Control & Coordination Important Questions Class 10 Science with Solutions

Living organisms are dynamic systems constantly responding to changes in their surroundings and within themselves. These responses require proper communication and regulation among various body parts. Chapter 6, Control and Coordination, explains the complex and intricate mechanisms that enable animals and plants to adapt, survive, and function effectively. This chapter provides good insights into how organisms maintain balance and respond to environmental changes. 

This chapter gives you insights into how the organs coordinate with each other in the human body and send signals so that they perform at their highest level. Also, you understand how the brain and central nervous system (CNS) control the entire human body, from which many Chapter 6 Science Class 10 Important Questions are framed in final examinations. 

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Chapter 6 Control and Coordination : Important Questions

1. Auxin is a plant hormone that promotes cell elongation and is produced by the apical meristem. It inhibits the growth of lateral buds which are present at nodes (where leaves attach to the stem). As long as sufficient auxin is produced by the apical meristem, the lateral buds remain dormant.

A gardener wants the plants in the hedge that he is growing to become bushier with more branches. Which of the following should he do?

Answer:

To make the plants in the hedge bushier with more branches, the gardener should encourage the growth of lateral buds. Since auxin inhibits the growth of lateral buds, the gardener should reduce the production or action of auxin at the apical meristem.

The gardener can do this by pruning the apical (tip) growth of the plants. By cutting back the main stem, the source of auxin production is reduced, which allows the lateral buds to become active and start growing. This process is known as apical dominance inhibition, which will result in a bushier plant with more branches.

2. During pollination, plants ensure that the pollen grain from a species germinates on the stigma of the same species.

Which of the following ensures this?

a. Chemotropism

b. Hydrotropism

c. Phototropism

d. geotropism

Answer:

‍(a) Chemotropism

Explanation:

Chemotropism refers to the growth or movement of an organism or part of an organism in response to a chemical stimulus. In the context of pollination, the pollen grain produces chemical signals that attract it to the stigma of the same species. These chemical signals ensure that the pollen germinates on the stigma of a flower of the same species, promoting successful fertilization.

3. Sheila saw a snake and instantly jumped back. She then slowly moved away from the snake.

What is the difference between the two actions of instantly jumping and walking away?

Answer:

‍The difference between Sheila instantly jumping back and slowly moving away from the snake lies in the type of response and the associated physiological processes:

‍Instantly jumping back: This action is an involuntary, reflexive response to the perceived danger (the snake). It is a quick, automatic reaction mediated by the nervous system, particularly the spinal cord, that occurs without conscious thought. This is often referred to as a startle reflex or escape reflex, which is a protective mechanism to quickly distance oneself from a threat.

‍Slowly moving away: This action is a voluntary, controlled movement that involves conscious thought. Sheila likely assessed the situation, decided to move away slowly to avoid further risk, and used her motor skills to walk. This movement is not an immediate reflex but rather a deliberate action based on her understanding of the situation.

In summary, the instant jump is a reflexive, unconscious reaction to danger, while slowly walking away is a voluntary, conscious action.

4. Hema bought some unripe tomatoes and left half of them in a brown paper bag and the other half in an open tray. After two days she noticed that the tomatoes in the paper bag had ripened, but the ones in the open tray had not.

(a) What hormone facilitated the ripening of tomatoes? 

(b) Why did the tomatoes in the paper bag ripen faster?

Answer:

(a) The hormone that facilitated the ripening of tomatoes is ethylene. Ethylene is a plant hormone that plays a crucial role in the ripening of fruits. It triggers various biochemical processes that lead to the softening, color change, and development of flavor in fruits like tomatoes.

(b) The tomatoes in the paper bag ripened faster because the bag trapped the ethylene gas that the tomatoes produced. Ethylene is a volatile gas, and when it accumulates around the fruit, it accelerates the ripening process. In the open tray, the ethylene gas dispersed into the surrounding environment, and the concentration around the tomatoes remained lower, which slowed down the ripening process. By keeping the tomatoes in a confined space like the paper bag, the concentration of ethylene remained high, speeding up the ripening.

5. While on a roller coaster ride, Aditya noticed an increase in his heartbeat and his breathing. Which hormone is responsible for the changes in Aditya's body?

Answer:

The hormone responsible for the increase in Aditya's heartbeat and breathing while on the roller coaster ride is adrenaline (also known as epinephrine).

Adrenaline is produced by the adrenal glands in response to stress or excitement (like during a roller coaster ride). It triggers the "fight or flight" response, which prepares the body for rapid action. Adrenaline increases the heart rate, dilates the airways to allow more oxygen to be taken in, and increases blood flow to muscles, among other effects. This results in the heightened heartbeat and faster breathing that Aditya experienced.

6. 'Plant growth regulators do not always promote growth.'

Cite one example in support of the above statement and mention the action of the same.

Answer:

‍An example that supports the statement "Plant growth regulators do not always promote growth" is abscisic acid (ABA).

‍Action of Abscisic Acid (ABA):
Abscisic acid is a plant hormone that generally inhibits growth. It plays a crucial role in promoting dormancy in seeds and buds, and in responding to stress conditions such as drought. During water scarcity, ABA helps to close stomata to reduce water loss and inhibits growth processes to conserve energy and resources. Therefore, unlike other plant growth regulators that promote growth, ABA acts to slow down or inhibit growth under certain conditions, especially during environmental stress.

7. (a) As first line of defense, stress hormones are released in humans. As an equivalent, which hormone is most likely to be released as first line of defense in plants?

(b) There have been reports of plant hormones being found in animal bodies even when they are not synthesised by the animal. What can be the most common pathway of entry of such hormones in animals?

Answer:

(a) The hormone most likely to be released as the first line of defense in plants is jasmonic acid.
Jasmonic acid is a plant hormone that is involved in the plant’s response to stress, such as herbivore attacks, pathogen infections, or physical damage. It acts as a signaling molecule, triggering the plant's defense mechanisms, including the production of defensive proteins and other compounds that help protect the plant from further damage. Just like stress hormones (like cortisol and adrenaline) in humans, jasmonic acid helps plants respond to stress by activating various defensive responses.

(b) The most common pathway of entry of plant hormones into animal bodies is through the food chain.
Plant hormones can enter animal bodies when animals consume plant materials such as fruits, vegetables, and other plant-based foods that contain these hormones. Once ingested, plant hormones may be absorbed into the bloodstream and can have physiological effects on the animal’s body, even though the animal does not synthesize them itself. This is a common way for plant hormones to influence animal biology, especially in cases where plant-derived substances have an effect on metabolism or development in animals.

8. (a) Name ONE plant hormone that controls directional growth.

(b) Plant hormones are also referred to as growth regulators and can be controlled by a number of stimuli.

Mention ONE point of difference between the functioning of animal growth hormones and plant growth regulators with respect to such control.

Answer:

(a) One plant hormone that controls directional growth is auxin.
Auxin regulates phototropism (growth in response to light) and gravitropism (growth in response to gravity). It promotes cell elongation on the shaded side of the plant during phototropism, causing the plant to grow toward the light.

(b) One point of difference between the functioning of animal growth hormones and plant growth regulators with respect to control is:

• Animal growth hormones are typically controlled by the endocrine system and are released into the bloodstream to target specific organs or tissues.
• Plant growth regulators, on the other hand, are often controlled by environmental stimuli (such as light, gravity, or temperature) and can act locally or throughout the plant in response to these external factors.
  In animals, the regulation is more systemic and involves feedback mechanisms, while in plants, the regulation can be more localized and responsive to immediate environmental changes.

9. Sapna suffers from a condition due to which her average blood sugar level is 174 mg/dL. The average blood sugar level in a healthy adult is <140 mg/dL.

Which of the following could be the cause of Sapna's condition?

a. insufficient production of thyroxine in her body

b. insufficient production of insulin in her body

c. excess production of thyroxine in her body

d. excess production of insulin in her body

Answer:

‍(b) insufficient production of insulin in her body

Explanation: 

Insulin is a hormone produced by the pancreas that helps regulate blood sugar levels by allowing cells to take in glucose from the blood. If there is insufficient production of insulin (a condition known as diabetes), glucose cannot be effectively transported into cells, causing elevated blood sugar levels.

The other options:

• Insufficient production of thyroxine: This could lead to hypothyroidism, which affects metabolism but is not directly linked to elevated blood sugar levels.
• Excess production of thyroxine: This would typically cause hyperthyroidism, which can accelerate metabolism but does not directly cause high blood sugar levels.
• Excess production of insulin: This would lower blood sugar levels, not increase them.

The Importance of Control and Coordination

Every living organism interacts with its environment, facing light, sound, temperature, or touch stimuli. Internally, it must regulate processes like digestion, respiration, and excretion. Without proper control:

• The body's processes may become chaotic or inefficient.
• Communication between different body parts would be lost.

Hence, control and coordination are fundamental to maintaining homeostasis and ensuring survival.

Summary of Control and Coordination in Humans

Humans have a highly developed system for control and coordination, including the nervous and endocrine systems.

The Nervous System

The nervous system uses electrical signals to communicate between body parts. It consists of:

Central Nervous System (CNS):

Brain: The command centre of the body. It processes information, makes decisions, and controls actions.

• Cerebrum - Controls voluntary actions, emotions, learning, and memory.
• Cerebellum - Maintains balance and coordinates muscles.
• Medulla Oblongata - Regulates involuntary functions like breathing and heartbeat.

Spinal Cord: Transmits messages between the brain and the rest of the body. It also controls reflex actions.

Peripheral Nervous System (PNS):

Composed of nerves that carry messages to and from the CNS. Subdivided into:

• Sensory nerves - Transmit signals from sense organs to the CNS.
• Motor nerves - Transmit commands from the CNS to muscles and glands.

1. Autonomic Nervous System (ANS):

Controls involuntary functions like digestion and sweating. Divided into:

Sympathetic system - Prepares the body for action (fight or flight).

Parasympathetic system - Calms the body after stressful events (rest and digest).

Reflex Actions - Reflexes are rapid, involuntary responses to stimuli, providing protection and quick reactions.

• Example: Pulling your hand away from a hot object.
• Pathway: Receptor → Sensory Neuron → Spinal Cord → Motor Neuron → Effector.

1. Endocrine System

The endocrine system complements the nervous system by using chemical messengers, or hormones, for slower but long-lasting control. Key endocrine glands include:

1. Pituitary Gland - Known as the "master gland," it regulates other glands and body growth.
2. Thyroid Gland - Produces thyroxine, which controls metabolism.
3. Adrenal Glands - Secrete adrenaline, the "stress hormone," for fight-or-flight responses.
4. Pancreas - Produces insulin and glucagon to regulate blood sugar levels.
5. Reproductive Glands -

• Testes: They produce testosterone and are responsible for male characteristics.
• Ovaries produce estrogen and progesterone and are responsible for female characteristics and menstrual regulation.

Summary of Control and Coordination in Plants

Unlike animals, plants do not have a nervous system or specialized organs. They rely on hormones and external cues for control and coordination.

1. Plant Hormones (Phytohormones):

Plant hormones regulate growth, development, and responses to the environment:

• Auxins: Promote growth in stems and roots and aid in phototropism (growth towards light).
• Gibberellins: Stimulate seed germination, stem elongation, and flowering.
• Cytokinins: Promote cell division and delay ageing in leaves.
• Ethylene: Helps ripen fruits and promotes flower shedding.
• Abscisic Acid: Inhibits growth and induces dormancy in unfavourable conditions.

1. Tropic Movements (Tropisms):

Plants exhibit directional growth in response to stimuli:

• Phototropism: Growth towards light (e.g., sunflower bending towards sunlight).
• Geotropism: Growth in response to gravity (roots grow down, stems grow up).
• Hydrotropism: Growth towards water.
• Thigmotropism: Growth in response to touch (e.g., tendrils of a vine).

Applications of Control and Coordination

Understanding that control and coordination have several real-world applications, like obviously:

1. Medicine and Health - Insights into nervous and endocrine systems help diagnose and treat conditions like diabetes, thyroid disorders, and neurological diseases.
2. Agriculture - Knowledge of plant hormones enables synthetic auxins and gibberellins to improve crop yield and quality.
3. Technology - Artificial intelligence and robotics mimic neural networks for decision-making and adaptive responses.

How to Prepare for Chapter 6: Control and Coordination

To master this chapter, a strategic approach to studying is essential. Here are some little tips to help you excel in this chapter with ease; let’s go:

Focus on Diagrams - Visual representation is a significant part of this chapter, and diagrams often appear in exams. 

• Human Brain - Label the cerebrum, cerebellum, medulla oblongata, and their functions. Understand the role of different brain parts in controlling voluntary and involuntary actions.
• Reflex Arc - Memorize the flow of information from sensory neurons to motor neurons via the spinal cord.
• Endocrine Glands - Label glands like the pituitary, thyroid, adrenal, and pancreas and understand their functions.

Understand Hormones - Hormones are pivotal in control and coordination.

• Human Hormones - Learn about adrenaline (stress response), insulin (blood sugar regulation), and thyroxine (metabolism control). Know the effects of hormonal imbalances.
• Plant Hormones - Study the role of auxins, gibberellins, cytokinins, abscisic acid, and ethylene in plant growth and development.

Practice Questions - Regular practice helps reinforce key concepts. Solve NCERT textbook exercises and exemplar problems.

• Attempt CBSE sample papers to understand the question pattern and difficulty level.
• Focus on application-based and diagram-based questions.

Learn Reflex Action Pathways - Reflex actions demonstrate the efficiency of the nervous system. Learn how sensory neurons detect stimuli and pass signals to motor neurons for immediate response. Examples of Reflex Actions:

• Blinking when something approaches the eye.
• Withdrawing a hand from a hot object.

Learn the Integration of Systems - The nervous and endocrine glands interplay is crucial.

• Understand how the hypothalamus bridges the nervous and endocrine systems.
• Study how feedback mechanisms (e.g., insulin-glucose regulation) maintain homeostasis.

The chapter "Control and Coordination" gives a glimpse into the mechanisms that enable living organisms to interact with their surroundings effectively. It highlights the complexities of the nervous system, endocrine system, and hormones in animals, as well as the unique adapting power of plants. Understanding these systems helps students excel academically and offers valuable insights into how life sustains itself amidst constant change.

Stay curious and explore this chapter to learn the science behind life's incredible coordination!

We hope that you practise the above Chapter 6 Class 10 Science Extra Questions and achieve your dream marks.

All the best!