17 Most VSAQ’s of Biology in Human Welfare Chapter in Inter 1st Year Zoology (TS/AP)
2 Marks
VSAQ-1 : Define parasitism and justify this term.
Parasitism is a symbiotic relationship in which one organism, the parasite, benefits at the expense of another organism, the host. This relationship is characterized by the parasite deriving nourishment and shelter from the host while causing harm to it. Parasites can be categorized into ectoparasites, which live on the host’s external surface, and endoparasites, which live inside the host’s body. Ectoparasites include examples like human body lice (Pediculus humanus), while endoparasites, such as Taenia solium, reside within the host’s digestive tract, body cavities, organs, or tissues. This relationship justifies the term “parasitism” as it illustrates the one-sided benefit of the parasite while potentially causing harm or negative effects to the host.
VSAQ-2 : What is a hyper-parasite? Mention the name of one hyper-parasite.
A hyper-parasite is a parasite that parasitizes another parasite. In this complex relationship, the hyper-parasite lives on or within the primary parasite, benefiting from its host-parasite interaction.
One example of a hyper-parasite is Nosema notabilis, a cnidosporan parasite that resides inside another cnidosporan parasite called Sphaerospora polymorpha. Interestingly, Sphaerospora polymorpha itself is a parasite living in the urinary bladder of toadfish. Therefore, Nosema notabilis is a hyper-parasite that exploits the host Sphaerospora polymorpha, which is already a parasite within the toadfish’s urinary bladder. This complex relationship highlights the intricate nature of parasitism within the biological world.
VSAQ-3 : What do you mean by parasitic castration? Give one example.
Parasitic castration is when a parasite manipulates the reproductive system of its host, rendering it unable to reproduce normally. For instance, the barnacle Sacculina infects crabs, consuming their reproductive organs. Male crabs change into functional females, while female crabs lose their ability to reproduce. This benefits Sacculina by redirecting the host’s resources to its own growth and reproduction.
VSAQ-4 : Define neoplasia. Give one example.
Neoplasia is the uncontrolled growth of cells, forming abnormal structures, often linked to cancer. Some viruses can trigger neoplasia by disrupting normal cell growth regulation, leading to tumors or cancerous growths.
VSAQ-5 : A person is suffering from bowel irregularity, abdominal pain, blood and mucus in stool, etc., Based on these symptoms, name the disease and its causative organism.
The symptoms mentioned are typical of amoebiasis, caused by the protozoan parasite Entamoeba histolytica. This infection can lead to bowel irregularity, abdominal pain, and the presence of blood and mucus in stool. Medical attention is crucial for proper diagnosis and treatment.
VSAQ-6 : Define prepatent period. What is its duration in the life cycle of plasmodium vivax?
The prepatent period is the duration between the introduction of Plasmodium sporozoites into the bloodstream by a mosquito and the emergence of merozoites from infected red blood cells. In the life cycle of Plasmodium vivax, this period typically lasts about 8 days. During this time, the parasite undergoes development in the liver before entering the bloodstream, where it starts causing the symptoms of malaria.
VSAQ-7 : Define incubation period. What is its duration in the life cycle of plasmodium vivax?
The incubation period is the time interval between the entry of Plasmodium sporozoites into the bloodstream following a mosquito bite and the onset of malaria symptoms. In the case of Plasmodium vivax, the incubation period usually lasts approximately 10 to 14 days. During this period, the parasite undergoes maturation within the liver before entering the bloodstream, where it begins to infect red blood cells, leading to the manifestation of malaria symptoms.
VSAQ-8 : The eggs of Ascaris are called ‘mammillated eggs’. Justify.
The eggs of Ascaris lumbricoides, a parasitic roundworm, are called “mammillated eggs” due to their bumpy or rippled appearance. This term originates from the unique protein coat surrounding the eggs, which helps protect them and increases their chances of survival outside the host’s body. This feature aids in the transmission of the parasite through contaminated soil or food.
VSAQ-9 : What is meant by nocturnal periodicity with reference to the life history of a nematode parasite you have studied?
Nocturnal periodicity, in the context of nematode parasites like Wuchereria bancrofti, refers to the behavior of microfilaria larvae, which exhibit increased activity and movement in the peripheral blood circulation during the nighttime hours, typically between 10 pm and 4 am. This behavior is significant because it coincides with the feeding activity of the mosquito vector (Culex), which becomes infected when it bites an infected human host during the night. Subsequently, the infected mosquito can transmit the parasite to other individuals when it bites during nighttime, contributing to the transmission cycle of lymphatic filariasis.
VSAQ-10 : Distinguish between lymphadenitis and lymphangitis?
Lymphangitis is the inflammation of lymphatic vessels, while lymphadenitis is the inflammation of lymph nodes.
VSAQ-11 : In which way does tobacco affect the respiration? Name the alkaloid found in tobacco.
Tobacco affects respiration by increasing carbon monoxide and reducing oxygen in the blood. The alkaloid found in tobacco is nicotine.
VSAQ-12 : Define drug abuse.
Drug abuse is the excessive and non-medical use of drugs, leading to physical and psychological disturbances, and potentially causing irreparable damage to the body.
VSAQ-13 : From which substances ‘Smack’ and ‘Coke’ are obtained?
- “Smack” is a common name for “Heroin,” which is obtained from the opium poppy plant (Papaver somniferum).
- “Coke” is a common name for “Cocaine,” which is obtained from the coca plant (Erythroxylum coca).
VSAQ-14 : ‘Entamoeba histolytica is an obligatory anaerobe’. Justify.
Entamoeba histolytica is considered an obligatory anaerobe because it lacks mitochondria in its endoplasm. Mitochondria are responsible for aerobic respiration, which relies on oxygen. Since this parasite lacks the necessary organelles for aerobic respiration, it is unable to utilize oxygen for energy production. Instead, it relies on anaerobic metabolic pathways to generate energy, making it obligatory for Entamoeba histolytica to live and function in an anaerobic environment where oxygen is absent or in low concentrations.
VSAQ-15 : What are haemozoin granules? What is their significance?
Haemozoin granules, also known as malaria pigment, are insoluble crystalline structures formed by the malaria parasite during its digestion of hemoglobin. When the parasite ingests hemoglobin from the host’s red blood cells, it breaks down the globin part and converts the heme portion into haemozoin. These granules serve as a disposal mechanism for the toxic heme molecules, preventing them from damaging the parasite’s own cellular components. Detecting haemozoin in blood samples is also used for diagnosing malaria infections.
VSAQ-16 : What is exflagellation and what are the resultant products called?
Exflagellation is the process in which male gametocytes (microgametocytes) of the malaria parasite undergo flagellar movements and separate from the cytoplasm. As a result of exflagellation, the male gametocytes produce motile structures called male gametes or microgametes. These male gametes are essential for fertilizing female gametes (macrogametes) to complete the sexual reproduction of the malaria parasite within the mosquito host.
VSAQ-17 : Why is the syngamy found in Plasmodium called anisogamy?
The syngamy (fertilization) found in Plasmodium is called anisogamy because the two gametes involved, namely the male (microgamete) and female (macrogamete) gametes, are dissimilar in size. The male gamete (microgamete) is small and motile, while the female gamete (macrogamete) is relatively larger and non-motile. This difference in size between the two gametes is characteristic of anisogamy.