Tag: biology

Questions Related to biology

Cortisol is secreted by the adrenal cortex in response to stress. In addition to its function in a stress response, it functions in negative feedback by

biology the endocrine system feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Inhibiting hypothalamus to secrete corticotropin releasing hormone or CRH

  2. Inhibiting anterior pituitary's ability to respond to CRH

  3. Inhibiting the epinephrine

  4. Both A and B

Show answer
Correct Option: D
Explanation:
  • One distinctive feature of hormones whose secretion is regulated through the hypothalamus and pituitary is that they regulate their own secretion through negative feedback inhibition. 
  •  for example, cortisol binds to its receptor on cells in the hypothalamus and adenohypophysis, and has the effect of inhibiting secretion of tropic hormones: in this case, CRH (corticotropin releasing hormone) and ACTH (adrenocorticotropic hormone). 
  • Less tropic hormone secretion leads to less stimulation of cortisol secretion by cells of the zona fasciculata of the adrenal cortex. Hence, Cortisol is secreted by the adrenal cortex in response to stress. In addition to its function in a stress response, it functions in negative feedback by Inhibiting hypothalamus to secrete corticotropin-releasing hormone or CRH and  Inhibiting anterior pituitary's ability to respond to CRH. 
So, the correct answer is 'both A and B.

Epinephrine level in blood increases in response to stress. This hormone is known to affect the rate of glycolysis in different organs of the body. The rates of glycolysis in liver, heart and skeletal muscles in response to rise in blood epinephrine (in comparison to non-stress condition) is expected to be

biology the endocrine system feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Unaffected in liver, low in heart, and high in skeletal muscles

  2. High in liver, low in heart, and low and skeletal muscles

  3. Unaffected in liver, high in heart, and low in skeletal muscles

  4. Low in liver, high in heart, and high in skeletal muscles

Show answer
Correct Option: D
Explanation:

Epinephrine is the hormone released in response to stress conditions. The rise in the hormone level in he blood causes an increase in ATP production for which the rates of glycolysis increases in the muscles (heart and skeletal muscles). The synthesis of glucose by gluconeogenesis takes place in the liver and so, the rate of glycolysis is low. 

Thus, the correct answer is option D. 

Which illustrates feed back in development

biology the endocrine system feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. As tissue 'X' develops, it secretes enzyme to inhibit development of tissue 'Y'

  2. As tissue 'X' develops, it secretes something that induces tissue 'Y' to develop

  3. As tissue 'X' develops, it secretes something that slows down growth of tissue 'Y'

  4. Tissue 'X' secretes RNA which changes the development of tissue 'Y'.

Show answer
Correct Option: A
Explanation:
The X and Y tissue system is observed in Crustaceans. The X organ produces hormones that control development, to prevent molting during development it releases an antiecdysis hormone, which stops the Y organ from secreting the molting hormone.
Therefore, the correct answer is' As tissue 'X' develops, it secretes enzyme to inhibit development of tissue 'Y'

Besides corticotropin releasing hormone(CRH) which other hormone also stimulate the release of adrenocorticotropic hormone(ACTH)?

biology the endocrine system feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Glucagon

  2. Insulin

  3. Aldosterone

  4. Epinephrine

Show answer
Correct Option: D
Explanation:

Epinephrine acts on nearly all body tissues and its actions vary by tissue type and tissue expression of adrenergic receptors. The  β adrenergic receptor binding helps in increasing the secretion of adrenocorticotropic hormone by the pituitary glands.

Blood sugar level is an example of _______

biology life processes: control and coordination feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Positive feed back mechanism

  2. Negative feedback mechanism

  3. Both A and B

  4. None of these

Show answer
Correct Option: B
Explanation:

The body has a mechanism to maintain a normal state. Whenever there is change in thus state there are messages through the body systems to increase if there is a fall below the normal , or decrease if there is rise above the normal. This kind of ordering for the opposite. Is negative feedback to restore the normal state.

Hormonal secretions are controlled by

biology life processes: control and coordination feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Feedback mechanism

  2. Autosomal disorder

  3. Genetic disorder

  4. None

Show answer
Correct Option: A
Explanation:

'Too much, slow down or too little, speed up' -this is the feedback mechanism. the body has a mechanism to maintain a normal state. Whenever there is a change in this state there are messages through the body systems to increase if there is a fall below the normal, or decrease if there is rise above the normal.  This kind of ordering for the opposite Is negative feedback to restore the normal state. examples of positive feedback mechanisms are very few. One example is that of uterine contractions during childbirth. The normal state of the uterus is uncontracted, one contraction instead of commanding to come to normal gives a message to continue further (positive feedback till the delivery is completed).

So, the correct answer is 'Feedback mechanism'.

Uterine contraction during child birth is an example of ______

biology life processes: control and coordination feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Positive feed back mechanism

  2. Negative feedback mechanism

  3. Both A and B

  4. None of these

Show answer
Correct Option: A
Explanation:

Examples of positive feed back mechanisms are very few. One example is that of uterine contractions during child birth. Normal state of uterus is un contacted, one contraction instead of commanding to come to normal gives a message to continue further (positive feedback till the delivery is completed).

'Too much, slow down or too little, speed up' this is the of

biology life processes: control and coordination feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Feedback mechanism

  2. Autosomal disorder

  3. Genetic disorder

  4. None

Show answer
Correct Option: A
Explanation:

'Too much, slow down or too little, speed up' -this is the feedback mechanism. the body has a mechanism to maintain a normal state. Whenever there is a change in this state there are messages through the body systems to increase if there is a fall below the normal, or decrease, if there is a rise above the normal. This kind of ordering for the opposite Is negative feedback to restore the normal state.

So, the correct answer is 'Feedback mechanism'.

Feedback mechanisms can be

biology life processes: control and coordination feedback mechanism mechanism of hormone action and feedback mechanisms role of hormones in coordination

  1. Positive

  2. Negative

  3. Both

  4. None

Show answer
Correct Option: C
Explanation:

'Too much, slow down or too little, speed up' -this is the feedback mechanism. the body has a mechanism to maintain a normal state. Whenever there is a change in this state there are messages through the body systems to increase if there is a fall below the normal, or decrease if there is rise above the normal.  This kind of ordering for the opposite Is negative feedback to restore the normal state. examples of positive feedback mechanisms are very few. One example is that of uterine contractions during childbirth. The normal state of the uterus is uncontracted, one contraction instead of commanding to come to normal gives a message to continue further (positive feedback till the delivery is completed).

So, the correct answer is 'Both'.

What evidence convinced scientists that Archaeopteryx should be classified as a bird rather than a small dinosaur?

biology skeleton and joints introduction to movement introduction to locomotion movement

  1. Scales.

  2. Toothless, elongated mouth like beak.

  3. A tail similar to that of modern birds.

  4. Fused collar bone, indicating flying ability.

Show answer
Correct Option: D