MEGA QUIZ- 2 (10 to 20)
Phase contrast microscopes can be very useful to observe the undistorted morphological features of
Dead cells
Live cells
Stained cells
None of the above
Phase contrast microscopy is a technique that allows the visualization of transparent or unstained specimens, such as live cells, by exploiting the differences in refractive index within the specimen. It enhances the contrast and provides detailed morphological information of the cells without the need for staining or fixing them.
The principle behind phase contrast microscopy is based on the fact that when light passes through a transparent object, it undergoes a phase shift. This phase shift is proportional to the difference in refractive index between the specimen and the surrounding medium. In a phase contrast microscope, this phase shift is converted into variations in brightness, enabling the visualization of transparent structures within the cells.
When observing live cells under a phase contrast microscope, the technique allows for the visualization of various morphological features. It enables the observation of cell shape, size, and internal structures such as organelles. By adjusting the settings of the microscope, it is possible to enhance specific cellular components, such as the nucleus or cytoplasm, providing detailed information about cellular dynamics and processes.
The advantage of phase contrast microscopy is that it allows for the observation of live cells in their natural state, without the need for staining or fixation. This is particularly important as staining or fixing cells can alter their morphology or introduce artifacts that may affect the accuracy of the observations. With phase contrast microscopy, researchers can observe dynamic cellular processes, such as cell division or cell migration, in real-time without disturbing the cells.
In summary, phase contrast microscopy is a valuable tool for observing the undistorted morphological features of live cells. It provides high contrast images that reveal the structures and dynamics of cells without the need for staining or fixing, making it an essential technique in cell biology and live cell imaging.
Absorbptive nutrition is shown by-
Bacteria
Fungi
Protozoan
All
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| source - wikipedia |
Absorbptive nutrition is primarily shown by fungi. Fungi are well-known for their ability to secrete enzymes that break down complex organic matter in their environment, such as dead plant material or decaying organic substances. These enzymes, known as extracellular enzymes, break down complex molecules like cellulose, lignin, and proteins into simpler forms, such as sugars and amino acids.
Once the complex molecules are broken down into simpler forms, the fungal hyphae (thread-like structures) extend and grow into the nutrient-rich environment, allowing them to absorb the digested molecules directly through their cell walls. The hyphae have a large surface area, which enhances their nutrient-absorbing capabilities.
Fungi have a specialized structure called the mycelium, which is a network of hyphae that spreads through the substrate or medium in which they are growing. The mycelium enables efficient nutrient absorption by maximizing the contact between the fungal cells and the nutrient source.
This absorbptive mode of nutrition allows fungi to thrive in diverse environments and play crucial roles in nutrient cycling and decomposition processes. Fungi are important decomposers, breaking down complex organic matter into simpler forms and releasing nutrients back into the ecosystem. They also form mutualistic associations with plants, such as mycorrhizal symbiosis, where they provide nutrients to the plants in exchange for carbohydrates.
To summarize, absorbptive nutrition is primarily exhibited by fungi. They secrete enzymes to break down complex organic matter in their environment and absorb the resulting simpler molecules through their hyphae, allowing them to obtain nutrients for growth and survival.
Gram +ve bacteria retains
Crystal violet
Methyl blue
Rose Bengal
Safranin
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| source - byjus |
Gram staining is a widely used technique to differentiate bacteria into two major groups: gram-positive and gram-negative. In this staining method, different dyes are applied to bacterial cells, and the retention or loss of these dyes helps to identify the bacterial group.
Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which allows them to retain the crystal violet dye during the staining process. The steps of the Gram staining procedure include:
1. Application of Crystal Violet: The first step involves applying crystal violet, a purple-colored dye, to the bacterial cells. Both gram-positive and gram-negative bacteria initially take up the crystal violet.
2. Application of Iodine: After the crystal violet, iodine solution (Gram's iodine) is added. Iodine forms a complex with crystal violet inside the bacterial cells, resulting in the formation of a crystal violet-iodine complex.
3. Decolorization: The decolorization step is critical in differentiating gram-positive and gram-negative bacteria. A decolorizing agent, typically ethanol or acetone, is used to wash away the dye from the bacterial cells.
Gram-positive bacteria have a thick peptidoglycan layer that retains the crystal violet-iodine complex, making them less susceptible to decolorization. As a result, they retain the purple color after the decolorization step.
4. Counterstaining: To visualize the decolorized gram-negative bacteria, a counterstain is applied. Typically, safranin or fuchsin is used as a counterstain. These dyes impart a pink or red color to the gram-negative bacteria, making them distinguishable from the purple-colored gram-positive bacteria.
In summary, gram-positive bacteria retain the crystal violet stain during the Gram staining procedure due to the presence of a thick peptidoglycan layer in their cell wall. This retention results in their characteristic purple color after the decolorization step, while gram-negative bacteria take up the counterstain and appear pink or red.
Bacteria which has only one Flagella is called as
Amphitrichous
Atrichous
Monotrichous
Lophotrichous
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| source - brain cart |
Bacteria that have only one flagellum are referred to as monotrichous. Monotrichous bacteria possess a single flagellum located at one end of the bacterial cell. This flagellum allows them to exhibit unidirectional motility.
Here's a brief overview of the different types of flagellar arrangements in bacteria:
1. Monotrichous: Bacteria with a single flagellum at one end of the cell are called monotrichous. The flagellum enables the bacterium to move in a single direction.
2. Amphitrichous: Bacteria with a single flagellum at each end of the cell are referred to as amphitrichous. The flagella can rotate independently or in coordination, enabling the bacterium to move in various directions.
3. Lophotrichous: Bacteria with multiple flagella located at one or both ends of the cell are known as lophotrichous. The flagella are often arranged in tufts or clusters, facilitating movement in a specific direction.
4. Peritrichous: Bacteria with flagella distributed uniformly around the entire cell are referred to as peritrichous. These flagella allow the bacterium to move in various directions and exhibit a swarming motility pattern.
5. Atrichous: Bacteria that lack flagella are referred to as atrichous. They are non-motile and do not possess the ability to actively move through their environment using flagella.
In summary, the term "monotrichous" is used to describe bacteria that have only one flagellum, typically located at one end of the cell, enabling them to exhibit unidirectional motility.
……….is called as Fungi Imperfecti
Zygomycota
Ascomycota
Basidiomycota
Deuteromycota
 |
| source - wikipedia |
The term "Fungi Imperfecti" is an older classification name that was used for a group of fungi that were not clearly placed in any specific taxonomic category based on their sexual reproductive structures. These fungi were considered to lack a known sexual reproductive stage or were not well-studied in terms of their sexual reproduction.
The classification name "Fungi Imperfecti" is no longer in use as it was recognized that the fungi classified under this group actually belong to various other taxonomic groups based on their sexual reproductive structures. Instead, the term "Deuteromycota" was used to encompass these fungi that had no known sexual reproductive stage or lacked sufficient information about their sexual reproduction.
Deuteromycota, also referred to as "Fungi Imperfecti" or "imperfect fungi," represents a heterogeneous group of fungi that reproduce solely by asexual means, such as fragmentation, budding, or production of asexual spores called conidia. These fungi do not have a known or well-defined sexual reproductive stage, which is why they were originally grouped together as "Fungi Imperfecti."
However, it is important to note that with advancements in fungal taxonomy and molecular techniques, many fungi previously classified as "Deuteromycota" have now been reclassified into other taxonomic groups based on the discovery of their sexual reproductive structures and genetic analysis. These fungi are now properly placed within taxonomic groups such as Ascomycota, Basidiomycota, Zygomycota, and others.
In summary, the term "Fungi Imperfecti" was used as an older classification name for a group of fungi that lacked a known sexual reproductive stage. The term "Deuteromycota" was later used to encompass these fungi, but with advancements in fungal taxonomy, many of them have been reclassified into other taxonomic groups based on their sexual reproductive structures and genetic analysis.
…………..is rich in Vitamin A&B.
Green algae
Golden brown algae
Brown algae
Dinoflagellates
Green algae are indeed rich in vitamins, including Vitamin A and B. Here are some details about their vitamin content:
1. Vitamin A: Green algae are a good source of Vitamin A, particularly in the form of beta-carotene. Beta-carotene is a pigment that gives green algae their characteristic green color. In the body, beta-carotene can be converted into Vitamin A, which is essential for maintaining healthy vision, supporting immune function, and promoting cell growth and development.
2. Vitamin B: Green algae also contain various B vitamins, including thiamine (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), and folate (B9). These B vitamins play vital roles in energy production, nervous system function, cell metabolism, and the synthesis of DNA and red blood cells.
The exact vitamin content and composition of green algae can vary depending on the specific species and environmental factors. Different species of green algae may have variations in their nutrient profiles, including vitamin content.
Green algae are commonly found in freshwater environments such as lakes, ponds, and rivers. They are photosynthetic organisms, utilizing chlorophyll to capture sunlight and convert it into energy through photosynthesis. As a result, they are able to produce and accumulate various nutrients, including vitamins, during their growth.
It's important to note that the vitamin content of green algae can vary and may be influenced by factors such as environmental conditions, cultivation methods, and processing techniques. Additionally, the bioavailability of vitamins from green algae may vary, meaning the body's ability to absorb and utilize the vitamins may differ.
While green algae can provide vitamins, it's worth considering a balanced and varied diet that includes other sources of vitamins to meet nutritional requirements. Consulting with a healthcare professional or registered dietitian can provide personalized guidance on meeting specific vitamin needs through dietary choices.
…………..is rich in Vitamin A&D.
Green algae
Golden brown algae
Brown algae
Red algae
Among the options mentioned, red algae (Rhodophyta) are known to be rich in Vitamin A and Vitamin D. Here are some details about their vitamin content:
1. Vitamin A: Red algae are a good source of Vitamin A. Vitamin A plays a crucial role in maintaining healthy vision, supporting immune function, and promoting cell growth and development.
2. Vitamin D: Red algae are also known to contain Vitamin D. Vitamin D is essential for bone health, as it helps in the absorption of calcium and promotes bone mineralization.
Red algae are primarily found in marine environments, including coral reefs and rocky coastlines. They have unique pigments, including phycoerythrins, that give them their characteristic red color. Red algae have the ability to synthesize and accumulate various nutrients, including vitamins, through photosynthesis.
It's important to note that the vitamin content of red algae can vary depending on the species, environmental conditions, and other factors. Additionally, the bioavailability of vitamins from red algae may vary, meaning the body's ability to absorb and utilize the vitamins may differ.
While red algae can provide vitamins, it's worth considering a balanced and varied diet that includes other sources of vitamins to meet nutritional requirements. Consulting with a healthcare professional or registered dietitian can provide personalized guidance on meeting specific vitamin needs through dietary choices.
Unit of Virus is called as
Virion
Capsid
Capsomere
Spikes
The unit of a virus is called a virion. It is a complete virus particle that consists of nucleic acid (DNA or RNA) surrounded by a protein coat called a capsid. The capsid is made up of protein subunits called capsomeres. Some viruses also have an outer envelope made of lipids and proteins derived from the host cell membrane. The virion is the infectious form of the virus. It can enter a host cell and replicate, producing new virions.
Bacteria that grows in low moisture is
Osmophile
Xerophile
Halophile
Alkinophile
 |
| source - planetpailly |
Bacteria that grow in low moisture environments are known as xerophiles. Xerophiles are adapted to survive and thrive in conditions with very limited water availability. These bacteria have specific adaptations that allow them to tolerate desiccation (extreme dryness) and maintain their cellular functions in low-moisture environments.
Xerophiles can be found in various habitats with low water content, such as deserts, dry soil, arid climates, and certain food products with low water activity. They have evolved mechanisms to protect their cellular structures and preserve essential metabolic functions during periods of water scarcity.
These adaptations include the production of protective molecules such as osmoprotectants or compatible solutes, which help maintain cellular hydration and prevent damage from dehydration. Xerophiles may also have unique cell membrane compositions and structures that provide stability and reduce water loss.
It's important to note that xerophiles have different thresholds of water availability and can exhibit varying degrees of tolerance to desiccation. Some xerophiles can survive extreme drying conditions for extended periods, while others are more sensitive and require at least a minimal level of moisture to maintain viability.
In summary, xerophiles are bacteria that can grow and survive in low-moisture environments. They have specific adaptations to cope with desiccation and maintain their cellular functions even in conditions with limited water availability.
Barotolerant bacteria tolerate pressure upto
50 atm
100 atm
200 atm
400 atm
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