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In angiosperm, the haploid, diploid and triploid structures of a fertilized embryo sac sequentially are:

Option: 1

Synergids, Primary endosperm nucleus and zygote


Option: 2

Antipodals, synergids, and primary endosperm nucleus


Option: 3

Synergids, Zygote and Primary endosperm nucleus


Option: 4

Synergids, antipodals and Polar nuclei


The correct option is Option 3) Synergids, Zygote, and Primary endosperm nucleus.

In angiosperms, the fertilized embryo sac, which is the female gametophyte, contains various structures at different ploidy levels after fertilization. These structures include synergids, zygote, and the primary endosperm nucleus.

Synergids: Synergids are haploid cells found within the embryo sac. They are located at the micropylar end and play a role in guiding the pollen tube to the embryo sac during fertilization.

Zygote: After the pollen tube reaches the embryo sac and delivers the male gametes, fertilization occurs. The fusion of the sperm cell with the egg cell results in the formation of a zygote. The zygote is the first cell of the sporophytic generation and is diploid (2n) in ploidy.

Primary endosperm nucleus: The primary endosperm nucleus, also known as the central cell, is located at the center of the embryo sac. It contains two polar nuclei and is involved in the formation of endosperm. After fertilization, the primary endosperm nucleus undergoes triple fusion with one sperm cell, resulting in the formation of a triploid (3n) primary endosperm nucleus.

Therefore, the correct sequence of haploid, diploid, and triploid structures in a fertilized embryo sac is Synergids, Zygote, and Primary endosperm nucleus, as stated in Option 3.

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Posted by

Gunjita

A massless string connects two pulley of masses ' 2 \mathrm{~kg}' and '1 \mathrm{~kg}' respectively as shown in the figure.

The heavier pulley is fixed and free to rotate about its central axis while the other is free to rotate as well as translate. Find the acceleration of the lower pulley if the system was released from the rest. [Given, g=10 \mathrm{~m} / \mathrm{s}^2]

Option: 1

\frac{4}{3} \mathrm{~gm} / \mathrm{s}^2


Option: 2

\frac{3}{2} \mathrm{~gm} / \mathrm{s}^2


Option: 3

\frac{3}{4} \mathrm{~gm} / \mathrm{s}^2


Option: 4

\frac{2}{3} \mathrm{~gm} / \mathrm{s}^2


Not understanding sir 

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Posted by

Raju vittal nandi

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The following is the biochemical pathway for purple pigment production in flowers of sweet pea:

Colorless precursor 1 —- Allele A—->  Colorless precursor 2 —--- Allele B—---> Purple pigment

Recessive mutation of either gene A or B leads to the formation of white flowers. A cross is made between two parents with the genotype: AaBb × aabb. Considering that the two genes are not linked, the phenotypes of the expected progenies are:

 

Option: 1

9 purple : 7 white


Option: 2

3 white : 1 purple


Option: 3

1 purple : 1 white


Option: 4

9 purple : 6 light purple : 1 white


3(white):1(purple)

In case of 'duplicate recessive epistasis homozygous recessive gene masks the other gene i.e., aa is epistatic to A or a || bb is epistatic to B or b

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Posted by

Riya

 What are the uses of beeswax?

Option: 1

 Preparation of cosmetics and polishes


Option: 2

Production of honey


Option: 3

Used as a food for bees

 


Option: 4

Used as a pesticide


Beeswax has many uses, one of which is the preparation of cosmetics and polishes. It is used in the manufacture of candles, crayons, lip balms, soaps, and other products. Beeswax is also used as a lubricant, in the preservation of leather, and as an ingredient in various pharmaceutical products. While beeswax is important to the bees themselves, it is not used as a food source, nor is it used as a pesticide. Therefore, option 1 is the correct answer.

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Posted by

Ramraj Saini

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pH of Arterial blood is

Option: 1

6.4


Option: 2

7.4


Option: 3

8.4


Option: 4

5.4


The pH of arterial blood is tightly regulated by the body, and it is maintained within a narrow range of 7.35-7.45. This is important for proper physiological functioning, as even small changes in pH can affect enzyme activity, membrane permeability, and other cellular processes.

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Posted by

qnaprep

Calculate the acceleration of block m_1 of the following diagram. Assume all surfaces are frictionless . Here m1 = 100kg and m2 = 50kg

 

Option: 1

0.33m/s2


Option: 2

0.66m/s2


Option: 3

1m/s2


Option: 4

1.32m/s2


1.32

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Posted by

balda gayathri

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No. of transition state in given figure

Option: 1

1


Option: 2

2


Option: 3

3


Option: 4

4


2

 

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Posted by

Mura

When cell has stalled DNA replication fork, which checkpoint should be predominantly activated?

Option: 1

G1/S

 

Option: 2

G2/M

 

 

 

Option: 3

M

 

 

Option: 4

Both G2 M and M

 

G2/M should be activated as the cell has stalled DNA replication fork.

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Posted by

Ajit Kumar Dubey

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A random variable X has the following probability distribution:          X: \: \: 1\; \; \: \: 2\; \;\: \: \: \: 3\; \; \: \: \: \: \: 4\: \: \: \; \; \: \: 5 P(X): \;K^{2}\; \; 2K\; \; K\; \; 2K\; \; 5K^{2} Then P(X>2) is equal to: 
Option: 1 \frac{7}{12}
Option: 2 \frac{23}{36}
Option: 3 \frac{1}{36}
Option: 4 \frac{1}{6}
 

Option 2

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Posted by

kpvalli2725@gmail.com

Let a_{n} be the nth term of a G.P. of positive terms. If \sum_{n=1}^{100}a_{2n+1}=200\: \: and\: \: \sum_{n=1}^{100}a_{2n}=100,\: \: then\: \sum_{n=1}^{200}a_n is equal to :   
Option: 1 300
Option: 2 175
Option: 3 225
Option: 4 150
 

150

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Posted by

Nalla mahalakshmi

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