What is crossing over? What is its significance?

What is crossing over? What is its significance?
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Ans: Exchange of genetic material between homologous chromosomes during pachytene of meiosis is called as crossing over. It brings about variations in the offspring due to recombination. It helps in natural selection and evolution.  
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Related questions

In which stage of cell does crossing over occur? What is its role in the origin of species?

Description : In which stage of cell does crossing over occur? What is its role in the origin of species? 

Last Answer : Ans: Pachytene of Meiosis. It brings about variations in the off spring. Continuation of these variations for several generations leads to origin of new species. 

‘Illegitimate crossing over’ is another term for (a) Transition (b) Transversion (c) Reciprocal translocation (d) None of the above

Description : ‘Illegitimate crossing over’ is another term for (a) Transition (b) Transversion (c) Reciprocal translocation (d) None of the above

Last Answer : Ans. ((c))

Write about the events of Pachytene and mention the significance of this phase.

Description : Write about the events of Pachytene and mention the significance of this phase. 

Last Answer : Ans: Events of Pachytene: 1. The two chromatids of chromosome are clearly seen. Each bivalent has 4 chromatids and known as Pachytene tetrad. Chromatids of the same chromosome are called as Sister ... This is responsible for the origin of new species which is one of the causes of evolution.

What is the significance of S-phase of cell cycle?

Description : What is the significance of S-phase of cell cycle? 

Last Answer : Ans: During S phase there is doubling of DNA due to semiconservative replication of DNA. The two chromatids of chromosomes are formed at the end of this stage. 

Consider the following statements: Marchantia polymorpha (1) Is dioecious (2) Possesses antheridiophores and archegoniophores (3) Lacks foot and seta in its sporophyte (4) Is heterosporous

Description : Consider the following statements: Marchantia polymorpha (1) Is dioecious (2) Possesses antheridiophores and archegoniophores (3) Lacks foot and seta in its sporophyte (4) Is heterosporous

Last Answer : Ans. ((b))

The study of interelationship between species and its environment of a forest is called: (a) Autecology (b) Syneocology (c) Forest ecology (d) Co-operation

Description : The study of interelationship between species and its environment of a forest is called: (a) Autecology (b) Syneocology (c) Forest ecology (d) Co-operation

Last Answer : Ans. ((a))

A plant having two types of haploid structures in its life cycle is known as: (a) Haplobiontic (b) Diplobiontic (c) Haplontic (d) Diplontic

Description : A plant having two types of haploid structures in its life cycle is known as: (a) Haplobiontic (b) Diplobiontic (c) Haplontic (d) Diplontic

Last Answer : Ans. ((a))

The abortive female flower in the male cone of Gnetum can be distinguished from the normal ovules of the female cone apart from its function by the presence of …. a) no envelops b) single envelope c) two envelopes d) several envelops.

Description : The abortive female flower in the male cone of Gnetum can be distinguished from the normal ovules of the female cone apart from its function by the presence of …. a) no envelops b) single envelope c) two envelopes d) several envelops.

Last Answer : b) single envelope

Name the living mechanical tissue? What is its function?

Description : Name the living mechanical tissue? What is its function?

Last Answer : Ans: Collenchyma. It helps in providing mechanical strength in aerial parts of dicots. If green, it carries out photosynthesis. Sometimes it is meristematic and gives rise cork cambium in dicot stems at the time of secondary growth.  

What is chlorenchyma? What is its function?

Description : What is chlorenchyma? What is its function? 

Last Answer : Ans: Parenchyma with chloroplasts is called as Chlorenchyma. It carries out photosynthesis.  

What is exodermis? What is its function.

Description : What is exodermis? What is its function. 

Last Answer : Ans: Suberised peripheral region of root cortex is called as exodermis. It provides mechanical strength and prevents the leakage absorbed mineral water.  

Name the special inflorescence which has a single flower and many male flowers. What are its cymose characters?

Description : Name the special inflorescence which has a single flower and many male flowers. What are its cymose characters?

Last Answer : Ans: The inflorescence is Cyathium. The male flowers are arranged in scorpioid cymes. 

Which underground stem modification does not possess roots? Mention its scientific name.

Description : Which underground stem modification does not possess roots? Mention its scientific name. 

Last Answer : Ans: Stem tuber is the underground stem modification that does not possess roots. Solanum tuberosum is its scientific name.  

Who invented Electron Microscope and what was its use?

Description : Who invented Electron Microscope and what was its use?

Last Answer : Ans: Knoll and Ruska invented Electron Microscope. It is used to know the finer details of the cell  

What is meant by unit membrane and what is its approximate thickness?

Description : What is meant by unit membrane and what is its approximate thickness? 

Last Answer : Ans: Any biological membrane with bimolecular lipid zone surrounded by monomolecular protein zones is called as unit membrane by Robertson. Its thickness is 75A0 .  

How do you care for an orchid?

Description : How do you care for an orchid?

Last Answer : I have two, and they require almost no care except water. It is the time of year they shed their blossoms so don’t worry. In the spring they will come right back.

Where's can I buy one of those new "Jumbo" Venus Flytrap's?

Description : Where's can I buy one of those new "Jumbo" Venus Flytrap's?

Last Answer : You can buy them at The Little Shop of Horrors.

What happens to a fully grown fruit tree if it is transplanted?

Description : What happens to a fully grown fruit tree if it is transplanted?

Last Answer : Fruit trees are so cheap…why not just plant a new one?

What is the mechanism for motion in plants?

Description : What is the mechanism for motion in plants?

Last Answer : dude, I think this can be googled…. ;-P sorry if i sound like a smart alec….

What is cookoo spit?

Description : What is cookoo spit?

Last Answer : answer:You’re close. The guys inside the foam are called Spittle Bugs and there are 23,000 species of them More info

What is Cerebellum ?

Description : What is Cerebellum ?

Last Answer : The segment on the opposite side of the pons is the cerebellum. It stays in a very buoyant state.

Why do fruits fall prematurely ?

Description : Why do fruits fall prematurely ?

Last Answer : Hormone is the chemical substance that is produced in the cell and carried from the place of origin to control the functions of the cell at a distant place. Hormone deficiency causes various problems in ... of fruits. If the plant lacks a hormone called auxin, the fruit will fall off prematurely.

What does tropic movement mean ?

Description : What does tropic movement mean ?

Last Answer : Plants have the same sensory capacity as other organisms. Therefore, the stimulation that externally stimulates the plant body results in the movement and growth of the plant. These movements are called tropical movements. For example, the effect of light is to move towards the light of the stem.

What is the role of auxin in plants ?

Description : What is the role of auxin in plants ?

Last Answer : The role of auxin in plants is as follows : Prevents premature fall of fruit. Helps to produce seedless fruit. Auxin is also used for seed germination and weed control.

Where is the lenticel located ?

Description : Where is the lenticel located ?

Last Answer : Located on the lenticel stem.

What is the name of the reproductive organ ?

Description : What is the name of the reproductive organ ?

Last Answer : Stolon is the name of the reproductive organ.

What is the upper part of the embryonic root called ?

Description : What is the upper part of the embryonic root called ?

Last Answer : The upper part of the embryonic root is called the hypocotyl.

What does Patal propagate through ?

Description : What does Patal propagate through ?

Last Answer : Patal propagates through roots.

What is the seed after fertilization ?

Description : What is the seed after fertilization ?

Last Answer : After fertilization, the egg becomes a seed.

What happens after fertilization ?

Description : What happens after fertilization ?

Last Answer : After fertilization, the uterus becomes a result.

title : _

Description : title : _

Last Answer : Kachura branch stems are changed for reproduction.

Why Flowers Are Needed ?

Description : Why Flowers Are Needed ?

Last Answer : The outermost stem of a flower is called a circle. The stalk protects other parts of the flower especially from sun , rain and insects in the twenties. That is why swelling is required.

Why Insects Are Called A Means Of Pollination ?

Description : Why Insects Are Called A Means Of Pollination ?

Last Answer : A means of insect pollination. Insects swarm around to eat honey or attract beautiful colors. At this time the pollen sticks to the carrier. Whenever this carrier sits on another flower of the same species ... to the head of the next flower. This is why insects are called the medium of pollination.

What do you mean by inflorescence ?

Description : What do you mean by inflorescence ?

Last Answer : The flowers are arranged in a special way on a branch arising from the desired buds at the apex of the stem. This branch with flowers is called inflorescence. It is very important for ... is infinite then irregular inflorescence and if the growth is finite then it is called infinite inflorescence.

Explain "Shimal Animal Pollen Flower" ?

Description : Explain "Shimal Animal Pollen Flower" ?

Last Answer : Animal flowers are usually fairly large. However, even though it is small, the flowers are decorated with inflorescences. Their colors are attractive. All these flowers may or may not have an odor. As these features are present in Shimul flower, Shimul flower is also an animal flower.

What does tuber mean ?

Description : What does tuber mean ?

Last Answer : Tuber is a type of transformed stem. Some plants swell as a result of food storage at the apex of the lower branches of the soil and form tubers , called tubers. In the future, this tuber works for ... scaly leaf-like (scales) chamber. From each eye an independent plant is born , such as a potato.

Why do cell walls absorb water ?

Description : Why do cell walls absorb water ?

Last Answer : Plant cell walls absorb water. Because in the case of plants the cell walls are colloidal substances. And different types of colloidal substances exist in plants. Such as starch , gelatin , cellulose etc. These substances are able to absorb water due to their colloidal properties.

Why is Chupri potato called Bulbil ?

Description : Why is Chupri potato called Bulbil ?

Last Answer : The desired buds of chupari potato do not grow properly but take the shape of a lump and after a while fall from the tree and fall to the ground and give birth to new tree. That is why chupari potato is called bulbil.

What is a seed bag ?

Description : What is a seed bag ?

Last Answer : Plant body cells change to form a germ-carrying organ, called a granule sac.

Why Artificial Organisms Are Reproduced in Non-Flowering Plants ?

Description : Why Artificial Organisms Are Reproduced in Non-Flowering Plants ?

Last Answer : As the sexual reproduction of non-flowering plants is not complete, artificial reproduction is done.

Why colorful flowers are helpful for pollination ?

Description : Why colorful flowers are helpful for pollination ?

Last Answer : Insects or birds float around in the attraction of the beautiful color of colorful flowers. At this time the pollen sticks to the carrier. When this carrier sits on another flower of the ... the work of pollination is done without their knowledge. So colored flowers are conducive to pollination.

What is organ reproduction ?

Description : What is organ reproduction ?

Last Answer : Reproduction that takes place when a part of the body is broken or an organ is transformed without producing any kind of asexual molecule or germ cell is called organ reproduction.

What is photosynthesis ?

Description : What is photosynthesis ?

Last Answer : The process by which green plants prepare sugary foods with carbon dioxide and water in the presence of sunlight is called photosynthesis.

Why is polythene called impenetrable curtain ?

Description : Why is polythene called impenetrable curtain ?

Last Answer : The membrane through which the molecules of both solvent and solvent cannot move is called impermeable membrane. Both solvents and solvent molecules cannot move through polythene. That is why polythene is called impermeable screen.

Why Water and Mineral Salt Are Important for Plant Growth ?

Description : Why Water and Mineral Salt Are Important for Plant Growth ?

Last Answer : Water and mineral salts are important for plant growth. This is because the solution of this water and mineral salt reaches the leaves through the stems and branches. The leaves use them in the process of ... parts of the body. And by eating this food, the plant survives and the plant grows.

Why is the process of perspiration very important for plants ?

Description : Why is the process of perspiration very important for plants ?

Last Answer : As a result of perspiration, the plant gets rid of excess water pressure by expelling water from its body. Perspiration increases the concentration of juice in the cells. Increasing the ... maintains the moisture of the leaves. For this reason perspiration is very necessary for plants.

Why is sweating called Necessary evil ?

Description : Why is sweating called Necessary evil ?

Last Answer : Perspiration is an inevitable process in plant life. As a result of perspiration, a lot of water evaporates from the body of the plant. It can also cause plant death. Therefore, perspiration seems to ... process in the life of plants. This is why perspiration is called a Necessary evil for plants .

What does Imbibition mean ?

Description : What does Imbibition mean ?

Last Answer : The process by which different colloidal substances absorb different types of liquids is called imbibition. Starch , cellulose , gelatin , cell wall etc. are colloidal substances in plants. ... colloidal properties. Dried seeds absorb the required amount of water during the germination process.

What do plants leave during photosynthesis ?

Description : What do plants leave during photosynthesis ?

Last Answer : Plants release oxygen during photosynthesis.

What is transportation ?

Description : What is transportation ?

Last Answer : Transportation of food made from leaves spread throughout the body of a plant is called transport.