105 terms

DAT Bootcamp - Cell Division

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_____ is nuclear division (karyokinesis) followed by cytokinesis
cell division
_____ is the nuclear division of cell division
karyokinesis
_____ is the division of the cytoplasm that happens at the end of cell division
cytokinesis
in _____ cells, there are 2 copies of every chromosome, forming a pair called _____ chromosomes
diploid; homologous
humans have _____ chromosomes, _____ homologous pairs, and a total of 92 chromatids (depending on the stage of division)
46, 23
humans have 46 chromosomes, 23 homologous pairs, and a total of _____ chromatids (depending on the stage of division)
92
a _____ is 1 of 2 identical parts of a duplicated chromosome
chromatid
microtubule organizing centers (MTOCs) are called _____ in animal cells
centrosomes

(MTOCs are just called MTOCs in plants/fungi)
MTOCs are found outside the _____ during interphase
nucleus
centrosomes (animal cell MTOCs) contain a pair of _____
centrioles
usually there is _____ MTOC per cell; however, cells replicate their MTOCs during _____
1; S phase
there are _____ MTOCs before cell division (after the S phase of interphase)
2
plants/fungi have MTOCs, but they are NOT _____
centrosomes

(plants/fungi just have "MTOCs")
_____ occurs in somatic cells and _____ occurs in gametes (egg, sperm, pollen)
mitosis; meiosis
mitosis occurs in _____ cells and meiosis occurs in _____ (egg, sperm, pollen)
somatic; gametes
what is fertilization?
the fusion of 2 haploid gamete nuclei to make 1 diploid zygote
what is syngamy?
fertilization - i.e., the fusion of 2 haploid gamete nuclei to make 1 diploid zygote
_____ is the phase of cell division, in which the nucleus disassembles and the nucleolus disappears
prophase
_____ is the phase of cell division in which chromatin condenses into chromosomes
prophase
_____ is the phase of cell division, in which the nuclear envelope breaks down
prophase
_____ is the phase of cell division in which the mitotic spindle forms
prometaphase
microtubules begin connecting to kinetochores during _____ of cell division
prometaphase
_____ is the phase of cell division in which chromosomes line up in a single file in the center
metaphase
_____ is the phase of cell division in which each chromatid is complete with a centromere and attached kinetochore
metaphase
_____ is the phase of cell division in which replicated centrosomes are at opposite ends of the cell
metaphase
_____ is the phase of cell division in which karyotyping is performed
metaphase
_____ is a visual depiction of one's chromosomes by homologous pairs, and it is usually performed during metaphase
karyotyping
_____ is the phase of cell division in which kinetochore microtubules shorten
anaphase
_____ is the phase of cell division in which polar microtubules lengthen
anaphase
_____ is the phase of cell division in which each chromosome is pulled apart
anaphase
once separated at anaphase, each _____ is considered a _____
chromatid; chromosome
_____ is the phase of cell division in which chromosomes are pulled to opposite poles (disjunction)
anaphase
at the end of _____, each pole has a complete set of chromosomes
anaphase
what is the shortest step of cell division?
anaphase
_____ is the phase of cell division when karyokinesis occurs
telophase

(karyokinesis = nuclear division - notice the formation of 2 nuclei)
_____ is the phase of cell division in which the nuclear envelopes re-develop
telophase
_____ is the phase of cell division in which chromosomes de-condense back into chromatin
telophase
_____ is the phase of cell division in which nucleoli reappear
telophase
the presence of chromosomes means _____ is occurring
mitosis/meiosis

(cell division)
in metaphase, a chromosome consists of 2 closely attached _____
sister chromatids
the end of _____ is denoted by the presence of centrosomes at opposite ends of the cell
metaphase
to keep track of the total number of chromosomes during cell division, count the number of _____
centromeres
in _____, the chromosome number doubles
anaphase
at the end of _____, each pole has a complete set of chromosomes, same as the original cell before replication
anaphase
at the end of anaphase, there would be a total of _____ chromosomes (separated chromatids) if a cell has 46 chromosomes at the beginning
92
genetic variation occurs in _____, but not in mitosis
meiosis
unlike meiosis, NO _____ occurs in mitosis
genetic variation
during cytokinesis, animal cells separate via creation of the _____
cleavage furrow
during _____ in animals, actin and myosin microfilaments shorten and the plasma membrane is pulled into the center, creating a _____
cytokinesis; contractile ring/cleavage furrow
plant cells undergo cytokinesis via formation of a _____
cell plate
as plant cells undergo cytokinesis, vesicles from _____ migrate and fuse to form a cell plate
golgi bodies
during plant cell division, the cells don't actually separate from each other because the _____ cements adjacent cells together
middle lamella
_____ begins after mitosis and cytokinesis complete
interphase
only the somatic cells that divide by _____ undergo interphase
mitotic
gametes do undergo _____ after they are made
interphase
what are the phases of interphase?
G1 (possibly G0), S, and G2 phase
what are the 3 *main* phases of the cell cycle?
mitosis, cytokinesis, interphase
90% of the cell cycle is spent in _____
interphase
the phase of interphase in which a checkpoint ensures everything is ready for DNA synthesis
G1
cells produce protein, ribosomes, and mitochondria in the _____ stage of interphase
G1
in what phase of the cell cycle will DNA synthesis occur?
the S phase of interphase
a second molecule of DNA is replicated from the first to provide sister chromatids in the _____ of interphase
S phase
the phase of interphase in which rapid cell growth occurs
G2
the cell prepares its genetic material for cellular division during the _____ of interphase
G2 phase
cells replicate their organelles during the _____ phase
gap 2 (G2)
when surface/volume ratio is _____, cellular exchange becomes easier
large
when surface/volume ratio is _____, cellular exchange is hard, and leads to cell death or cell division to increase surface area
small
what happens as the genome/volume ratio decreases (volume gets bigger)?
the cell exceeds the ability of its genome to produce sufficient amounts of regulation for cellular activities
some large cells (paramecium, human skeletal muscle) are _____ to deal with problems associated with ever decreasing genome/volume ratios
multinucleated
what is the most important checkpoint of the cell cycle?
the G1 checkpoint
_____ is assessed and _____ conditions are checked during the G1 checkpoint
cell growth; favorable
what happens if the G1 checkpoint fails?
the cell enters G0
the _____ is viewed as either an extended G1 phase, where the cell is neither dividing nor preparing to divide, or a distinct quiescent stage that occurs outside of the cell cycle
G0 phase
some cells (liver, kidney) can be _____ of G0, while some cells (nerve, muscle) _____ in G0
induced out; permanently remain
cells can either never proceed from the _____ of interphase, or they can wait until the cell is ready to divide
G0 phase
at the end of the_____, the cell evaluates the accuracy of DNA replication and signals whether to begin mitosis
G2 phase
cells check for sufficient _____ levels during the G2 checkpoint and if there is a sufficient amount, the cell will proceed into the M phase
mitosis promoting factor (MPF)
the M checkpoint occurs during _____
metaphase
the _____ stops division to check if the chromosomes are attached to spindle fibers
M checkpoint
what happens if kinetochores are not attached to microtubules during the M checkpoint?
the cell will not proceed to anaphase until the appropriate connections have been made
_____ are enzymes that activate proteins, which regulate the cell cycle by phosphorylation
cyclin-dependent kinases (CDKs)
_____ is a protein that activates CDKs
cyclin
the plasma membrane has receptors for _____ that stimulate cells for division (such as damaged cells)
growth factors
cells stop dividing when surrounding cell density reaches a maximum - this is called _____
density-dependent inhibition
most cells only divide when attached to an external surface, such as neighboring cells or a side of culture dish - this is called _____
anchorage dependence
cancer cells defy the five cell-specific regulations in place - such cells are called _____ cells
transformed
cancer drugs that inhibit mitosis do so by disrupting the ability of _____ to separate chromosomes during anaphase, thus stopping replication
microtubules
cancerous cells are a manifestation of defective cell _____ & cell cycle _____
differentiation; regulation
in meiosis I, crossing over occurs during _____, which introduces genetic variation to gametes
prophase I
the _____ is the region where crossing over occurs between non-sister chromatids during prophase I of meiosis I
chiasmata
_____ describes the process when homologous chromosomes pair up during prophase I of meiosis I
synapsis
the _____ is a protein structure that temporarily forms between homologous chromosomes during prophase I of meiosis I
synaptonemal complex
paired homologous chromosomes are referred to as _____ or _____ during early meiosis I
tetrads; bivalents
_____ are groups of 4 chromatids (due to the pairing of 2 homologous chromosomes) seen early in meiosis I
tetrads

(analogous to a bivalent)
_____ are pairs of homologous chromosomes
bivalents

(analogous to a tetrad)
what happens during the diakinesis sub-step of prophase I?
chromosomes complete condensing, the nuclear envelope begins to fragement, and tetrads/bivalents are ready for metaphase

(diakinesis is the final sub-step of prophase I)
chromosomes line up in _____ during metaphase I
double file
in meiosis, disjunction of homologs occurs during _____
anaphase I
_____ is the phase of meiosis I in which each pole forms a new nucleus that now has half the number of chromosomes
telophase I
daughter cells are converted from _____ to _____ at the end of meiosis I
diploid; haploid

(meiosis I is the reductional division)
what is the difference between prophase I and II of meiosis?
there is no chiasmata or crossing over during prophase II because the cells have been reduced to haploidy
_____ is similar to mitotic metaphase because the chromosomes align along the metaphase plate in _____
metaphase II; single file
what is different between metaphase II and mitotic metaphase?
metaphase II has a haploid number of chromosomes, while mitotic metaphase has a diploid number of chromosomes
what is the phase of meiosis in which sister chromatids separate?
anaphase II
what is the phase of meiosis in which nuclear envelopes re-develop, and cytokinesis occurs to produce 4 haploid cells?
telophase II
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