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Ask QuestionPosted by Vinay Malik 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Hemophilia A. Hemophilia A is a disorder where the blood cannot clot properly due to a deficiency of a clotting factor called Factor VIII. This results in abnormally heavy bleeding that will not stop, even from a small cut. People with hemophilia A bruise easily and can have internal bleeding into their joints and muscles. The occurrence of hemophilia A (Factor VIII deficiency) is around 1 in 4500 live male births worldwide. The occurrence of hemophilia B (Factor IX deficiency) is one in 20,000 live male births worldwide. Hemophilia A accounts for most cases. Treatment is available by infusion of Factor VIII (blood transfusion). Female carriers of the gene may show some mild signs of Factor VIII deficiency, such as bruising easily or taking longer than usual to stop bleeding when cut. However, not all female carriers present these symptoms. One-third of all cases are thought to be new mutations in the family
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Yogita Ingle 5 years, 1 month ago
DNA is the main hereditary material, but some contain RNA too, e.g. retrovirus. RNA mostly plays the role of a messenger in higher organisms. Though both are nucleic acids, why is there a difference in functions? Scientists elucidate that, this is due to the difference between the chemical structure of DNA and RNA. For a molecule to be considered as genetic material, it must accomplish certain properties. They are as follows:
- Replication- the ability to make its copies.
- It should have chemical and structural stability.
- Mutation- it should offer a chance for evolution.
- It should possess a hereditary unit which follows “Mendelian inheritance”.
Posted by A Roy 5 years, 1 month ago
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Posted by A Roy 5 years, 1 month ago
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Meghna Thapar 5 years, 1 month ago
Regarding the distribution of blood volume within the circulation, the greatest volume resides in the venous vasculature, where 70-80% of the blood volume is found. For this reason, veins are referred to as capacitance vessels. The main difference between nerve and vein is that nerve is an axon bundle of neurons in the peripheral nervous system, which carries nerve impulses whereas veins are blood vessels, which return deoxygenated blood towards the heart. Both nerves and veins vary in size.
Posted by A Roy 5 years, 1 month ago
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Vansh Prajapati 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817. The presence of magnesium in chlorophyll was discovered in 1906, and was the first time that magnesium had been detected in living tissue.
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Posted by Ghost Of Tercia 5 years, 1 month ago
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Meghna Thapar 5 years, 1 month ago
- In DNA one strand is in 5' to 3' direction and another strand is in 3' to 5' direction. The DNA polymerase synthesize the new strand in 5' to 3' direction so one strand is synthesized continuously and other discontinuously.
- The strand which is synthesized regularly is called the leading strand and the strand which is synthesized in a discontinuous manner is called the lagging strand.
- The origin of replication is the site in DNA from where the replication starts. It is AT-rich region. So it is important to start replication in the direction of the replication fork.
Posted by ? Yang ? 5 years, 1 month ago
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Posted by Gowtham C S 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Anther is a four side structure consisting of four microsporangia located at each lobe. Each microsporangium consists of a unilayer of epidermal cells. Below epidermis, a layer of radially elongated cells called endothecium exists. Endothecium is followed by 2 or 3 middle layers of flattened and crushed parenchymatous cells. Below the middle layers is present tapetum, which is the innermost layer of microsporangium.
Posted by Gowtham C S 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Micropyle helps pollen tube to enter the ovule and then enters one of the synergids through the filiform apparatus.
Posted by Gowtham C S 5 years, 1 month ago
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Posted by Gowtham C S 5 years, 1 month ago
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Posted by Gowtham C S 5 years, 1 month ago
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Posted by Gowtham C S 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
A typical mature embryo sac of Angiosperms is a 7-celled and 8-nucleate structure.
(i) At the micropylar end, an egg apparatus is present which consists of an egg cell and 2 synergid cells. Synergids contain filiform apparatus which guides the pollen tube entry into the embryo sac during fertilisation.
(ii) At the chalazal end, three antipodal cells are present.
(iii) In the centre, two polar nuclei are present which get fused prior to fertilisation to form a diploid secondary nucleus.
Hence, 8 nuclei are constituted within 7 cells. Thus, embryo sac is 7-celled and 8-nucleate.
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Posted by Gowtham C S 11 months, 2 weeks ago
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Meghna Thapar 5 years ago
A monocot is a type of flowering plant that is characterized by having a single cotyledon, trimerous flowers, and parallel leaf veins. Monocots are economically important as food sources for both humans and animals, The embryo of each seed plant possesses one or more leaf-like structures called cotyledons, which absorb nutrients and may function as the first leaves in some plants. Monocots have a single such cotyledon, while other flowering plants usually have two. ... The image below at right shows a monocot embryo with cotyledon.
Posted by Gowtham C S 5 years, 1 month ago
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Meghna Thapar 5 years ago
Parts of typical dicot embryo includes- Plumule, cotyledons, hypocotyl, radical and root cap. A typical dicotyledonous embryo, consists of an embryonal axis and two cotyledons. The portion of embryonal axis above the level of cotyledons is the epicotyl, which terminates with the plumule or stem tip.
Development of a dicot embryo (i) Embryo formation starts after a certain amount of endosperm is formed. (ii) Zygote divides by mitosis to form a proembryo. (iii) Formation of globular and heart-shaped embryo occurs, which finally becomes horse shoe-shaped forms a mature embryo.
Posted by Gowtham C S 5 years, 1 month ago
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Posted by Gowtham C S 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Pollen-Pistil interaction
The pollen landing on stigma of pistil might be compatible or incompatible with the stigma. Therefore the acceptance or rejection of the pollen by stigma depends on the compatibility.
If the pollen & pistil are compatible with each other, following events will take place:
- Pistil accepts pollen
- Formation of pollen tube
- Pollen tube reaches ovary
- Pollen grains move into pollen tube
- Pollen tube enters ovule through micropyle
- Pollen tube enters a synergid through filiform apparatus
- Fertilization occurs
On the other hand, If the pollen & pistil are incompatible with each other, following events will take place:
- Pistil rejects pollen
- Prevents pollen tube growth
- Prevents fertilization
Therefore, Pollen-Pistil interaction can be defined as follows:
Pollen-pistil interaction is a dynamic process of pollen recognition followed by promotion or inhibition of the pollen. Chemical components of the pollen interact with those of the pistil.
Posted by Gowtham C S 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Entomophilous flowers: Flowers which are pollinated by insect are called entomophilous flowers.
Characters of Entomophilous flowers
(1) The flowers are of large size.
(2) Corolla of flowers is brightly coloured to attract insects. Bracts may become bright coloured
(3) If the flowers are small they are grouped together to form inflorescence which helps attracting insects.
(4) They may produce nectar to lure insects.
(5) The pollen grains are heavy with rough and spiny surface so that they stick to the insects body.
Posted by Gowtham C S 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
In vallisneria, the female flower reach the surface of water by the long stalk and the male flower or pollen grains are released into the surface of water. They are carried by water currents reaching the female flowers and the stigma.
In Water lily pollination takes place through wind or insect, female flower imerges above the surface of water and gets pollinated.
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Yogita Ingle 5 years, 1 month ago
Red-green color blindness. Red-green color blindness means that a person cannot distinguish shades of red and green (usually blue-green), but their ability to see is normal. There are no serious complications; however, those affected may not be considered for certain occupations involving transportation or the Armed Forces where color recognition is required. Males are affected more often than females, because the gene is located on the X chromosome.
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