Question 1

Question 1The kidneys in human beings are a part of the system fornutritionrespirationexcretiontransportation

Accepted Answer

excretionReason— Kidneys carry out filtration of blood and remove waste materials.

Question 2

Question 2The xylem in plants are responsible fortransport of watertransport of foodtransport of amino acidstransport of oxygen

Accepted Answer

transport of waterReason— Xylem vessels are responsible for transport of water in upward direction.

Question 3

Question 3The autotrophic mode of nutrition requirescarbon dioxide and waterchlorophyllsunlightall of the above

Accepted Answer

all of the aboveReason— Autotrophs make their food by using carbon dioxide and water in presence of chlorophyll and sunlight.

Question 4

Question 4The breakdown of pyruvate to give carbon dioxide, water and energy takes place incytoplasmmitochondriachloroplastnucleus

Accepted Answer

mitochondriaReason— Breakdown of pyruvate using oxygen takes place in the mitochondria.

Question 5

Question 5How are fats digested in our bodies? Where does this process take place?

Accepted Answer

Fats are present in the intestine in the form of large globules which makes it difficult for enzymes to act on them. Bile salts break them down into smaller globules increasing the efficiency of enzyme action. The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats. The fat is finally broken into fatty acids and glycerol.The digestion of fats take place in small intestine.

Question 6

Question 6What is the role of saliva in the digestion of food?

Accepted Answer

The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give simple sugar. It also makes passage of food through oesophagus easier.

Question 7

Question 7What are the necessary conditions for autotrophic nutrition and what are its byproducts?

Accepted Answer

The necessary conditions for autotrophic nutrition are carbon dioxide, water, presence of sunlight and chlorophyll which are necessary for the process of photosynthesis.The byproducts of photosynthesis are water and oxygen.

Question 8

Question 8What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Accepted Answer

Aerobic respirationAnaerobic respirationProceeds in the presence of oxygen.Proceeds without using oxygen.Complete breakdown of glucose.Incomplete breakdown of glucose.End products are carbon dioxide and water.End-products are ethyl alcohol and carbon dioxide.More energy is released.Less energy is released.Some organisms that use the anaerobic mode of respiration are yeast, lactic acid bacteria and some parasitic worms like tape worm.

Question 9

Question 9How are the alveoli designed to maximise the exchange of gases?

Accepted Answer

The alveoli provide a large surface area for the exchange of gases to take place. The walls of the alveoli contain an extensive network of blood-vessels. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body.

Question 10

Question 10What would be the consequences of a deficiency of haemoglobin in our bodies?

Accepted Answer

Hemoglobin deficiency, also known as anemia, is characterized by a decrease in the number of red blood cells or a lower concentration of hemoglobin in the blood. Hemoglobin deficiency can have serious consequences for our bodies, some of which are listed below:Hemoglobin deficiency deprives the body of the oxygen it needs, leading to persistent fatigue, weakness and shortness of breath.Due to inadequate oxygen supply to the brain we may may experience difficulty concentrating, memory problems, and decreased mental alertness.

Question 11

Question 11Describe double circulation of blood in human beings. Why is it necessary?

Accepted Answer

Double circulation is a process during which blood passes twice through the heart during one complete cycle through the human body. First, the deoxygenated blood is send to lungs and oxygenated blood from lungs reaches heart. This circulation is known as pulmonary circulation. Oxygenated blood that reaches the heart is send to whole body and the deoxygenated blood from different body parts is again brought to heart. This is known as systemic circulation.Human beings constantly use energy to maintain their body temperature. Therefore, they need a highly efficient supply of oxygen to the body. The mixing of oxygenated and deoxygenated blood lowers the efficiency to supply oxygen. Therefore, it is necessary to separate oxygenated and deoxygenated blood

Question 12

Question 12What are the differences between the transport of materials in xylem and phloem?

Accepted Answer

Xylem TransportPhloem TransportIt transports water and minerals.It transports food.It does not require expense of energy.It requires energy for transportation of food.The movement is unidirectional i.e. upwardThe movement is in both upward and downward direction.

Question 13

Question 13Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Accepted Answer

Structure and functioning of alveoli in the lungs and nephrons in the kidneys is compared below:AlveoliNephronStructureAlveoli are balloon shaped tiny air sacs present in lungs.Nephron is cup shaped with long tube like structure present in kidneys.The walls of alveoli are thin, allowing for efficient gas exchange.Each nephron consists of bowman's capsule, glomerulus and renal tubule.FunctionAlveoli are the site of gaseous exchange.The nephron is the primary filtration unit of the kidney.Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled.The blood flows through capillary cluster i.e glomerulus under high pressure which results in collection of filtrate.

Question 14

Question 1Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?

Accepted Answer

Multicellular organisms like humans require a more efficient circulatory system for transportation of oxygen as diffusion cannot transport oxygen to longer distances in the body. In multi-cellular organisms, all the cells may not be in direct contact with the surrounding environment. Thus, simple diffusion will not meet the requirements of all the cells. So, in multicellular organisms like humans, transport of oxygen through blood stream ensures its efficient supply to each cell of body.

Question 15

Question 2What criteria do we use to decide whether something is alive?

Accepted Answer

The presence of movement whether noticeable and visible or at a molecular level invisible to naked eye is the main criteria that we can use to decide whether something is alive or not.

Question 16

Question 3What are outside raw materials used for by an organism?

Accepted Answer

Outside raw materials used by autotrophs are carbon dioxide, water and sunlight. Besides these they also need other raw materials like nitrogen, phosphorus, iron, magnesium, etc. for building their body.Outside raw materials used by heterotrophs are food, water and oxygen.

Question 17

Question 4What processes would you consider essential for maintaining life?

Accepted Answer

Processes considered essential for maintaining life are:BreathingNutrition & DigestionTransportationExcretion

Question 18

Question 1What are the differences between autotrophic nutrition and heterotrophic nutrition?

Accepted Answer

Autotrophic nutritionHeterotrophic nutritionAutotrophic nutrition is present in organisms that can prepare their own food.Heterotrophic nutrition is present in organisms that cannot prepare their own food and depend on other organism for food.Autotrophic nutrition requires Chlorophyll.Heterotrophic nutrition does not require Chlorophyll.Food is prepared in the presence of sunlight during the day time only.Food can be obtained anytime.Green plants and some bacteria show autotrophic nutrition.Animals and fungi show heterotrophic nutrition.

Question 19

Question 2Where do plants get each of the raw materials required for photosynthesis?

Accepted Answer

Plants take energy from sunlight, water from soil and carbon dioxide from air to carry out photosynthesis.

Question 20

Question 3What is the role of the acid in our stomach?

Accepted Answer

Hydrochloric acid performs the following functions in our stomach:It creates an acidic medium which facilitates the action of the protein digesting enzyme called pepsin.It kills any germs which may have entered along with the food.

Life Processes

Exercises

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