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

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

1 Answer

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. 
by

Related questions

What is crossing over? What is its significance?

Description : What is crossing over? What is its significance?

Last Answer : 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.  

‘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))

Individuals of species which occur in a particular area constitute: (a) Flora (b) Fauna (c) Population (d) Flora and fauna

Description : Individuals of species which occur in a particular area constitute: (a) Flora (b) Fauna (c) Population (d) Flora and fauna

Last Answer : Ans. ((c))

What is the role of golgi complex in cell division?

Description : What is the role of golgi complex in cell division?

Last Answer : Ans: During cell division the vesicles of Golgi are involved in the formation of cell plate at the equatorial region which eventually forms the middle lamellum. In this way Golgi plays a role in cytokinesis. 

Whent the subsidiary or neighboring cells have a common origin with the guard cells such type of stomata ontogeny is called as –

Description : Whent the subsidiary or neighboring cells have a common origin with the guard cells such type of stomata ontogeny is called as –

Last Answer : Whent the subsidiary or neighboring cells have a common origin with the guard cells such type of stomata ontogeny is called as – Mesogenous development

Crossing over takes place between which chromatids and in which stage of the cell cycle ? (a) Non-sister chromatids of non-homologous chromosomes at Zygotene stage of prophase I. (b) Non-sister chromatids of homologous chromosomes at Pachytene stage of prophase I. (c) Non-sister chromatids of homologous chromosomes at Zygotene stage of prophase I. (d) Non-sister chromatids of non-homologous chromosomes at Pachytene stage of prophase I.

Description : Crossing over takes place between which chromatids and in which stage of the cell cycle ? (a) Non-sister chromatids of non-homologous chromosomes at Zygotene stage of prophase I. (b) Non- ... prophase I. (d) Non-sister chromatids of non-homologous chromosomes at Pachytene stage of prophase I.

Last Answer : (b) Non-sister chromatids of homologous chromosomes at Pachytene stage of prophase I.

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))

What is Chakra Species ?

Description : What is Chakra Species ?

Last Answer : In this figure , the interbreeding populations are represented by colored blocks. Variation can form a circle by bending in front of Klein. In nature some populations are observed ... becomes impossible. The interbreeding populations of this circle were then collectively called chakra species.

The species of Pinus, seeds of which are edible is/ chilgoza comes from: (a) P. roxburghii (b) P. gerardiand (c) P. monophylla (d) P. sylvestris

Description : The species of Pinus, seeds of which are edible is/ chilgoza comes from: (a) P. roxburghii (b) P. gerardiand (c) P. monophylla (d) P. sylvestris

Last Answer : Ans. ((b))

Mary’s biological concept of species is mainly based on: (a) Morphological traits (b) Reproductive isolation (c) Modes of reproduction (d) Morphology and reproduction

Description : Mary’s biological concept of species is mainly based on: (a) Morphological traits (b) Reproductive isolation (c) Modes of reproduction (d) Morphology and reproduction

Last Answer : Ans. ((b))

Which of the following species of Pinus has trifoliar spur…. a) P. sylvestris b) P. merkusii c) P. gerardiana ' d) P. wallichiana

Description : Which of the following species of Pinus has trifoliar spur…. a) P. sylvestris b) P. merkusii c) P. gerardiana ' d) P. wallichiana

Last Answer : c) P. gerardiana '

Which of the following species of Pinus is commonly known as chir pine ......... a) P. roxburghii b) P. wallichiana c) P. insularis d) P. gerardiana

Description : Which of the following species of Pinus is commonly known as chir pine ......... a) P. roxburghii b) P. wallichiana c) P. insularis d) P. gerardiana

Last Answer : a) P. roxburghii

Which of the following species of Pinus is not found in India ............. a) Pinus merkusii b) P. gerardiana c) P. wallichiana d) P. maritima.

Description : Which of the following species of Pinus is not found in India ............. a) Pinus merkusii b) P. gerardiana c) P. wallichiana d) P. maritima.

Last Answer : d) P. maritima.

Basic taxonomic unit is a) Kingdom b) Genus c) Species d) Order

Description : Basic taxonomic unit is a) Kingdom b) Genus c) Species d) Order

Last Answer : c) Species

For successful grafting, stock and scion shall be a) Of different species b) Of same species c) Of similar groups d) Of different classA

Description : For successful grafting, stock and scion shall be a) Of different species b) Of same species c) Of similar groups d) Of different classA

Last Answer : b) Of same species

Roses can grow successfully if stock and scion are a) Of related species b)Of different species c) Of different groups d) Of similar class

Description : Roses can grow successfully if stock and scion are a) Of related species b)Of different species c) Of different groups d) Of similar class

Last Answer : a) Of related species

Where does convergence occur ?

Description : Where does convergence occur ?

Last Answer : Absorption occurs at the root.

How do flower pollinators occur ?

Description : How do flower pollinators occur ?

Last Answer : Two ways. 1. Self-pollination. 2. After pollination.

Consider the following statements: (1) Cucurbits are monoecious plant (2) In mango, neuter, male and female and female flowers occur together (3) Legumenous plants how unisexuality (4) Oblique septa is found in Rosaceae

Description : Consider the following statements: (1) Cucurbits are monoecious plant (2) In mango, neuter, male and female and female flowers occur together (3) Legumenous plants how unisexuality (4) Oblique septa is found in Rosaceae

Last Answer : Ans. ((b))

Which one does not occur is Seleaginella? (a) Heterospory (b) Hetorophylly (c) Homospory (d) Ligulate Leaves

Description : Which one does not occur is Seleaginella? (a) Heterospory (b) Hetorophylly (c) Homospory (d) Ligulate Leaves

Last Answer : Ans. ((c))

What is microsporogenesis? Where does it occur in angiosperm?

Description : What is microsporogenesis? Where does it occur in angiosperm?  

Last Answer : Ans: It is formation of microspores from microspore mother cell upon reduction division. It occurs in the microsporangium of Anther. 

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.

What are bundle sheath extensions? What is their role?

Description : What are bundle sheath extensions? What is their role? 

Last Answer : Ans: The extensions of bundle sheath of leaf towards adaxial and abaxial sides of leaf are called as bundle sheath extensions. They help in conduction and providing mechanical strength. 

What are bulliform cells? What is their role?

Description : What are bulliform cells? What is their role?

Last Answer : Ans: Specialised larger epidermal cells seen in the upper epidermis of grass leaves which store water are called as bulliform cells or motor cells. They help in rolling and unrolling of lamina. 

Role of CFC present in atmosphere is to a) Reduction in ozone b) Ozone formation c) Formation of leg haemoglobin a) Enhance chlorophyll formation.

Description : Role of CFC present in atmosphere is to a) Reduction in ozone b) Ozone formation c) Formation of leg haemoglobin a) Enhance chlorophyll formation.

Last Answer : a) Reduction in ozone

Which does NOT occur in a cell stimulated by a steroid hormone? A) The steroid hormone enters the cell by crossing the plasma membrane. B) The hormone binds to a receptor molecule in the cytoplasm. C) The second messenger cyclic AMP is stimulated by the hormone-receptor complex. D) The hormone-receptor complex binds the chromatin and activates certain genes. E) DNA is transcribed, mRNA is translated, and the result is protein synthesis.

Description : Which does NOT occur in a cell stimulated by a steroid hormone? A) The steroid hormone enters the cell by crossing the plasma membrane. B) The hormone binds to a receptor molecule in the ... activates certain genes. E) DNA is transcribed, mRNA is translated, and the result is protein synthesis.

Last Answer : C) The second messenger cyclic AMP is stimulated by the hormone-receptor complex. D) The hormone-receptor complex binds the chromatin and activates certain genes.

Assertion : Crossing over take place during pachytene stage. Reason : It is a process of interchange of chromatid material between non sister chromati

Description : Assertion : Crossing over take place during pachytene stage. Reason : It is a process of interchange of chromatid material between non sister chromati

Last Answer : Assertion : Crossing over take place during pachytene stage. Reason : It is a process of interchange of ... D. If both Assertion & Reason are false.

In which stage, crossing over takes place?

Description : In which stage, crossing over takes place?

Last Answer : Ans. Pachytene stage

why crossing over cannot occur of linked genes -Biology

Description : why crossing over cannot occur of linked genes -Biology

Last Answer : answer:

why crossing over cannot occur of linked genes -Biology

Description : why crossing over cannot occur of linked genes -Biology

Last Answer : answer:

Crossing over and recombination occur during

Description : Crossing over and recombination occur during

Last Answer : Ans. Meiosis division

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.

In which process of plant protoplasm and cell wall absorbs water ?

Description : In which process of plant protoplasm and cell wall absorbs water ?

Last Answer : The plant absorbs water in the process of protoplasm and cell wall adsorption.

Which cell acts as a semi-permeable screen in a cell ?

Description : Which cell acts as a semi-permeable screen in a cell ?

Last Answer : Answer : The plasma membrane in a cell acts as a semipermeable membrane.

What is the cell wall made of ?

Description : What is the cell wall made of ?

Last Answer : The cell wall is made up of cellulose.

Which of the following are true archaebacteria? (1) Extreme halophiles (2) Extreme thermophyles (3) Methanogens (4) Presence of peptidoglycan cell wall Ans. (a) 43; Which of the following are endangered plants ? (1) Saintpaulia ionantha (2) Ceratozamia hildae (3) Punica granatum (4) Senecio hadrasomum

Description : Which of the following are true archaebacteria? (1) Extreme halophiles (2) Extreme thermophyles (3) Methanogens (4) Presence of peptidoglycan cell wall Ans. (a) 43; Which of the following are ... plants ? (1) Saintpaulia ionantha (2) Ceratozamia hildae (3) Punica granatum (4) Senecio hadrasomum

Last Answer : Ans. ((c))

Consider the following statement: (1) In plant cells, cytokinesis start with the formation of the phragmoplast (2) Phragmoplast comprises intrazonal microtubules and Golgi vesicles (3) Primary cell wall is produced by microtubules (4) Phragmoplast is formed by nucleus

Description : Consider the following statement: (1) In plant cells, cytokinesis start with the formation of the phragmoplast (2) Phragmoplast comprises intrazonal microtubules and Golgi vesicles (3) Primary cell wall is produced by microtubules (4) Phragmoplast is formed by nucleus

Last Answer : Ans. ((a))

Which of the following statement is correct? (1) The causal organism for foolish seedling disease is the source of gibberellin (2) Abscisic acid is a growth promoter (3) The ratio of auxin : cytokinin control cell differentiation (4) Bolting of cabbage can be induced by treatment with IAA

Description : Which of the following statement is correct? (1) The causal organism for foolish seedling disease is the source of gibberellin (2) Abscisic acid is a growth promoter (3) The ratio of auxin : cytokinin control cell differentiation (4) Bolting of cabbage can be induced by treatment with IAA

Last Answer : Ans. ((d))

Cell ‘A’ with O.P = 10 atm and T.P =5 atm is in contact with cell ‘B’ having O.P = 15 atm and T.P = 12 atm. The flow of water will be: (a) From A to B (b) Equal flow (c) From B to A (d) No flow

Description : Cell ‘A’ with O.P = 10 atm and T.P =5 atm is in contact with cell ‘B’ having O.P = 15 atm and T.P = 12 atm. The flow of water will be: (a) From A to B (b) Equal flow (c) From B to A (d) No flow

Last Answer : Ans. ((c))

Colchicines bring about: (a) Polyploidy (b) Cell division (c) Cell elongation (d) Cell differentiation

Description : Colchicines bring about: (a) Polyploidy (b) Cell division (c) Cell elongation (d) Cell differentiation

Last Answer : Ans. ((a))

The process by which the amount of DNA, RNA and protein can be known at a time is: (a) Cell fractionation (b) Autoradiography (c) Phase-contrast microscopy (d) Tissue culture

Description : The process by which the amount of DNA, RNA and protein can be known at a time is: (a) Cell fractionation (b) Autoradiography (c) Phase-contrast microscopy (d) Tissue culture

Last Answer : Ans. ((b))

Cell organelle covered by single unit membrane is: (a) Glyoxisome (b) Lysosome (c) Peroxisomes (d) All of these.

Description : Cell organelle covered by single unit membrane is: (a) Glyoxisome (b) Lysosome (c) Peroxisomes (d) All of these.

Last Answer : Ans. ((d))

The cell wall of both bacteria and cyanobactena contains: (a) Lipid (b) Pectin (c) Protein (d) muramic acid

Description : The cell wall of both bacteria and cyanobactena contains: (a) Lipid (b) Pectin (c) Protein (d) muramic acid

Last Answer : Ans. ((d))

If a sporangium derived from a single cell is called (a) Leptosporangiate (b) Eusporangiate (c) Heterosporangiate (d) None of the above

Description : If a sporangium derived from a single cell is called (a) Leptosporangiate (b) Eusporangiate (c) Heterosporangiate (d) None of the above

Last Answer : Ans. ((a))

In angiosperms regarding development of microgametophyte each microspore mother cell undergoes (a) Mitosis to produce 4 microspores (b) Two successive mitosis to form 4 microspores (c) Two successive meiotic division to form 4 microspores (d) Meiosis to produce 4 haploid microspores

Description : In angiosperms regarding development of microgametophyte each microspore mother cell undergoes (a) Mitosis to produce 4 microspores (b) Two successive mitosis to form 4 microspores (c) Two successive meiotic division to form 4 microspores (d) Meiosis to produce 4 haploid microspores

Last Answer : Ans. ((d))

In spite of several angiospermic features Gnetum is a gymnosperm because…. a) polyembryony is a common features b) prothallial cell is present in the male gametophyte c) seed is naked d) stem exhibit anomalous secondary growth

Description : In spite of several angiospermic features Gnetum is a gymnosperm because…. a) polyembryony is a common features b) prothallial cell is present in the male gametophyte c) seed is naked d) stem exhibit anomalous secondary growth

Last Answer : c) seed is naked

Cell sap is found inside a. Protoplasm b. Cytoplasm c. Nucleoplasm d. Vacuole

Description : Cell sap is found inside a. Protoplasm b. Cytoplasm c. Nucleoplasm d. Vacuole

Last Answer : d. Vacuole

When the embryo develops from haploid egg cell without fertilization, the phenomenon is called as

Description : When the embryo develops from haploid egg cell without fertilization, the phenomenon is called as

Last Answer : When the embryo develops from haploid egg cell without fertilization, the phenomenon is called as – Haploid parthenogenesis

When a diploid embryosac is formed from a megaspore mother cell without meiosis, it is called as

Description : When a diploid embryosac is formed from a megaspore mother cell without meiosis, it is called as

Last Answer : When a diploid embryosac is formed from a megaspore mother cell without meiosis, it is called as – Diplospory

During microsporogenesis, successive type of cell division is found in

Description : During microsporogenesis, successive type of cell division is found in

Last Answer : During microsporogenesis, successive type of cell division is found in – Monocots