Life processes chap 6 class 10

 

What are life processes?

The processes which together perform their maintainence job are called life processes.

Important life processes are:-

• Nutritional processes
• Respiration
• Transpotation
• Excretions
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Need of nutrition:- To get energy for growth, development, synthesising protein and other substances in the body.

Source:- Food rich in carbohydrates , fat, vitamins etc. (Balanced diet)

Mode of nutrition:- On the Basis of type of raw material:-two types

•  Autotrophic nutrition
• Heterotrophic nutrition 

Autotrophs:- Organisms make their own food itself from inorganic substances .(CO2 and H2O)

Example:- Green plants , cyanobacteria.

Autotrophic nutrition:- 

Mode of nutrition which is adopted by autotrophs.

Autotrophs makes their food by the process of photosynthesis.

Photosynthesis:- process by which autotrophs takes up substances (carbon dioxide and water) from outside and convert them into stored form of energy (starch).

Process takes place in the presence of sunlight and chlorophyll.

Stored carbohydrate are utilized slowly by plants whenever needed.

Reaction involved in photosynthesis:-

CO2 + H2O ( sunlight , chorophyll)-- > C6H12O6 + O2 + energy

Event occurs during the process of photosynthesis:- 

1. Absorption of light energy by chlorophyll

2. Conversion of light energy into chemical energy and splitting of water into H2 and O2

3. Reduction of CO2 to carbohydrate.

Note:- 

• In cross section ,green Dots are cell organelles called chloroplast.
• Chloroplasts contain CHLOROPHYLL.
  
  
  

Do all these events need to take place one after other? Justify with example.

No.

In desert plants , CO2 is taken up by plants at night and prepare an intermediate.

During day , energy absorbed by chlorophyll is acted upon intermediate to produce carbohydrate

How do plants exchange gases?

• By stomata (at leaf)
• By lenticels(at stem)
• By roots surface

Stomata:- 

Location:- Tiny pores on the surface of leaf

Function:- 

• gaseous exchange
• Transpiration (loss of water from the aerial part of plant)
• Photosynthesis .

Stomatal apparatus:-

• pore
• Guard cells ( contains chlorophyll)
• Subsidiary cells 

Function of guard cells:- 

• Opening and closing of pores 
• Guard cell swell when water flow into them 
• Due to this , stomatal pore open 
• When guard cell shrink , pore closes.
  
  
  

How plants take up material for meet their energy requirements?

• From air :- it takes CO2 ,
• Sunlight is trapped by chlorophyll.
• From soil it takes water and. Other nutrients like nitrates, nitrites, iron, magnesium, phosphorus etc. for healthy growth.

2. Heterotrophs:- 

• Organisms which depend upon plants directly or indirectly for their nutrition are called heterotrophs.
• It take complex substances and broken down into simpler ones with the help of  biocatalysis called enzymes.

Holozoic nutrition :- 

• Organism takes up solid food and break it inside the body 
• Example:- Amoeba, Cow, lion and man

On the basis of material intakes , it is of 3 types :- 

• Herbivores ;- eat herbs . Example :- cow, deer 
• Carnivores :- eat flesh. Example :- lion , tiger.
• Omnivores :- eat herbs and meat . Example :- man

Saprophytic nutrition:- 

• Organism which take food from dead and decay material.
• These break down the food material outside the body and then absorb it .
• Example :- fungi like yeast , mushroom and bread moulds

Parasitic nutrition :- 

• Organism which live either in or on the host body and harm it .
• Types :- Two types 
• Ectoparasite:-  Live on the body of host. 
• Example :- lice and ticks 
• Endoparasite :- live inside the body of host .
• Example :- leeches and tapeworm.

How do organisms obtain their nutrition ?

• Different organisms obtain 
• their nutrition in different ways:-
• Example:- In Amoeba (unicellular Organism) , food is taken in by the entire surface .

Process involved :-

Pseudopodia--> capture food --> take in (food vacuole) --> digestion of food in food vacuole--> undigested food moves to the surface of cell and thrown out.

In Paramecium (unicellular Organism) :-

Food is taken in with the help of cilia present all over the body.

Ingestion occur at specific spot called gullet.

Nutrition in Multicellular organisms:- 

Steps involved :-

• Ingestion (intake of food).
• Digestion (break down of food)
• Absorption ( movement of digested food into blood)
• Assimilation (utilisation of material
• Egestion (removal of waste)

Digestive system in human:-

Consist of digestive gland and alimentary canal

Parts involved in alimentary canal 

• Mouth 
• Oral cavity/ buccal cavity
• Oesophagus / food pipe
• Stomach (J shaped)

• Small intestine
• Large intestine
• Rectum 
• Anus

Digestive glands:-

• Salivary gland
• Gastric gland 
• Liver  and pancreas
• Intestinal gland

Function of oesophagus:- pushes the food into stomach by peristaltic movement.

Stomach:- contains gastric glands that secrete HCl , mucus and pepsin

HCl:- provide acidic medium for action of pepsin . Pepsin is a proteolytic enzyme.

Kill harmful bacteria that enters the food.

Mucus:- protect inner lining of stomach for corrosive action of HCl

Pepsin:- digest protein

Further details are mentioned in table 

Absorption at small intestine:- 

• Inner lining of small intestine has small finger like projections called villi .
• Villi provide greater surface area for absorption.
• It is richly supplied with blood vessels.
• Blood vessels take away the absorbed food to each and every cell of the body.
• In each cell this energy is utilised for obtaining energy, building up new tissues and repair the old tissues.

Absorption of water at large intestine:-

• Unabsorbed food is sent to large intestine.
• More villi absorb water material.
• Rest removed from body via anus.
• Exit of waste material is regulated by anil sphincter.

Breathing Vs Respiration

Enzyme :- these are biocatalyst which increases the rate of reaction (metabolic reaction) but itself remain same.

Breakdown of glucose by various pathways:-

First step :- breakdown of glucose into pyruvate.

Takes place in cytoplasm

 Anaerobic respiration :- 

• Occur in absence of oxygen
• Pyruvate gets converted into ethanol , carbon dioxide and energy
• Example :- yeast
• Takes place in cytoplasm.

Aerobic respiration :-

• Presence of oxygen.
• Pyruvate gets converted into CO2 ,H2O and energy
• Example :- Homosapiens (the man)
• Takes place in mitochondria.

Lack of O2 :- 

• Pyruvate gets converted into lactic acid and energy.
• Lactic acid produces cramps.
• Occur in muscle cells during vigorous exercise.
• Takes place in cytoplasm.

The energy released during cellular respiration is immediately used to synthesise a molecule of ATP.

ATP used as fuel in all the life activities.

Energy released by 1 mole of ATP is 30.5 KJ

Aerobic respiration in Plants :-

• Plant exchange gases through stomata and the large intercellular spaces ensures that all cells are in contact with air.
• Carbon dioxide and oxygen are exchanged by diffusion  

Direction of diffusion depends on :-

• Environmental conditions and 
• Requirements  of the plant.

At night :- 

• No photosynthesis occur.
• So carbon dioxide elimination is the major exchange.

During day:- 

• CO2 used for photosynthesis 
• So no Carbon dioxide release.
• Oxygen release is the major events.

Aerobic respiration in aquatic organisms :- 

• Use dissolved oxygen in water
• Amount of dissolved oxygen is low as compared to amount of oxygen in air. So breathing rate in aquatic organisms is high.
• Fishes take in water through their mouths and passes it to gills where the dissolved oxygen is taken up by blood.

Aerobic respiration in terrestrial Organisms :-

• Use oxygen in atmosphere 
• Oxygen is absorbed by different organs in different animals.
• All these organs have a structure that increases the surface area which is in contact with oxygen rich atmosphere.
• Since exchange of Carbon dioxide and oxygen has to take place across the surface and the surface is very fine and delicate so it has to be protected.
• In order to protect these surface, these organs are placed within body.
• Also there have to be passages that will take air to this area.

Human respiratory system:- 

Nostril :- Air is taken into the body through the nostril.

Nasal chamber :- 

• Consist of fine hair and mucus 
• Hair filter the air passing through nostril.
• Mucus stick unwanted substances coming along with air.

Trachea:-

•  contain rings of cartilage
• Ensures air passage does not collapse

Bronchi:-

•  Trachea divide into two and enter into lungs 
• Now trachea , after entering into lungs is called bronchi

Bronchioles :- bronchi further divided into bronchioles 

Alveoli :- 

• bronchioles finally terminate in balloon like structure which are called alveoli 
• Alveoli provide a surface where exchange of gases can take place.
• Wall of alveoli contain an extensive network of blood vessels which carry oxygen to different body cells and carbon dioxide to outside by alveoli surface.
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Exchange of gases between alveoli blood and tissue :- 

• Since in humans body size is large , the diffusion pressure alone cannot take care of O2 delivery to all parts of body .
• So respiratory pigment (haemoglobin) is present in RBCs  whic combine with oxygen and take up it to tissues which are deficient in oxygen.
• CO2 is more Soluble in water and hence is mostly transported in the dissolved form in our blood.
• Residual volume:-  quantity of air that remains in the lungs after deepest forceful expiration.

Transportation in Human Beings:- 

• Human beings like other multicellular organisms need regular supply of food and oxygen etc. 
• This function is performed by circulatory system or transport system.

Circulatory system in human beings consists of:-

• A pumping organ - Heart
• Blood vessels - Arteries , veins and capillaries
• A circulatory medium - blood and lymph

Our pump - the heart

• Muscular organ which is as big as our fist.
• Four chambered to prevent oxygen rich blood from mixing with blood containing CO2 .
• Atrium are thick walled 
• Left side of heart carry oxygenated blood bring by pulmonary vein from lungs.
• This oxygenated blood is then pumped to rest of body by dorsal aorta
• Right side of heart carry deoxygenated blood bring by Vena Cava from different body parts.

Process step by step :- 

Step 1:- Oxygen rich blood from lungs comes to thin walled left atrium. 

This atrium relaxed when it is collecting this blood.

Step 2:- Left Atrium contract so that blood is transferred to left ventricle.

Left ventricle relax this time.

Step 3:- Left ventricle contract and blood is pumped out to the body

Step 4:- De oxygenated blood comes from body to right atrium, as it expands.

Step 5:- The right atrium contracts and the right ventricle dilates.

This transfer blood to right ventricle.

After this blood pumps to lungs for oxygenation.

Valves ensures that blood does not flow backward when atria or ventricles contract.

Double circulation:- Blood travels twice through the heart in one complete cycle of the body.

Pulmonary circulation :- Blood moves from heart to lungs and back to the heart.

Systemic circulation :- Blood moves from heart to rest of the body and back to the heart.

Fishes have two chambered heart.

Amphibians and reptiles have three chambered heart.

The tubes - blood vessels 

Arteries , veins and capallaries

Capillaries:- On reaching an organ or tissue, Arteries divides into smaller and smaller vessels to bring the blood in contact with all the individual cells.

The smallest vessels have one celled thick wall and called capillaries

Exchange of material between blood and surrounding cells takes place across this thin wall.

The capallaries then join together to form veins.

A circulating medium :- 

• Blood and lymph

Blood:- 

• A fluid connective tissue 
• Two components :-
• Solid components - blood  corpuscles and
• Liquid component - plasma

Plasma :-  A yellow colour fluid contain 90% water and 10% organic substances like proteins (Albumin, Globulin , inorganic mineral ions)

Functions of Plasma:- Transport food , carbon dioxide and nitrogenous wastes in dissolved form .

Functions of platelets :- 

Platelets plugs the leaks (if occur) in the blood vessels by helping to clot the blood at these points of injury.

Lymph / Tissue fluid :- Through the pores present in the walls of capallaries some amount of plasma , proteins and blood escape into intercellular spaces in the tissue to form lymph

Properties of lymph:-

Similar to plasma of blood but colourless and contains less protein

How lymph circulate:-

• Lymph drain into lymphatic capallaries.
• Lymphatic capallaries join to form large vessels
• Lymph vessels open into larger veins.

Functions of lymph:- 

• Lymph carries digested and absorbed fat from intestine
• It drains excess fluid from extra cellular space back into blood.

Blood pressure:- 

•  Force that blood exerts against wall of a vessel is called blood pressure.
• BP is greater in arteries 
• BP is less in veins

Systolic pressure:- Pressure f blood inside the artery during ventricular systole (contraction) is called systolic pressure.

Normal systolic pressure is about 120 mm of Hg

Diastolic pressure :- pressure of blood inside the artery during ventricular diastole (relaxation) is called diastolic pressure.

Normal diastolic pressure is 80 mm of Hg.

Sphygmo-mamo-meter :- Instrument that measured BP.

Hypertension / high BP:-  caused by constriction of arterioles.

Results in increased resistance to blood flow 

Can lead to rupture of artery

Transportation in plants:- 

• If the distance between the soil contacting organs and chlorophyll containing organs are small, then energy and raw material can easily diffuse to all parts of plant body.
• But if these distances become large , diffusion process will not be sufficient to provide raw material in leaves and energy in roots 
• So a proper system of transportation is essential

Transport of water by xylem and phloem :- 

• Vessels and tracheids of roots , stem and leaves are interconnected.
• This forms a continuous system of water conducting channels reaching all parts of plants.
• At roots , cells in contact with soil actively take up ions.
• This create concentration difference between root and soil.
• So to eliminate  this difference water moves into root from the soil.
• In this way  there is steady movement of water into root xylem , creating a column of water that is steadily pushed upward.
• Along with this evaporation of water molecules from stomata also create a suction which pulls water from xylem cells of root.
• This evaporation is called transpiration.

Transpiration :-  loss of water in the form of vapour from aerial parts of plants.

Role of Transpiration:- Help in absoption and upward movement of water and minerals.

Help in temperature regulation.

Transport of food and other substances by phloem :- 

• The transport of soluble product of photosynthesis is called translocation.
• Phloem transport this Soluble product .
• Phloem also transport amino acids and other substances ( derived by root , stem etc)
•  Translocation of food and other substances takes place by sieve tubes and companion cells .
• It occur in both upward and downward direction.
• Occur by active transport so energy use.

Mechanism :- 

• Material like sucrose is transferred into phloem tissue by using energy from ATP 
• This increases osmotic pressure of tissue causing water to move into it.
• This pressure move material in the phloem to tissues which have less pressure.
• This allow phloem to move material according to plants need.

Excretion:- 

• The biological process of removal of harmful metabolic nitrogenous wastes from the body .
• Unicellular Organism remove waste by simple diffusion.
• Multicellular organisms have specialized organs to do this job .

Excretion in human beings:- 

• Consists of :-
• One pair of kidney
• One pair of ureter
• A urinary bladder
• A urethra

How is urine produced?

Purpose:-

• To filter out waste products from blood .
• Waste products are nitrogenous wastes like urea (human beings) or uric acid (birds) or Ammonia( aquatic life)
• Basic filtration unit is nephron
• Nephron is structural and functional unit of kidney.

Mechanism :- 

Step 1 :- Glomerular filtration :-

•  The first step in urine formation is filteration of blood, which is carried out by glomerulus and is called glomerular filtration.
• Glomerulus reside in Bowmans' capsules.

Step 2:- Tubular reabsorption :- 

• Useful substances from filterate like Na+ ,K+ , C6H12O6 etc are reabsorbed by capillaries surrounding nephron into blood.

Step 3:- secretion :- 

• Urea , extra water and salts are secreted into tubules which open into collecting duct and then into ureter.
• Ureter take the urine from kidney to urinary bladder and then it come out through urethra.
  
  
  

Hemodialysis / Artificial kidney:- 

• A device used to remove nitrogenous wastes products from blood through dialysis.
• Meant for kidney failure patient.

Excretion in plants :- 

• O2 released during photosynthesis 
• H2O by Transpiration 
• Waste may be stored in leaves, bark etc which fall off from tree.
• Waste products stored as gums , resin in old roots .
• Plants excrete some waste into soil around them.