and
cell differentiation are evident. |
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Definition
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Term
By the end of G2, the volume
of the cell has roughly doubled, DNA has been replicated,
and ________ is initiated. |
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Definition
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Term
| one of the early stages of this event is migration of two pairs of centrioles to opposite ends of the cell. |
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Definition
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Term
two parts of each chromosome
are ______ _______ because the DNA
contained in each of them is genetically identical, having
formed from a single replicative event. |
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Definition
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Term
Sister chromatids are
held together by a multi-subunit protein complex called |
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Definition
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Term
| the period of chromosome movement |
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Definition
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Term
| the chromosome configuration following migration. |
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Definition
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Term
| unique protein family protects cohesin from being degraded by separase at the centromeric regions. |
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Definition
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Term
During
this phase, sister chromatids of each chromosome, held together only at their centromere regions, disjoin from one another and are pulled to opposite ends of the cell. |
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Definition
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Term
| migrating chromosome as anaphase proceeds |
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Definition
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Term
At its beginning of this final stage of mitosis, two complete sets of
chromosomes are present, one set at each pole. The most
significant event of this stage is cytokinesis, the division
or partitioning of the cytoplasm. |
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Definition
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Term
| Checkpoint that monitors the size the cell has achieved since its previous mitosis and also evaluates the condition of the DNA. |
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Definition
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Term
| checkpoint where DNA is monitored prior to the start of mitosis. |
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Definition
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Term
checkpoint where the successful formation of the spindle
fiber system and the attachment of spindle fibers to the kinetochores
associated with the centromeres are monitored. |
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Definition
| M checkpoint (Spindle Assembly checkpoint) |
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Term
| first division in meiosis I (because the number of centromeres, each representing one chromosome, is reduced by one-half).2n to n |
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Definition
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Term
second division during meiosis II (because the number of centromeres
remains equal); sister chromatids separated into daughter cells |
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Definition
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Term
First, as in mitosis, chromatin present
in interphase thickens and coils into visible chromosomes. And each chromosome is a double structure,
held together by the molecular complex called cohesin. Second,
unlike mitosis, members of each homologous pair of
chromosomes pair up, undergoing synapsis. Third, crossing
over occurs between chromatids of synapsed homologs. |
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Definition
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Term
homologous chromosomes
form pairs; that is, they synapse (or undergo) _________. |
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Definition
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Term
During the leptotene stage, the interphase
chromatin material begins to condense, and the chromosomes,
though still extended, become visible; where chromosome fibers begin to condense |
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Definition
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Term
The chromosomes continue to shorten and
thicken during the zygotene stage;where each homologous chromosome pair is joined together by a synaptonemal protein complex. The process is called synapsis and the synapsed chromosomes are called bivalent or tetrads (four chromatids) |
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Definition
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Term
In the transition from the zygotene to the pachytene stage, the chromosomes continue to coil and shorten, and further development of the synaptonemal
complex occurs between the two members of each bivalent.This leads to synapsis, a more intimate pairing; where DNA exchanges occur between non-sister chromatids. A cross-shaped structure called a chiasma (chiasmata plural) forms at the point of exchange. |
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Definition
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Term
During the ensuing diplotene stage, it is even more apparent that each tetrad consists of two pairs of sister
chromatids. Within each tetrad, each pair of sister chromatids begins to separate; where the synaptonemal complex begins to disappear but chiasmata is still visible;where the synaptonemal complex begins to disappear but chiasmata is still visible |
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Definition
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Term
The final stage of prophase I
chromosomes pull farther apart, but nonsister chromatids remain loosely associated at the chiasmata. As separation proceeds, the chiasmata move toward the ends of the tetrad; Chromosomes are maximally condensed and chiasmata migrate toward the ends of the chromosome. Homologous pairs begin to pull away from each other so chiasmata are clearly seen. Nucleoli and nuclear membrane disappear and spindle apparatus begin to form. |
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Definition
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Term
the chromosomes have maximally shortened and thickened. The terminal chiasmata of each tetrad are visible and appear to
be the major factor holding the nonsister chromatids together;Bivalents (tetrads) are oriented on the equatorial plane. |
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Definition
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Term
| Cohesin is degraded between sister chromatids,except at the centromere region, which, as in mitosis, is protectedby a shugoshin complex. Then, one-half of each tetrad(a dyad) is pulled toward each pole of the dividing cell;Chiasmata dissolve, centormeres do not separate so whole chromosomes (2 sister chromatids) move to opposite poles of the cell. This reduces the chromosome number from 2n to n. |
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Definition
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Term
reveals a nuclear membrane
forming around the dyads; is completed when the nuclear membrane reforms around the chromosomes at either end of the cell. |
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Definition
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Term
is essential if each
gamete or spore is to receive only one chromatid from each
original tetrad. |
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Definition
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Term
| each dyad is composed of one pair of sister chromatids attached by the common centromeric region;Spindle apparatus reforms and chromosomes re-condense |
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Definition
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Term
| the centromeres are positioned on the equatorial plate,the shugoshin complex is degraded, and the centromeres separate; Chromosomes line up along the equatorial plane. |
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Definition
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Term
reveals one
member of each pair of homologous chromosomes present at each pole. Each chromosome is now a monad; Nuclear membranes reform around chromosomes at opposite poles. |
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Definition
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Term
In ____________, the formation of ova (sing. ovum),
or eggs, occurs in the ovaries, the female reproductive
organs |
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Definition
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Term
| M phase is itself composed of two tightly coupled processes:________, in which the cell's chromosomes are divided between the two daughter cells, and ___________, in which the cell's cytoplasm physically divides |
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Definition
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Term
| Cells that have temporarily or reversibly stopped dividing are said to have entered a state of _________ called G0 phase |
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Definition
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Term
| cells that have permanently stopped dividing due to age or accumulated DNA damage are said to be |
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Definition
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Term
| The first phase within interphase is called __ ; during this phase the biosynthetic activities of the cell, which had been considerably slowed down during M phase, resume at a high rate; Required for cell growth and preparation of DNA synthesis |
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Definition
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Term
| phase starts when DNA synthesis commences, when it is complete, all of the chromosomes have been replicated; synthesis and replication of genome |
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Definition
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Term
| is required for cell growth and cell division into two daughter cells. |
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Definition
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Term
| phase is needed or cell growth and preparation of mitosis |
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Definition
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Term
| phase in which cells segregate duplicated chromosomes |
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Definition
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Term
| Upon perturbation of DNA replication by drugs that interfere with DNA synthesis,cells activate ______ that arrests cell cycle at G2/M transition until DNA replication is complete |
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Definition
| DNA replication checkpoint |
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Term
| arrests cell cycle at M phase until all chromosomes are aligned on spindle. |
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Definition
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Term
| detects abnormality in the cytoskeleton and arrests cell cycle at G2/M transition. |
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Definition
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Term
| division of a haploid (n) or diploid (2n) cell into two duplicate daughter cells;the division of a nucleus (karyokinesis) into two duplicate nuclei, each with identical sets of chromosomes.(duplication) |
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Definition
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Term
| special kind of cell division in which the chromosome number is reduced in half. This is how the chromosome number in a life cycle changes from diploid (2n) to haploid (n). (reduction) |
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Definition
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Term
| Cytoplasmic division initiated by the assembly of contractile elements at the equatorial plate in animal cells |
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Definition
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Term
| Centromeres split and separated chromosomes are pulled to opposite poles of the cell. |
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Definition
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