Life process 2

Questions

Q1	What is the type of life process displayed by a butterfly sucking nectar from a flower?

Q2	Name the organ which secretes the enzyme pepsin.

Q3	What is the full form of ATP?

Q4	Name the respiratory pigment in human beings.

Q5	In normal expiration how is the diaphragm shaped?

Q6	Which organ is part of two body systems?

Q7	Which is the largest artery?

Q8	What role do digestive enzymes play in our body?

Q9	Why is the glottis guarded by epiglottis?

Q10	What is the significance of blood coagulation?

Q11	Why is saliva required in the digestion of food?

Q12	What helps the alveoli to increase the exchange of gases?

Q13	What is peristaltic movement?

Q14	Why are valves unidirectional?

Q15	Where and how is fat digested in our body?

Q16	How is an autotrophic nutrition different from a heterotrophic nutrition?

Q17	Explain the transportation of water, minerals and food in plants.

Q18	Distinguish between the alveoli and nephrons.

Q19	Briefly describe the digestive system of human beings with illustration.

Q20	Distinguish between artery, capillary and vein.

Questions

Q1	What is the type of life process displayed by a butterfly sucking nectar from a flower?

A1	A butterfly sucking nectar from a flower, displays life process of nutrition.

Q2	Name the organ which secretes the enzyme pepsin.

A2	Gastric lining of stomach secretes the enzyme pepsin.

Q3	What is the full form of ATP?

A3	The full form of ATP is Adenosine triphosphate, which is an energy carrier that stores energy we need to do everything we do.

Q4	Name the respiratory pigment in human beings.

A4	Haemoglobin is the respiratory pigment in the red blood cells of human beings.

Q5	In normal expiration how is the diaphragm shaped?

A5	In normal expiration the diaphragm is arch-shaped.

Q6	Which organ is part of two body systems?

A6	Pancreas is an organ which is part of both the endocrine as well as the digestive system.

Q7	Which is the largest artery?

A7	Aorta is the largest and main artery supplying oxygenated blood to the circulatory system.

Q8	What role do digestive enzymes play in our body?

A8	Amylase, lipase are different digestive enzymes which help in breaking down of complex food particles into simple ones that can be easily taken up by the blood and subsequently transported to all the cells of a body.

Q9	Why is the glottis guarded by epiglottis?

A9	Epiglottis guards the entrance of the glottis and prevents flow of food into the wind pipe and prevents choking.

Q10	What is the significance of blood coagulation?

A10	Blood coagulation is a defence mechanism that prevents excess loss of blood in case of an injury.

Q11	Why is saliva required in the digestion of food?

A11	The watery substance called saliva found in our mouth contains the enzyme amylase which breaks complex molecules into sugar and thereby aids in digestion.

Q12	What helps the alveoli to increase the exchange of gases?

A12	A membrane of alveoli contains a fine network of blood capillaries that ensures maximum exchange of gases.

Q13	What is peristaltic movement?

A13	Rhythmic contraction of muscles of the alimentary canal that pushes the food downward is known as peristaltic movement.

Q14	Why are valves unidirectional?

A14	Tissue flaps forming valves in the heart are unidirectional to prevent the backward flow of blood and thereby make sure that blood flows in the right direction.

Q15	Where and how is fat digested in our body?

A15

By action of intestinal and pancreatic lipase, fat is digested mainly in the small intestine. Fat is digested with great difficulty because it is in the form of big globules. The salt of bile juice from liver emulsifies large fat globules into fine droplets so that the lipase can take action suitably and bring about quicker breakdown of fats into fatty acids and glycerol. The pancreatic and intestinal juice contains an enzyme named lipase which acts on fat digestion and alters it to fatty acid and glycerol. The digested fat is then absorbed into the lymph capillaries present in the villi. Along with fat, fat soluble vitamins A, D, E and K are also taken into the lymph capillaries.

Q16	How is an autotrophic nutrition different from a heterotrophic nutrition?

A16

Autotrophic Nutrition Heterotrophic Nutrition Chlorophyll is required. Chlorophyll is not required. Organic food is synthesised from simple inorganic raw materials such as carbon dioxide and water. Food is obtained directly or indirectly from autotrophs which is again broken down with the help of enzymes for digestion. Food is generally prepared during day time because they depend on solar energy directly. Food can be obtained at all time because they do not depend on solar energy directly This type of nutrition is mainly of two types: photo-autotrophic and chemo-autotrophic nutrition. This type of nutrition may be holozoic, saprozoic, osmotrophic and parasitic. All green plants and some animals like Euglena have this type of nutrition. All animals and fungi have this type of nutrition.

Q17	Explain the transportation of water, minerals and food in plants.

A17

In plants, water and minerals are transported from soil to the leaves through one of the two types of transport tissues called xylem cells. Xylem cells of leaves, stems and roots are interconnected to develop a conducting channel that reaches all parts of a plant. The root cells capture ions from the soil, which thereby creates dissimilarity between the concentration of ions in roots and in soil. This gives rise to a steady movement of water through xylem. An osmotic pressure is formed and water and minerals are transported from one cell to the other cell due to osmosis. The continuous loss of water from the plant takes place due to transpiration, as a result of which a suction pressure is created, resulting in forcing of water into the xylem cells of roots. During day time transpiration pull is the major driving force whereas at night time the effect of root pressure becomes more important for transportation of water and nutrients in plants. In plants, food is transported by translocation in the solution form through another plant transport tissues called phloem. Phloem carries dissolved sugar like glucose or sucrose and amino acids from the leaves where these are manufactured, to the other parts of the plant body and also to the storage organs. Using energy from ATP, water-soluble carbohydrates like sucrose are transported actively to the sieve tubes of phloem. Due to this, water moves into the sieve tubes by endosmosis generating high pressure inside. As a result, water moves in the sieve tubes from the supply end (leaves) to the storage organs. In the storage organs the dissolved sugar is removed from the sieve tubes. As a result, the sieve tubes also lose water by exosmosis. This water is carried up back to the leaf cells through the xylem vessels.

Q18	Distinguish between the alveoli and nephrons.

A18

Alveoli Nephrons Alveoli are tiny balloon-like air-sacs present inside the lungs. Nephrons are tubular structures present inside the kidneys which are units of excretory system in which blood is filtered and re-assimilation of useful substances takes place. The walls of the alveoli are just one cell thick for easy movement of gas molecules and it contains a wide-ranging network of blood capillaries. Nephrons are made of glomerulus, bowman’s capsule and a long renal tube, and have a network of capillaries and a thin permeable membrane for easy movement of molecules. Alveoli are the place of gaseous exchange. Nephrons are the vital filtration unit.

Q19	Briefly describe the digestive system of human beings with illustration.

A19

All human beings eat food through their mouth and digest it with the assistance of particular organs for digestion. At the end of the digestion process the undigested food is defecated. The food that we take passes through a definite canal which starts from the  buccal cavity and ends at the anus. This canal is called the digestive tract or the alimentary canal which is illustrated by the following diagram: Mouth cavity: Also called the vestibule of mouth, this is where the digestive process begins. Food is chewed in the mouth and is therefore partly broken down by the process of chewing and also by the chemical action of the salivary enzymes. Esophagus: After being chewed and swallowed, the food lumps, that is, bolus, as well as liquid products enter a long muscular tube called oesophagus. Oesophagus is also known as food pipe. It runs from the mouth to the stomach. By a series of wave-like muscle contractions the food moves down the digestive tract, from the mouth into the stomach. Stomach: Stomach is a sac-like muscular organ, located at the left side of the upper abdomen which helps in churning the food for digestion. The walls of stomach secrete hydrochloric acid that kills the germs which may be present in food and also makes the medium inside the stomach acidic which is required for the gastric enzymes to work. The enzyme pepsin secreted in stomach does partial digestion of protein. Small Intestine: After leaving the stomach, the food enters a part of the gastrointestinal tract called the small intestine, which is a highly convoluted tube-like structure, comprising of the duodenum, jejunum, and ileum all collectively termed as the small intestine. Small intestine runs between the stomach and the large intestine. In the small intestine, bile helps in the breakdown of food. Bile is a fluid released by the liver and stored in the gall bladder, along with pancreatic enzymes, and other digestive enzymes produced by the inner wall of the small intestine. Bile breaks down fat into smaller particles by the process called emulsification of fat. After that, the enzyme lipase digests fat into fatty acids and glycerol. Trypsin and chymotrypsin are enzymes which digest protein into amino acids. Complex carbohydrates are digested into glucose. The major part of digestion takes place in the duodenum. No digestion takes place in jejunum. The inner wall in the ileum is projected into numerous finger-like structures called villi which increase the surface area inside the ileum so that optimum absorption can take place. About 90% of the nutrients are absorbed by villi. Large Intestine: After the small intestine finishes its process of digestion, the undigested food passes into the final section of the gastrointestinal tract, which is the large intestine, also known as colon. Large intestine is shorter in length than small intestine. In the large intestine, some of the water and vitamins are absorbed by its walls. After that, the undigested food goes to the rectum from where it is expelled out through the anus.

Q20	Distinguish between artery, capillary and vein.

A20

Artery Capillary Vein i. It is a thick-walled blood vessel having two more tunics that surround the endothelium: the middle one is composed of smooth muscle that regulates blood flow, while the outer one is connective tissue that supports blood vessels.   It is an extremely narrow blood vessel having very thin walls made up of a single layer of cells.   It is a thin-walled blood vessel having two more tunics that surround the endothelium: middle one is composed of smooth muscle that regulates blood flow, while the outer one is connective tissue that supports blood vessels.   ii. It carries blood away from the heart to different parts of the body. The main artery is the aorta. They form an extensive network throughout all living cells in the body and connect arteries and veins     and exchange nutrients, waste, and oxygen with tissues at the cellular level.   It brings blood from the different parts of the body to the heart and drains blood from organs and limbs. iii. It does not contain any valve.   It does not contain any valves. It contains simple valves which permit blood flow only towards the heart. Veins have valves because veins have to work against gravity to get blood back to the heart.   iv. It can dilate or constrict depending upon the regulatory requirement of the body.   It can dilate or constrict according to the requirement of the tissue. It cannot dilate or constrict.   Question 9 How is the small intestine designed to absorb digested food? Solution: Small intestine has millions of tiny finger-like projections called villi. These villi increase the absorbing surface of small intestine. The blood capillaries in villi absorb digested food and carry it to the blood stream. Question 10 What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration? Solution: Terrestrial organisms take up oxygen from atmosphere whereas aquatic animals obtain oxygen from water. Air contains more O 2 as compared to water. Therefore, terrestrial animals do not have to breathe quicker to get more oxygen. Therefore, terrestrial organisms can facilitate better utilization of food by way of respiration. Question 11 What are the different ways in which glucose is oxidised to provide energy in various organisms? Solution: There are two types of respiration for oxidization of glucose.  Anaerobic Respiration: This process takes place in absence of oxygen. For example, during yeast fermentation, pyruvate is converted into ethanol and carbon dioxide.  Aerobic Respiration: In aerobic respiration, breakdown of pyruvate takes place in presence of oxygen. Hence, optimum output of energy is achieved. Question 12 How is oxygen and carbon dioxide transported in human beings? Solution: Transport of Oxygen: The respiratory pigment (haemoglobin) present in red blood cell carry oxygen in blood. It carries oxygen to tissues which are deficient in oxygen. Transport of carbon dioxide: Carbon Dioxide is more soluble in water. Hence, it is mostly transported from body tissues in dissolved form. It is transported from blood plasma to lungs. In the lungs, it diffuses from blood to air and then is expelled out through nostrils. Question 13 How are lungs designed in human beings to maximise area for exchange of gases? Solution: Lungs contain millions of air sacs called alveoli. The structure of the air sac increases surface area inside lungs. This helps in making a larger area for exchange of gases. Question 14 What are the components of the transport system in human beings? What are the functions of these components? Solution: The main components of transport system in human beings are heart, blood, and blood vessels, and lungs.  Heart pumps oxygenated blood throughout the body. It receives deoxygenated blood from the various body parts and sends this impure blood to lungs for oxygenation.  Blood helps in transportation of oxygen, nutrients, CO 2 , and other nitrogenous wastes.  Blood vessels such as arteries, veins, and capillaries carry blood either from the heart to various organs or from various organs to the heart.  Lungs facilitate transportation of oxygen and carbon dioxide to and from the body respectively.