Standard/ Class/ Grade - X SSC, CBSE; - VIII ICSE
Life Processes
Gurudatta K Wagh
Life Processes
Processes that are common to all living beings are called as life processes• nutrition • respiration • excretion • transportation • reproduction • sensitivity • growth
Overview of the Chapter
Nutrition• Digestive system in human beings• PhotosynthesisRespiration• Respiratory system in human beings• In plantsTransportation• Circulatory system in human beings• In plants (Root pressure, Transpiration,
Translocation)Excretion• Excretory system in human beings• In plants
Food contains several components called as nutrients
Nutrients and their functions
Based on their functions nutrients are divided into three types.
Types FunctionsEnergy giving Carbohydrates, fatsBody building ProteinsProtecting and regulating
Vitamins, minerals
Nutrition
Types Source FunctionsInorganic nutrients from inorganic
substances present in the soil and atmosphere through leaves and roots
for growth and to form various parts of the plant
Organic nutrients carbohydrates, proteins and fats of animal and plant origin
build the body
Nutrients and their types
On the basis of chemical nature, the nutrients are of two types
Nutrition
Nutrition The process of intake of nutrients and its utilization by an organism
Nutrition provides the raw materials needed to sustain life
Mode of nutrition
Mode of nutrition The way by which an organism obtains its food
Nutrition
Mode of nutrition DependencyAutotrophic Plantsuse simple inorganic substances
Independent - organisms synthesize their own organic food
Heterotrophic animals and fungi
Dependent - depend on other organisms
Autotrophic Heterotrophic
Nutrition
Heterotrophic nutritionOrganism How do they obtain their
food?Fungi like yeast, mushrooms and some carnivorous plants
break down the food material into simple substances outside the body and then absorb it
Human being, cat, cow, etc. take in whole food and then break it down to simple substances inside their bodies and then absorb it
Cuscuta, ticks, lice, leeches, tapeworms, etc.
derive nutrition from other plants or animals without killing them but during the process they harm the host plant or animal
Nutrition
Basic steps of nutrition remain the sameName ProcessIngestion taking food insideDigestion The process of breaking down of complex organic
food into simpler soluble substances. Mechanically by teeth and chemically with the help of enzymes
Absorption After digestion is completed soluble digested food is absorbed into the blood
Assimilation The absorbed food is transported into tissues and cells of the body where they are used to produce energy for growth and development or stored for future use
Egestion The undigested and unabsorbed residues of food are thrown out of the body
Nutrition
Digestive system
As the complexity of organism increases some of the organs of the body become specialized to perform specific functions
Some of these organs together constitute a complex digestive system
All the processes involved in nutrition in human beings take place by association of digestive organs called the digestive system
Digestive system = alimentary canal + digestive glands
Digestive system
Alimentary canal 1) is a long and muscular tube of varying diameter 2) which extends from the mouth to the anus.
Digestive glands associated with the alimentary canal
1.salivary glands, 2.liver, 3.pancreas, 4.gastric glands (fundic, cardiac, pyloric)
The fundic glands (or oxyntic glands), are found in the fundus and body of the stomach. They are simple almost straight tubes, two or more of which open into a single duct.Oxyntic means acid-secreting and they secrete hydrochloric acid (HCl) and intrinsic factor.
Digestive system
The food that we take is of complex nature. It is converted into simpler molecules with the help of biological catalysts called as enzymes. Enzyme salivary amylase breaks down starch into a simple sugar maltose. Thus digestion starts in the mouth itself.
Mouth Food has to be processed to generate particles with small size. The chewed and crushed food is wetted with saliva secreted by the salivary glands so the food can smoothly pass through the soft lining of the alimentary canal.
Digestive system
Stomach The partly digested food goes down through the oesophagus into a 'J' shaped stomach placed on the left side of the abdomen
The food is pushed forward in the canal due to rhythmic contraction and relaxation of the muscles of the canal called as peristaltic movement.
The gastric glands present in the wall of the stomach release three gastric juices namely hydrochloric acid, enzyme pepsin and mucus
Hydrochloric acid creates acidic conditions which are necessary for the action of the enzyme pepsin which digests proteins
Mucus protects the inner lining of the stomach from the action of acids under normal conditions
Digestive system
Small Intestine The small intestine is the longest part (5 - 6 m) of the alimentary canal fitted into a compact space in the belly by extensive coiling
Digestive system
Although it is much longer than the large intestine, it gets its name from its comparatively smaller diameter
Herbivores (grass eating) need longer intestine, carnivores like tigers (meat eating) have short intestine
The length of small intestine differs in various animals depending on the food they eat
Carbohydrates, fats and proteins are fully digested in the small intestine
Digestive system
Since this action takes place only in alkaline conditions the acidic food received from the stomach has to be first made alkaline
Liver the largest gland in the body secretes bile juice which is stored in the gall bladder
Whenever food enters the small intestine, the gall bladder releases bile into it through a duct
Digestive system
Bile makes the food alkaline and breaks the large fat globules into smaller ones, this increases the enzyme action
Pancreas secretes pancreatic juice. It has digestive enzymes like trypsin (to digest proteins), lipase (to break down fats) pancreatic amylase (to digest carbohydrates)
The bile and the pancreatic juice enter the small intestine through a common duct
Digestive system
Various intestinal juices are also secreted by walls of the small intestine to complete the digestion process of converting proteins to amino acids, complex carbohydrates to glucose, and fats into fatty acids.
The digested food is absorbed by the walls of the small intestine having numerous finger like projections called villi
Digestive system
Villi, which absorb the food are richly supplied with blood vessels
The absorbed food is taken to each and every cell of the body where it is utilized for obtaining energy
Unused glucose is stored in the liver in the form of glycogen
The unabsorbed food is sent to the large intestine
Digestive system
This part of the intestine does not have any digestive function as the digestion is already completed. The walls of the large intestine have villi which absorb most of the water and salts. The rest of the material is removed from the body through the anus. Here too the exit is regulated by the muscle called sphincter.
Large intestine Undigested food and the residue of the digested food pass into the large intestine (about 1.5 m long).
Digestive system
Photosynthesis
Green plants synthesize their food
Photosynthesis They take in carbon dioxide and water and convert them into carbohydrates (glucose) in the presence of chlorophyll and sunlight
Carbohydrates provide energy
Unutilized carbohydrates are stored in the form of starch
Process Carbon dioxide enters into the leaves through tiny pores present on the surface of the leaf called stomata. Water is taken up from the soil. Chlorophyll present in the chloroplasts absorbs the radiant energy from the sunlight
Light energy splits up the water molecules into hydrogen and oxygen, releasing energy in the form of Adenosine TriPhosphate (ATP)
Photosynthesis
The energy produced is used to reduce carbon dioxide to carbohydrates
The above steps may or may not take place one after another immediately
e.g. desert plants take up carbon dioxide at night and prepare an intermediate product which is acted upon during the day by the energy absorbed by chlorophyll
Photosynthesis
Photosynthesis
Site of photosynthesis Mostly in the leaves and to a lesser extent in green stems and floral parts
Photosynthesis takes place only in the presence of chlorophyll
There is an absence of starch in the parts of the leaf which are devoid of chlorophyll
Without carbon dioxide photosynthesis cannot take place
Photosynthesis
Photosynthesis
Raw materials of photosynthesis
carbon dioxide + water
taken in through the stomata of the leaves
With the help of sunlight, chlorophyll, water and carbon dioxide, autotrophs synthesize carbohydrates and meet their energy requirements.
Photosynthesis
Plants also need body building and regulating nutrients like nitrogen, phosphorus, iron, magnesium etc. which are taken up from the soil
Nitrogen is essential for synthesis of proteins
Nitrogen is taken up in the inorganic form or in the form of an organic compound.
Photosynthesis
Respiration Process of release of energy from the assimilated food
Respiration is of two types
1. aerobic presence of oxygen 2. anaerobic absence of oxygen
Respiration involves two distinct phases
1. breathing/ external respiration and 2. cellular/ internal respiration
Respiration
(1) Breathing or external respiration
Breathing involves movement which brings the air into the lungs and expels the air containing more of carbon dioxide from the lungs to the outer environment.
Exchange of gases in and out of the blood also takes place simultaneously.
External respiration is a physical process.
It involves taking in oxygen rich air, absorption of oxygen from it and giving out air containing more carbon dioxide with the help of respiratory organs.
Respiration
(2) Cellular or internal respiration
Takes place in the mitochondria of the cells to release energy in the form of ATP.
Respiration
Exchange of Gases in Animals
Organs of respiration, e.g. gills, lungs, skin, etc.
Aquatic Animals Use oxygen dissolved in water
Solubility of oxygen in water is much lower
Amount of oxygen available is much lesser than air, hence the rate of breathing is faster in aquatic animals
Respiration
Fish take in water through the mouth and release it over the gills
Gills are the site for uptake of the dissolved oxygen into the blood by diffusion
Respiration
Terrestrial Animals Take oxygen from the air
The respiratory organs in different animals are different but process of diffusion is common
These organs have special structures which increase the surface area that is in contact with the oxygen rich atmosphere
But these structures are delicate, so they are placed within the body
A special passage takes the air to these structures
Respiration
Respiratory/ Breathing tract
The human respiratory tract starts with the nostrils
The air passing through the nostrils is filtered by the fine hair that lines the passage
The air also becomes moist and warm
The dust particles are trapped in the mucus
Respiration
Respiratory tract = external nostrils, pharynx, larynx and trachea
Trachea/ wind pipe divided into two bronchi One enters the right lung and the other the left lung
Though conventionally called as respiratory tract, this tract carries out only breathing (part of respiration) so we can also call it as breathing tract
Respiration
Respiration
Respiratory Organs (Breathing Organs)
Lungs They lie in the thoracic cavity on both the sides of the heart
Within each lung the major bronchus divides into two bronchi and further into smaller and smaller bronchioles which finally terminate into balloon like structures called alveoli (singular alveolus; means cavity in Latin)
Role of alveoliAlveoli provide the surface for exchange of gases
The thin walls of the alveoli are closely surrounded by a network of blood capillaries
Respiration
The haemoglobin present in the RBCs of the blood absorbs the oxygen from the air present in the alveoli through the thin walls of the capillaries
At the same time C02 from the blood is released into the alveoli by diffusion, which goes out of the body when we breathe out air
The oxygen is carried to all the tissues of the body which are deficient in oxygen.
Respiration
Respiration
Fascinating
Alveoli If the alveolar surface of lungs is spread out, it will cover about 80 m2 area
Haemoglobin If haemoglobin was absent and oxygen would have to move only by diffusion from lungs to toes, it would take three years for the oxygen to reach to the toes from the lungs
Respiration
Mechanism of breathing in human beingsAction Inhalation Exhalation muscular diaphragm
contracts relaxes or becomes convex
volume of the thoracic cavity
increases decreases
air pressure inside the cavity
decreases increases
air enters the lungs Leaves the lungsalveolar sacs filled with air rich
in oxygenEmpty the carbon dioxide received from the blood
Respiration
Some facts
A human adult at rest, on an average breathes about 12-20 times per minute, i.e. 28200 times per day
Keep your lungs healthy. Don't smoke. Don't expose yourself to the tobacco smoke given out by cigarette smokers
Avoid being a passive smoker
Respiration
Exchange of gases in plants
Plants are stationary so their energy requirement is less The process of respiration is slower as compared to that of the animals
The process involves exchange of carbon dioxide and oxygen
Respiration
Plants do not have a special respiratory organ and there is very little transport of gases from one part of the plant to another
They have the source of oxygen in their own body as oxygen is released during the process of photosynthesis Large intracellular spaces ensure that all the cells are in contact with the air that enters through the stomatal opening
Respiration
All parts of the plants like root, stem and leaf perform respiration
The gases are exchanged by the process of diffusion
Respiration
Time Day Night C02 02
Photosynthesis Yes No used more releasedRespiration Yes Yes released released
During the day time, photosynthesis and respiration go on simultaneously in a plant
The C02 released during respiration is utilized for photosynthesis and more 02 is released
At night, when there is no photosynthesis, only respiration goes on and more C02 is eliminated
Respiration
Cellular/ Internal respiration
Cellular respiration is a biochemical process in which the simple nutrients like glucose are oxidized within the cells to release energy
This process takes place in the mitochondria of the cells and involves a series of biochemical reactions
The process of cellular respiration varies greatly in different organisms yet the first step is common in all
Respiration
The six carbon molecule (C6H1206) is broken down in the cytoplasm into a three carbon molecule called pyruvate
This process is anaerobic and is called as glycolysis
Respiration
Respiration
Respiration
Respiration
The energy released during cellular respiration is immediately used to synthesize ATP which is used to fuel all other activities in the cell
The energy released during aerobic respiration is more than the energy released during anaerobic respiration
Few intestinal parasites like liverfluke, tapeworm and roundworm respire anaerobically because they live in environments which have less amount of oxygen
Certain cells, such as mammalian RBCs carry out only anaerobic respiration because mitochondria are absent in them
Respiration
Transportation
The substance synthesized or absorbed in one part of the body is moved to the other part of the body by the process of transportation, e.g. carbohydrates, oxygen, etc.
Transportation in human beingsThe process of transportation of materials in animals is called as circulation
Blood and lymph help in this process
Blood
Blood is the fluid connective tissue in human beings
It carries out the function of transport of various materials in the body
A pumping organ is needed to push the blood around the body along with a network of tubes to reach all the tissues and a system to repair the network from time to time if it is damaged
Transportation
Heart – the involuntary pump
The human heart is a muscular organ which pumps blood
The heart is covered by the pericardial membrane
It is of the size of a human fist and weighs about 360 gm
Transportation
Transportation
As oxygen and carbon dioxide both have to be transported by the blood, the heart has different chambers, the left and the right, to prevent oxygen rich blood from mixing with the blood containing carbon dioxide
The left half carries oxygenated blood. Such separation allows a highly efficient supply of oxygen to the body
Transportation
This is very essential in animals that have high energy needs, such as birds and mammals, which constantly use energy to maintain their body temperature
Each half is further divided into two chambers
The upper one is called atrium and the lower one is termed as the ventricle
The human heart has four chambers
Transportation
Circulation of blood within the heart
Right side Left sideAtrium – deoxygenated blood from the body via vena cava
Atrium – oxygen rich blood from lungs via four pulmonary veins
Valve ValveVentricle - deoxygenated blood Ventricle - oxygenated bloodPulmonary artery – lungs - oxygenation
Aorta – to the body
Transportation
The muscles of the atria are relaxed
The right atrium receives deoxygenated blood collected from different organs of the body via large veins called vena cava
The left atrium too receives oxygen rich blood from the lungs simultaneously through the four pulmonary veins
The atria contract and pour the blood into respective ventricles which expand to receive the blood
Transportation
Left ventricle gets filled with oxygenated blood and right gets filled with deoxygenated blood
Now both the thick walled ventricles contract resulting in pumping out the oxygenated blood to all the parts of the body through the aorta (the largest artery) and the deoxygenated blood from the right ventricle enters the lungs through the pulmonary artery for oxygenation
Transportation
The valves between the atria and ventricles ensure that the blood does not flow backwards
Thus the deoxygenated blood enters the right part of the heart and again after oxygenation it enters the left part of the heart so the blood goes through the heart twice during each cycle
This is known as double circulation
Transportation
Double circulationTransportation
The body temperature of cold blooded animals varies according to environmental temperature
Such animals can tolerate some mixing of oxygenated and deoxygenated blood
Such animals have three chambered heart e.g. amphibians and many reptiles
Fish have only a two chambered heart so blood goes through the heart only once
Transportation
Transportation
Blood pressureThe force exerted by the blood on the wall of a blood vessel is called the blood pressure
This pressure is greater in the arteries than the veins
The pressure in the artery during ventricular contraction is called the systolic pressure and the pressure in the artery during ventricular relaxation is called diastolic pressure
Transportation
The normal systolic pressure is 120 mm of Hg and diastolic pressure is 80 mm of Hg
Blood pressure is measured by an instrument called as Sphygmomanometer
High blood pressure is also called Hypertension
Transportation
Capillaries and veins
Arteries carry blood away from the heart and have to tolerate the force exerted by the blood which is under high pressure exerted by the heart
The walls of the arteries are thick and elastic
Veins collect the blood from different parts of the body and bring it back to the heart. They do not need thick walls as blood is no longer under high pressure; instead they have valves to prevent the backward flow of blood
Transportation
On reaching the tissues arteries divide and redivide into smaller and smaller vessels called capillaries to bring the blood in contact with individual cells
Exchange of material between the blood and the surrounding cells takes place across the thin walls of the capillaries
The capillaries join together to form veins which take the blood away from the organ but towards the heart
Transportation
Repair of damaged network by the blood platelets
A cut damages the network of blood vessels
A leakage in such a closed system would lead to loss of blood and loss of pressure and thus reduce the efficiency of the pumping system
The blood platelets do the work of plugging these leaks by clotting the blood at the point of injury
Transportation
Lymph
When blood flows in the capillaries, some amount of the water, proteins and dissolved solutes are filtered out from the blood plasma into the tissue spaces
It forms the tissue fluid
It is similar to blood plasma except that it has very less amount of proteins in it because the capillary wall is impermeable to plasma proteins
Transportation
Some amount of this fluid enters small channels called lymph vessels and the fluid now is known as lymph
This light yellow fluid flows only in one direction that is from tissues to the heart
Role Lymph helps to destroy potentially dangerous bacteria and cancer cells and filter waste and toxins. It is also responsible for working with the circulatory system to help deliver hormones and nutrients to the tissues of the body. (https://www.sharecare.com/health/immune-lymphatic-system-health/what-role-lymph-my-body)
Transportation
Transportation in plants
Plants are stationary, they also have many dead cells in their body therefore their energy requirement is less and their transport system is quite slow
Plants need inorganic material like nitrogen, phosphorus, magnesium, manganese, sodium, etc.
Transportation
Soil is the nearest and the richest source of these minerals
Roots absorb them and transport them
Special tissues like xylem (carries water) and phloem (carries food) are present
All the parts of the plant are interconnected with these conducting tissues
Transportation
Transport of water in plants1) Root pressureRoot cells are in contact with water and minerals present in the soil
Due to the difference in concentration, water molecules and minerals enter the cells of roots
The cells at the surface become turgid and exert pressure on neighbouring cells called as root pressure
The minerals and water reach the root xylem and is pushed further and further to eliminate this difference
This steady movement creates a column of water that is steadily pushed upwards
Transportation
However this pressure by itself is unlikely to be enough to move the water up in tall trees though it is adequate in small plants like herbs and shrubs or even small trees
2) TranspirationThe loss of water in the form of water vapour from the aerial parts of the plants, like stomata of leaves, is known as transpiration
Evaporation of water from the leaves to atmosphere results in a decrease in the water potential of the epidermal cells
The water which is lost is replaced by the water from xylem vessels in the leaf
Transportation
Gradually it creates suction which pulls water from xylem cells of roots which in turn absorb more water
Thus the pull due to transpiration helps in absorption and movement of water and dissolved minerals in tall plants during the day when the stomata are open, while effect of root pressure is important during night
Root pressure TranspirationNight Day
An oak tree may transpire from its leaves 151,000 litres of water per yearAn acre of corn crop gives off 11,400 - 15,100 litres of water each day
Transportation
Transport of food and other substances
Translocation Food manufactured in the cells of the leaves is transported to each cell of the plant
Besides amino acids excess food is taken to the storage organs like roots, fruits and seeds
This process is called translocation and it takes place through phloem in upward as well as downward direction
Transportation
Translocation is not a simple physical process but needs energy which is obtained from ATP
When food material like sucrose is transferred to phloem tissue, using ATP, the concentration of water molecules decreases in that area
This results in the movement of water into the cells due to osmosis
The increased contents within the cells exert a high amount of pressure on their wall
Transportation
This pressure moves the food materials to the adjacent cells with low pressure
This allows the phloem to move material according to the plant's needs
In the flowering season, sugar stored in the roots or stem is translocated to the buds for growing them into flowers
Transportation
Excretion
Biochemical reactions constantly occur in the cells of a living organism. However, these reactions produce not only the required substances but also produce several unwanted harmful products like urea, uric acid, ammonia, etc.
These unwanted and harmful waste products need to be eliminated from the body. Different organisms employ different strategies for this.
Excretion in human beings
The excretory system in human beings
• a pair of kidneys, • a pair of ureters, • urinary bladder and • urethra
Excretion
Kidneys remove the waste products from the blood and urine
Kidneys are two bean shaped structures located at the back of the abdomen, one on either side of the vertebral column
The basic filtration unit in the kidney is a cluster of thin walled blood capillaries called as a nephron
Excretion
Excretion
Each nephron has a cup shaped thin walled upper end called Bowman's capsule which contains a bundle of blood capillaries called glomerulus Urea formed in the liver enters the blood
When blood containing urea enters the glomerulus it gets filtered through glomerular capillaries
Excretion
Excretion
The selectively permeable wall of the Bowman's capsule allows the water molecules and small molecules of the other substances to pass through them and forms glomerular filtrate
The blood, free from these materials is taken to the heart through the renal vein
The glomerular filtrate collected in the Bowman's capsule further passes through the nephron tubule where reabsorption of water and useful molecules takes place
Excretion
The remaining fluid containing the waste forms the urine which eventually enters a long tube called the ureter
It is further stored in the urinary bladder and from there it is thrown out through the urethra
As the bladder is muscular it is under the control of the nerves
As a result we can usually control the urge to urinateThough the kidneys are the major excretory organs in a human being the skin and the lungs also help in the process of excretion
Excretion
Right kidney is placed slightly lower than left kidney
Each kidney has approximately a million nephrons
An average person has around 5 litres of blood which the kidneys filter about 400 times in a day
Kidneys filter out about 190 litres of filtrate daily to produce 1-1.9 litres of urine, rest is absorbed
Excretion
HaemodialysisMany factors like injury, infections or restricted blood flow to kidneys reduce the activity of kidneys
This leads to accumulation of poisonous wastes in the body which may lead to death
In case of kidney failure an artificial device is used to remove the nitrogenous waste products from the blood This process is called dialysis
At one time 500 ml of blood is passed through the dialyzing machine
The purified blood is pumped back into the body of the patient
Excretion
Excretion
Excretion in Plants
Excretion in plants is much simpler than that of animals
No definite excretory system or organ is present in plants for removal of wastes
Gaseous excretory materials are eliminated by diffusion
Excretion
Many plant waste products are stored in the vacuoles of the leaves, flowers, fruits and even in the bark that falls off
Other waste products are stored as resins and gum in old xylem
Gum Resin
Excretion
Gums ResinsContain high amounts of sugar Soluble in water, either dissolving entirely or swellingExude naturally from the stems or in response to wounding of the plantCommon in plants of dry regions
UseAdhesives, in printing and finishing textiles, sizing for paper, paint and candy industries
Usually secreted in definite cavities or passagesFrequently oozes out through the bark and hardens on exposure to airResins, unlike gums, are insoluble in water
UseDissolved in solvents and surfaces are painted; for waterproof coatings, decorative coatings
http://www.faculty.ucr.edu/~legneref/botany/gumresin.htm
Excretion
Plants also excrete some waste substances into the soil around them
In some plants waste is in the form of needle-shaped calcium oxalate crystals called as raphides
Excretion
Some plant wastes are very useful to human beings e.g. rubber latex, gum, resins and essential oils like eucalyptus or sandalwood oil
Rubber latex
An oil is "essential" in the sense that it contains the "essence of" the plant's fragrance
Excretion
THANK YOU
SSC Std 10th TextbookCBSE Std 10th Textbook
YouTubeGoogle
Wikipedia
Suggestions and Appreciations welcome