QUIZ 107 - 16/4 (solution)
QUIZ 107 - 16/4 (solution)
This is 107th quiz of series Quiz 2023 presented by step to fisheries.
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- The size of rotifer is
(a) 100 – 500 micron
(b) 75
micron
(c) 25 micron
(d) 100 - 500 micron.
The size of a rotifer can vary depending on the species. Rotifers are a group of microscopic, aquatic animals that are found in freshwater, marine, and damp soil environments. Some species of rotifers are as small as 50 micrometers in length, while others can grow up to several millimeters in length. The largest species of rotifers can reach up to 2 millimeters in length. Despite their small size, rotifers are important members of aquatic ecosystems and play an important role in nutrient cycling and food webs.
Rotifers are commonly used in aquaculture as a live food source for larval fish, shrimp, and other aquatic animals. They are rich in essential nutrients such as proteins, lipids, and amino acids, which are important for the growth and development of aquatic organisms.
Rotifers are relatively easy to culture and can be produced in large numbers using simple culture techniques. They are also highly adaptable and can tolerate a wide range of environmental conditions, making them an ideal food source for aquaculture.
In addition to being used as a live food source, rotifers are also used in aquaculture as a bioindicator of water quality. Because rotifers are sensitive to changes in water quality, their presence or absence can be used as an indicator of the health of an aquatic ecosystem. By monitoring rotifer populations, aquaculturists can detect changes in water quality early and take corrective actions to maintain a healthy environment for their aquatic animals.
Overall, rotifers are an important component of aquaculture and play a critical role in the production of healthy and sustainable seafood.
- A Predator known to consume the daphnids is
(a) Calanus
(b) Tetraselmis
(c) Chlorella
(d) Rotifer.
There are many predators that consume daphnids, which are small freshwater crustaceans commonly known as water fleas. Some of the most common predators of daphnids include fish, insects, and other aquatic invertebrates.
One predator that is known to consume daphnids is the hydra, a small freshwater predatory animal that belongs to the phylum Cnidaria. Hydras are known to capture and consume a wide range of small aquatic animals, including daphnids.
Hydras use their tentacles, which are armed with stinging cells called nematocysts, to capture their prey. When a daphnid or other small aquatic animal comes into contact with the tentacles, the nematocysts fire, injecting toxins into the prey and immobilizing it. The hydra then uses its tentacles to move the immobilized prey to its mouth, where it is consumed.
Other predators of daphnids include fish such as sunfish, bluegill, and trout, as well as insects such as dragonfly larvae and water striders.
There are many predators that consume daphnids, which are small freshwater crustaceans commonly known as water fleas. Some of the most common predators of daphnids include fish, insects, and other aquatic invertebrates.
One predator that is known to consume daphnids is the hydra, a small freshwater predatory animal that belongs to the phylum Cnidaria. Hydras are known to capture and consume a wide range of small aquatic animals, including daphnids.
Hydras use their tentacles, which are armed with stinging cells called nematocysts, to capture their prey. When a daphnid or other small aquatic animal comes into contact with the tentacles, the nematocysts fire, injecting toxins into the prey and immobilizing it. The hydra then uses its tentacles to move the immobilized prey to its mouth, where it is consumed.
Other predators of daphnids include fish such as sunfish, bluegill, and trout, as well as insects such as dragonfly larvae and water striders.
- The yolk sac is segmented in __________
(a) sciaenids
(b) clupeids
(c) serranids
(d) carangids
The yolk sac is an important structure in the development of fish embryos, providing essential nutrients to the developing embryo until it is able to feed on its own.
Carangids, also known as jacks or trevallies, are a family of marine fishes that includes many important commercial and game fish species.
In carangids, the yolk sac is segmented, meaning that it is divided into several compartments or lobes. This segmentation allows for more efficient absorption of nutrients from the yolk sac, which is important for the development of the embryo. As the embryo grows and consumes the nutrients in the yolk sac, the sac gradually shrinks and is eventually reabsorbed by the embryo.
The segmentation of the yolk sac in carangids is thought to be an adaptation to their pelagic lifestyle. Because carangids are active, fast-swimming predators that are often found in open water, they may have evolved a more efficient yolk sac structure to ensure the survival of their developing embryos in the challenging marine environment.
- Antibody molecules in fish are
(a) Pentamer
(b) Tetramer
(c) Trimer
(d) Dimer
- Primers are
(a) Double
stranded RNA molecules
(b) Single
stranded RNA molecules
(c) Single stranded short oligonucleotides
(d) Double
stranded short oligonucleotides
The segmentation of the yolk sac in carangids is thought to be an adaptation to their pelagic lifestyle. Because carangids are active, fast-swimming predators that are often found in open water, they may have evolved a more efficient yolk sac structure to ensure the survival of their developing embryos in the challenging marine environment.
Primers are short, single-stranded oligonucleotides that are used in polymerase chain reaction (PCR) and other molecular biology techniques to amplify specific DNA sequences.
Primers are designed to be complementary to the DNA sequences flanking the region of interest, and they serve as the starting point for DNA polymerase to extend and synthesize new strands of DNA.
Typically, PCR primers are around 20-30 nucleotides in length and are designed with a specific melting temperature (Tm) to ensure efficient annealing to the template DNA. The primers are usually synthesized chemically and purified to ensure high specificity and purity.
Once the primers have annealed to the template DNA, DNA polymerase extends the primers by adding complementary nucleotides to the 3' end of the primers, resulting in the synthesis of new DNA strands that are complementary to the original template DNA. By repeating this process through multiple cycles of denaturation, annealing, and extension, PCR can amplify specific DNA sequences exponentially, allowing for the detection and analysis of low-abundance DNA samples.
- Defence mechanisms in shrimp does not include
(a) Encapsulation
(b) ProPO
system
(c) Complement
fixation
(d) Phagocytosis
Complement is not considered a major defense mechanism in shrimp.
Shrimp have a variety of other mechanisms for defending themselves against pathogens, including the following:
Hemocytes: Shrimp have specialized immune cells called hemocytes that can recognize and engulf invading pathogens.
Antimicrobial peptides: Shrimp produce small peptides that can kill or inhibit the growth of bacteria and other pathogens.
Phenoloxidase: Shrimp have an enzyme called phenoloxidase that is involved in the process of melanization, which can encapsulate and kill invading pathogens.
Reactive oxygen species: Shrimp can produce reactive oxygen species (ROS) that can damage the DNA and cell membranes of invading pathogens.
Prophenoloxidase activation system: The prophenoloxidase activation system in shrimp is similar to the complement system in mammals, but it is not considered a major defense mechanism. It is involved in the process of melanization and can help to encapsulate and kill invading pathogens.
Overall, shrimp have a complex and effective immune system that relies on multiple mechanisms for defense against pathogens.
- Parasite responsible for white spot disease in fish
(a) white
spot syndrome virus
(b) Ichtyophonus
hoeferi
(c) Ichthyophthirius
multifilis
(d) Myxosoma
cerebralis
Ichthyophthirius multifilis, also known as "ich," is a protozoan parasite that can infect a variety of freshwater fish species. It is characterized by the formation of white spots or patches on the skin and fins of infected fish, as well as a range of other symptoms, such as flashing, scratching, and respiratory distress.
White spot disease in fish, on the other hand, is caused by the white spot syndrome virus (WSSV), which is a large, double-stranded DNA virus that primarily infects crustaceans but can also infect and cause disease in many species of finfish, including tilapia, catfish, and penaeid shrimp.
While both diseases can cause white spots on fish, they are caused by very different pathogens and have different modes of transmission, symptoms, and treatments.
- Recommended treatment for fungal infection is
(a) Tetracycline
(b) Ozone
(c) Chlorine
(d) Formalin
Formaline (also known as formaldehyde) is sometimes used as a treatment for fungal infections in fish, but it is not typically the first-line treatment and is generally not recommended due to its potential toxicity to fish and other aquatic organisms.
Formaline can be effective against some types of fungi, but it can also be harmful to fish and other aquatic organisms, especially at higher concentrations or with prolonged exposure. Additionally, formaline can be irritating to human skin and respiratory system, so it should be handled with care and used in a well-ventilated area.
Other antifungal treatments, such as malachite green, methylene blue, and potassium permanganate, are generally considered safer and more effective for treating fungal infections in fish. These treatments should be used under the guidance of a veterinarian or experienced fish health professional, and it is important to follow the instructions carefully to ensure the safety and effectiveness of the treatment.
- Epizootic ulcerative syndrome in fish is spread due to
(a) Saprolegnia
(b) Aphanomyces
(c) Achyla
(d) Branchyomyces
Epizootic ulcerative syndrome (EUS) is a disease that affects a wide range of freshwater and marine fish species, and is caused by a water mold (fungus-like organism) called Aphanomyces invadans.
The disease is primarily spread through the introduction of infected fish or contaminated water into new habitats. The water mold can survive in aquatic environments for extended periods of time and can be spread through the movement of infected fish, water, or equipment.
Environmental factors, such as temperature, water quality, and stress, can also play a role in the development and spread of EUS. High water temperatures, low dissolved oxygen levels, and poor water quality can all increase the susceptibility of fish to EUS, while overcrowding, handling, and transportation can also increase stress levels and make fish more susceptible to infection.
Preventing the spread of EUS requires careful management of aquatic habitats, including proper screening and quarantine of new fish populations, regular monitoring and maintenance of water quality, and prompt removal and treatment of any infected fish or aquatic organisms.
- Enzyme of retroviruses, which is essential for their replication
(a) RNA
dependent RNA polymerase
(b) Reverse
transcriptase
(c) DNA
gyrase
(d) Taq
DNA polymerase
The enzyme that is essential for the replication of retroviruses is called reverse transcriptase.
Reverse transcriptase is an RNA-dependent DNA polymerase that catalyzes the reverse transcription of the retroviral RNA genome into DNA. The retroviral RNA genome is first converted into a single-stranded DNA intermediate called cDNA (complementary DNA), which is then converted into double-stranded DNA by the action of another retroviral enzyme called integrase. The resulting DNA is then integrated into the host cell genome, where it can be transcribed and translated into new virus particles.
Reverse transcriptase is a unique enzyme because it allows retroviruses to convert RNA into DNA, which is the opposite of the normal flow of genetic information in cells (from DNA to RNA to protein). This process is prone to errors, which can lead to the accumulation of mutations and genetic variability in retroviral populations, contributing to their evolution and adaptability.
Reverse transcriptase is also the target of many antiretroviral drugs, which work by inhibiting the enzyme's activity and preventing viral replication.
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