Life Processes Notes PDF

LIFE PROCESSES NOTES Living organism shows various kind of movement and processes that help us to distinguish them from non-living. Even though plants do not move, yet they perform various processes which makes them living. On the other hand, various molecules and...

LIFE PROCESSES NOTES Living organism shows various kind of movement and processes that help us to distinguish them from non-living. Even though plants do not move, yet they perform various processes which makes them living. On the other hand, various molecules and microorganism which are not visible to our naked eye shows movement as well on the molecular level. Organisms like viruses which are neither living or non-living as they are non-living when present outside living body (host) and show no movement at all while when it enters any living host body, it infect the cell and increase its number. Hence, it is neither living or non-living (obligate parasite). LIFE PROCESSES INTRODUCTION The maintenance of various functions of an organism must be continued even when it is not moving. This is required so as to prevent damage and breakdown and energy is required as well. Also, the flow of energy is continuous in nature. So, the energy from outside is continuously transferred in the body and vice-versa. Nutrition is defined as series of process of intake of food by the body. It is not a single step process rather a multi-step process. Most of the food that we consume are carbon based (made up of carbon and its molecules). Various organisms uses different method of intaking nutrition. The energy that is being transferred in the body (in the form of food) is broken down or built-up in the body and then it is finally converted to uniform source of energy which is used for various movement and processes. Hence, various chemical reaction (series wise) takes place in our body. These chemical reactions are mostly redox reaction (reduction-oxidation) for breaking down of molecules. Many organisms uses oxygen sourced from outside to use in breakdown processes and it is generally termed as respiration. In case of unicellular organisms, there is no specific organ for taking of food, removal of waste, assimilation of food. Rather, each and every process is being carried out by single cell by simple diffusion. This process is more advanced in case of multi-cellular organisms as the cell are not in direct contact with the environment and hence, simple diffusion is not enough to meet the daily requirement of all the cell.  NOTE- chemical reaction uses carbon as it source and oxygen to generate oxygen. NUTRITION We need energy to maintain the state of order in our body. We need material from outside to grow, develop, synthesize protein and other substances required by our body. These reactions are carried out by bio-catalyst called enzymes. AUTOTROPHS HETEROTROPHS 1. organisms uses simple food material 1. organisms uses complex substances obtained from inorganic sources in the which is broken down into simpler form of carbon dioxide and water. substances from which energy is derived 2. plants, blue-green algae (cyanobacteria), 2. Ex- animals and fungi. and certain bacteria. 3. They prepare their own food using these 3. they are dependent on autotrophs for inorganic raw material and chlorophyll. their energy requirements. 4. they are termed as producers. 4. they are termed as consumers. 5. energy reserve is in the form of starch. 5. energy reserve is in the form of glycogen. AUTOTROPHIC NUTRITION Their energy and carbon requirement is fulfilled by photosynthesis. In this, they take in substances from outside and convert it into form of stored energy. They intake CO2 and H2O and convert it in the form of carbohydrate in the presence of sunlight and chlorophyll. This carbohydrate is either used up to produce energy or is stored in the plant body in the form of starch. EVENTS OF PHOTOSYNTHESIS Events of photosynthesis are- ✓ Absorption of light energy by chlorophyll. ✓ Conversion of light energy into chemical energy and splitting of water molecules int hydrogen and oxygen. ✓ Reduction of carbon dioxide to carbohydrate. These processes need not take place one after the other. In case of desert plants, intake of CO2 occurs at night and intermediate is prepared. The process is completed in the day time by capturing of light by chlorophyll. ACTIVITY – to demonstrate that chlorophyll is necessary for photosynthesis and starch formation. (Procedure is same as given in activity 6.1) OBSERVATION AND EXPLANATION– A variegated leaf contains green as well as a non-green part. The green part contains chlorophyll, while the non-green part does not. When Leaf is kept in dark for a few days, no photosynthesis takes place and plant takes up reserved starch for its activity. Now when the plant is kept in the light, the chloroplast synthesize new starch but a broken leaf cannot transport starch to different parts of the body. So, this starch now remains localized to the green area only. When this leaf was kept in boiling solution of alcohol, it breaks the cell wall and chloroplast which causes washing away of chloroplast in the solution. As a result, leaf loses its green color and become colorless. Now, when this colorless leaf is put into an iodine solution, only the green part of the leaf turn blue. Hence, we can conclude that only green part of the leaf containing chlorophyll can synthesize starch and perform photosynthesis. MECHANISM OF OBTAINING CARBON DIOXIDE BY PLANTS We know that various tiny pores are present on the surface of plants which are termed as stomata. Stomata helps in gaseous exchange for the purpose of photosynthesis. Also, it should be noted that gaseous exchange occurs through root, stem, and leaves as well but massive exchange occurs through stomata. The opening and closing of stomata is regulated by guard cells. Stomata also regulate loss of excess water through it. When there is excess water, guard cell swells up, which causes stomatal pore to open. Similarly, they closes the pore when guard cells shrinks. In case of desert plants, they closes this pore when gaseous exchange is not required to prevent loss of water. ACTIVITY – TO PROVE THAT CARBON DIOXIDE IS NECESSARY FOR PHOTOSYNTHESIS PROCEDURE – SAME AS GIVEN IN BOOK In bell jar containing KOH, it was seen that the leaf did not take up the iodine and did not turn blue-black as KOH absorbs all the carbon dioxide present in the surrounding. Hence, the process of photosynthesis did not take place.  While in bell jar devoid of KOH, the normal process of photosynthesis takes place as all the essential raw material was present in the surrounding. Hence, leaf of this plant turned blue-black hence, showed the presence of starch. OTHER IMPORTANT MINERALS AND SUBSTANCES FOR PLANTS Other minerals like nitrogen, phosphorous, sulphur are taken up by plants through roots. Nitrogen is required for synthesis of protein, enzymes, and other compounds. Nitrogen is taken up in the form of nitrates and nitrites (Nitrogen cycle) or ammonium ions which is fixed by bacteria like rhizobium. HETEROTROPHIC NUTRITION Different types of heterotrophic nutrition is seen depending upon the type of organism and different range of mobility and movement. It is of three types – holozoic (human and amoeba), Saprophytic, and parasitic. In case of fungi like bread mould, yeast, and mushroom, they break down the substances outside their body and then absorb them. They are termed as saprophytes. Some organisms like humans and various animals, they take in complex substances and breakdown of food substance occurs inside the body. It is called holozoic. Some are simply parasites which derive nutrition from plants or animals without killing them. Eg- lice, termites, cascuta (amar-bel), tapeworm, leeches. METHOD TO OBTAIN NUTRITION IN DIFFERENT ORGANISMS The way of obtaining food is different in different organisms and so is the digestive system found in them. In unicellular organism, the food is taken in by the entire surface but when the complexity of organism increases (ie organism with tissue level organization or organ level or organ system level) their body develops specialized organs/tissue for the same. NUTRITION IN AMOEBA In case of amoeba, the intake of food is through the process of endocytosis. This process include 5 steps – ingestion, digestion, absorption, assimilation, and egestion. Amoeba has finger-like projections called pseudopodia (false feet) which fuses with the food and forms a temporary food vacuole. This step is ingestion. After ingestion, the complex substance is broken down into simpler form (digestion) which then diffuses into cytoplasm. This step constitutes assimilation and absorption. The remaining undigested food then move to the surface of cell and is excreted out. This step is called egestion. NUTRITION IN PARAMOECIUM  It is also unicellular. In this, the cell has a definite shape (unlike amoeba) and food is taken in at a specific spot. The food is moved to the specific spot by cilia (hair-like projection) which covers the entire surface of the cell. ACTIVITY TO DETECT THE PRESENCE OF STARCH PROCEDURE SAME AS GIVEN IN ACTIVITY 6.3 RESULT AND EXPLANATION In test tube A, since saliva was added which contains an enzyme called salivary amylase which was able to digest the starch into simpler form while in test tube B, no saliva was added. Hence, the starch breakdown did not occur. Hence, the test tube B will stain blue black while test tube will not give the desired color. NUTRITION IN HUMAN BEINGS Alimentary canal is defined as long tube extending from mouth till anus. Alimentary canal has different parts and region having specific role and function. The food after being ingested is broken down into simpler pieces by the teeth. Along with this, the saliva is also present there which contains a biological enzyme called salivary amylase. This amylase helps in breakdown of starch (complex sugar) into simple sugar. The food is mixed thoroughly with saliva due to even chewing and muscular action of tongue. To make the passage of food smoother, the lining of alimentary canal is soft. The lining of canal has muscle that contracts rhythmically in order to push the food forward. This movement is known as peristaltic movement that promote passage of food in a regulated manner. From mouth the food now reached the stomach through esophagus or food pipe. STOMACH The stomach is a large organ which expands as the food enters it. The walls of stomach is muscular which helps in even mixing of food particles with digestive juices and enzyme. The process is initiated by gastric gland present in wall of stomach. It releases HCl (hydrochloric acid), mucus, and pepsin (protein digesting enzyme). The pepsin which is released initially is present in the inactive form as pepsinogen. This pepsinogen is activated to pepsin by the acidic medium provided by HCl. The role of mucus is to protect the inner lining of stomach from the effect of HCl.  The excess amount of HCl in the stomach causes tearing and breakage of mucus lining. Hence, it leads to condition called acidity. The exit of food from stomach is regulated by sphincter muscle which releases food into small intestine. It should be noted that only carbohydrate digestion, protein digestion occurs in stomach. No fat has been digested so far. SMALL INTESTINE Small intestine is the longest canal which is fit into compact structure. It is the site of complete digestion. The length of small intestine differs in organism due to the type of food consumed by them. In herbivores, the length of small intestine is longer as compared to herbivores as herbivores eat grass which contains cellulose. Hence, require longer canal for proper digestion. While in case of carnivores, they feed on flesh and meat. Hence, have shorter intestine. The small intestine receives secretion from liver and pancreas for digestion. Since food from stomach is acidic and needs to be made alkaline for pancreatic juices to act. Liver secretes bile juice which acts on fat. Fats are present as large globule which is difficult to digest. Hence, bile salts breaks them down into small globules which helps the enzyme to act on them. This is known as emulsification of fats. Pancreatic juices contain trypsin (for protein digestion) and lipases (for fat digestion). The wall of small intestine also contains gland that secrete intestinal juices which contains enzyme and finally converts protein into amino acid, carbohydrate into glucose, and fats into glycerol and fatty acids (FA). The digested food is absorbed by the intestine as it has numerous fingerlike projections called villi which increases SA for absorption. Villi are richly supplied with blood vessels and helps in transportation of nutrients to every cell of the body. LARGE INTESTINE All the unabsorbed food reaches here. The walls of large intestine helps in absorbing water from the material. The rest food is released out through anus and exit of this material is regulated by anal sphincter. DENTAL CARE Our teeth contains a very hard protective layer called enamel which protects dentine.  When bacteria enters in our mouth, it acts on sugar which get stuck on our teeth and produces acid that results in softening or demineralization of enamel. This results in formation of dental plague (accumulation of large no of bacteria) and results in tooth decay or dental caries. Hence, it is advised by the doctors to brush your teeth twice. NOTE – in worst cases, bacteria invades the pulp (soft region of gums) and causes inflammation and infection. TRYPSIN PEPSIN 1. It is released by pancreas and present in 1. It is released by gastric gland in stomach. pancreatic juices. 2. It break down peptones into aa. 2. It break down proteins into peptones. 3. It works in alkaline environment in small 3. It works in acidic environment in intestine. stomach. RESPIRATION Now that the food has been converted to simpler form, this simpler form is further broken down by the cell to produce energy to carry out life processes. Energy is produced in the form of ATP (adenosine triphosphate). The glucose is the most common source for the production of energy. The glucose is first converted to pyruvate/pyruvic acid in the cytoplasm of all cell. One glucose produces 2 molecules of pyruvate. This step is common in both aerobic and anaerobic organisms. Further depending upon the type of process, various products are formed. In case of aerobic respiration, which occurs in the presence of oxygen, the pyruvate is broken down into CO2, H2O, and energy (ATP). In case of anaerobic respiration in fermentation by yeast, which takes place in the absence of oxygen, pyruvate is broken down into ethanol (2C), CO2, and energy (ATP). (Ethanol fermentation) In case of vigorous exercises and lack of oxygen occurs in muscle cell, here also anaerobic respiration occurs which results in the production of lactic acid (3C) and energy. Accumulation of lactic acid leads to cramp and pain. (Lactic acid fermentation). NOTE – ATP is used to derive endothermic reaction which are taking place in the cell. Energy equivalent of 1ATP is 30.5KJ/mol. That’s why it is the energy currency of the cell. Uses of ATP – for the contraction of muscle, for the production of protein synthesis, conduction of nerve impulses, and etc. ACTIVITY 6.4 RESULT AND EXPLANATION When air is passed through the lime water, the carbon dioxide present in it turns lime water milky (formation of calcium carbonate). ACTIVITY 6.5 RESULT AND EXPLANATION In case of yeast, the type of respiration occurs here is anaerobic respiration. In this process, the glucose is converted to ethanol, CO2, and energy. This CO2 when passed through the tube into lime water, it turns it into milky. This process is also known as fermentation in yeast. DIFFUSION OF OXYGEN AND CARBON DIOXIDE The diffusion of gases takes place depending upon the requirement of an organism and environmental conditions. In case of plants, at night, no photosynthesis occurs, hence CO2 elimination is the major process while at day time, photosynthesis occurs in plants. Hence, CO2 is generated during respiration is not released out rather oxygen release is the major event. Terrestrial animals breath the oxygen in the atmosphere while aquatic animals uses dissolved oxygen found in water. The rate of respiration is higher in aquatic animals as compared to terrestrial animals because the amount of oxygen dissolved is comparatively less and fishes take in water and force it down the gill to take up dissolved oxygen. Terrestrial organisms have various mechanism to obtain oxygen. BREATHING RESPIRATION 1. It is a physical process. 1. it is chemical process. 2. in involves inhale (intake of air) and 2. in this, exchange of gases takes place. exhale (release of air). 3. No energy is produced. 3. it results in the formation of energy in the form of ATP. 4. it is a voluntary process. 4. It is an involuntary process. RESPIRATION IN HUMANS  Intake of air is carried out through nostrils which contains fine hair and is also lined with mucus. Fine hair increases SA to absorb dust particles and mucus being fluid also helps in trapping of germs and other foreign particles. The air is then passed to throat (trachea) which contains rings of cartilage which are C shaped that prevents collapsing of trachea. The air is then passed to bronchi which divides into lungs. Within the lung, the passage divides into smaller and smaller branches of tubes called bronchioles which are lined with balloon-like structure called alveoli. Alveoli is the site of exchange of gases. The walls of alveoli are lined with blood vessels. INHALE During intake of air, our chest cavity expands and volume of chest cavity increases and rises up. This is accompanied by relaxation or flattening of diaphragm. This results in air to move inside the lungs and filling of expanded alveoli takes place. The blood vessels bring blood containing carbon dioxide. As alveoli is the site of gaseous exchange, the alveolar cavity takes up oxygen. EXHALE During expelling of air, our lung cavity relaxes and volume of chest cavity decreases. This is followed by contraction of diaphragm. This results in carbon dioxide to expel out from the body. NOTE – there is always some residual volume in the lungs so that there is sufficient time for oxygen absorption and carbon dioxide release. WHY DIFFUSION IS NOT ENOUGH IN CASE OF COMPLEX ORGANISMS It is because as the body size increases the diffusion pressure alone cannot meet the oxygen requirement of the all the parts of body. Instead, respiratory pigment called hemoglobin is required to carry oxygen to all parts of the body. Hemoglobin is present in RBC (red blood corpuscles) and it has high affinity for oxygen. In case of CO2, which is soluble in water than oxygen, it is usually transported in the soluble form. TRANSPORTATION IN HUMAN BEINGS Blood consist of fluid matrix called plasma in which cell (RBC, WBC, platelet) are suspended. It Is known as systemic fluid. Plasma helps in transportation of food, oxygen, carbon dioxide, and nitrogenous waste in dissolved form.  Oxygen is carried by RBC. Main component of transport system in human includes – heart, blood, and blood vessels. HEART It is the muscular organ, approximately the size of our fist which helps in pumping of the blood. Heart has different chambers for oxygen and CO2 in order to prevent mixing of two. In humans, the heart has 4 chambers in it. The upper two chambers of heart are termed as atria (atrium singular) and bottom two chambers are called ventricles. The left atrium is thin walled. All these chambers are separated from each other by a wall called septum. Septum between atrium – interatrio septum ; between ventricle – interventricular septum ; between atrium and ventricle – atrio-ventricular septum. The left side of the heart receives oxygenated blood (rich in oxygen) while right side of the heart receives deoxygenated blood (rich in carbon dioxide). The process of circulation takes place twice in human. Hence, it is known as double circulation in humans. BLOOD VESSELS There are three blood vessels present in our body – arteries, veins, and capillaries. Exceptional artery – pulmonary artery that carries deoxygenated blood. Exceptional vein – pulmonary vein that carries oxygenated blood. Capillaries – these are the smallest blood vessels that have walls which are one cell thick. It helps in the exchange of material between blood and surrounding cells. Capillaries from various organs join together to form vein to convey blood away from tissue/organ. ARTERIES VEINS 1. it carries blood away from the heart. 1. it carries blood towards the heart. 2. they have thick and elastic walls. 2. they have thin walls as blood is not under the pressure. 3. here blood pressure is higher. 3. here blood pressure is slightly lower. 4. It lacks valves 4. It contains valve. 5. It is deep-seated. 5. It is superficial. 6. Pulmonary artery carries deoxygenated 6. Pulmonary veins carry oxygenated blood blood away from the heart to lungs. from lungs to heart. DOUBLE CIRCULATION  The right atrium of the heart receives deoxygenated blood through largest vein called vena cava. The largest vein coming from upper part of body is termed as superior vena cava while vein coming from lower body is termed as inferior vena cava. The filling of blood in right atrium causes right ventricle to open so that blood from atrium can fill the ventricle (atrium contraction). The deoxygenated blood is then transported to lungs through pulmonary artery. After reaching lungs, exchange of gases takes place which results in the oxygenation of blood. This oxygenated blood is then taken up by the pulmonary vein to the left atrium of the heart. This atrium contracts and causes filling of the left ventricle. The oxygenated blood from left ventricle is taken to the body parts via largest artery called aorta. Since the blood is passed twice during each cycle, it is termed as double circulation. HEART IN OTHER ORGANISMS In animals like reptiles, amphibians they have three chambered heart since their body temperature depends on the temperature of environment. These animals are cold- blooded animals. In animals like mammals, birds (aves) they have four chambered heart to prevent mixing of oxygenated and deoxygenated blood. also, this promotes highly efficient energy supply of oxygen to the body. Hence, they are known as warm blooded animals as they can regulate their body temperature. Even though crocodile is a reptile, it has 4 chambered heart. In fishes, they have only chambers in their heart in which blood is pumped to gills where it is oxygenated and then passed to the entire body. In fishes, blood is passed once per cycle. It is defined as force exerted by blood against the wall of the vessels. Systolic pressure is defined as pressure of blood inside artery during ventricular systole (contraction). It’s value is 120mm Hg. Diastolic pressure is defined as pressure in artery during ventricular diastole (relaxation). It’s value is 80mm Hg. BP is measured through an instrument called sphygmomanometer. High BP can result in hypertension due to constriction in arteriole which increases resistance in blood flow which can leads to rupturing of artery and internal bleeding. PLATELETS Platelets are the cells of blood that causes clotting or coagulation of blood at the site of injury/wound to prevent or minimize loss of blood through body.  Excess loss of blood can result in reduced blood pressure which can hinder the efficiency of pumping system. LYMPH It is known as tissue fluid. Sometimes plasma, proteins, and blood cells escape through the pores present in the capillaries into the interstitial spaces in the tissue which forms lymph. It is colorless and contains less protein than blood. It drains into lymphatic capillaries from the spaces and joins large lymph vessels which open into large vein. FUNCTIONS OF LYMPH It also carries digested and absorbed fats from intestine. It drains excess fluid from extra cellular spaces into blood. It transports oxygen, hormones and nutrients to different parts of the body and removes metabolic waste from the cells. It transports antibodies and lymphocytes to the blood. TRANSPORTATION IN PLANTS The food is stored in plants in the chlorophyll-containing part called leaves in the form of starch. The plant obtained other raw materials like nutrients and water from soil. Major nutrients include nitrogen phosphorous, and potassium. The absorption of these substances is done by roots. Since the various body parts are not in close proximity with the roots, the process of diffusion of these minerals is not possible and inefficient. Different organs and tissue of plant has different requirements due to different body design. For the transportation of water and minerals, there is conducting system called xylem while for food transportation is done by phloem. TRANSPORTATION OF WATER AND MINERALS Xylem tissue has interconnected network of vessels and tracheid’s of roots, stem, and leaves. The cells of root which are in direct contact with the soil actively takes up ions. This is facilitated due to concentration difference between cells of root and soil and we know that movement occurs from high conc to low conc. Hence, movement of water takes place in root to eliminate this difference.  This means that a column is created which will push the water to move in upward direction. But this pressure is not enough to move the water completely to highest point. So other mechanisms include evaporation and transpiration pull. We know that excess water is lost through stomata via evaporation which creates suction that pulls the water from root towards upward direction. Transpiration pull works in the same manner as well. Transpiration is defined as loss of water in the form of vapors from aerial parts of the plant. During day time, the stomata is open. Hence, transpiration pull becomes major driving force in the movement of water in the xylem. Transportation of water is a unidirectional process. BENEFITS OF TRANSPIRATION Helps in absorption and upward movement of water and minerals dissolved in it from roots to leaves. It regulates temperature. NOTE – the effect of root pressure in transportation of water is more important at night. TRANSPORTATION OF FOOD AND OTHER SUBSTANCES The metabolites/substance formed during photosynthesis are moved from leaves to the other parts of plant. The transportation of soluble products of photosynthesis is called translocation and it occurs through phloem. Phloem transports amino acid and other substances as well which is delivered to storage organs of roots, fruits, seeds, and growing organs. This process takes place in sieve tubes with the help of companion cells in both upward and downward direction. Transportation of food is an energy requiring process which require energy in the form of ATP. This results in osmotic pressure difference between tissue and phloem This causes water to move into the tissue due to high osmotic pressure and material or substances is moved into phloem tissue which has less pressure. This causes movement of substances according to the needs of plant. NOTE – in springs, sugar stored in root or stem is transported to buds which needs energy to grow. EXCRETION  The removal of harmful metabolic waste (nitrogenous waste) from the body is known as excretion. Unicellular organisms uses simple diffusion for the removal of these substances. Multicellular organisms have various methods. EXCRETION IN HUMANS Excretory system of human includes a pair of kidneys, a pair of ureters, a urinary bladder, and urethra. Kidney is located in abdominal region (one on either side of backbone). Passage of urine – kidney (forms urine), passes to ureter, stored in urinary bladder, and released through urethra. FORMATION OF URINE Urine is formed by the kidney. The significance/purpose of urine formation is to filter out nitrogenous waste in the form of urea or uric acid from the blood. This process is done by basic filtration unit of kidney called nephron. Nephron is the cluster of thin-walled capillaries. There are 1 million nephrons in each kidney. There are three steps of urine formation – filtration, reabsorption, and secretion. Nephron is composed of cup-shaped structure called bowmann’s capsule which contains highly coiled vessels called glomerulus which helps in the filtration of blood. This filtered blood is passed through various tubules like proximal convoluted tubule (PCT), loop of henle (LOH), and distal convoluted tubule (DCT) which helps in the reabsorption of glucose, amino acid, salts, and water. The amount of water reabsorbed depends on the level of water present in body and dissolved waste. Some salts like NaCl and urea are secreted out. It should be noted that even though filtrate produced by kidney through nephron is 180L/day but due to reabsorption process, most of the filtrate is reabsorbed and generally 1-2L is passed as urine. Also, our body losses nitrogenous waste through sweating as well. In winters, due to less or no sweating, the removal of nitrogenous waste can occur via urination only. Hence, we tend to urinate more in winters than summers. This urine is then passed through ureter to urinary bladder where it is stored until pressure of expanded bladder causes urge to pass it out via urethra. The bladder is muscular and is under nervous control. NOTE – we can control the urge to urinate. HEMODIALYSIS (ARTIFICIAL KIDNEY) Infections, injury, or restricted blood flow can impair activity of kidney that can lead to accumulation of poisonous substances in the body that can cause health issue and death in extreme cases. Artificial kidney is a device to remove poisonous nitrogenous waste of body through dialysis. It contains a no of tubes having semi-permeable lining which are kept in dialysing fluid. The osmotic pressure of these tube is same as that found in our blood vessels but this dialysing fluid is devoid (free) from nitrogenous waste. The patient’s blood is passed through this tube and waste product is passed into dialysing fluid via diffusion. The purified blood is passed into the patient body back. It is similar to what is happening in kidney but no reabsorption occurs in this process. EXCRETION IN PLANTS In plants, oxygen is a waste product which is removed during photosynthesis. Excess water in plants is removed through transpiration. Various plant parts contain dead cells and they even lose some parts like leaves. Waste products in plants is stored in vacuoles and in leaves that have the tendency to fall off. Waste products like resin, and gums are stored in old xylem. Some waste product is stored released into soil around them.