Tag: biology

Questions Related to biology

Choose the correct answer from the alternatives given.
Which of the following is not involved in calcium metabolism?

biology chemical coordination and integration hormones coordination in human beings- chemical control endocrine system in humans

  1. Calmodulin

  2. Calcitonin

  3. Parathyroid hormone

  4. Atrial natriuretic factor

Show answer
Correct Option: D
Explanation:

(A)Calmodulin is a multifunctional intermediate calcium binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the binding of Ca2+ is required for the activation of calmodulin. 

(B) Calcitonin is a hypocalcemic hormone. This is secreted by the C-cells in the thyroid gland. It acts on bone and the kidney to reduce the blood calcium level. It reduces the reabsorption of calcium from bones and inhibits reabsorption of calcium by the renal tubules.
(C) The parathyroid gland secretes a peptide hormone called parathyroid hormone (PTH). The secretion of PTH is regulated by the circulating levels of calcium ions. PTH increases the calcium levels in the blood. PTH also stimulates reabsorption of calcium by the renal tubules and increase calcium absorption from the digested food.
(D) Atrial Natriuretic Factor (ANF) is released when there is an increase in blood flow to the atria of the heart. ANF can cause vasodilation (dilation of blood vessels) and thereby decrease the blood pressure. ANF mechanism, therefore, acts as a check on the renin-angiotensin mechanism.
So the correct answer is the Atrial Natriuretic Factor. 

Choose the correct answer from the alternatives given.
Steroid hormones mediate their action by:

biology chemical coordination and integration hormones coordination in human beings- chemical control endocrine system in humans

  1. activating adenylate cydase

  2. activating gene expression

  3. binding to the surface membrane of the cells

  4. inhibiting an enzyme

Show answer
Correct Option: B
Explanation:

Steroid hormones and thyroid hormones do not bind to the cell surface receptors. Being lipid soluble, these are able to enter the cells and their nuclei and influence the gene action. The hormone binds to the receptors forming a hormone-receptor complex. It binds to the transcription factors that in turn to DNA and a particular gene is activated. Their transcription leads to the synthesis of a specific protein to influence the metabolism of the recipient cell. Thus, the peptide hormones activate existing enzymes in the cell while steroid hormones bring about the synthesis of new enzymes.

So the correct answer is activating gene expression.

Which of these is a correct statement? 

biology chemical coordination and integration hormones coordination in human beings- chemical control endocrine system in humans

  1. Neurons regulate endocrine activity but not vice versa.

  2. Endocrine glands regulate neural activity and nervous system regulates endocrine glands.

  3. Neither hormones control neural activity nor neurons control endocrine activity.

  4. Endocrine glands regulate neural activity but not vice versa.

Show answer
Correct Option: B
Explanation:

  • Nervous system is a coordinated network of nerve cells and fibres by which nerve impulses are transmitted throughout the body.
  • Endocrine system consists of glands that produce hormones.
In our body, nervous system and endocrine system jointly integrate all the activities as nervous system directs endocrine system to secrete hormones that act on the target organs.
So, the correct answer is 'Endocrine glands regulate neural activity and nervous system regulates endocrine glands.'.

Consider the following statements (a-d) and select the option which includes the correct ones only.
(a) The thyroid hormone plays an important role in the maintenance of the basal metabolic rate & erythropoiesis.
(b) Glucocorticoids inhibit inflammatory reactions by suppressing the immune system and promote erythropoiesis.
(c) Androgens promote development, maturation & function of the male sex organs as well as erythropoiesis.
(d) The gastrointestinal tract not only secretes gastric inhibitory peptide but also promotes the formation of RBCs.

biology chemical coordination and integration hormones coordination in human beings- chemical control endocrine system in humans

  1. 4

  2. 3

  3. 2

  4. 1

Show answer
Correct Option: A
Explanation:
In the given question, all the statements are correct as they all mention the correct function and effect of their respective hormones.
So, the correct answer is '4'.

Choose the incorrect pair among the Mendel choose for his experiments.

biology mendel's law of inheritance experiments of mendel works of mendel mendel's laws of inheritance

  1. Pod shape - Elongated/constricted

  2. Seed color - Yellow/green

  3. Seed shape - Round/wrinkled

  4. Flower position - Axial/terminal

Show answer
Correct Option: A
Explanation:

The incorrect pair here is the contrasting feature of the pod shape is "Elongated/constricted" which should be smooth/constricted in reality.

Which of the following law was discovered first by Mendel?

biology mendel's law of inheritance experiments of mendel works of mendel mendel's laws of inheritance

  1. Law of dominance

  2. Law of segregation

  3. Law of independent assortment

  4. Law of sex determination

Show answer
Correct Option: B

Which of the following scientists rediscover Mendel's work?

biology mendel's law of inheritance experiments of mendel works of mendel mendel's laws of inheritance

  1. Correns, Bateson, Tschermak

  2. Correns, Devries, Tschermark

  3. Devries, Morgan, Tschermak

  4. Correns, Tschermak, Garrod

Show answer
Correct Option: B
Explanation:

In 1990, three scientists (Correns, de Vries and Von Tschermak) independently rediscovered Mendel's results on the inheritance of character.

So the correct answer is "Correns, de Vries and Von Tschermak".

Mendel's work was republished

biology mendel's law of inheritance experiments of mendel works of mendel mendel's laws of inheritance

  1. In 1900

  2. At the beginning of 20 th centuary

  3. In the proceedings of the "Natural History" Society of Brunn

  4. Both A and C

Show answer
Correct Option: A
Explanation:

Answer is A.

In 1900
The apparently simultaneous discovery of Mendel's laws by de Vries, Correns, and Tschermak suggests that by 1900 rediscovery had become inevitable.

The main reason for the success of Mendel was that

biology mendel's law of inheritance experiments of mendel works of mendel mendel's laws of inheritance

  1. He made statistical analysis of the offsprings.

  2. He first took only one character at a time in his crosses.

  3. He kept pedigree records.

  4. He selected pea plants.

Show answer
Correct Option: B
Explanation:

Main reasons for the success of Gregor Mendel: 

1. Mendel concentrated in one or few characters at a time.
2. He made controlled crosses and kept careful numerical records of the results.
3. He suggested 'factors' as a cause of characters.
4. The experimental material Pisum sativum was a wise choice.

Correct reason of Mendel's success was

biology mendel's law of inheritance experiments of mendel works of mendel mendel's laws of inheritance

  1. He repeated each experiment several times.

  2. Traits chosen by him had genes far apart so that linkage was absent.

  3. He kept record of all experiments.

  4. He used statistical techniques.

Show answer
Correct Option: B
Explanation:

Mendel chose seven pairs of contrasting traits, the gene for each of which is present on seven different chromosomes of pea plant. Due to the presence on different chromosomes, Mendel's trait followed independent assortment during meiosis and produced the expected parental and recombinant phenotypes. If genes of these traits would have present together showing linkage, Mendel would not have got the expected results. Repeating the experiment, keeping records and use of statistical analysis were the secondary factors; major being the chosen traits not showing linkage. 

So, the correct answer is 'Traits chosen by him had genes far apart so that linkage was absent'.