Chapter-6
Life Processes
All living things perform certain life processes like growth, excretion, respiration, circulation etc.
All the processes like respiration, digestion, whcih together keep the living organisms alive and perform the job of body maintenance are called life processes.
Examples :
| ↓ | ↓ | ↓ | ↓ | ↓ |
|---|---|---|---|---|
| Growth | Digestion | Respiration | Circulation | Excretion |
I. Nutrition
( The whole process by which an organism obtain its food )
| Nutrition in Plants | Nutrition in Animals |
|---|---|
|
↓ Plants are autotrophic ↓ Can make their own food. |
↓
Animals are hetrotrophic ↓ Depends on plants or other animals for their food. |
| Autotrophic | Hetrotrophic |
|---|---|
|
Kind of nutrition in which
inorganic materials like CO2,
Water etc. are untilized to prepare
Organic food by the process of
Photosynthesis. E.g., Green plants |
Kind of nutrition in which organisms do not process
the ability to synthesize their own food. They depend on
autotrophic for their food
Supply directly or indirectly.
E.g., Animals, fungi |
Autotrophic Nutrition :
The organism which carry out Autotrophic nutrition are called autotrophic (green plants).
Autotrophic ---- Use → Simple inorganic material--- Convert →Complex high energy molecules (Carbohydrates)
inno
Autotrophic nutrition is the process by which autotrophic take in CO2 and H2O convert these into carbohydrates in the presence of chlorophyll, sunlight is called Photosynthesis.
Raw Materials For Photosynthesis :
• Sunlight
• Chlorophyll → Sunlight absrobed by chlorophyll
• CO2 → Enters through stomata and oxygen (O2) is released as by-product through stomata on leaf.
• Water → Water + dissolved minerals like nitrogen, phosphorus etc. are taken up by the roots of the soil.
Site of Photosynthesis :
• Absorption of light energy by chlorophyll
• Conversion of light energy into chemical energy + splitting (breaking) or water inot hydrogen and oxygen.
• Reduction of CO2 to carbohydrates.
Stomata : Tiny pores present on the surface of the leaves.
Functions :
(a) Exchange of gases O2/ CO2.
(b) Loses large amount of water (water vapour) during transpiration.
Hetrotrophic Nutrition
| Holozoic | Saprophytic | Parasitic |
|---|---|---|
| Animals take in solid food and breakdown inside the body. E.g., Amoeba, animals. |
Organisms feed on dead, decaying matter. E.g. Fungi |
Parasites live inside or outside other organism (host) and derive nutrition from it. E.g. Cuscuta (plant parasites), Ticks leech etc. |
How do organism obtain their food
Unicellular/Single called organisms : Food is taken up through entire surface.
Example : (i) Amoeba, (ii) Paramaecium
(i) Amoeba
(ii) Paramaecium
Paramaecium → Cilia → Take in food → At a specific spot (Present all over the body)
NUTRITION :
| Ingestion (Intake of food) |
Digestion (Breakdown of complex material into simple ones) |
Absorption (Movement of digested food) |
Assimilation (Utilisation of food) |
Egestion (Removal of waste products) |
Different organisms utilize different nutritional processes as it depends upon the
Nutrition in Human Beings
Respiration
| Respiration involves : |
(i) Gaseous exchange : Intake of oxygen from the atmosphere and release of CO2 → Breathing.
(ii) Breakdown of simple food in order in release energy inside the cell → Cellular respiration. |
Breakdown of Glucose by Various Pathways
| Aerobic | Anaerobic |
|---|---|
| • Takes place in the presence of oxygen. | • Takes place in the absence of oxygen. |
| • Occurs in mitochondria. | • Occurs in cytoplasm. |
| • End products are CO2 and H2O. | • End products are alchol or lactic acid. |
| • More amount of energy is released. | • Less amount of energy is released. |
Human Respiration System
Passage of air through the respiratory system :
Mechanism of Breathing
| Inhalation | Exhalation |
|---|---|
| • During inhalation the thoracic cavity (chest cavity) expands. | • Thoracic cavity contracts. |
| • Ribs lift up. | • Ribs move downwards. |
| • Diaphragm become flat in shape. | • Diaphragm becomes dome shaped. |
| • Volume of lungs increases and air enters the lungs. | • Volume of lungs decreases and air exits from the lungs. |
Exchange of gases between alveolus, blood and tissues
(i) Air (rich in O2) → Blood → Binds with haemoglobin in RBC → O2 is released in (in alveolus) (through blood vessels) tissues.
(ii) CO2 Released in blood → Dissolved in blood → Blood vessels → Released in alveolar sac → Sent out through nostrils.
(from tissue) (in alveoli)
Terrestail Organisms : Use atmoshpheric oxygen for respiration.
Aquatic Organisms : Use dissolved oxygen for respiration.
Respiration in Plants :
Respiration in plants in simpler than the respiration in animals. Gaseous exchange occur through :
(a) Stomata in leaves.
(b) Lenticels in stems.
(c) General surface of the root.
Transportation
Human beings like other multicellular organism need regular supply of food, oxygen etc. This function is performed by circulatory system.
| ↓ Heart |
↓ Arteries and Veins |
↓ Blood and lymph |
|---|---|---|
| (A pumping organ) | (Blood vessels) | (A circulatory medium) |
Diagram to show blood circulation in human body
Double Circulation :
Blood travels twice through the heart in one complete cycle of the body.
Direction of blood flow through human heart
• Pulmonary Circulation : Blood moves from the heart to the lungs and back to the heart.
• Systemic Circulation : Blood moves from the heart to rest of the body and back to the
Blood
| ↓ Granular Component |
↓ Liquid Comonent |
|---|---|
| Blood Corpuscles | Plasma |
| ↓ | ↓ |
| R. B. C.s ↓ |
Blood Platelets ↓ |
W. B. C. ↓ |
|
|---|---|---|---|
| • Carries gas, (O2, CO2) • Contain Hb, impart red colour to the blood |
• helps to Blood Clotting |
• Provide body defence by engulfing the germs & producing antibodies |
A yellow colour fluid contain 90% water & 10% organic substance like - plasma, proteins viz. albumin, globulin, inorganic-mineral ions. |
Lymph : A yelloish fluid escapes from the blood capillaries into the intercellular spaces contain less proteins than blood. Lymph flows from the tissue to the heart assisting in transportation and destroying germs.
| Arterise | Veins |
|---|---|
| 1. Carry oxygenated blood from heart to body parts excepts pulmonary artery. | 1. Carry deoxygenated blood from body parts to heart except pulmonary vein. |
| 2. Also called distributing vessel. | 2. Also called collecting vessel |
| 3. Thick and elastic. | 3. Thin and less elastic. |
| 4. Deep Seated | 4. Superficial as compared to arteries |
| Xylem | Phloem |
|---|---|
| 1. Carries water & minerals from the roots to other parts of the plant. | 1. Carries product of photosynthesis from leaves to the parts of the plant. |
| 2. No energy is used. | 2.Energy is used from ATP. |
Transpiration is the process of loss of water as vapour from aerial parts of the plant.
Functions :
(a) Absorption and upward movement of water and minerals by creating transpiration pull.
(b) Helps in temperature regualation in plant.
Transport of food from leaves (food factory) to different part of the part plant is called Translocation.
EXCRETORY SYSTEM IN MAN
| Excretory/Urinary system consists of : |
|---|
|
(1) The kidneys :The excertory organ
(2) The ureters :The ducts which drain out urine from the kidneys. (3) The urinary bladder :The urinary reservoir (4) The unethra :The channel to the exterior. |
The Human Excretory System
EXCRETION
1. The metabolic activites in the body generates many kind of wastes including nitrogenous wastes which are harmful for the body and hence needed to be removed. Excertion is a process by which these wastes are removed from our body.
2. Unicellular organisms remove these wastes by simple diffusion.
Human Excretory System
1. It maintains water equilibrium, pH equilibrium, ionic equilibrium of the blood and osmotic equilibrium.
2. It helps to excrete out waste product urea in the dissolved from the blood.
3. It excretes poisoneous substance like drugs, toxins etc. from the body.
4. It regulates blood pressure by controlling he fluid balance in the body.
Formation of Urine
• Each kidneys contains many filtration units called as nephrons.
• Nephrons are made up of a cluster of thin walled capillaries called glomerulus which is associated with a cup like structure called as Bowman's capsule and the long tube which terminates through this capsule.
• The renal artery brings oxygenated blood to the kidneys along with the nitrogenous wastes like urea and uric acid and many other substances.
• As this filtrate moves down the tubular part, glucose, amino acids, salts and excess of water gets selectively reabsorbed by the blood vessels surrounding these tubules.
• The amount fo water reabsorbed depends upon :
• How much excess of water is there in the body and,
• How much nitrogenous wastes need to be excreted out.
• So the fluid now flowing in the tubular part in urine which gets collected in collecting ducts of nephrons.
• These collecting ducts together leave the kidneys at a common point by forming the ureter.
• Each ureter drains the urine in the urinary bladder where it is stored until the pressure of expanded bladder leads to an urge to pass it out through urethra.
• This bladder is muscular structure which is under nervous control.
• 180 litres of filtrate is formed daily but only 2 litres is excreted out as urine so the rest is reabsorbed in the body.
Function of Nephron :
• Excertion of nitrogenous wastes.
• To maintain the water and ionic balance (osmic regualation).
Function in Plants :
Plants use different strategies for excretion of different products :
• Oxygen and carbon dioxide is difffused through stomata.
• Excess water is removed by transpiration.
• Plants can even loose some of their old parts like old leaves and bark of tree.
• Other waste products like raisins and gums especially in old xylem cells which can also be lost by plants.
• Plants also secrete some waste substances into the soil around them.
Structure of a Nephron
The Urine formation involves three Steps :
1. Glomerular filtration : Nitrogenous wastes, glucose water, amino acid filter from the blood into Bowman Capsule of the nephrons.
2. Tubular reabsorption : Now, useful substances from the filtrate are reabsorbed back by capillaries surrounding the nephron.
3. Secretion : Uream extra water and salts are secreted into the tubule which open up into the collecting duct & then into the ureter.
Artifical Kidney
Haemodialysis : The process of purifying blood by an aritificial kidney. It is meant for kidney failure patients.
