Life Process Exercise Question Answer Solutions

1. The kidneys in human beings are a part of the system for

(a) nutrition. (c) excretion. (b) respiration. (d) transportation.

Ans: (c) excretion.

2. The xylem in plants are responsible for

(a) transport of water. (c) transport of amino acids. (b) transport of food. (d) transport of oxygen.

Ans: (a) transport of water.

3. The autotrophic mode of nutrition requires

(a) carbon dioxide and water. (c) sunlight. (b) chlorophyll. (d) all of the above.

Ans: (d) all of the above.

4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

(a) cytoplasm. (c) chloroplast. (b) mitochondria. (d) nucleus.

Ans: (b) mitochondria.

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

Ans: Fats are digested in our bodies through a process called emulsification (process of mixing two immiscible solution (e.g., oil and water) ), which is facilitated by bile produced in the liver and stored in the gallbladder. Bile breaks down large fat globules into smaller ones, increasing the surface area for the action of the enzyme lipase, which is secreted by the pancreas.

This process primarily takes place in the small intestine. The lipase enzyme further breaks down the emulsified fats into fatty acids and glycerol, which are then absorbed by the intestinal walls into the bloodstream.

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

Ans: Saliva plays a important role in the digestion of food by moistening and lubricating it, which aids in the formation of a food bolus for easier swallowing. Saliva contains the enzyme amylase, which begins the chemical breakdown of starches into simpler sugars. Additionally, saliva has antibacterial properties that help maintain oral hygiene.

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

Ans: The necessary conditions for autotrophic nutrition include:

Carbon dioxide (CO₂)
Water (H₂O)
Sunlight
Chlorophyll (the pigment in plants that captures light energy)

The byproducts of autotrophic nutrition (photosynthesis) are:

Glucose (C₆H₁₂O₆) which is used as an energy source
Oxygen (O₂) which is released into the atmosphere

Reaction Involved: 6CO2 +6H2O+light energy→C6H12O6 +6O2

Breakdown Process:

Carbon Dioxide (CO₂): Taken from the air through the stomata in leaves.
Water (H₂O): Absorbed by roots from the soil and transported to the leaves through the xylem.
Sunlight: Provides the energy required for the reaction, captured by chlorophyll in the chloroplasts of plant cells.
Chlorophyll: The green pigment in the chloroplasts that captures light energy and converts it into chemical energy.

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

Ans: Aerobic Respiration:

Requires oxygen.
Occurs in the mitochondria.
Produces a large amount of energy (ATP).
End products are carbon dioxide and water.
Reaction Involved in Aerobic Reaction: C6H12O6 +6O2 →6CO2 +6H2O+ energy (ATP)

Anaerobic Respiration:

Does not require oxygen.
Occurs in the cytoplasm.
Produces less energy (ATP) compared to aerobic respiration.
End products vary (e.g., lactic acid in animals, ethanol, and carbon dioxide in yeast).
The reaction involved in Anaerobic Reaction: Lactic Acid Fermentation: C6H12O6 →2C3H6O3 +2 ATP and Alcoholic Fermentation: C6H12O6 →2C2H5OH+2CO2 +2ATP

Some organisms that use anaerobic respiration include yeast (for fermentation) and some bacteria. In humans, muscle cells can also undergo anaerobic respiration temporarily during intense exercise, leading to the production of lactic acid.

9. How are the alveoli designed to maximise the exchange of gases?

Alveoli are designed to maximize the exchange of gases through:

A large surface area due to the numerous alveoli (about 300 million in human lungs).
Thin walls (one cell thick) to facilitate quick diffusion.
A rich supply of blood capillaries to maintain a concentration gradient.
Moist surfaces to allow gases to dissolve and diffuse more efficiently.

10. What would be the consequences of a deficiency of haemoglobin in our bodies?

Ans: A deficiency of hemoglobin can lead to a condition called anemia. Consequences include:

Reduced oxygen-carrying capacity of the blood.
Fatigue and weakness.
Shortness of breath.
Pale skin.
Increased heart rate as the body attempts to compensate for the reduced oxygen levels.

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

Ans: Double circulation in humans involves two separate circuits: the pulmonary circulation and the systemic circulation.

Pulmonary Circulation: Carries deoxygenated blood from the right ventricle to the lungs for oxygenation and then brings oxygenated blood back to the left atrium.
Systemic Circulation: Carries oxygenated blood from the left ventricle to the rest of the body and returns deoxygenated blood to the right atrium.

Double circulation is necessary to ensure that oxygen-rich blood is efficiently delivered to body tissues while carbon dioxide is removed, optimizing the oxygenation process and maintaining efficient metabolic activity.

12. What are the differences between the transport of materials in xylem and phloem?

Ans: Xylem:

Transports water and minerals.
Movement is unidirectional (from roots to leaves).
Consists of dead cells (vessels and tracheids).

Phloem:

Transports organic nutrients (mainly sucrose).
Movement is bidirectional (from source to sink; i.e., from leaves to storage organs or growing parts).
Consists of living cells (sieve tubes and companion cells).

13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Ans: Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Alveoli (Lungs):
- Structure: Small, balloon-like sacs at the end of bronchioles; one cell thick; surrounded by a network of capillaries.
- Function: Gas exchange (oxygen into blood, carbon dioxide out of blood).
Nephrons (Kidneys):
- Structure: Tubular structures; include Bowman’s capsule, proximal tubule, loop of Henle, distal tubule, and collecting duct; surrounded by a network of capillaries.
- Function: Filtration of blood to form urine; reabsorption of essential nutrients, ions, and water; secretion of waste products into the tubular fluid.
Comparison:
- Both have extensive surface areas for efficient exchange.
- Alveoli exchange gases (O₂ and CO₂), while nephrons filter blood and regulate water, electrolytes, and waste removal.
- Both are crucial for maintaining homeostasis but in different systems (respiratory vs. excretory).

Other Questions of Intext of Life Process

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

Diffusion is insufficient for multicellular organisms like humans because it is too slow and inefficient for transporting oxygen over long distances within the body. In multicellular organisms, cells are located far from the surface where oxygen enters the body. To meet the oxygen demands of all cells, a specialized circulatory system with blood vessels and a pump (the heart) is necessary to quickly and efficiently deliver oxygen to every cell.

What is Diffusion? Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. This plays a vital role in oxygen intake for multicellular organisms

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

To determine if something is alive, we use the following criteria:

Growth: The ability to grow and develop over time.
Reproduction: The capability to produce offspring.
Metabolism: The ability to convert energy from the environment for sustenance.
Response to Stimuli: Reacting to environmental changes.
Homeostasis: Maintaining a stable internal environment.
Cellular Organization: Being composed of one or more cells.
Adaptation: The ability to change over time in response to the environment.

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

Outside raw materials used by an organism include:

Water: Essential for metabolic processes and maintaining cell structure.
Oxygen: Required for cellular respiration to produce energy.
Nutrients: Such as carbohydrates, proteins, fats, vitamins, and minerals, necessary for growth, energy, and cellular repair.
Carbon Dioxide: Used by plants for photosynthesis to produce food.

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

Essential processes for maintaining life include:

Nutrition: Intake and digestion of food to provide energy and building materials.
Respiration: Converting food into usable energy.
Excretion: Removing waste products from the body.
Circulation: Distributing nutrients, gases, and waste products throughout the body.
Growth and Repair: Increasing in size and repairing damaged tissues.
Reproduction: Producing offspring to continue the species.

5. What are the differences between autotrophic nutrition and heterotrophic nutrition?

Autotrophic Nutrition:

Organisms produce their own food using light (photosynthesis) or chemical energy (chemosynthesis).
Examples: Plants, algae, and some bacteria.
Requires: Carbon dioxide, water, and sunlight (for photosynthesis).

Heterotrophic Nutrition:

Organisms obtain food by consuming other organisms or organic matter.
Examples: Animals, fungi, and most bacteria.
Requires: Preformed organic molecules for energy and growth.

6. Where do plants get each of the raw materials required for photosynthesis?

Plants obtain the raw materials for photosynthesis as follows:

Carbon Dioxide (CO2): From the air through small openings called stomata on the leaves.
Water (H2O): Absorbed by the roots from the soil.
Sunlight: Captured by chlorophyll in the chloroplasts of leaf cells.

7. What is the role of the acid in our stomach?

The acid in our stomach, primarily hydrochloric acid (HCl), plays several crucial roles:

Digesting Food: Helps break down proteins into smaller peptides.
Killing Pathogens: Destroys bacteria and other harmful organisms ingested with food.
Activating Enzymes: Converts the enzyme pepsinogen into its active form, pepsin, which aids in protein digestion.

8. What is the function of digestive enzymes?

Digestive enzymes are responsible for breaking down complex food molecules into simpler, absorbable forms:

Amylase: Breaks down carbohydrates into simple sugars.
Protease: Breaks down proteins into amino acids.
Lipase: Breaks down fats into fatty acids and glycerol.

These enzymes ensure that nutrients can be absorbed by the body’s cells.

9. How is the small intestine designed to absorb digested food?

The small intestine is designed to absorb digested food efficiently through:

Villi and Microvilli: Tiny, finger-like projections that increase the surface area for absorption.
Thin Walls: Allow for easy transfer of nutrients into the blood vessels.
Rich Blood Supply: Numerous capillaries in the villi absorb nutrients and transport them to the rest of the body.

These adaptations ensure maximum absorption of nutrients into the bloodstream.

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

Terrestrial organisms have the advantage of accessing a higher concentration of oxygen in the air compared to aquatic organisms that rely on dissolved oxygen in water. Air contains about 21% oxygen, whereas water typically contains much less dissolved oxygen, making gas exchange more efficient for terrestrial organisms. Additionally, terrestrial organisms often have specialized respiratory structures like lungs, which provide a large surface area for efficient oxygen uptake.

2. What are the different ways in which glucose is oxidised to provide energy in various organisms?

Glucose is oxidized to provide energy through different pathways depending on the availability of oxygen:

Aerobic Respiration: Occurs in the presence of oxygen. Glucose is fully oxidized to carbon dioxide and water, producing a large amount of energy (ATP). This process takes place in the mitochondria.

C6H12O6+6O2→6CO2+6H2O+Energy (ATP)

Anaerobic Respiration: Occurs in the absence of oxygen. Glucose is partially broken down, producing less energy. Examples include:

Lactic Acid Fermentation: In muscle cells and some bacteria, glucose is converted to lactic acid.
- C6H12O6→2C3H6O3+Energy (ATP)

Alcoholic Fermentation: In yeast and some plant cells, glucose is converted to ethanol and carbon dioxide.
- C6H12O6→2C2H5OH+2CO2+Energy (ATP)

3. How is oxygen and carbon dioxide transported in human beings?

Oxygen Transport:

Oxygen is inhaled into the lungs and diffuses into the blood, where it binds to hemoglobin in red blood cells to form oxyhemoglobin.
This oxygen-rich blood is then transported through the circulatory system to various tissues, where oxygen is released for cellular respiration.

Carbon Dioxide Transport:

Carbon dioxide produced as a waste product of cellular respiration diffuses into the blood and is transported back to the lungs.
It is carried in three forms: dissolved in plasma, as bicarbonate ions (HCO₃⁻), and bound to hemoglobin (as carbaminohemoglobin).
In the lungs, carbon dioxide diffuses out of the blood into the alveoli and is exhaled.

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

The lungs are designed to maximize the area for gas exchange through the following features:

Alveoli: Tiny air sacs with thin walls (one cell thick) that provide a large surface area for gas exchange.
Capillary Network: Dense network of capillaries surrounding each alveolus to facilitate the efficient exchange of oxygen and carbon dioxide.
Elastic Fibers: Alveoli are surrounded by elastic fibers that help maintain their shape and increase surface area during inhalation.
Surfactant: A substance secreted within the alveoli that reduces surface tension, preventing the alveoli from collapsing and ensuring they remain open for gas exchange.

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

The transport system in human beings, also known as the circulatory system, includes the following components:

Heart: A muscular organ that pumps blood throughout the body.
- Function: Ensures continuous blood flow through the blood vessels.
Blood Vessels:
- Arteries: Carry oxygen-rich blood away from the heart to the tissues.
- Veins: Carry oxygen-poor blood back to the heart.
- Capillaries: Smallest blood vessels where exchange of gases, nutrients, and waste occurs between blood and tissues.
Blood:
- Red Blood Cells (RBCs): Carry oxygen from the lungs to the body tissues and return carbon dioxide from the tissues to the lungs.
- White Blood Cells (WBCs): Fight infection and provide immunity.
- Platelets: Help in blood clotting to prevent excessive bleeding.
- Plasma: The liquid part of blood that transports nutrients, hormones, and waste products.

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

It is necessary to separate oxygenated and deoxygenated blood in mammals and birds to ensure efficient oxygen delivery to tissues and maintain high metabolic rates. This separation allows for:

Efficient Oxygen Supply: Oxygen-rich blood is pumped directly to body tissues without mixing with oxygen-poor blood, ensuring maximum oxygen delivery.
High Metabolism Support: Birds and mammals have high metabolic rates and energy demands. Separation allows for efficient energy production needed for activities like flight, running, and maintaining body temperature.
Temperature Regulation: Efficient oxygen delivery helps in maintaining a stable body temperature, crucial for homeothermic organisms like mammals and birds.

3. What are the components of the transport system in highly organised plants?

In highly organized plants, the transport system consists of:

Xylem: Transports water and minerals from roots to leaves.
- Components: Tracheids, vessel elements, xylem fibers, and xylem parenchyma.
Phloem: Transports the products of photosynthesis (mainly sugars) from leaves to other parts of the plant.
- Components: Sieve tube elements, companion cells, phloem fibers, and phloem parenchyma.

4. How are water and minerals transported in plants?

Water and minerals are transported in plants through the following steps:

Absorption by Roots: Root hairs absorb water and minerals from the soil.
Movement through Xylem: Water and minerals travel upward through the xylem vessels via capillary action, root pressure, and transpiration pull.
Transpiration: The evaporation of water from the leaves creates a suction force that pulls water upward from the roots through the xylem.

5. How is food transported in plants?

Food in plants (mainly in the form of sugars) is transported through the phloem by a process called translocation:

Movement from source to sink: Sugars are produced in the leaves (source) and transported to other parts of the plant (sink) such as roots, stems, and fruits.
Pressure flow mechanism: Sucrose is loaded into sieve tube elements at the source, creating high osmotic pressure. Water follows by osmosis, creating pressure that drives the flow of sap to the sink where the sucrose is unloaded.

1. Describe the structure and functioning of nephrons.

Structure of Nephron:

Bowman’s Capsule: A cup-like sac at the beginning of the nephron that encases the glomerulus, a network of capillaries.
Proximal Convoluted Tubule (PCT): The tubule leading from Bowman’s capsule where reabsorption of water, ions, and nutrients occurs.
Loop of Henle: A U-shaped loop that concentrates urine and reabsorbs water and salts.
Distal Convoluted Tubule (DCT): The tubule after the Loop of Henle where further ion exchange and water reabsorption occur.
- Collecting Duct: Collects urine from multiple nephrons and channels it to the renal pelvis.

Functioning of Nephron:

Filtration: Blood is filtered in the glomerulus, and the filtrate enters Bowman’s capsule.
Reabsorption: Essential substances and water are reabsorbed from the filtrate in the PCT, Loop of Henle, and DCT back into the blood.
Secretion: Additional waste products and excess ions are secreted into the DCT.
Excretion: The final urine, composed of wastes and excess substances, moves to the collecting duct and then to the bladder for excretion.

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

Plants use several methods to get rid of excretory products:

Leaf Shedding: Waste products are accumulated in leaves which are eventually shed.
Gum and Resin Secretion: Excretes waste substances as gums and resins.
Stomatal Excretion: Some gaseous wastes are released through stomata.
Lenticels: Gaseous wastes can also be expelled through lenticels in the bark.

3. How is the amount of urine produced regulated?

The amount of urine produced is regulated by:

Antidiuretic Hormone (ADH): Increases water reabsorption in the kidneys, reducing urine volume. When body water levels are low, ADH is released, making the kidneys reabsorb more water and concentrate the urine.
Aldosterone: Promotes sodium and water reabsorption in the kidney tubules, increasing blood volume and decreasing urine output.
Hydration Levels: Increased fluid intake leads to higher urine production, while dehydration reduces it.
Blood Pressure: Low blood pressure triggers the release of renin, leading to aldosterone secretion, which increases water reabsorption and reduces urine volume.