Life Processes Revision Notes: Types and Explanation

The life process is said to be the activities that are necessary for living organisms to survive.

• All living things both animals and plants, are called living organisms.
• Life on Earth depends mainly on specific functions and processes.
• Certain basic processes are required for an organism to be healthy and sustain normal organ system function.
• The basic processes like circulation, excretion, respiration, nutrition, Movement, sensitivity, and growth are performed by a living being to live are called life processes.
• These seven processes are very important for a living being in survival and maintenance.

Key Terms: Life Processes, Circulation, Excretion, Respiration, Nutrition, Movement, Sensitivity, Growth, Living organisms, Photosynthesis, Egestion, Amoeba

Life Processes

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The seven life processes are discussed in the below points:

Movement

Both plants and animals have the capability to move. Plants are rooted and they make their movement slowly as they grow. On the other hand, animals can quickly move and can move their whole bodies.

Respiration

The process of extraction of energy out of the food we consume is called respiration. Respiration is necessary for a living being to move, replace worn-out parts, and need the energy to grow. In the mitochondria of the cell, the process of respiration takes place.

Sensitivity

All living organisms are sensitive. As they are sensitive, they are aware of the changes in the environment. Plants are less sensitive and their response is slow. On the other hand, animals are more sensitive and can quickly respond to stimuli like light, sound, heat, touch, and chemicals. 

Growth

Both animals and plants grow. Once animals reach adulthood, they stop growing. On the other hand, plants grow throughout their lives.

Excretion

The process of getting relief from metabolic waste is known as Excretion. Out of waste carbon dioxide, animals breathe out. Plants in their leaves keep the waste substances. When the leaves fall off, the waste is removed.

Reproduction

The biological process by which living organisms reproduce an offspring that is biologically similar to the organism. In order to survive, all living organisms produce offspring like themselves. Reproduction is divided into two types- sexual and asexual. 

Nutrition

Nutrition is needed for growth and energy. Both animals and plants need food. Animals cannot make their own food. So they depend on other animals and plants for nutrition, whereas plants can make their own food with the help of photosynthesis. Thus, nutrition is defined as the process of acquiring food needed for the sustenance and nourishment of an organism.

Nutrition is divided into two modes:

• Autotrophic: Autotrophs can make their own food using chemicals or sunlight. For eg: Some bacteria and Green plants. 
• Heterotrophic: Heterotrophs cannot make their own food. For getting complex organic substances, heterotrophs depend on other organisms. For eg: Fungi and Animals. 

Heterotrophic Nutrition is divided into three types:

• Holozoic Nutrition: It is defined as a type of nutrition in which an organism breaks it inside the body and takes place in whole food. For eg: Humans, Amoeba
• Saprophytic Nutrition: It is a type of heterotrophic nutrition in which organisms feed on decaying and dead matter. E.g.: Fungi.
• Parasitic Nutrition: In Parasitic nutrition, organisms obtain feed from other living organisms. For eg: lice, leeches, Cuscuta, ticks, lice, etc.

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Nutrition

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Nutrition in Amoeba

• By holozoic nutrition, amoeba feeds.
• By using pseudopodia, it immerses the food particles known as phagocytosis.
• In a food vacuole, the immersed food gets enclosed.
• Assimilation and absorption take place as the food vacuole passes through digestion and cytoplasm.
• Egestion of undigested food occurs when the food vacuole opens to the outside.

Nutrition in Human Beings

• Humans are said to be omnivores as they eat both animal and plant-based food.
• Humans have a nutrition system that is very complicated.
• The human digestive system has digestive glands and alimentary canals that function together to nourish the body.
• Human nutrition consists of five stages- Absorption, Ingestion, Assimilation, Egestion, and Digestion.
• In the alimentary canal, the four stages- Absorption, Ingestion, Egestion, and Digestion take place whereas, in the whole body, the assimilation of food takes place.

The human body consists of an alimentary canal that starts from the mouth and finishes at the anus. The alimentary canal consists of:

• Mouth
• Pharynx
• Food Pipe/ Oesophagus
• Stomach
• Small Intestine
• Large Intestine
• Rectum 
• Anus

Associated Gland consists of the following parts:

• Gastric Glands
• Salivary Glands
• Pancreas
• Liver

Mechanism of Digestion of Food

• Digestion of food starts in the mouth. 
• We need enzymes, a biological catalyst to absorb and break down food.
• An important enzyme that saliva contains is known as the salivary enzyme. To secrete saliva, the mouth contains salivary glands. 
• The stomach consists of gastric glands that secrete hydrochloric acid, pepsin, and mucus. 
• Food goes to the small intestine after the stomach.
• In the small intestine, complete digestion of proteins, fats, and carbohydrates occurs.
• The small intestine gets bile from the liver and secretions from the pancreas.
• The pancreas helps to secrete enzymes for protein digestion like trypsin whereas bile helps in the emulsification of fats. T
• o secrete intestinal juice, the intestinal wall also contains glands.
• To absorb food, the small intestine has villi.
• To the large intestine, the food that is unabsorbed is transferred. 
• The food that is undigested is removed from the anus.

Nutrition in Paramoecium

• Paramoecium is also present in holozoic nutrition.
• Paramoecium moves through cytoplasm known as cyclosis.
• Enclosing the food, a food vacuole is created.
• The food that is digested in the food vacuole is soaked up by cytoplasm.
• Cytopyge or anal pore is the undigested food that is given out to a very small pore.

Respiration

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• Respiration is a metabolic process in which food is broken down to release energy.
• Respiration is divided into two types on the basis of the requirement of oxygen: Aerobic and Anaerobic respiration.
• Fermentation is the breakdown of pyruvate into carbon dioxide and ethanol in the absence of oxygen.
• The process that takes place in the absence of oxygen (air) is known as Anaerobic respiration.
• The breakdown of pyruvate in water and carbon dioxide takes place in the presence of oxygen (air) and is called Aerobic respiration.
• The energy that frees during the process is used to synthesize Adenosine triphosphate (ATP). 
• Plants use stomata to exchange oxygen and carbon dioxide in comparison to animals.
• Thus, diffusion takes place through this exchange.

Respiration in Human Beings

In human beings, inhalation of air goes through in the following ways: Nostrils- Nasal passage- Pharynx -Larynx- Trachea- Bronchus- Bronchiole- Alveolus. The alveolus is present in the lungs in which exchange between oxygen and carbon dioxide occurs. In human beings, the respiratory pigment called hemoglobin carries oxygen to different parts of the body.

Transportation

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Transportation in Human Beings

The circulatory system is a collection of blood vessels and the heart that transport various materials like nitrogenous waste, carbon dioxide, food, and oxygen. Blood contains blood cells and plasma. Throughout the body, red blood cells carry oxygen. The heart is said to be the pumping organ of the body. 

• The human heart is composed of four chambers- two atria (left and right) and two ventricles (left and right).
• From the lungs, the left atrium gets oxygen-rich blood. It relaxes while getting blood.
• Throughout the body, the left ventricle pumps oxygen-rich blood.
• To the above right atrium, the deoxygenated blood comes from the human body. 
• For oxygenation, the right ventricle pumps the blood to the lungs.

The Human Heart

Double Circulation

To prevent the mixing of deoxygenated and oxygenated blood, the left and the right sides of the heart are separated. During each cycle, blood passes through the heart twice to the vertebrates which is known as double circulation.

Transportation in Plants:

• For the transportation of water, plants have a xylem.
• From roots to different parts of plants, the xylem transports water.
• Xylem tissue consists of tracheids and vessels.
• Transpiration is the loss of water in the type of water vapor.
• It creates a suction that pulls water to the higher plants. 
• Through phloem, the transport of food in plants takes place.
• From leaves to many parts of the plant, it transports food.

Excretion

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The removal of nitrogenous waste from the human body is called excretion.

Excretion in Human Beings

• The excretory systems in the human body consist of the urinary bladder, urethra, a pair of ureters, and a pair of kidneys.
• Nephrons are the basic filtration of kidneys. It is the functional and structural unit of the kidneys.
• Nephrons consist of the renal tubule and the bowman's capsule.
• Substances like amino acids and glucose are selectively reabsorbed to form urine.
• The amount of re-absorbed water depends on how much-dissolved waste is and how much excess water is there to be excreted.
• The urinary bladder is under nervous control and is a muscular structure.

Excretion in Plants

Plants carry out excretion in many ways like releasing wastes, storing waste materials, losing their leaves, transpiration in cell vacuoles as they do not have an excretory system. The rest of the waste materials are stored as gums and resins in the old xylem.

Difference Between Plants and Animals Life Processes

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The following are the differences between Life Processes of Plants and Animals

Things to Remember

• The life process is said to be the processes that are necessary for living organisms to survive.
• There are seven processes that are very important for a living being in survival and maintenance.
• These are circulation, excretion, respiration, nutrition, Movement, sensitivity, and growth.
• The process of extraction of energy out of the food we consume is called respiration.
• Reproduction is divided into two types- sexual and asexual. 
• Nutrition is defined as the process of acquiring food needed for the sustenance and nourishment of an organism.
• Humans are said to be omnivores as they eat both animal and plant-based food.

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