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Practice each question, then open the answer or worked solution.
Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?
Ans: Diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans because the process of diffusion is very slow and will take a lot of time to reach each and every cell of the body since our body is very huge and complex and each and every cell of the body requires oxygen.
What criteria do we use to decide whether something is alive?
Ans: The main criteria that we use to decide whether something is alive or dead are the events of Life processes. These fundamental life processes include nutrition, respiration, transportation, excretion, control and coordination, growth, and reproduction. If these processes occur normally then the organism is considered living because in the case of non-living organisms these processes do not take place
What are outside raw materials used by an organism?
Ans: Food, water, and oxygen are the outside raw materials that are used by an organism. These raw materials vary in amounts, source, and type depending upon various organisms and are used mainly for some important functions in the body of the organisms. They also provide energy to the body to perform various functions.
What processes would you consider essential for maintaining life?
Ans: The processes that are essential for maintaining life are nutrition, respiration, transportation, excretion, and control, and coordination. These are the processes that make the organism living.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
Ans: The differences between autotrophic nutrition and heterotrophic nutrition are:
Autotrophic Nutrition | Heterotrophic Nutrition |
The organisms make their own food with the help of various raw materials that include carbon dioxide and water and the process occurs in the presence of sunlight and chlorophyll. | The organisms do not make their own food, instead obtain their nutrition from other living organisms like plants (autotrophs). |
Autotrophs require energy that is obtained from light to synthesize their food. | Heterotrophs obtain energy from food that they consume by digesting them and other organic substances as well. |
Eg: All green plants, algae, some bacteria, seaweeds, etc. | Eg: All animals, Humans, fungi such as mushrooms, yeast, etc. |
Where do plants get each of the raw materials required for photosynthesis?
Ans: These raw materials required by plants for photosynthesis are as follows: sunlight, water, carbon dioxide, and chlorophyll.
Carbon dioxide in plants can be obtained from the atmosphere and is absorbed through the stomata.
Water is absorbed by the roots of plants from the soil as soil mainly holds the water.
Sunlight is obtained from nature.
Chlorophyll acts as the main component and is found in the plant organelle called a chloroplast. (Chlorophyll is found in all of the green parts of the plants).
What is the role of the acid in our stomach?
Ans: The role of the acid in our stomach is to mainly dissolve the large chunks of food and create an acidic medium to activate various digestive enzymes. In the acidic medium, the enzyme pepsinogen is activated and then converted to pepsin, which is a protein-digesting enzyme and helps in the digestion of proteins and can also kill the bacteria present in the stomach that enters along with food. The enzyme pepsin requires HCl to get activated in the presence of HCl. The acid will break down the food more easily and helps in absorbing nutrients and easy digestion of food.
What is the function of digestive enzymes?
Ans: The digestive enzymes perform certain important functions that include the breaking down of complex food molecules into simpler food molecules that can be easily absorbed by the cells of the body. These enzymes also function as a biocatalyst that increases the rate of reaction and thus accelerates the rate of breaking down of complex food. There are various digestive enzymes present in the body, such as pepsin, trypsin, amylase, lipase, etc.
Write the role of villi in the human digestive system.
Ans: Villi are the finger-like projections that are present throughout the lining of the internal surface of the small intestine. They are primarily responsible for increasing the surface area of the small intestine which in turn increases surface area for absorption of the digested food. Villi are majorly supplied with blood vessels that help to absorb digested food into the bloodstream.
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Ans: The advantage terrestrial organisms have over aquatic organisms is the amount of oxygen present in the surroundings. Terrestrial organisms have air in the atmosphere that surrounds them making it easy for them to breathe while in the case of aquatic organisms they breathe the air which is dissolved in the water. Thus the amount of oxygen present in the air is much more than the amount of oxygen present in the water.