Column I	Column II
A.Initiation of spindle fibres	1.Anaphase-I
B.Synthesis of RNA and protein	2.Zygotene
C.Action of endonuclease	3.G₁phase
D.Movement of chromatids towards opposite poles	4.Pachytene
	5.Anaphase-II

The correct match is

Match the following and choose the correct option.

Column I	Column II
A.Chromosomes are moved spindle equator	1.Pachyteneto
B.Centromere splits and chromatids apart	2.Zygotene
C.Pairing between homologous chromosomes takes place	3.Anaphase
D.Crossing between homologous chromosomes	4.Metaphase

The following diagram is of a typical cell cycle.

Mark the correct option.

A cell undergoing in Prophase I.

Which of the following diagram is correct for one of the cell at the end of meiosis?

Which one is the right option for the given diagram?

Choose and labelled the diagram from the given options.

Identify the phases from the graph given below that shows the change in DNA content during various phases (A to D) of mitotic cell cycle.

S.No.	A	B	C	D
a.	G₂	G₁	S	M

S.No.	A	B	C	D
a.	G₂	S	G₁	M

S.No.	A	B	C	D
a.	G₁	S	G₂	M

S.No.	A	B	C	D
a.	M	G₁	S	G₂

A stage of mitosis is shown in the diagram. Which stageis it and what are its characteristics?

Late prophase – chromosomes move to spindle equator
Metaphase – spindle fibres attached to kinetochores,centromeres split and chromatids separate
Metaphase –chromosomes moved to spindle equator chromosomes made up of two sister chromatids
Anaphase –centromeres split and chromatids separate and start moving away

Solution

Metaphase chromosome is made up of two sister chromatides which are held together by the centromere.Chromosomes are moved to spindle equator and gets aligned along metaphase plate through spindle fibres to both poles.

During meiosis I, the chromosomes start pairing at

Solution

During zygotene, a substage of Prophase I of meiosis I,chromosomes start pairing together called synapsis.Suchpaired chromosomes are called as homologous chromo-somes. A complex structure i.e., synaptonemal complexis formed by a pair of synapsed homologous chromosomes called a bivalent or a tetrad.

During the metaphase stage of mitosis spindle fibres attach to chromosomes at

Solution

Kinetochores are small disc-shaped structures at the sur-face of the centromeres which serve as the sites of at-tachment of spindle fibres to the chromosomes that are moved into position at the centre of the cell. Hence, the metaphase is characterised by all the chromosomes coming to lie at the equator

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