Life Processes Class 10 || Science|| Chapter 5 Notes

Life Processes Class 10 ||Science|| Chapter 5 Notes

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1. What Are Life Processes?

Life processes are the essential activities performed by living organisms to sustain life. These include:

• Nutrition
• Respiration
• Transportation
• Excretion
• Growth
• Movement
• Reproduction

2. Nutrition

Nutrition is the process by which living organisms obtain and use food to provide energy for carrying out various life processes. It is classified into two types:

1. Autotrophic Nutrition

• Autotrophs are organisms that can make their own food using simple substances like carbon dioxide and water, typically through the process of photosynthesis.
• Example: Green plants, algae, and some bacteria.

Photosynthesis: The process by which green plants (and some other organisms) use sunlight to synthesize foods from carbon dioxide and water. The equation for photosynthesis is:

$$\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">C</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">+</span></span>\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">H</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}\stackrel{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">s</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">u</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">n</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">l</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">i</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">g</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">h</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">t</span></span>}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">,</span></span>\text{<span style="background-color: white;"><span style="font-family: Kanit; font-size: medium;"> </span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">c</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">h</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">l</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">o</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">r</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">o</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">p</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">h</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">y</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">l</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">l</span></span>}}{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">\to </span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">C</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">H</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">12</span></span>}}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">+</span></span>\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}$$

This process occurs in the chloroplasts of plant cells, which contain the green pigment chlorophyll.

2. Heterotrophic Nutrition

• Heterotrophs cannot make their own food and must rely on other organisms for nutrition. They obtain complex organic substances.
• Examples: Humans, animals, fungi, and many bacteria.

Types of heterotrophic nutrition:

• Holozoic nutrition: Organisms ingest solid food (e.g., humans).
• Saprophytic nutrition: Organisms feed on dead and decaying matter (e.g., fungi).
• Parasitic nutrition: Organisms derive nutrition from other living organisms (e.g., tapeworms).

Nutrition in Human Beings

In humans, the process of digestion takes place in the alimentary canal, which consists of several parts:

• Mouth: Digestion starts here with the action of saliva (which contains the enzyme amylase).
• Esophagus: The food is swallowed and moves to the stomach.
• Stomach: Gastric juices containing pepsin and hydrochloric acid (HCl) break down proteins.
• Small intestine: Most digestion and absorption take place here. Enzymes from the pancreas and bile from the liver aid in digestion.
• Large intestine: Absorption of water occurs here, and waste is excreted through the anus.

3. Respiration

Respiration is the process of breaking down food (glucose) to release energy, which is then used by cells to carry out various functions. It can occur in two ways:

1. Aerobic Respiration

• This type of respiration occurs in the presence of oxygen.
• Glucose is completely broken down into carbon dioxide and water, releasing a large amount of energy.
• The equation for aerobic respiration is:$${\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">C</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">H</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">12</span></span>}}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">+</span></span>\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">\to </span></span>\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">C</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">+</span></span>\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">H</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">+</span></span>\text{<span style="background-color: white;"><span style="font-family: Kanit; font-size: medium;">Energy (ATP)</span></span>}$$

2. Anaerobic Respiration

• This type of respiration occurs in the absence of oxygen.

• Glucose is partially broken down, releasing less energy compared to aerobic respiration.

• In yeast, anaerobic respiration produces ethanol and carbon dioxide. In muscles (during strenuous activity), it produces lactic acid, which causes muscle cramps.

  $${\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">C</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">H</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">12</span></span>}}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">6</span></span>}}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">\to </span></span>\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">C</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">H</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">5</span></span>}}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">H</span></span>}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">+</span></span>\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">C</span></span>}{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">O</span></span>}}_{\mathrm{<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">2</span></span>}}<span\; style="background-color:\; white;"><span\; style="font-family:\; Kanit;\; font-size:\; medium;">+</span></span>\text{<span style="background-color: white;"><span style="font-family: Kanit; font-size: medium;">Energy</span></span>}$$

Respiration in Human Beings

• Air enters the respiratory system through the nose and passes through the trachea into the lungs.
• In the lungs, gas exchange occurs in tiny air sacs called alveoli, where oxygen is absorbed into the blood and carbon dioxide is released from the blood into the air.
• Oxygenated blood is carried by the bloodstream to all parts of the body, where oxygen is utilized in the cells for respiration.

4. Transportation

Transportation is the movement of substances such as nutrients, gases, and waste products in living organisms. In both plants and animals, different mechanisms ensure proper transportation.

Transportation in Human Beings

In humans, transportation is carried out by the circulatory system, which consists of:

• Heart: The heart pumps blood throughout the body.

• Blood vessels: Blood is transported through arteries, veins, and capillaries.

• Blood: Carries oxygen, nutrients, carbon dioxide, and waste products.

  • Red blood cells (RBCs) carry oxygen using a pigment called hemoglobin.
  • White blood cells (WBCs) fight against infections.
  • Platelets help in clotting of blood.

The heart pumps oxygenated blood from the lungs to the body and deoxygenated blood from the body back to the lungs.

Transportation in Plants

In plants, transportation occurs through two main tissues:

• Xylem: Transports water and minerals from the roots to the rest of the plant.
• Phloem: Transports food (sugars) from the leaves to other parts of the plant.

5. Excretion

Excretion is the process of removing waste products from the body. These waste products can be toxic if accumulated.

Excretion in Human Beings

• The kidneys play a major role in excretion by filtering blood to remove waste products like urea, excess salts, and water, forming urine.
• Urine is stored in the bladder and later expelled through the urethra.

The process of urine formation involves:

1. Filtration: Blood is filtered in the nephrons (functional units of the kidney).
2. Reabsorption: Useful substances like glucose, amino acids, and water are reabsorbed back into the blood.
3. Excretion: The remaining waste is passed as urine.

Excretion in Plants

Plants do not have a well-developed excretory system, but they excrete waste products through processes like:

• Transpiration: Loss of water vapor through stomata.
• Guttation: Exudation of water droplets from the edges of leaves.
• Plants also store waste products in old leaves, bark, or in vacuoles.

Summary:

• Nutrition: Process of taking in and utilizing food. Autotrophic organisms like plants make their own food through photosynthesis, while heterotrophs rely on other organisms for food.
• Respiration: Breakdown of glucose to release energy. It can be aerobic (with oxygen) or anaerobic (without oxygen).
• Transportation: Movement of materials in the body, carried out by the circulatory system in humans and xylem and phloem in plants.
• Excretion: Removal of metabolic waste products. In humans, the kidneys filter blood to produce urine, and in plants, waste is excreted through transpiration, guttation, and storage in dead tissues.

These essential life processes ensure that living organisms can grow, reproduce, and maintain their internal environment, allowing them to survive in various conditions.