2018 Solved Old Paper (BOT-101)
Ans.
Archaebacteria:-
> Archaebacteria are known to be the oldest living organisms on earth.
> They belong to the kingdom Monera and are classified as bacteria because they resemble bacteria when observed under a microscope.
> They are completely distinct from prokaryotes.
> They share slightly common characteristics with the eukaryotes.
Ans.
> The individual cells are prokaryotic in nature.
> Cell wall is made up of microfibrils and is differentiated into four (4) layers. The cell wall composed of mucopeptide, along with carbohydrates, amino acids and fatty acids.
Ans.
Virions:-
> Virion is different from a virus.
> It is nothing but a virus in an extracellular phase.
> Furthermore, it is a fully furnished viral molecule consisting of DNA or RNA material.
> It is also encapsulated by an external protein shell called a capsid.
> Mostly, these virions are spherical or rod-shaped structures.
> They usually provide a safe passage from the initial host to the second host.
> Also, they shield the genetic material from external damage.
Ans.
शुद्ध जलीय शैवाल (Fresh water Algae):- ये रूप ताजे जल या तालाबों, पूल, झीलों आदि के कम लवणता वाले जल में होते हैं।
(These forms occur in fresh water or in low salinity water of ponds, pool, lakes etc.)
i. स्थिर जल शैवाल (Stagnant water algae):- अधिकतर, मिक्सोफाइसी और क्लोरोफाइसी के सदस्य रुके हुए जल में विकसित होते हैं। जैसे- जिग्नीमा, ऊडोगोनियम, कारा, रिवुलेरिया, ग्लियोट्राइकिया
(Mostly, members of Myxophyceae and Chlorophyceae develop in stagnant water. Eg.- Zygnema, Oedogonium, Chara, Rivularia, Gleotrichia)
ii. प्रवाहित जल शैवाल (Running water algae):- कुछ शैवाल बहते पानी में पाए जाते हैं। ऐसे आवासों में पानी की गुणवत्ता में ऑक्सीजन की मात्रा अधिक होती है। जैसे- क्लैडोफोरा, यूलोथ्रिक्स, वाउचेरिया, बेट्रेकोस्पर्मम
(Some algae are found in running water. In such habitats, the quality of water contains a higher amount of oxygen. Eg.- Chladophora, Ulothrix, Vaucheria, Batrachospermum)
Ans.
The principal pigments are chlorophylls a (green), c-phycocyanin (blue) and c-phyco- erythrin (red). In addition, other pigments like β-carotene and different xanthophylls like myxoxanthin and myxoxanthophyll are also present.
Ans.
Phytoplasma:-
> Mycoplasmas are the smallest among the known aerobic prokaryotes.
> They were first discovered by Pasteur in 1843, during his work on the possible causal agent of pleuropneumonia of cattle. Thus they were called pleuro- pneumonia-like organism (PPLO). Pasteur was unable to isolate them in pure culture.
> Later, Nocard and Roux (1898), the French microbiologists, were successful in growing them in pure culture-medium containing serum and confirmed by inoculation and subsequent expression of disease in healthy cattle.
> Mycoplasmas are commonly found in soil, hot spring, sewage water and also in plants and animals including man. Borrel (1910) named these organisms Asterococcus mycoides. Later, in 1929, Nowak placed them under the genus Mycoplasma.
Ans.
Types of Vaccines:- Vaccines can be synthesized in many ways based on which they are classified:
1. Live attenuated vaccines:- Pathogens like virus or bacteria are weakened by genetic manipulations to limit its growth and thus do not cause disease to the host. In some modified versions of live vaccine an organism that is related to the pathogen is used that naturally grows poorly in humans. The weakened pathogen generates a broad immune response in the host similar to that shown by an infected individual with a natural pathogen.
Examples:-
i. Oral Sabin polio vaccine
ii. MRV Vaccine (Measles, Mumps, Rubella, and Varicella)
iii. Nasal influenza vaccine
iv. Bacille Calmette-Guerin (BCG) vaccine
v. Varicella vaccine
vi. Rotavirus vaccine
2. Inactivated or Dead vaccines:- The disease-causing pathogen is killed or inactivated, usually through a thermal (application of high temperature) or chemical (formalin etc.) process. Such vaccines, when administered, elicit a robust immune response that mimics most of the responses seen during an infection.
Examples:-
i. Typhoid vaccine
ii. Influenza vaccine
iii. Salk polio vaccine
iv. Hepatitis A vaccine
3. Acellular or Subunit vaccines:- Acellular means not containing the whole cells. Acellular vaccines do not contain the whole bacteria or viruses. Instead, they contain polysaccharides or proteins from the surface of the bacteria or virus. These polysaccharides or proteins are the parts that our immune system recognizes as ‘foreign’ and evoke immune response against them. There are many types of a cellular vaccines:
a. Toxoid Vaccine:- Some pathogenic bacteria release toxins or poisonous proteins when they attack the body. Some vaccines are made by inactivating these toxins chemically and called ‘toxoids’, because they look like toxins but not poisonous. They trigger a strong immune response.
Examples:-
i. Diphtheria vaccine
ii. Tetanus vaccine
iii. Pertussis vaccine
b. Conjugate Vaccine:- Earlier polysaccharide vaccines were made using sugar molecules present on the surface of the bacteria but it was found to be less effective in babies and young children. Researchers discovered that these vaccines can work better if the bacterial polysaccharide molecules are chemically linked or conjugated to a carrier protein. Addition of other proteins confers the immunological attributes of the carrier to the antigen and thus induces a stronger immune response effective enough for younger children also.
Examples:-
i. Haemophilus influenza type b (Hib) conjugate vaccine
ii. Pneumococcal conjugate vaccine
iii. Meningococcal C conjugate vaccine
c. Recombinant Vaccine:- A small piece of the DNA is taken from the disease-causing bacterium or virus. The particular gene is incorporated into plasmid or a carrier vehicle which enables production of large quantities of well-defined proteins, which are then used as vaccines.
Examples:-
i. Hepatitis B vaccine
ii. Human papillomavirus (HPV) vaccine
d. DNA/RNA Vaccine:- Genetic material, either DNA or RNA, from the pathogenic bacteria or virus is introduced into the human cells and then the cell machinery is employed to produce the protein encoded by the inserted gene(s) of the pathogen. Our body’s immune system detects such protein as a foreign agent and produces an immune response against the whole pathogen. At present, different types of nucleic-acid vaccines are in developmental, pre-clinical and clinical evaluation phases
Examples:- HIV vaccine
%20of%20New%20Picture.png){kind=small}
Ans.
Sexual Reproduction:- Except for individuals of the Cyanophyceae class, almost all algae undergo sexual reproduction. Gametes unite to produce zygotes while sexual reproduction. The combination of gametes from different parents will result in a new genetic establishment.
1. Autogamy:-
> Fusing gametes are formed from the very same mother cell throughout this process, and then after fusion, these produce a zygote.
> For the reasons mentioned above, autogamous plants do not display the emergence of any new characteristics, such as Diatoms (Amphora normani).
2. Hologamy:-
> Vegetative cells of various strains (+ and -) act as gametes in certain unicellular members, and then after fusion, they result in the formation of a zygote.
> This seems to be an inefficient method in terms of multiplication, however, it does result in the creation of new genetic varieties, such as Chlamydomonas.
3. Isogamy:-
> It is the merger of two gametes that are physiologically and morphologically identical, resulting in the formation of a zygote. Isogametes are a form of gamete.
> These are typically flagellates, such as Chlamydomonas Eugametos, Ulothrix, and others.
4. Anisogamy:-
> The uniting gametes are physiologically and morphologically distinct during this phase.
> The microgamete (male) is small and more aggressive, while the macrogamete (female) is bigger and less active, such as Chlamydomonas braunii.
> Physiological anisogamy differs from traditional anisogamy in that the uniting gametes share morphological similarities but vary physiologically.
> Zygnema, Spirogyra, can be some examples.
5. Oogamy:-
> It is a complex process in which a small motile (non-motile in Rhodophyceae) male gamete (sperm or antherozoids) is fertilised by a large non-motile female gamete (egg or ovum).
> Male gametes grow in antheridium, while female gametes grow in oogonium, such as Polysiphonia, Oedogonium, Chara, Batrachospermum, Vaucheria, Sargassum, Laminaria, and so on.
%20of%20New%20Picture.png)
Ans.
Reserve food material:-
> The primary product of photosynthesis i.e., starch is same in all groups of algae but due to accumulation of food over long period the nature of insoluble reserve food may be different.
> The nature of reserve food can be a criterion for distinction of different groups of algae.
> In Chlorophyceae the reserve food is starch.
> In Xanthophyceae oil and leucosine are reserve food materials.
> In Rhodophyceae rhodophycean or floridean starch.
> In Cyanophyceae myxophycean starches are the reserve foods.
> In Phaeophyceae the reserve food material is laminarin or mannitol.
%20of%20New%20Picture.png){kind=small}
Ans.
Nitrogen fixation in Algae:-
A. Nitrogen fixing Blue Green Algae:- Both free-living and symbiotic blue-green are found to fix N2. Three groups of freeliving N2-fixing blue-green algae are recognized: heterocystous algae, nonheterocystous filamentous algae and unicellar algae.
1. Heterocystous blue-green algae:-
> These algae fix N2 aerobically and microaerobically.
> The most common N2-fixing species belong to the genera:
i. Anabaena
ii. Aulosira
iii. Calothrix
iv. Cylindrospermum
v. Nostoc
vi. Scytonema
vii. Tolypothrix
viii. Fischerella
ix. Mastigocladus
x. Stigonema.
> These algae usually differentiate vegetative cells into heterocysts only when grown in the absence of combined nitrogen.
> This observation led Fogg (1949) to suggest that heterocysts are the sites of N2 fixation.
> Nitrogenase is located in the heterocysts under aerobic growth conditions.
> Heterocysts are suitable sites for nitrogenase because oxygen evolving Photosystem II is absent in them.
2. Nonheterocystous filamentous blue-green algae:-
> Most of these algae fix N2 only under microaerobic conditions.
Exceptions:- Trichodesmium and Microcoleus are exceptions to this general observation, since they were found to fix N2 in aerobic conditions.
> The most common N2-fixing species belong to the genera:
i. Lyngbya
ii. Phormidium
iii. Plectonema
iv. Oscillatoria
v. Trichodesmium
3. Symbiotic blue-green algae:-
> Some heterocystous and unicellular blue-green algae develop in symbiosis.
> They are found in association with other organism:
i. With Bryophytes:- Nostoc in Anthoceros.
ii. With Ferns:- Anabaena in Azolla
iii. With Gymnosperms:- Nostoc in Macrozamia
> The importance of Azolla containing Anabaena azollae has been recognized by farmers of the Southeast Asian countries for centuries. Azolla is commonly used as a green manure to improve the nitrogen balance in rice fields.
B. Biochemistry of Nitrogen fixation:-
- The nodule serves as site for N2 fixation.
- Nodule contains nitrogenase and leghaemoglobin.
- The nitrogenase has 2 components:
i. Molybdoferredoxin (Mo-Fe protein)
ii. Azoferredoxin (Fe-protein)
- The free di-nitrogen first bound to MoFe protein and is not released until completely reduced to ammonia.
- In this process ferredoxin serves as an electron donor to Fe-protein (nitrogenase reductase) which in turn hydrolyzes ATP and reduce Mo-Fe protein, the Mo-Fe protein in Turn reduce the substrate N2. The electrons and ATP are provided by photosynthesis and respiration of the host cells.
- Many intermediates are formed to form ammonia (NH3).
Dinitrogen → Hydrazine → Diamine → Ammonia
- Ammonia (NH3) is immediately protonated at physiological pH to form ammonium ion (NH4+). As NH4+ is toxic to plants, it is rapidly used near the site of generation to synthesize amino acids.
Ans.
General account of immunology:-
> Immunology is the study of the immune system and is a very important branch of the medical and biological sciences.
> The immune system protects us from infection through various lines of defence.
> If the immune system is not functioning as it should, it can result in disease, such as autoimmunity, allergy and cancer.
> The immune system consists of a complex network of cells and molecules, and their interactions.
Types of immunity:- There are two major types of immunity:
1. Innate Immunity or Natural or Non-specific Immunity
2. Acquired Immunity or Adaptive Immunity
1. Innate Immunity or Natural or Non-specific Immunity:-
> This type of immunity is present in an organism by birth.
> This is activated immediately when the pathogen attacks. Innate immunity includes certain barriers and defence mechanisms that keep foreign particles out of the body.
> Innate immunity refers to the body’s defence system.
> This immunity helps us by providing the natural resistance components including salivary enzymes, natural killer cells, intact skin and neutrophils, etc. which produce an initial response against the infections at birth prior to exposure to a pathogen or antigens.
> It is a long-term immunity in which our body produces the antibodies on its own. Our body has few natural barriers to prevent the entry of pathogens.
Types of Barriers:- The four types of barriers are:
i. Physical barrier:-
- These include the skin, body hair, cilia, eyelashes, the respiratory tract, and the gastrointestinal tract.
- These form the first line of defence.
- The skin does more than providing us with fair or dark complexions.
- Our skin acts as a physical barrier to the entry of pathogens.
- The mucus coating in our nose and ear is a protective barrier which traps the pathogen before it gets inside.
ii. Physiological barriers:-
- We know that our stomach uses hydrochloric acid to break down the food molecules.
- Due to such a strongly acidic environment, most of the germs that enter our body along with the food are killed before the further process is carried on.
- Saliva in our mouth and tears in our eyes also have the antibiotic property that does not allow the growth of pathogens even though they are exposed all day.
iii. Cellular barriers:-
- In spite of the physical and physiological barriers, certain pathogens manage to enter our body.
- The cells involved in this barrier are leukocytes (WBC), neutrophils, lymphocytes, basophil, eosinophil, and monocytes. All these cells are all present in the blood and tissues.
iv. Cytokine barriers:- The cells in our body are smarter than we give them credit for. For instance, in case a cell in our body experiences a virus invasion, it automatically secretes proteins called interferons which forms a coating around the infected cell and prevents the cells around it from further infections.
Cells Involved In Innate Immunity:-
i. Phagocytes:- These circulate through the body and look for any foreign substance. They engulf and destroy it defending the body against that pathogen.
ii. Macrophages:- These have the ability to move across the walls of the circulatory system. They release certain signals as cytokines to recruit other cells at the site of infections.
iii. Mast Cells:- These are important for healing wounds and defence against infections.
iv. Neutrophils:- These contain granules that are toxic in nature and kill any pathogen that comes in contact.
v. Eosinophils:- These contain highly toxic proteins that kill any bacteria or parasite in contact.
vi. Basophils:- These attack multicellular parasites. Like the mast cells, these release histamine.
vii. Natural Killer Cells:- These stop the spread of infections by destroying the infected host cells.
viii. Dendritic Cells:- These are located in the tissues that are the points for initial infections. These cells sense the infection and send the message to the rest of the immune system by antigen presentation.
2. Acquired Immunity or Adaptive Immunity:-
> Acquired immunity or adaptive immunity is the immunity that our body acquires or gains over time. Unlike the innate immunity, this is not present by birth.
> The ability of the immune system to adapt itself to disease and to generate pathogen-specific immunity is termed as acquired immunity. It is also known as adaptive immunity.
> An individual acquires the immunity after the birth, hence is called as the acquired immunity.
> It is specific and mediated by antibodies or lymphocytes which make the antigen harmless.
> The main function of acquired immunity is to relieve the victim of the infectious disease and also prevent its attack in future.
> It mainly consists of an advanced lymphatic defence system which functions by recognizing the own body cells and not reacting to them.
> The immune system of our body identifies the pathogens which have encountered in the past. It is mainly caused when a person comes in contact with the pathogen or its antigen.
> Our body starts producing antibodies to engulf the pathogen and destroy its antigen.
> When it encounters for the first time, it is called a primary response. Once a body gets used to these pathogens, antibodies are ready to attack them for the second time and are known as naturally acquired immunity.
> The acquired immunity in our body has certain special features.
Features of Acquired Immunity:-
i. Specificity:- Our body has the ability to differentiate between different types of pathogens, whether it is harmful or not, and devise ways to destroy them.
ii. Diversity:- Our body can detect vast varieties of pathogens, ranging from protozoa to viruses.
iii. Differentiate between self and non-self:- Our body has the unique ability to differentiate between its own cells and foreign cells. It immediately starts rejecting any foreign cell in the body.
iv. Memory:- Once our body encounters a pathogen, it activates the immune system to destroy it. It also remembers what antibodies were released in response to that pathogen, so that, the next time it enters, a similar procedure is followed by the body to eliminate it.
Cells Involved in Acquired Immunity:- The acquired immunity involves two types of cells: B-cells and T-cells.
i. B-cells:-
- They develop in the bone marrow.
- These cells are activated on their encounter with foreign agents. These foreign particles act as foreign markers.
- The B-cells immediately differentiate into plasma cells which produce antibodies specific to that foreign particle or so-called antigen.
- These antibodies attach to the surface of the antigen/foreign agent.
- These antibodies detect any antigen in the body and destroy it.
- The immunity dependent on B-cells is called humoral immunity.
ii. T-cells:-
- They originate in the bone marrow and develop in the thymus.
- T-cells differentiate into helper cells, cytotoxic cells, and regulatory cells. These cells are released into the bloodstream.
- When these cells are triggered by an antigen, helper T-cells release cytokines that act as messengers.
- These cytokines initiate the differentiation of B-cells into plasma cells which release antibodies against the antigens.
- The cytotoxic T-cells kills the cancer cells.
- Regulatory T-cells regulate immune reactions.
Types of Acquired Immunity:-
i. Humoral Immunity:-
- The antibodies produced by B-lymphocytes are present in the blood cells and they are transported all over the body. This is why it is called the humoral immune response as it consists of an antibody produced by the lymphocytes.
- It depends upon the action of antibodies circulating in the body. When an antibody on a B-cell binds with an antigen, humoral immunity comes into play. The antigen is internalized by the B cell and presented on the helper T cell. This activates the B-cell.
- The activated B cells grow and produce plasma cells.
- These plasma cells release antibodies in the bloodstream. The memory B cells retain the information about the pathogen to prevent any disease caused by that pathogen in the near future.
ii. Cell-mediated Immunity:-
- Cell-mediated immunity is initiated by the T helper cells.
- The cytotoxic T cells eliminate the infected cells from the body by releasing toxins, thereby, promoting apoptosis or programmed cell death.
- The T helper cells help to activate other immune cells. Cell-mediated immunity becomes clear in the case of transplant patients.
%20of%20New%20Picture.png){kind=small}
Ans.
Pigmentation:-
> The pigment is one of the most important criteria used in differentiation of classes in algae, as algae were initially and primarily separated on the basis of colour.
> The pigments in algae can be chlorophylls, carotenoids and Phycobilins.
a. Chlorophylls:-
- The chlorophylls in algae are chlorophyll a, b, c, d and e types.
- Chlorophyll a is present in all classes of algae.
- Only Chlorophyll a is found in Cyanophyceae.
- Chlorophyll a + b is found in Chlorophyceae and Charophyceae.
- Chlorophyll a + c is found in Phaeophyceae.
- Chlorophyll a + d is found in Rhodophyceae.
- Chlorophyll a+ e is found in Xanthophyceae.
b. Carotenoids:-
- The carotenoids are of two kinds: carotenes and xanthophylls.
i. Carotenes:- C40H56
- Carotenes play a key role in converting nascent oxygen produced during the photolysis of water into molecular oxygen. Therefore carotene prevents chlorophyll from photooxidation.
- There are 7-8 different types of carotenes in algae.
- β carotene is found in all classes of algae.
- α Carotene is found in Rhodophyceae.
- γ Carotene and lycopene are found in Chlorophyceae.
- ε Carotene is present in Bacillariophyceae.
ii. Xanthophylls:- C40H56O2
- There are about 22 types of xanthophyll’s commonly found in algae.
- The brown color in brown algae is because of a xanthophyll called fucoxanthin
- Xanthophylls are mono or dihydroxy carotenes.
- Red algae have red color also due to xanthophyll Phycoerythrin.
c. Phycobilins:-
- The phycobilins are water soluble pigments and can be phycocyanin, phycoerythrin and allophycocyanin.
- These are common only in Rhodophyceae and Cyanophyceae.
- In Rhodophyceae, R-phycoerythrin is the chief pigment and in Cyanophyceae, C-phycocyanin is the chief pigment.
%20of%20New%20Picture.png)
Ans.
Algal blooms:-
> An algal bloom is a rapid increase in the popullation of algae in an aquatic system.
> Algal blooms may occur in freshwater as well as marine environments.
> Result of an excess of nutrients (particularly p and n).
> Their growth - cause for other plants to die.
Harmful algal blooms (HAB):-
> A harmful algal blooms is an algal bloom that causes negative impacts to aquatic organisms via production of natural toxins, mechanical damage to aquatic organism.
> HABs are often associated with large-scale marine mortality events and have been associated with various types of shellfish poisonings and also fin fishes and other aquatic organisms .
> HABs in India:-
- Researchers have found toxic bloom has increased around 15 percent over the 12 years in indian seas.
- There was 80 harmful bloom recorded between the 1998-2010 in indian water.
> Worldwide Effects of HABs:-
- Light penetration levels in water decrease altering photosynthesis rate.
- Algal blooms may be harmful to seagrass and coral reef ecosystems and the connected food webs.
- Shellfish may accumulate algal toxins by feeding on the toxic phytoplankton resulting in fish kills, marine mammal distress, human illness and possible death.
> Reasons for Increase in HABs:-
- Global climate changes producing wider ranges for some species.
- Human contributions of increased nutrients and pollution in coastal waters and also fresh waters.
- Changes in local ecosystems that may allow exotic species to thrive if introduced.
- Upwelling.
- Formation of mud banks.
- Nutrients discharge on sea or fresh water through river.
- Eutrophication:- It is a process where by water bodies receive excessive amounts of nutrients, which results in excessive plant growth and formed algal bloom.
> Factors that can contribute to HABs:-
i. Excess nutrients (Eg.- phosphorus or nitrogen)
ii. Sunlight
iii. Low-water levels or low-flow conditions
iv. Calm water (low-wind conditions)
v. Warmer temperatures
> Examples of some HABs:-
i. Cyanobacteria (blue-green algae)
ii. Redtides:- Neurotoxic shellfish poisoning
iii. Ciguatera:- Gambierdiscus toxicus
iv. Alexandrium
v. Gymnodium
vi. Dynophysis
vii. Coolia monotis
viii. Prorocentrum lima.
Harmful effect of algal bloom:-
> Changes in levels of chemicals such as nitrogen and phosphorus from fertilizer, in the water.
> Algal blooms can deplete the oxygen and block the sunlight that other organisms need to live.
> Some can produce toxins that are harmful to the health of the environment- plants, animals, and people etc.
> Aquaculture industries.
Control method:-
> Biological:- Bacteria (Gymnodinium mikimotoi), Virus, Bivalves, Zooplankton etc.
> Chemical:- Copper sulfate, Alum etc.
> Physical