Daily Quiz – 12th Apr 2024

Exp) Option c is the correct answer.

Living beings constantly require energy to perform various functions. Respiration breaks down glucose and other nutrients from food into a molecule called ATP (adenosine triphosphate). The main purpose of ATP is to store and transport energy within the cell for various cellular functions and processes. Hence respiration aids in the transport of energy through out the body.

While aerobic respiration takes place in the presence of oxygen, the anaerobic respiration takes place in the absence of oxygen.

Option 1 is correct: Yeast is both aerobic and anaerobic, meaning it can survive and thrive both in the presence and absence of oxygen. In the presence of oxygen, they undergo aerobic respiration for more energy, but when oxygen is absent, they switch to anaerobic fermentation (producing alcohol or CO2).

Option 2 is correct: Lactobacillus bacteria can also survive in the absence of oxygen. In fact, these bacteria are obligate anaerobes, meaning they absolutely require the absence of oxygen for their metabolism. Oxygen is toxic to them, and they die in its presence.

Option 3 is incorrect: Earthworms require oxygen to survive, without oxygen they suffocate and die. They breathe through their skin, absorbing oxygen from the air in the soil.

Option 4 is correct: Certain parasites can survive in environments with low or no oxygen. For example Platyhelminthes (flatworms) exhibit both aerobic and anaerobic metabolism depending on the availability of oxygen in their environment, thus respire and survive without oxygen.

Exp) Option c is the correct answer.

Antioxidants play a crucial role in maintaining health and promoting longevity by neutralizing harmful free radicals in the body. Free radicals are highly reactive molecules produced during metabolism, and they can damage cells and DNA, contributing to various diseases and the aging process. Antioxidants counteract this damage by donating electrons to stabilize free radicals, preventing cellular harm. Thus, a diet rich in antioxidants, primarily found in fruits and vegetables, helps protect cells, reduce oxidative stress, and supports overall health and longevity.

Exp) Option c is the correct answer.

The immune system plays a pivotal role in safeguarding the body against various pathogens and foreign invaders. Among the key players in this defense mechanism are B-cells and T-cells, two types of lymphocytes (white blood cells).

Statement 1 is correct: B-cells are responsible for producing antibodies, which are proteins that play a crucial role in the immune response by binding to and neutralizing pathogens such as viruses and bacteria. T-cells, on the other hand, do not themselves produce antibodies but contribute to the immune response by recognizing and attacking infected cells.

Statement 2 is correct: Vaccines are designed to stimulate the immune system, and many vaccines induce responses from both B-cells and T-cells. B-cells are activated to produce antibodies, while T-cells are triggered to recognize and eliminate infected cells. Thus, by stimulating response from both the cells, vaccination enhances the immune system's ability to effectively combat future infections.

Exp) Option b is the correct answer.

Unlike sexual reproduction, which involves the mixing of genetic material from two parents, asexual reproduction allows a single parent to pass on its entire set of genes to its offspring. This results in offspring that are genetically identical to the parent, essentially clones.

Vegetative propagation is a method wherein new plants are produced asexually by vegetative parts of a plant such as the leaf, stem and root.

Statement 1 is correct: In Vegetative propagation, reproduction involves the growth of new plants from vegetative parts of the parent plant, such as stems, leaves, or roots. Potatoes, strawberries, and spider plants are all examples of plants that can reproduce vegetatively. Hence Vegetative reproduction in plants does not require any seeds.

Statement 2 is correct: One of the key features of vegetative reproduction is that the offspring produced are genetically identical to the parent plant. This is because the new plant arises directly from the parent's vegetative tissues, which already carry the parent's complete genetic information. There's no fusion of gametes or exchange of genetic material with another individual, as in sexual reproduction.

Statement 3 is incorrect: Vegetative propagation is propagate and perpetuate viruses. When a plant is infected systemically with a virus, it typically stays infected throughout its life. As a result, any vegetative parts used for propagation, like tubers, bulbs, corns, runners, or cuttings, will likely to carry the infection.

Some of the most common types of asexual reproduction:

1) Binary fission: This is the simplest type of asexual reproduction, where a single-celled organism simply divides in two, creating two genetically identical offspring. Bacteria and many protists reproduce this way.

2) Budding: In this type of reproduction, a small outgrowth, or bud, forms on the parent organism. The bud eventually grows and breaks off, becoming a new independent organism. Hydra, yeast, and some plants reproduce this way.

3) Spores: Some plants and fungi produce tiny reproductive units called spores. These spores can be carried by the wind or water, and if they land in a suitable environment, they can germinate and grow into new organisms. Ferns, mosses, and mushrooms all reproduce using spores.

Exp) Option b is the correct answer.

Acclimatization is a process by which organisms adjust to changes in their environment. This adjustment can involve physiological, behavioral, or morphological changes in response to short-term or reversible environmental conditions. For example, humans can acclimatize to high altitudes by increasing their red blood cell production and breathing rate.

Importantly, acclimatization is not a permanent genetic adaptation; instead, it is a mechanism that allows an organism to cope with variations in its surroundings without altering its genetic code. The changes associated with acclimatization are reversible, meaning that when the environmental conditions return to their original state, the organism can revert to its previous state. For example, when plants are exposed to cold temperatures, they produce antifreeze proteins and sugars to prevent ice formation and damage to their cells. This helps them survive the winter. However, when the temperature rises, they stop producing these substances and resume their normal growth.