Ch 5: Life Processes (NCERT Solutions)

NCERT Solutions for Class 10 Science Ch 5: Life Processes, is given below.

You will get solutions for;

• In-text questions as well as,
• Exercises questions.

So let’s dive into it!

In-text Questions Set-1

1) Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans?

Solution:
Multicellular organisms, like humans, have large bodies and need a lot of oxygen quickly. Diffusion, which is a slow process, can’t provide enough oxygen fast enough to all the cells. Therefore, diffusion alone is not enough to meet the oxygen needs of these organisms.

2) What criteria do we use to decide whether something is alive?

Solution:
To determine if something is alive or dead, we can look for signs like walking, breathing, and growth. However, some living things have changes that aren’t visible to the naked eye. Therefore, the presence of life processes is the key factor in deciding if something is alive.

3) What are outside raw materials used for by an organism?

Solution:
Organisms use outside raw materials for food and oxygen. The types and amounts of these materials depend on the complexity of the organism and its environment.

4) What processes would you consider essential for maintaining life?

Solution:
Life processes like respiration, digestion, excretion, circulation, and transportation are crucial for staying alive.

In-text Questions Set-2

2) Where do plants get each of the raw materials required for photosynthesis?

Solution:
Plants need these materials for photosynthesis:
1. CO₂: Absorbed from the air through the stomata.
2. Water: Taken up by the roots from the soil.
3. Sunlight: Essential for the process.
4. Nutrients: Absorbed from the soil by the roots.

3) What is the role of the acid in our stomach?

Solution:
Hydrochloric acid (HCl) in the stomach helps dissolve food and creates an acidic environment. This acidity converts pepsinogen, an enzyme, into pepsin, which helps digest proteins. HCl also helps protect against harmful pathogens.

4) What is the function of digestive enzymes?

Solution:
Digestive enzymes break down complex food molecules into simpler ones, making it easier for the body to absorb the food. The absorbed nutrients are then carried by the blood to all parts of the body.

5) How is the small intestine designed to absorb digested food?

Solution:
The small intestine has tiny projections called microvilli that increase its surface area, making absorption more efficient. Inside the villi, there are many blood vessels that absorb digested food and transport it to the bloodstream, which then carries the nutrients to different parts of the body.

In-text Questions Set-3

1) What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?

Solution:
Terrestrial organisms breathe atmospheric oxygen, which is more plentiful, so they don’t need to breathe quickly. In contrast, aquatic organisms rely on oxygen dissolved in water, which is less abundant, so they need to breathe faster to get enough oxygen.

3) How are oxygen and carbon dioxide transported in human beings?

Solution:
Oxygen and carbon dioxide are transported in the human body through the bloodstream. Oxygen is delivered to the cells, while carbon dioxide is removed from them. Gas exchange occurs between the alveoli in the lungs and the surrounding blood capillaries. Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli.

4) How are the lungs designed in human beings to maximize the area for the exchange of gases?

Solution:
The lungs are crucial for breathing. Inside the lungs, the airways branch into smaller tubes that end in tiny, balloon-like structures called alveoli.

– Alveoli: These are where gas exchange happens. They have many tiny blood vessels around them.

– Breathing Process: When we inhale, our ribs lift, our diaphragm flattens, and the chest cavity expands. This creates a vacuum that draws air into the lungs and fills the alveoli.

– Gas Exchange: The blood brings carbon dioxide from the body to the alveoli and picks up oxygen from the alveoli to deliver to the rest of the body. During normal breathing, the lungs always have some air left inside to ensure there’s enough time for oxygen to enter the blood and carbon dioxide to be expelled.

In-text Questions Set-4

1) What are the components of the transport system in human beings? What are the functions of these components?

Solution:
The human transport system consists of the heart, blood, and blood vessels. Here’s what each component does:

– Heart: Pumps oxygen-rich blood throughout the body and sends deoxygenated blood to the lungs for oxygenation.

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

– Blood Vessels: Arteries and veins transport blood to all parts of the body.

2) Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?

Solution:
Mammals and birds are warm-blooded animals that maintain a constant body temperature regardless of their environment. To do this, they need a lot of oxygen for cellular respiration, which helps them produce the energy needed to regulate their temperature. Therefore, it’s crucial for warm-blooded animals to separate oxygen-rich and oxygen-poor blood to keep their circulatory system efficient.

3) What are the components of the transport system in highly organized plants?

Solution:
In highly organized plants, there are two types of conducting tissues that manage transport:
– Xylem: Carries water and minerals from the roots to the rest of the plant.
– Phloem: Transports food from the leaves to other parts of the plant.

4) How are water and minerals transported in plants?

Solution:
The xylem, made up of tracheids and vessels in roots, stems, and leaves, forms a continuous system of water-conducting channels throughout the plant. Transpiration creates a suction that pulls water into the xylem cells of the roots. This water then moves steadily from the roots to all parts of the plant through the connected xylem channels.

5) How is food transported in plants?

Solution:
In plants, food is moved through a special tissue called the phloem. The phloem transports food from the leaves to other parts of the plant. This process requires energy from ATP, which increases the osmotic pressure in the phloem. As a result, water moves, creating pressure that pushes the food to areas with lower pressure. This helps distribute food, such as sucrose, where it’s needed.

In-text Questions Set-5

2) What are the methods used by plants to get rid of excretory products?

Solution:
Plants get rid of excess water through transpiration. They handle other wastes by storing them in parts of the plant made of dead cells, like leaves that eventually fall off. Many waste products are stored in cellular vacuoles, while others, like resins and gums, are stored in old xylem. Some waste substances are also excreted into the surrounding soil.

3) How is the amount of urine produced regulated?

Solution:
The amount of urine produced depends on how much excess water and dissolved waste is in the body. Other factors, like the environment and the ADH hormone, also play a role in regulating urine production.

Exercise Questions

1) The kidneys in human beings are a part of the system for
(a) nutrition
(b) respiration
(c) excretion
(d) transportation

Solution:
(c) excretion 

2) The xylem in plants is responsible for
(a) transport of water
(b) transport of food
(c) transport of amino acids
(d) transport of oxygen

Solution:
(a) transport of water 

3) The autotrophic mode of nutrition requires
(a) carbon dioxide and water
(b) chlorophyll
(c) sunlight
(d) all of the above

Solution:
(d) all of the above

4) The breakdown of pyruvate to give carbon dioxide, water, and energy takes place in
(a) cytoplasm
(b) mitochondria
(c) chloroplast
(d) nucleus

Solution:
(b) mitochondria 

5) How are fats digested in our bodies? Where does this process take place?

Solution:
The small intestine is where carbohydrates, fats, and proteins are fully digested. It receives secretions from the liver and pancreas to aid in this process.

– The food from the stomach is acidic and needs to be made alkaline for pancreatic enzymes to work. Bile juice from the liver does this.

– Fats in the intestine are present as large globules, which are hard for enzymes to digest. Bile salts break these down into smaller globules. The pancreas produces pancreatic juice, containing enzymes like trypsin for protein digestion and lipase for breaking down fats.

– The walls of the small intestine have glands that secrete intestinal juice. This juice contains enzymes that convert proteins into amino acids, complex carbohydrates into glucose, and fats into fatty acids and glycerol.

6) What is the role of saliva in the digestion of food?

Solution:
The food we eat is complex and needs to be broken down into smaller molecules to be absorbed by the body. This breakdown is mainly done by enzymes, which are biological catalysts. Saliva contains an enzyme called salivary amylase that converts starch, a complex molecule, into sugar.

As we chew, food is mixed with saliva and moved around by the tongue. Therefore, saliva plays a crucial role in the digestion and absorption of food.

7) What are the necessary conditions for autotrophic nutrition, and what are its byproducts?

Solution:
Autotrophic organisms obtain their energy and carbon through photosynthesis. In this process, they take in carbon dioxide and water from their surroundings and convert them into carbohydrates using sunlight and chlorophyll. These carbohydrates provide energy for the plant.

Instead of being used immediately, they are stored as starch, which serves as an internal energy reserve that the plant can use whenever needed.

8) What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Solution:
Aerobic Respiration
– Occurs in the presence of oxygen.
– Produces carbon dioxide, water, and energy.
– Begins with glycolysis in the cytoplasm and continues in the mitochondria.
– Involves complete oxidation of glucose.
– It happens in all higher organisms.

Anaerobic Respiration
– Occurs in the absence of oxygen.
– Produces ethyl alcohol, carbon dioxide, and a small amount of energy.
– Also starts in the cytoplasm but proceeds differently after that.
– Involves incomplete breakdown of glucose.
– Takes place in lower organisms like yeast, certain bacteria, and parasites like tapeworms.

9) How are the alveoli designed to maximize the exchange of gases?

Solution:
The lungs are a vital part of the body. Inside the lungs, air passages branch into smaller tubes, ending in tiny balloon-like structures called alveoli.

– Alveoli provide a surface for gas exchange. Their walls are lined with a network of blood vessels. When we breathe in, our ribs lift, the diaphragm flattens, and the chest cavity expands.

– This expansion causes air to be drawn into the lungs, filling the alveoli.

– Blood carries carbon dioxide from the body to the alveoli and absorbs oxygen from the alveolar air to transport it throughout the body. Even during normal breathing, the lungs retain a small amount of air, ensuring there’s enough time for oxygen absorption and carbon dioxide release.

10) What would be the consequences of a deficiency of hemoglobin in our bodies?

Solution:
Hemoglobin is a protein that carries oxygen to body cells for cellular respiration. If hemoglobin levels are low, red blood cells can’t carry enough oxygen, leading to a shortage in the body. This deficiency causes a condition called anemia.

11) Describe the double circulation of blood in human beings. Why is it necessary?

Solution:
Double circulation means that blood passes through the heart twice in one complete cycle. This process separates oxygenated and deoxygenated blood, helping to maintain a constant body temperature. The double circulatory system consists of:

– Pulmonary Circulation: The right ventricle pumps deoxygenated blood to the lungs, where it gets oxygenated. The oxygen-rich blood returns to the left atrium, moves to the left ventricle, and then is sent out through the aorta for systemic circulation.

– Systemic Circulation: The oxygenated blood is pumped from the left ventricle to various parts of the body. Deoxygenated blood from these areas returns to the right atrium via the vena cava and is then transferred to the right ventricle to start the cycle again.