Quick Review CH - 6 Life Processes

Class X       CH-6 Life Processes 

Syllabus of Life processes: "living being". Basic concept of nutrition, respiration, transport, and excretion in plants and animals.

1. Life processes -The basic essential activities like nutrition, excretion, reproduction, movement, respiration, growth, and sensitivity performed by an organism to withstand its life is called as life processes.

2. Autotrophic nutrition - The intake of simple inorganic materials from the environment and using an external energy source like the Sun to synthesize complex high-energy organic material. The carbon and energy requirements of the autotrophic organism are fulfilled by photosynthesis.

3. Photosynthesis- Plants prepare carbohydrates by the process of  photosynthesis in the presence  of sunlight, water and carbondioxide and when these carbohydrates are not used immediately are stored in the form of starch, which serves as the internal energy reserve to be used as and when required by the plant. A somewhat similar situation is seen in us where some of the energy derived from the food we eat is stored in our body in the form of glycogen.

4. Heterotrophic nutrition - The intake of complex material prepared by other organisms is called heterotrophic nutrition.

5. Nutrition- Nutrition is the source of energy which is needed to maintain a state of order in our body. We also need materials from outside in order to grow, develop, synthesize protein and other substances needed in the body. This source of energy and materials is the food we eat.

6. Outside raw materials for organisms –Food, minerals, water, and gases are outside raw materials for organisms.

7. Different mode of nutrition – 

i. Autotrophic nutrition   

ii. Heterotrophic nutrition.

I. Autotrophic nutrition - The method of nutrition in which an organism prepares its food is called autotrophic nutrition. Green plant and blue-green algae follow the autotrophic mode of nutrition and these organisms are called autotrophs. This nutrition is accomplished by the photosynthesis process in which the green plan takes carbon dioxide and water and converts into carbohydrates in the presence of chlorophyll and solar energy.

Autotrophs  →  Simple Organic materials convert into →Complex molecules of Carbohydrates.

Photosynthesis –  

CO₂ + H₂O + (solar energy + Chlorophyll)→ 

Carbon Water

dioxide   

C₆H₁₂O₆ + O₂

Carbohydrate  Oxygen

8. Raw materials for Photosynthesis – Sunlight, Chlorophyll, Carbon dioxide, Water and minerals.

9. Stomata - Stomata are small pores present in the leaf through which O₂ and CO₂ are exchanged and large amounts of water are lost during transportation.

10. Opening and closing of stomata pores –

(a) The opening and closing of stomatal pores are controlled by gourd cells.

(b) When the gourd cells absorb water from their surroundings, they swell to become a turgid body, which increases the pores that are stomatal opening.

(c)  When water is realized, they become flaccid shrinking to close the pores that are stomatal closing.

10. Heterotrophic Nutrition - The methods of nutrition in which an organism takes food from other organisms are called heterotrophic nutrition. Organisms other than green plants follow heterotrophic nutrition.

There are three types of heterotrophic nutrition - saprophytic, holozoic and parasitic nutrition.

i. Saprophytic Nutrition - In saprophytic nutrition, the organism secretes the juice on the food and digests the food. The digested food is then ingested by the organism. All decomposers follow saprophytic nutrition.

ii. Holozoic Nutrition - In Holozoic nutrition, digestion takes place inside the body of an organism. The amoeba follows this method of nutrition.

11. Steps of holozoic nutrition –

(a) Ingestion (a process of taking food).

(b) Digestion ( Process of breaking complex food into simple molecules and then absorbed by the body).

(c) Absorption ( Process of absorption of digested food).

(d) Assimilation ( Process of the utilization of digested food).

(e) Egestion ( Process removing undigested food from the body.

12.Parasitic Nutrition – Organism which lives inside or outside of another organism and gets nutrition from it is known as parasitic nutrition. Cuscuta and Tick are following this method of nutrition.

13. Process essential for maintaining life – Nutrition, reproduction, excretion, respiration, and movement or locomotion.

i. In the case of a single-celled organism, there is no specific organ to take food, exchange gases or to remove waste because the entire surface of the organism is in contact with the environment. In multicellular organisms, not all cells can be in direct contact with the surrounding environment.

ii.Thus, simple proliferation or diffusion will not meet the requirements of all cells.

iii. In human beings, the food eaten is broken down by various steps along the alimentary canal and the digested food is absorbed in the small intestine to be sent to all cells in the body.

14. Nutrition in Human Beings - The alimentary canal is basically a long tube extending from the mouth to the anus. It comprises of mouth oesophagus, stomach, small intestine, and large intestine.

15. Main associate glands are salivary gland, gastric gland, liver, and pancreas.

i. Salivary gland secrets saliva that makes the food slippery which makes it easy to swallow the food. Saliva contain salivary amylase that digests starch and convert it into maltose (sucrose).

ii. Gastric gland secrets gastric juices that help in the digestion.

iii. Liver - The liver is the largest gland in the human body. It secrets bile juice, which gets stored in the gallbladder.

vi. Pancreas secrets pancreatic juice which contains many digestive enzymes.

16. Parasitic movement – Rhythmic contraction of muscles of the lining of the elementary canal to push the food forward is called parasitic movement. Food goes from mouth to stomach by parasitic movement.

17. Stomach – It is a bag-like structure with muscular walls that help in churning the food. The gastric gland present in the stomach secretes gastric juice. Gastric juice secreted by stomach wall contains HCl hydrochloric acid to make medium of the stomach acidic and helps to kill germs that may be present in food, the enzyme pepsin helps to digest protein and the mucus to protects the inner lining of the stomach from getting damage from HCl acid.

18. Small intestine – The small intestine is the place of the complete digestion of carbohydrates, proteins, and fats. 

I. It is highly coiled like a structure.

ii. It has three parts duodenum, jejunum, and ileum.

iii. It receives the secretions of the liver (bile juice) and pancreas (pancreatic juice) for the digestion process. Bile juice secrets from the liver, break down large fat globules present in the small intestine, into smaller globules to increase the efficiency of enzyme action. The food coming from the stomach is acidic and change into alkaline by pancreatic enzymes. The pancreas secretes pancreatic juice that contains enzymes like trypsin for digesting proteins and lipase and use for breaking down emulsified fats.

iv. The walls of the small intestine contain glands that secrete intestinal juice and enzymes present in it convert the proteins to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.

v. The digested food is then taken up by the walls of the intestine that contains numerous finger-like projections called villi which increases the surface area for absorption. The villi are richly supplied with blood vessels which absorb nutrients from the digested food transported to different organs of the body where they are used to build complex substances such as the proteins required by our body.

vi. From the small intestine the unabsorbed food is sent into the large intestine where more villi absorb the excess of water from this material.

vi. The rest of the material is removed from the body via the anus. The exit of this waste material is regulated by the anal sphincter.

19. Respiration- The process of acquiring oxygen from outside the body, and to use it in the process of break-down of food sources for cellular needs is what we call respiration.

During the process of respiration, complex organic compounds such as glucose are broken down to provide energy in the form of ATP. ATP is used to provide energy for other reactions in the cellRespiration may be aerobic or anaerobic.

20. Aerobic respiration – Aerobic respiration takes place in mitochondria present in the cell in the presence of oxygen and CO₂, Water and a large amount of energy produced.

21. Anaerobic respiration - Anaerobic respiration takes place in the cytoplasm present in the cell in the absence of oxygen and alcohol, lactic acid, and less amount of energy produced.

22. Passage of air through the respiratory system –

Air is taken through the nostril and pass into the nasal cavity.

The nasal cavity contains hair and mucus to moisturize and warms the air and filter the air from dust. Air then passes into the pharynx and larynx that contains a ring of cartilage and vocal cord respectively. Ring of curtilage protects air passes from collapse and the vocal cord helps to produce a sound which is known as the voice box.

Air from pharynx and larynx pass to the trachea and then to the bronchi. Trachea provides airflow to and from the lungs for respiration.

Bronchi is the main passageway of air to the lungs. Bronchi become smaller when they reach the lungs and called bronchioles. Bronchioles divided into smaller tubes and finally converted into a balloon-like structure called alveoli that allow oxygen and carbon dioxide to move between the lungs and bloodstreams. The alveoli provide a surface where the exchange of gases can take place.

23. Breathing is the process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly by bringing in oxygen and flushing out carbon dioxide.

24. Mechanism of breathing: Inhalation – During inhalation, ribs lift up and the chest cavity becomes larger due to this volume of lungs increases, the air is sucked into the lungs and air enters the lungs to fills the expanded alveoli                         

25. Exhalation - During exhalation ribs moves downward and the chest cavity becomes smaller due to this volume of lungs decreases, air exists from the lungs.

26. Exchange of gases between blood and alveoli - 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 the blood in the alveolar blood vessels to be transported to all the cells in the body. During the breathing cycle, when air is taken in and let out, the lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.

27.Heoglobin - In human beings, the respiratory pigment is hemoglobin which has a very high affinity for oxygen. This pigment is present in the red blood corpuscles.

28. Transportation - Transportation is the process of transporting water, minerals, and food to all parts of the body.

29. Circulatory system- In human beings, the transport of materials such as oxygen, carbon dioxide, food, and excretory products is a function of the circulatory system. The circulatory system consists of the blood, heart, and blood vessels.

30. Transportation in human –

i. Blood is connective tissue. Components of blood are RBCs, WBCs, platelets, and plasma. Fluid medium blood plasma that transports food, carbon dioxide, nitrogen, and waste materials in our bodies and red blood cells transport oxygen and many other salts.

ii. Pumping organ heart pushes the blood around the body by a network of tubes to reach all the tissues and a system of the body. It is a muscular organ. It has four chambers – right auricle, right ventricle, left auricle and left ventricle to prevent the oxygen-rich blood from mixing with the blood containing carbon dioxide. The right side of the heart gets deoxygenated blood from different cells of the body and the left side of the heart receives oxygenated blood from the lungs. The carbon dioxide-rich blood reaches the lungs for the carbon dioxide to be removed, and the oxygenated blood from the lungs brought back to the heart to pumped to the rest of the body.

31. Mechanism of heart - Oxygen-rich blood from the lungs comes to the upper chamber of the heart on the left called the left atrium. When left atrium relaxes blood enters into it and when it contracts the left ventricle expands so that the blood is transferred to it. When the left ventricle contracts the blood is pumped out to the body. When right atrium expands de-oxygenated blood comes from the body to the upper chamber on the right called right atrium and when the right atrium contracts, blood transfer to the right ventricle (lower chamber), which in turn pumps it to the lungs for oxygenation.

Since ventricles have to pump blood into various organs, they have thicker muscular walls and arteries have a thin wall. Valves do not allow the blood flow backward when the atria or ventricles contract.

32. Differences in the structure of the heart in human, birds and amphibians and fishes –In human heart –

I. Humans have four-chambered hearts. The separation of the right side and the left side of the heart prevent the oxygen-rich blood from mixing with the blood containing carbon dioxide. This separation provides a highly efficient supply of oxygen to the body that is useful for animals that need high energy.

ii. Birds and mammals are use energy constantly to maintain their body temperature. Such animals, like amphibians or many reptiles, have three-chambered hearts and tolerate some mixing of the oxygenated and deoxygenated bloodstreams.

iii. Fishes have only two chambers to their hearts and the blood is pumped to the gills to be oxygenated there and passes the body directly. Thus, blood goes only once through the heart in the fish during one cycle of passage through the body. In other vertebrates, blood goes through the heart twice during each cycle. This is known as double circulation.

33. Differences between arteries and veins: 

Arteries are the vessels that carry blood away from the heart to various organs of the body. Since the blood comes from the heart with high pressure, the arteries have thick and elastic walls.

Veins collect the blood from different organs and send to the heart. Veins do not have thick walls because the blood is no longer under pressure, but they have valves that allow the blood flow only in one direction.

34. Capillaries- On reaching an organ the artery divides into smaller vessels to bring the blood in contact with all the individual cells. The smallest vessels have walls that are one-cell thick and are called capillaries. The exchange of material between the blood and surrounding cells takes place across this thin wall. The capillaries then join together to form veins that convey the blood away from the tissue or organ.

35. Blood platelets - When we are injured and start bleeding, it would lead to the loss of blood from the system. Due to the leakage of blood, would lead to a loss of pressure which would reduce the efficiency of the pumping system. To avoid this, the blood has platelet cells that help to clot the blood at these points of injury.

36. Lymph – Lymph is the fluid called tissue fluid that also involved in transportation. When some amount of plasma, proteins and blood cells escape into intercellular spaces through the pores present in the walls of capillaries in the tissues to form the tissue fluid or lymph. It is colourless and contains less protein than blood. From the intercellular space, lymph passes into lymphatic capillaries and join to form large lymph vessels which finally open into larger veins. It carries digested absorbed fat from the intestine and removes excess fluid from extracellular space back into the blood.

37. Transportation in plant – There are two path-way to transport stored energy from leaves and raw materials from roots. These two pathways are conducted by two tubes xylem and phloem. Xylem transport water and minerals obtained from the soil and phloem transports products of photosynthesis from the leaves where they are synthesized to other parts of the plant.

38. Transport of water - In xylem tissue, vessels and tracheid of the roots, stems, and leaves are interconnected and form a continuous system of water-conducting channels. At the roots, cells in contact with the soil and take ions which creates a difference in the concentration of ions between the root and the soil. The water there for moves into the root from the soil to remove this difference. So there is a steady movement of water into root xylem, creating a column of water that is the regular pushed upwards. This pressure is not enough to move water over the heights.

39. Transpiration - The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration. Evaporation of water molecules from the cells of a leaf creates a suction that pulls water from the xylem cells of roots. Plants use this method to move water in the xylem upwards to the highest points of the plant body because root pressure is not enough to move water at the highest point. Transpiration helps in the absorption and upward movement of water and minerals dissolved in it from roots to the leaves. It also helps in temperature regulation.

40. Translocation - Transport of soluble products of photosynthesis from leaves, where they are formed, to other parts of the plant is called translocation and it occurs in the part of the vascular tissue is known as phloem. Phloem transports amino acids and other substances also. The translocation of food and other substances take place in the sieve tubes with the help of adjacent companion cells both in upward and downward directions

41. Excretion - The biological process to the removal of harmful metabolic wastes generated during photosynthesis or respiration from the body is called excretion.

42.The excretory system of human beings - The excretory system of human beings consists of a pair of kidneys, a pair of ureters, a urinary bladder and a urethra. Kidneys are located in the abdomen, one on either side of the backbone. Urine produced in the kidneys passes through the ureters into the urinary bladder where it is stored until it is released through the urethra.

43. Nephron - The basic filtration unit in the kidneys is the nephron. Each kidney has large numbers of nephrons packed close together.

It is a cluster of very thin-walled blood capillaries. Each capillary cluster in the kidney is associated with the cup-shaped end of a tube that collects the filtered urine. Glucose, amino acids, salts and a major amount of water, are selectively re-absorbed as the urine flows along the tube.

44. The amount of water reabsorbed depends on how much excess water there is in the body, and on how much of dissolve waste there is to be excreted.

Urine is stored in the urinary bladder until the pressure of the expanded bladder leads to the urge to pass it out through the urethra. The bladder is muscular, so it is under nervous control and we can usually control the urge to urinate.

45. Artificial kidney (Hemodialysis) - An artificial kidney is a device to remove nitrogenous waste products from the blood through dialysis. It contains a number of tubes with a semi-permeable lining, suspended in a tank filled with dialyzing fluid. During the patient’s blood passing through these tubes, the waste products from the blood pass into a dialyzing fluid by diffusion and after which the purified blood is pumped back into the patient.

46. Differences between the function of an artificial kidney from natural are - There is no re-absorption involved and dialysis fluid of artificial kidney has the lacking of nitrogenous wastes.

47. Excretion in Plants - Plants can get clear of excess water by transpiration. For other wastes, plants use the fact that many of their tissues consist of dead cells, and that they can even lose some parts such as leaves. Many plant waste products are stored in cellular vacuoles. Waste products may be stored in leaves that fall off. Other waste products are stored as resins and gums, especially in old xylem. Plants also excrete some waste substances into the soil around them.

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