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प्रश्न
Is the chromosome number of zygote, embryonal cells and adult of a particular organism always constant? How is the constancy maintained in these three stages?
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उत्तर
Mitosis is a cell division which results in the formation of two daughter cells from a cell with the same number of chromosomes. Zygote undergoes mitotic divisions to develop into an embryo which in turn, also undergoes mitotic divisions to become an adult. So, the constancy of chromosomes is maintained in these three stages.
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संबंधित प्रश्न
A student has to perform the experiment "To identify the different parts of an embryo of a dicot seed." Select from the following an appropriate group of seeds:
(a) Pea, gram, wheat
(b) Red kidney bean, maize, gram
(c) Maize, wheat, red kidney bean
(d) Red kidney bean, pea, gram
How is the process of pollination different from fertilization?
State the name of the functional unit concerned with sexual reproduction.
Where are the pollen grains produced?
What are the reproductive organs in a flower?
Where is the male gamete formed in flowering plants?
Fill in the following blank with suitable word :
The.......... at the base of the carpel contains egg cells.
Fill in the following blank with suitable word :
The term used to refer to the transfer of pollen from the stamen of one flower to the carpel of another flower of the same species is...........
Name the part of a seed which contains stored food.
The part of a seed which grows and develops into root on germination is :
(a) cotyledon
(b) plumule
(c) follicle
(d) radicle
When an insect sits on the flower of a plant then some particles A present in the top of little stalks in the flower attach to its body hair. When this insect now sits on the flower of another similar plant, then particles A attached to the hair of insect are put on the top of a flask-shaped organ at the centre of flower. The particle A grows a long tube b from the top of flask-shaped organ through which C moves down and reaches the bottom part of flask-shaped organ. Here C fuses with the nucleus of d contained in structure E. the fusion of C and D forms a new cell f which grows and develops into a seed of the plant.
(a) What are particles A? What is the process of transferring A from one flower to another flower of similar plant by the insect known as?
(b) What is the name of tube B?
(c) What is C which moves down through the tube B?
(d) Name D and E.
(e) What is F?
You have to perform the experiment, "To identify the different parts of an embryo of a gram seed." Describe the procedure that you would follow.
Explain the process of fertilisation in flowers.
(a) Identify A, B and C in the given diagram and write their functions.
(b) Mention the role of gamete and zygote in sexually reproducing organisms.
Describe an activity to demonstrate phototropism.
Find an odd one out.
How many middle layers are generally present in the wall of the anther lobes?
The seed that contains the future plant is called the ______
Trace the path a male gamete takes to fertilise a female gamete after being released from the penis.
Consider the following three flowers namely X, Y and Z. Which flower(s) would develop into a fruit?
| Flower X | Flower Y | Flower Z |
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