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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

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

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 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

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

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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

Which part of cell is known as Kitchen ? a) Mitochondria b) Chloroplasts c) Membranes d) Cytoplasm

Chloroplasts is known as the Kitchen of the cell. Thus the option (b) is the right answer. 

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Posted by

Deependra Verma

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Write the name of some carnivorous animals?

Carnivorous animals depend for food and energy requirements on animals flesh and other animal products. Some carnivorous animals are following- 

1- Lion

2- Polar Bear 

3- Leopard 

4- Wolf 

5- Tiger

6- Giant Panda

 

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Posted by

Deependra Verma

Who is the father of human cell?

Robert Hooke is the father of human cell. He discovered cell in 1665.

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Posted by

Deependra Verma

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What os Pathogen? What are the types of pathogen?

Pathogens are an agents, causing illness. Pathogens are usually known as microorganisms that causes serious diseases. There are five types of Pathogen-

1- Virus 

2- Bacteria 

3- Fungi

4- Protozoa 

5- Worms 

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Posted by

Deependra Verma

Which part of brain is responsible for intelligence?

Cerebrum is responsible for intelligence. Cerebrum is the largest part of the brain. It performs higher functions like interpreting touch, vision, hearing, intelligence emotions etc.

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Posted by

Deependra Verma

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