Regeneration - class-VI

Starfish are known for their ability to regenerate amputated limbs and are characterized by flexible arms attached to a central disc. The central disc is essential for complete regeneration, however arms that are partially damaged/lost are regenerated by the organism

• There are different methods of asexual reproduction. 
• They include binary fission, fragmentation, and budding. 
• Binary fission occurs when a parent cell splits into two identical daughter cells of the same size.
• Fragmentation occurs when a parent organism breaks into fragments or pieces, and each fragment develops into a new organism. Starfish, like the one in Figure below, reproduce this way.
• Budding occurs when a parent cell forms a bubble-like bud. The bud stays attached to the parent cell while it grows and develops.

Regeneration is the ability to replace the lost or damaged body parts. Plants can regenerate all body parts from the precursor cells. Many trees, for example, can be cut off at the ground and in due course, sprouts appear. These go on to develop the new stem, leaves and flowers. So, regeneration is a process of restoration and growth and also a process of renewal.
Thus, the correct answer is option D.

Regeneration is the process of renewal, restoration, and growth of cells which lead to the renewal of lost or damaged parts or cells. All the cells of the body do not take part in the regeneration rather the cells involved in regeneration are cells which have immense potential to divide and differentiate. In lizards, the cells of blastema actively takes part in the regeneration and it is capable of growth composed of pleuripotent cells which retains memory of tissue origin. So, the given statement is true.

• The liver is the only internal organ that can regenerate itself.
• Hepatocytes are the liver cells that are responsible for the liver's ability to regenerate; they act as stem cells that can re-form liver tissue. The liver can regenerate after either surgical removal or after chemical injury. It is known that as little as 25% of the original liver mass can regenerate back to its full size.
• The lost portion of dissected liver regenerates by Compensatory hypertrophy i.e The growth which is a result of increased cell size.
• So, the correct answer is 'Compensatory hypertrophy'.

• The ability of the multicellular organism to repair certain damaged cells present in the Damaged parts and organs is called Reparative regeneration.
• Reparative regeneration is observed in both invertebrates and vertebrates.
• Hence Damaged parts and organs can be repaired by Reparative regeneration.
• So, the correct answer is 'Reparative regeneration'.

• Nemathelminthes  is a phylum of unsegmented, triploblastic, pseudocoelomic, cylindrical or thread-like worms which are covered by a body wall having cuticle and epidermis. They are commonly called threadworm or roundworm.
• The members of the phylum Nemathelminthes lacks the ability of regeneration because they do not have stem cells required for regeneration.
• So, the correct answer is 'Nemathelminthes'.

C- A mass of cell capable of growth and regeneration into organs or body parts is called as blastema that means these cells can grow in any type of cells except neurons.For the formation of blastema adult stem cells known as neoblasts are required before occurence of any regeneration.

• Regeneration process in higher animals involves a series of steps.1)Wound closure 2) Demolition and Defence 3)De-differentiation 4)Blastema Formation 5) Growth and 6)Re-differentiation.
• WOUND HEALING: Amputation or injury to organ results in exposure of the interior tissues to the outside. Some cells in the injured region get destroyed. There may be bleeding at the injured surface. The blood soon clots and blocks further flow of blood to the outside. Hence bleeding is stopped.
• Then the epidermal cells proliferate and migrate from all sides towards the center of the wound. Thus the epithelium forms a complete covering over the injured tissues underneath the blood clot. 
• Hence Wound closure step of regeneration stops the bleeding at the site of amputation.
• So, the correct answer is 'Wound closure'.

• Growth factors involved in regeneration phenomenon include Glial growth factor,  transferring, Epidermal growth factor, fibroblast growth factors.
• Fibroblast Growth Factors (FGFs) are potent regulators of cell proliferation, differentiation, and function and are critically important in normal development, tissue maintenance, wound repair and angiogenesis. 
  
• Fibroblast growth factor helps to induce the regeneration of blood vessels.
  
• So, the correct answer is ' Fibroblast Growth Factors (FGFs) '.

The process of storing energy in order for the body to maintain itself and grow is referred to as constructive metabolism or anabolism.
Anabolism is the synthesis process which requires energy (ATP). To gain energy, the cell undergoes glycolysis. As a result of glycolysis, there is decrease in the production of lactic acid and also RQ increases. RQ is the respiratory quotient which is calculated as:
RQ = (Volume of carbon dioxide released/ Volume of oxygen consumed)/ per unit time.
Thus, the correct answer is option D.

• The liver is the only internal organ that can regenerate itself.
• Hepatocytes are the liver cells that are responsible for the liver's ability to regenerate; they act as stem cells that can re-form liver tissue.
• The lost portion of dissected liver regenerates. It is an example of Compensatory hypertrophy i.e The growth which is a result of increased cell size.
  
• So, the correct answer is 'Compensatory hypertrophy'.

• Heteromorphic regeneration is the phenomenon in which a different organ develops from the one that has been removed. For example, In lobsters, the eye is regenerated, If it is removed from the eyestalk. But if the eye is removed along with optic ganglion, instead of eye an antenna like the organ is regenerated.
• This type of regeneration occurs in lower animals.
• Hence The eye of lobster is replaced by an antenna-like structure. It is an example of Heteromorphic regeneration.
• So, the correct answer is 'Heteromorphic regeneration'.

The process of renewal, restoration, and growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage is called Repetitive regeneration. In Hydra, it occurs as foot regeneration arising from the basal part of the body, and head regeneration, arising from the apical region. Head regeneration requires complex reconstruction of the area, while foot regeneration is much simpler, similar to tissue repair.

So,
the correct option is ‘Hydra’.

Formation
of new parts of the body, which are lost due to injury or accidents is called
Restorative regeneration. Regeneration  of broken arms is called Restorative
regeneration. It occurs in Echinoderms.

Formation of new parts of the body, which are lost due to injury or accidents is called Restorative regeneration. In tadpoles, regeneration of tails and hind limbs occur. It is restorative regeneration.

So,
the correct option is ‘Tail and hind limbs’.

Regeneration of damaged cells or tissues in the injured parts, in multicellular organisms is called reparative regeneration. It occurs in invertebrates and vertebrates.

So,
the correct option is ‘Healing of injury’.

Formation of new parts of the body, which are lost due to injury or accidents is called Restorative regeneration. In Salamander and Axolotl larvae regenerate Limbs, eye structures and intestine, jaws and external gills. It is called restorative regeneration.

So,
the correct option is ‘Both A and B’.

Formation of new cells or tissues in the body organs is called Regeneration. It is first discovered in hydra by Abraham Trembley.

So,
the correct option is ‘Trembly’.

Formation of new cells or tissues from injured parts of the body is called Regeneration. It occurs in plants as well as animals. Regeneration of Beak in birds, tails in lizards, fish fins are best examples of regeneration.

So,
the correct option is ‘all the above’.

Formation of new parts of the body, which are lost due to injury or accidents is called Restorative regeneration. It is found in invertebrates.

So,
the correct option is ‘in some invertebrate groups’.

The reconstruction of an entire animal from a small fragment by reorganizing the existing cells, is called Morphallaxis. The regenerated animal is far smaller than the original one after the completion of the process. It grows to attain the normal size. eg:Hydra.

So,
the correct option is ‘Reconstruction of the whole body’.

Formation of new parts of the body, which are lost due to injury or accidents is called Restorative regeneration. It decreases with increase in complexity of body organisation.

So,
the correct option is ‘increase in complexity of organisation’.

Formation of new cells or tissues from injured parts of the body is called Regeneration. It is controlled by epithelial cover, neural trophic factor, and hormones like adrenal and pituitary glands.

So,
the correct option is ‘Both neural and hormonal’.

Formation of new cells or tissues from injured parts of the body is called Regeneration. It occurs in plants as well as animals and human beings.  In human body, the only organ performs regeneration is liver.

So,
the correct option is ‘Liver'.

The ability of animals to regenerate lost parts is called regeneration. This was first reported by Abraham Trembely.

So,
the correct option is ‘Trembely’.

A.Morphallaxis - The reconstruction of an entire animal from a small fragment by reorganizing the existing cells, is called Morphallaxis.

B.Reparative bud - Regeneration of buds  in multicellular organisms is called reparative bud.

C.Blastema – A stumpy outgrowth or bulge or formed, by the accumulation of cells, during regeneration of injured part is called Blastema. It is one of the important step in the process of regeneration.

So,
the correct option is ‘Blastema’.

Regeneration of limbs or tail is a epimorphosis regeneration. Replacement of lost organ of the body by proliferating new cells from the surface of the injured part is called Epimorphosis regeneration. eg: Limb in a Salamander, Tail in a Lizard.

So,
the correct option is ‘Epimorphosis’.

a)Type of regeneration in Hydra is known as epimorphosis is false, because it is Morphallaxis.

b)Members of reptiles such as lizards exhibit autotomy are true.

c)Regeneration of limb in amphibians involves morphallaxis is false because it is a epimorphisms.

So, the correct option is ‘a and c are false but b is true’.

The reconstruction of an entire animal from a small fragment by reorganizing the existing cells is called Morphallaxis. The regenerated animal is far smaller than the original one after the completion of the process. It grows to attain the normal size. eg: Hydra.

So, the correct option is ‘Every fragment will grow into complete Hydra’.

The reconstruction of an entire animal from a small fragment by reorganizing the existing cells is called Morphallaxis. The regenerated animal is far smaller than the original one after the completion of the process. It grows to attain the normal size. In Hydra, morphallaxis takes place by intestinal cells.

So, the correct option is ‘Morphollaxis by intestinal cells’.

A.Morphogenesis – Formation of organs from the embryo is called Morphogenesis or organogenesis.

B.Epimorphosis - Regeneration of limbs or tail is an epimorphosis regeneration. Replacement of lost organ of the body by proliferating new cells from the surface of the injured part is called Epimorphosis.

C. Morphallaxis - The reconstruction of an entire animal from a small fragment by reorganizing the existing cells, is called Morphallaxis.

D. Accretionary growth – It involves a cell secretion to increase the volume of the extracellular spaces. Many adult tissues will only divide when induced by injury or other stimuli. It occurs in cartilage and bone.

So, the correct option is ‘Morphallaxis’.

Formation of new cells or tissues from injured parts of the body is called Regeneration. The greatest ability for regeneration is found in Planaria.

So,
the correct option is ‘Planaria’.

A.Morphallaxis – Regeneration of two transversely cut equal pieces of one Hydra into small Hydras is true.

B.Epimorphosis – Replacement of old and dead erythrocytes by the new ones is false because The regeneration of tissues or organs through the dedifferentiation of existing, differentiated adult tissues is called Epimorphosis.

C.Morphallaxis – Healing of wounds in the skin is false, because, The reconstruction of an entire animal from a small fragment by reorganizing the existing cells, is called Morphallaxis.

D.Epimorphosis – Regeneration of crushed and filtered out pieces of Planaria into as many new planarians is false, because The reconstruction of an entire animal from a small fragment by reorganizing the existing cells, is called Morphallaxis.

So, the correct option is ‘Morphallaxis – Regeneration of two transversely cut equal pieces of one Hydra into small Hydras is true’.

The spontaneous removal or casting off of a body part, especially when the organism is injured or under attack is autotomy or self ampulation. It is recorded in loss legs in crabs, loss of tails in lizards, loss of viscera in Holothurian echinoderms.

So,
the correct option is ‘Lizzards’.

a)Type of regeneration in Hydra is known as epimorphosis is false, because it is Morphallaxis.

b)Members of reptiles such as lizards exhibit autotomy is true.

c)Regeneration of limb in amphibians involves morphallaxis is false because it is an epimorphism.

So, the correct option is ‘a and c are false, but b is true’.

The spontaneous removal or casting off of a body part, especially when the organism is injured or under attack is autotomy or self amputation. It is recorded in loss legs in crabs, loss of tails in lizards, loss of viscera in Holothurian echinoderms.

So, the correct option is ‘Tail’.

A. Fish - can regenerate almost any part of their central nervous system.

B.Amphibia – can regenerate their limbs.

C.Birds – regenerate their hair cells, feathers.

D.Sea cucumber - can regenerate entire alimentary canal.

So, the correct option is ‘
Sea cucumber’.

A. Epimorphosis - Regeneration of limbs or tail is an epimorphosis regeneration. Replacement of lost organ of the body by proliferating new cells from the surface of the injured part is called Epimorphosis.

B. Reparative regeneration - Regeneration of damaged cells or tissues in the injured parts, in multicellular organisms is called reparative regeneration.

C. Metamorphosis - the process of transformation from an immature form to an adult form in two or more distinct stages.

D. Morphogenesis - the biological process that causes an organism to develop its shape.

So, the correct option is ‘Reparative regeneration’.

In Hydra, the germ cells are derived from the interstitial cells, which are ectodermal in origin.

Regeneration is the process by which certain organisms can replace or restore their lost or amputated body parts. Different organisms have different ability to regenerate their body parts. There are certain organisms such as starfish, crayfish, many reptiles and amphibians which exhibit remarkable tissue regeneration. For example, deer can regrow their antlers, lizards can regrow their tails and starfishes can regrow their limbs. Lizards discard their tails as a result of defense mechanism and can regrow it within 60 days. 

Regeneration is the process of renewal, restoration and growth that makes genomes, cells , organisms and ecosystems.
While reproduction is the biological process by which new individual organism, i.e., offspring are produced form their parents.
Thus, the correct answer is option (B), 'False'.

Planaria belongs to the phylum Platyhelminthes.

Many animals can regenerate, that is, regrow or grow new parts of their bodies to replace those that have been damaged. Echinoderms can regenerate missing limbs, arms, spines and even intestines (for example sea cucumbers). Some brittle stars and sea stars can reproduce asexually by breaking a ray or arm or by deliberately splitting the body in half. Each half then becomes a whole new animal. Planarians are flatworms when cut into pieces, each piece can grow into a new worm. Sea cucumbers have bodies that can grow to be three feet long and shows the phenomena of regeneration. Spiders can regrow missing legs or parts of legs. Sponges can be divided. The cells of the sponge will regrow and combine exactly as before. Starfish that lose arms can grow new ones, sometimes an entire animal can grow from a single lost arm. Birds (Aves) on the other hand, do not have this ability

Epimorphosis is a type of regeneration involving the formation of a blastema and cell proliferation. The formation of sperms is gametogenesis, not regeneration.

The spontaneous removal or casting off of a body part, especially when the organism is injured or under attack is autotomy or self ampulation. It is recorded in loss legs in crabs, loss of tails in lizards, loss of viscera in Holothurian echinoderms.

So,
the correct option is ‘All the above’.

The reconstruction of an entire animal from a small fragment by reorganizing the existing cells, is called Morphallaxis. The regenerated animal is far smaller than the original one after the completion of the process. It grows to attain the normal size. It is reported in Porifers, Coelenterates, flatworms, Nemarteans, and some ascidians.

So,
the correct option is ‘Porifers, Coelenterates, flatworms, Nemarteans, and some
ascidians’.

A. Morphallaxis - The reconstruction of an entire animal from a small fragment by reorganizing the existing cells, is called Morphallaxis.

B.Epimorphosis - The regeneration of tissues or organs through the dedifferentiation of existing, differentiated adult tissues

C.Epigenesis - The theory, now generally held, that an embryo develops progressively from an undifferentiated egg cell.

D. Auxetic growth – Growth takes place by the influence of auxins.

So, the correct option is ‘Auxetic growth’.

Formation of new cells or tissues in the body organs is called Regeneration. It is first discovered in hydra by Abraham Trembley.

So,
the correct option is ‘Hydra’.