When cell has stalled DNA replication fork, which checkpoint should be predominantly activated?
G1/s
G2/M
M
Both G2/M and M
A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that his cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is containing more number of chromosomes as compared to other dividing cells. This would result in
polyploidy
somaclonal variation
polyteny
aneuploidy
Which of the following is not a characteristic feature during mitosis in somatic cells
Chromosome movement
Synapsis
Spindle fibres
Spindle fibres attach on to
Kinetochore of the chromosome
centromere of the chromosome
Kinetosome of the chromosome
telomere of the chormosome
In meiosis crossing over is initiated at
leptotene
Zygotene
diplotene
pachytene
Arrange the following events of meiosis in correct sequences
I. Crossing Over
II. Synapsis
III. terminalisation of chaismata
IV. Disapperance of nucleolus
II, I, IV, III
II, I, III, IV
I, II, III, IV
II, III, IV, I
A somatic cell that has just completed the S-phase of its cell cycle, as compared to gamete of the same species has
twice the number of chromosomes and twice the amount of DNA
same number of chromosomes but twice the amount of DNA
twice the number of chromosomes and four times the amount of DNA
four times the number of chromosomes and twice the amount of DNA
During which phase(s) of cell cycle, amount of DNA in a cell remains at 4C level if the
inital amount is denoted as 2C?
G0 and G1
G1 and S
Only G2
G2 and M
In S-phase of the cell cycle
amount of DNA doubles in each cell
amount of DNA remains same in each cell
chromosome number is increased
amount of DNA is reduced to half in each cell
The complex formed by a pair of synapsed homologous chromosomes is called
equatorial plate
Kinetochore
bivalent
axoneme
A stage in cell division is shown in the figure. Select the answer which gives correct
identification of the stage with its characteristics.
present
Telophase - Nuclear envelope reforms, Golgi complex reforms
Late anaphase - Chromosomes move away from equatorial plate, Golgi complex not
Cytokinesis - Cell plate formed, mitochondria distributed between two daughter cells
Telophase - Endoplasmic reticulum and nucleolus not reformed yet
During gamete formation, the enzyme recombinase participates during
Metaphase-I
Anaphase-II
Prophase-I
Prophase-II
Given below is the representation of a certain event at a particular stage of a type of cell division. Which is this stage?
Prophase-I during meiosis
Prophase-II during meiosis
Prophase of mitosis
Both prophase and metaphase of mitosis
Select the correct option with respect to mitosis.
Chromatids start moving towards opposite poles in telophase
Golgi complex and endoplasmic reticulum are still visible at the end of prophase
Chromosomes move to the spindle equator and get aligned along equatorial plate in metaphase
Chromatids separate but remains in the centre of the cell in anaphase
Given below is a schematic break-up of the phases/stages of the cell cycle
Which one of the following is the correct indication of the stage/phase in the cell cycle?
B-Metaphase
C-Karyokinesis
D-Synthesis phase
A-Cytokinesis
The drug colchicines, used to obtain polyploidy cells, acts on the cytoskeletal structures of
the plant cells called
microtubules
actin filaments
intermediate filaments
all of the above.
Astral rays arise from
centriole
cytoplasm
chromatid
centromere.
Number of mitotic division required in a cell of root tip for formation of 128 cells is
12
3
7
6
Barr body is found in the cytoplasm during
interphase in cell of female mammal.
interphase in cell of male mammal.
prophase in cell of female mammal.
prophase in cell of male mammal.
When synapsis is complete all along the chromosome, the cell is said to have entered a stage called
diakinesis.
Many cells function properly and divide mitotically even though they do not have
Plasma membrane
Cytoskeleton
Mitochondria
Plastids
Which of the following is not a characteristic of meiosis?
It involves recombination and crossing over
Sister chromatids separate during anaphase- II
Nuclear membrane disappears during prophase.
Microtubule depolymerizing drug such as colchicine is expected to
inhibit spindle formation during mitosis
inhibit cytokinesis
allow mitosis beyond metaphase
induce formation of multiple contractile
Which of the following statements is incorrect about G0 phase.
Biocatalysts can be used to exit G0 phase.
Cell volume keeps on increasing during this phase.
Cell metabolism occurs continuously in G0 phase.
Beads on string like structures of A are seen in B, which further condense to form chromosomes in C stage of cell division.
A B C
Chromonema Chromatin Metaphase
Chromatin Chromatid Metaphase
Chromonema Chromosome Anaphase
Chromonema Chromatid Anaphase.
Which is the longest phase of the cell cycle?
Interphase
Leptotene
S-phase
The checkpoint in cell cycle plays important role in
repairing DNA damage
apoptosis initiation
assessing DNA damage
none of these.
Identify the correct matched pair.
Significance of meiosis-production of genetically similar cells
Exchange of genetic material- DIakinesis
Anaphase ll of meiosis-Centromeric division
The mandatory combination responsible for assembly of microtubules are
Na+ and Ca2+
Mg2+ and Ca2+
Cl- and Ca2+
Na+ and K+
The exchange of segments of non-sister chromatids between chromosomes of a homologous pair termed as
transformation
translocation
crossing over
chromosomal aberration
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