Life process notes class 10 science

INTRODUCTION

It is simple to find that object is either living or non-living on the basis of following points:-

1.     Nutrition: Process by which organisms obtain and utilise the nutrients. Plant nutrition involves the photosynthesis process animal nutrition involve taking of food inside the body and its digestion.

2.     Respiration: It is a process that involves breakdown of respiratory substrates through oxidation and release of energy.

3.     Excretion: It is process involved removal of harmful or tonic washes from the body.

4.     Transport: It is a process in which the substances observed or synthesized in one part of body are carried to other parts of body.

5.     Control and coordination: It is the process that helps living organism to receive information from surrounding and behave accordingly in order to survive in the changing environment around them.

6.     Growth and development: Growth is a permanent increase in size of organism. Development is the whole series of changes which an organism goes through during its life cycle.

7.     Movement and locomotion: Movement of entire organism from one place to another is called locomotion. When the organism remains fixed moving only its body parts, it is called movement.

Nutrition

All living organisms need nutrients to build up most of their own body molecules and to get energy for doing work.

·       Nutrients are inorganic as well as organic substance which the organisms obtain from their surrounding in order to synthesize their body constituents and use them as a source of energy.

·       Nutrition id defined as the process of intake of nutrients and its utilisation by an organism in various biological activities.

Modes of Nutrition

On the basis of mode of nutrition organisms are classified into two:

A)  Autotrophic

It is a kind of nutrition in which organism prepares their own organic food and utilising only the inorganic raw materials present in the surroundings. Such as plants are called Autotrophs.

B)  Heterotrophic

It is a kind of nutrition in which the organism derive energy from the intake and digestion of the organic substances prepared by autotrophic and other organic source.

Types of Heterotrophic nutrition

1.     Saprophytic nutrition- In this organism derive their nutrient from dead and decaying organic matter (that may be leaves, household wastes etc.) as mushroom.

2.     Parasitic nutrition- In this organism derives nutrient or food from other living organisms. Such as cuscuta, fasciola, ascaris, Taenia etc.

3.     Holozoic nutrition. In this organisms take food in the form of the complex organic matter by ingestion is called holozoic nutrition. Such as cow, tiger, human, etc.

Nutrition in Plant

Plant also needs organic food to fulfil their requirement of energy for various metabolic activities. Green plants are autotrophic since they synthesise their food by photosynthesis process.

·       The process of photosynthesis can be defined as the conversion of photon energy into chemical energy by green parts of the plants.

6CO2 + 12H2O C6H12O6 + 6H2O + 6O2

·       Chlorophyll is the coloured organic substance that absorbs visible light. The process of photosynthesis does not occur only in those cells which possess green coloured plastids called as Chloroplast. It is not usually found in upper and lower epidermis of green leaf except in guard cells of stomata. They occur in mesophyll cells that occupy the space b/w upper and lower epidermis.

·       In chloroplast thylakoid is the site where chlorophyll and carotenoids are located and shows light reaction of photosynthesis.

Factors affecting Photosynthesis

1.     Light 2.     Temperature. 3.     Carbon-di-oxide. 4.     Water

Chloroplast

Nutrition in Animals

Majority of invertebrates and all vertebrate eat food through the mouth. This is called ingestion. After ingestion they break up large organic molecules into smaller ones in their own body with help of enzymes. Simple molecules are then absorbed into the cells & utilised. This is known as digestion, absorption and assimilation, such kind of nutrition is called holozoic nutrition and the organisms are holozoic organism.

These organisms are classified in three:

·       Herbivores: that eats only algae or plant materials. Such as cow, rabbit, goat, camel, horse, hippopotamus, deer, etc.

·       Carnivores: that eats only flesh of other animal such as loin, tiger, lizard, frog, snake, vulture, etc.

·       Omnivores: That eats both plants and animals as food. Such as Man, sparrow, rat, cockroach, bear, dog, ant etc.

Nutrition in Amoeba

Amoeba is an aquatic protozoan that lives at bottom of fresh water pools and streams of water. It is microscopic organism. It occurs in water which has lot of vegetation, decaying organic matter and bacteria. It shows the holozoic nutrition. Process of obtaining food is called phagocytosis and various steps that involves in its digestion are:

·       Ingestion: Amoeba ingests the food by help of pseudopodia. After ingestion of food particle it forms food vacuoles inside its body.

·       Digestion: Food is digested in food vacuole by help of digestive enzymes due to which large molecules becomes converted into simpler form.

·       Absorption: Digested food from vacuoles is directly absorbed into cytoplasm of Amoeba by process of dissension. After it food vacuoles become disappears.

·       Assimilation: Absorbed food in cell of Amoeba is used to form energy through respiration. Remaining part of absorbed food used for growth of Amoeba. Thus grow in size and then reproduce.

·       Egestion: Amoeba has no fixed place for removing of undigested part of food, when a considerable amount of food collects inside amoeba, then its cell membrane ruptures at any place and wastes thrown from it.

Human Digestive system

Human beings are heterotrophic omnivore’s organisms. They obtain their food from plants, Animal and their products by holozoic mode of nutrition. Human digestive system consists of an alimentary canal and many digestive glands.

Alimentary canal is a long tube with muscular wall, glandular epithelial lining and varying diameter. It extends from mouth to the anal opening. Alimentary canal measures about 9 meter long tube in which duct of several digestive glands open to secretes their respective digestive secretions. Alimentary canal consists of several organs.

·       Mouth: Opening of human digestive system which gives passage for ingestion of food. It is guarded by pair of labia.

·       Oral Cavity: large space bounded above by the palate. There are pair of jaws and soft muscular tongue, each jaw has 16 teeth with formula I2/2, C1/1, Pm 2/2, M3/3 and four types of teeth in each jaws. Teeth cut the food into small pieces and chew them to make it soft for easy swallowing. Salivary gland secretes salvia in oral cavity through their duct that is ptyalin also called the salivary amylase. It act on carbohydrate and split into simple form thus digestion of carbohydrates begins from it.

·       Pharynx: It funnel shaped vertical canal that serves as a passage way for food from buccal cavity to the oesophagus.

·       Oesophagus: It is a tubular structure which serves as to carry the food from pharynx to stomach. It is not concerned with digestion but represents the contraction and expansion of walls i.e. peristaltic movement.

·       Stomach: It is site for food where it stored for short interval of time. Here protein digestion starts this will occur by the help of gastric juice (Action of pepsin).

·       Small Intestine: It is the longest part of alimentary canal. It has three parts. Duodenum, jejunum & ileum. Here each type of food completely digested. In this pancreatic and bile juice help to increase its absorption area.

·       Large intestine: It also consists of three parts Caecum, colon & Rectum. It is shorter but wider in diameter. It also secretes mucus for lubrication. Fecal matter is egested through the anus.

Digestion of fat

In small Intestine

Fat Bile juice Emulsified fat Lipase Fatty Acid

Digestion of Protein

Stomach

Protein pepsin peptones

Small intestine

Peptones Trypsin Amino Acid

Digestion of carbohydrates

Mouth

Starch salivary Amylase maltose + Iso-maltose + dextrin.

Small intestine

Maltose maltase Glucose

Iso-maltose Isomaltase Glucose

Dextrin Dextrinase Glucose

Accesory glands

1.     Liver: It is the largest gland. Cell of which produce bile juice are called Hepatic cells. Bile juice has no enzyme but have bile salts that help in digestion of fat in small intestine. Bile also change acidic medium into basic medium.

2.     Pancreas: It is second largest gland that poured into small intestine and help in all three types of the digestion by producing lipase for fat, Trypsin for protein & pancreatic amylase for starch.

3.     Gall bladder: It store bile Juice when there is (small Intestine) absence of fatty food.

4.     Salivary gland: it is subdivided into three parts, all of which produces the saliva that help in digestion of carbohydrate.

Hydrochloric Acid: It present in gastric juice and help in activation of pepsin from its inactive form pepsinogen. It also helps to kill the bacteria that come along with food.

Mucus: It protects the internal layer of stomach from action of HCl.

Dental Carries

Formation of small cavities in teeth due to the action of acid forming bacteria and the improper dental care is called Dental carries. If teeth are not cleaned regularly, they become covered with a sticky, yellowish layer of food particles and bacterial cells called the Dental plaque.

Life Processes (part - 2)