Free Chemical Coordination and Hormones MCQs with Answers

• A. Indole propionic acid.
• B. Indole carboxylic acid.
• C. Indole acetaldehyde
• D. Indole acetic acid.Scheduling Virtual Doctor Consultations

Explanation: The principal natural auxin is indole-3-acetic acid, commonly written as indole acetic acid or IAA.

• A. Accumulation of toxic waste products in leaves.
• B. Deficiency of chlorophyll.
• C. Short supplies of mineral nutrients in the soil.
• D. All of these

Explanation: Chlorosis is the yellowing of leaves caused by reduced chlorophyll, and it can result from mineral deficiency or injury caused by…

• A. IAA
• B. NAA
• C. 2 4-D
• D. GA

Explanation: 2,4-D is a synthetic auxin that acts as a selective herbicide, especially against many broad-leaved weeds.

• A. ADH
• B. MSH
• C. Oxytocin
• D. Progesterone

Explanation: Oxytocin stimulates contraction of the uterine smooth muscle during labour and also helps the uterus contract after birth, reducing…

• A. Photoperiodism
• B. Thermotropism
• C. Vernalisation
• D. Thermoregulation

Explanation: Vernalisation is the induction or acceleration of flowering after exposure to a prolonged period of low temperature.

• A. Turgor movements
• B. Growth movements
• C. Tactic movements
• D. Paratonic movments

Explanation: Sleep movements in plants are usually turgor movements, produced by reversible changes in water content and pressure in specialised motor…

• A. Movement of the eyeball
• B. Movement of the tongue
• C. Swallowing
• D. Movement of the neck

Explanation: Abducens is the sixth cranial nerve that innervates the external rectus muscle of the eyeball.

• A. Epiphyseal plates close after adolescence
• B. Bones loose their sensitivity to growth hormone in adults
• C. Muscle fibres do not grow in size after birth
• D. Growth hormone becomes inactive in adults

Explanation: Epiphyseal plate is a hyaline cartilage plate in the metaphysis at each end of long bone.

• A. It is provided with a duct
• B. It only stores and releases hormones
• C. It is under the regulation of hypothalamus
• D. It secretes enzymes

Explanation: The posterior pituitary is not a true endocrine gland because it does not produce its own hormones.

• A. Thermoregulation
• B. Vision
• C. Memory
• D. Autonomic functions like breathing and heart rate

Explanation: Sensory processing occurs in the spinal cord and somatosensory cortex, but reflex responses like withdrawing from pain involve brainstem…

• A. Adrenocorticotropic hormone
• B. Insulin and glucagon
• C. Epinephrine and norepinephrine
• D. Aldosterone

Explanation: Epinephrine and norepinephrine are responsible for the physical symptoms described because they trigger the 'fight-or-flight' response in…

• A. Glomerulus
• B. Bowman's capsule
• C. Thymus
• D. Collecting tubules of the nephron

Explanation: Antidiuretic hormone (ADH) is a chemical produced in the brain that causes the kidneys to release less water, decreasing the amount of…

• A. Endocrine glands are ductless
• B. Parathormone is the flight or fight hormone
• C. The islet cells in the pancreas produce both glucagon and insulin
• D. Ecdysone controls metamorphosis in some insects

Explanation: Adrenaline and noradrenaline are dubbed emergency hormones or Fight or Flight hormones.

• A. Increase in blood sugar
• B. Increase in digestion
• C. Increase in breathing rate
• D. Increase in adrenaline

Explanation: The parasympathetic nervous system predominates in quiet "rest and digest" conditions while the sympathetic nervous system drives the…

• A. Dwarfism
• B. GERD
• C. Addison's Disease
• D. Acromegaly

Explanation: When adrenal glands don't produce enough hormones, this can lead to adrenal insufficiency (Addison's disease).

• A. Prostaglandins
• B. Estrogen and progesterone
• C. Insulin and glucagon
• D. Thyroid hormones (T3 and T4)

Explanation: Prostaglandins are regulatory molecules but are not considered hormones. Estrogens and progesterones are nonpolar but are steroids.

• A. Target cells must have specific receptor proteins with which these molecules combine
• B. When these molecules bind to target cells, specific sequences of changes must occur
• C. There must be an 'off-switch' that will stop the induced changes
• D. Second messengers will always be involved in the response of the target cell

Explanation: This statement is false because not all hormones and neurotransmitters utilize second messengers.

• A. Estrogen for prolactin on the mammary glands during pregnancy
• B. Parathyroid hormone for vitamin D3 on blood Ca2+ levels
• C. Estrogen for progesterone on the uterus
• D. Insulin for glucagon on adipose tissue

Explanation: The action of insulin and glucagon on adipose tissue is an example of antagonistic effect.

• A. Stimulate gluconeogenesis
• B. Cause lipolysis
• C. Cause proteolysis
• D. Stimulate cellular uptake and utilization of amino acids

Explanation: Lucocorticoids are steroids chemically. Cortisol is an example of glucocorticoid.

• A. Estrogen
• B. Calcitonin
• C. Norepinephrine
• D. Calcium

Explanation: Norepinephrine is a chemical released from the sympathetic nervous system in response to stress.