Test: Control & Coordination - 2 - UPSC MCQ

Artificial ripening of fruits is carried out by:
Ethylene
- Ethylene is a plant hormone that is responsible for the ripening of fruits.
- It is a gaseous hormone that is naturally produced by fruits during the ripening process.
- Artificial ripening of fruits is done by exposing them to ethylene gas.
- Ethylene gas can be produced artificially and used to accelerate the ripening process of fruits.
Auxin, Cytokinin, and Gibberellin
- These are other plant hormones that play different roles in plant growth and development, but they are not directly involved in the ripening of fruits.
- Auxin is responsible for cell elongation and tropisms.
- Cytokinin promotes cell division and delays senescence.
- Gibberellin promotes stem elongation and seed germination.
Conclusion:
- Artificial ripening of fruits is carried out by ethylene gas.
- Ethylene is a plant hormone that naturally promotes fruit ripening.
- Exposing fruits to ethylene gas can accelerate the ripening process.

Neuromuscular junctions are between axon ending and muscles and junction between axon ending of one neuron and dendrites of another neuron is termed synapse.

Abscisic acid is generally associated with inhibiting growth, inducing dormancy, and helping the plant to withstand stress conditions such as drought. It is often referred to as a stress hormone or a growth inhibitor in plants, rather than a promoter of growth. On the other hand, auxins, gibberellins, and cytokinins are hormones that promote various aspects of plant growth and development.

Pancreas is located in the duodenum (first part of intestine), loop. So, it is not paired with endocrine glands.

Correct Statement about Receptors:

Statement A: Gustatory receptors detect taste while olfactory receptors detect smell

Explanation:

Receptors are specialized cells or structures that detect and respond to specific stimuli. In the case of taste and smell, there are specific receptors involved:

• Gustatory Receptors: These receptors are responsible for detecting taste. They are located primarily on the taste buds, which are found on the tongue and other parts of the oral cavity.


• Olfactory Receptors: These receptors are responsible for detecting smell. They are located in the olfactory epithelium, which is found in the upper part of the nasal cavity.

Therefore, Statement A: Gustatory receptors detect taste while olfactory receptors detect smell is the correct statement.

Explanation of incorrect options:

Option A:

The spontaneous responses to the activation of a receptor are known as natural reflex activities. For example knee-jerk.

Option B:

Blinking of eyes due to strong light is also a natural reflex.

Option C:

Sneezing when an irritant enters the nose is the result of natural reflex activities.

The correct answer is d

According to immunity theory, ageing is associated with the disappearance of the thymus gland by the late middle age in man and replaced by fat. It causes a weakening in the defense mechanisms of the body and in the course of time, leads to a large-scale decay and destruction of cells and tissues.

Excess secretion of growth hormone by pituitary gland causes gigantism while its deficiency causes dwarfism.

The correct answer is B: Liver because the liver is not a ductless gland.
Explanation:
Ductless glands are also known as endocrine glands. These glands secrete hormones directly into the bloodstream rather than through ducts. They play a crucial role in regulating various bodily functions.
Let's discuss the other options to understand why they are ductless glands:
- A: Adrenal gland: The adrenal glands are located on top of the kidneys and produce hormones such as adrenaline and cortisol. They are ductless glands.
- C: Thyroid gland: The thyroid gland is located in the neck and produces hormones that regulate metabolism and growth. It is a ductless gland.
- D: Pituitary gland: The pituitary gland is often referred to as the "master gland" because it controls the functions of other endocrine glands. It secretes various hormones and is a ductless gland.
Therefore, the liver is not a ductless gland. The liver is an essential organ involved in various metabolic processes, including detoxification, protein synthesis, and bile production. It does not produce hormones directly into the bloodstream like ductless glands.

Answer:
The correct answer is A: 31 pairs.
Here is a detailed explanation:
Spinal Nerves:
- Spinal nerves are the nerves that emerge from the spinal cord and innervate different parts of the body.
- They are named according to their location along the vertebral column.
- Each spinal nerve consists of two roots: the dorsal root and the ventral root.
Number of Spinal Nerves:
- There are a total of 31 pairs of spinal nerves in humans.
- These spinal nerves are classified into different regions based on their location:
1. Cervical Nerves: There are 8 pairs of cervical nerves that emerge from the cervical region of the spinal cord (C1-C8).
2. Thoracic Nerves: There are 12 pairs of thoracic nerves that emerge from the thoracic region of the spinal cord (T1-T12).
3. Lumbar Nerves: There are 5 pairs of lumbar nerves that emerge from the lumbar region of the spinal cord (L1-L5).
4. Sacral Nerves: There are 5 pairs of sacral nerves that emerge from the sacral region of the spinal cord (S1-S5).
5. Coccygeal Nerve: There is 1 pair of coccygeal nerve that emerges from the coccygeal region of the spinal cord.
In Conclusion:
- The number of spinal nerves in humans is 31 pairs.
- These spinal nerves play a crucial role in transmitting sensory and motor information between the brain and different parts of the body.

The hormone that regulates the ionic balance in the body is Vasopressin.
Vasopressin, also known as antidiuretic hormone (ADH), is a hormone produced in the hypothalamus and released by the posterior pituitary gland. It plays a crucial role in regulating the balance of ions in the body.
Functions of Vasopressin:
1. Water reabsorption: Vasopressin acts on the kidneys to increase the reabsorption of water, which helps in maintaining the body's fluid balance.
2. Electrolyte balance: Vasopressin influences the reabsorption of electrolytes, such as sodium and chloride, in the kidneys. It helps in maintaining the proper concentration of these ions in the body.
3. Osmoregulation: Vasopressin responds to changes in the body's osmotic pressure. When the concentration of solutes in the blood increases, vasopressin is released to conserve water and prevent dehydration.
4. Blood pressure regulation: Vasopressin has vasoconstrictive effects, which can increase blood pressure. It acts on the smooth muscles of blood vessels, causing them to constrict and narrowing the diameter of blood vessels.
Conclusion:
Vasopressin, also known as antidiuretic hormone (ADH), is the hormone that regulates the ionic balance in the body. It plays a crucial role in maintaining water and electrolyte balance, osmoregulation, and blood pressure regulation.

For secretion of thyroid, iodine is essential and not iron.

Pancreas are both exocrine and endocrine glands ; they are exocrine glands because they secrete products - pancreatic juice and endocrine because they secrete other substances directly into the blood stream. 

When the electrical impulse reaches the axon ending at synapse chemicals are released which on reaching the dendrite of next neuron again give rise to electrical impulse.

The endocrine gland known as the 'master gland' is the Pituitary gland.
The pituitary gland is located at the base of the brain and is considered the most important endocrine gland in the body. It is often referred to as the 'master gland' because it plays a crucial role in regulating and controlling the functions of other endocrine glands.
Functions of the pituitary gland:
- Secretion of hormones: The pituitary gland produces and releases several hormones that regulate various bodily functions. These hormones include growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, prolactin, and oxytocin.
- Growth and development: The growth hormone secreted by the pituitary gland stimulates the growth and development of bones, muscles, and tissues.
- Reproduction: The follicle-stimulating hormone and luteinizing hormone released by the pituitary gland play a crucial role in regulating the reproductive system in both males and females.
- Regulation of other endocrine glands: The pituitary gland controls the activities of other endocrine glands such as the thyroid gland, adrenal glands, and ovaries/testes by secreting hormones that stimulate or inhibit their hormone production.
Conclusion:
The pituitary gland, also known as the 'master gland,' plays a vital role in regulating various bodily functions by secreting hormones that control the activities of other endocrine glands.

Cerebellum is responsible for maintenance of body balance and posture.

Abscisic acid  is a plant  hormone that plays important role abscission of leave. It inhibits  stem elongation by inhibiting gibberellic acid. It prevents loss of dormancy in seeds. 

Medulla is the last part of hind-brain, spinal cord arises from it.

Cytokinin are a class of plant growth substances that promote cell division, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth. Cytokinin are the plant hormones which promote cell division in plants. So, the correct answer is " Stimulate cell division. "