Please refer to Chemical Coordination and Integration Class 11 Biology Exam Questions provided below. These questions and answers for Class 11 Biology have been designed based on the past trend of questions and important topics in your class 11 Biology books. You should go through all Class 11 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 11 Biology Exam Questions Chemical Coordination and Integration
Class 11 Biology students should read and understand the important questions and answers provided below for Chemical Coordination and Integration which will help them to understand all important and difficult topics.
Very Short Answer Type Questions:
Question. What is erythropoiesis? Which hormone stimulates it?
Ans. Erythropoiesis is the process of formation of RBC. Peptide hormone erythropoietin secreted from the juxtaglomerular cells of kidney stimulates erythropoiesis.
Question. Name the endocrine gland that produces calcitonin and mention the role played by this hormone.
Ans. Calcitonin/thyrocalcitonin is a 32 amino acid, linear polypeptide hormone that is produced in humans primarily by the parafollicular cells of the thyroid gland. It checks excess Ca2+ and phosphate in plasma by decreasing mobilisation from bones.
Deficiency of calcitonin results in osteoporesis or loss of bone density (due to dissolution of parathormone).
Question. Correct the following statements by replacing the term underlined.
(a) Insulin is a steroid hormone.
(b) TSH is secreted from the corpus luteum.
(c) Tetraiodothyronine is an emergency hormone.
(d) The pineal gland is located on the anterior part of the kidney.
Ans. (a) Insulin is a peptide hormone
(b) TSH is secreted from the pars distalis region of pituitary.
(c) Adrenaline is an emergency hormone.
(d) The adrenal gland is located on the anterior part of the kidney.
Question. Name the hormone that helps in cell-mediated immunity.
Ans. Thymosins play a major role in the development and differentiation of T-lymphocytes, which provide cell-mediated immunity. Thymosins also hastens attainment of sexual maturity.
Question. Name the only hormone secreted by pars intermedia of the pituitary gland.
Ans. Pars intermedia of pituitary gland secretes only one hormone called Melanocyte Stimulating Hormone (MSH). This hormone causes dispersal of pigment granules in the pigment cells, thereby darkening the colour in certain animals like fishes and amphibians.
Question. Match the following columns.
Ans. The correct matching is as follows
Question. What is the role of second messenger in the mechanism of protein hormone action?
Ans. The hormones that are derivatives of amino acids, polypeptides or proteins are called peptide hormones. These being insoluble in lipids can not enter the target cell.
These act at the surface of target cell as primary messengers and bind to the cell-surface receptor forming the hormone-receptor complex.
It involves following steps
(i) Hormone called first messenger attaches to the cell surface receptor protein on the outer surface of plasma membrane of the target cell, forming a hormone-receptor complex.
(ii) This complex activates the enzyme adenyl cyclase.
(iii) Adenyl cyclase catalyses the conversion of ATP to cyclic AMP on the inner surface of plasma membrane.
(iv) cAMP serves as the second messenger or intracelluar hormonal mediator delivering information inside the target cells. This activates appropriate cellular enzyme system by cascade effect. Which induces the cell machinery to perform its specialised function.
(v) cAMP has a very short existence. It is rapidly degraded by the cAMP phosphodiesterase.
Water soluble hormones, such as amines, peptides, proteins and glycoproteins exert their control through the cyclic AMP. These are quick acting hormones and produce immediate effect.
Question. There are many endocrine glands in human body. Name the glands which is absent in male and the one absent in female.
Ans. In males a pair of testis is present in the scrotal sac. Testes perform dual functions as a primary sex organ as well as an endocrine gland. This gland is absent in females.
In females a pair of ovaries is present which are located in the abdomen. Ovary is the primary female sex organ which produces ovum during menstrual cycle and act as an endocrine gland in producing hormone like estrogen and progesterone. This gland is absent in males.
Question. A patient complains of constant thirst, excessive passing of urine and low blood pressure. When the doctor checked the patients’ blood glucose and blood insulin level, the level were normal or slightly low. The doctor diagnosed the condition as diabetes insipidus. But he decided to measure one more hormone in patients blood. Which hormone does the doctor intend to measure?
Ans. It is also known as hyperglycaemia hormone, and its action is opposite to that of insulin Excess of glucose in blood suppress the secretion of glucose, whereas fall in glucose level starts glucose production (since, doctor fend the slight line level of blood glucose).
Question. Which of the two adrenocortial layers, zona glomerulosa and zona reticularis lies outside enveloping the other?
Ans. Zona glomerulosa (outer layer) envelops zona reticularis (inner layer) from the outside.
Question. State whether true or false
(a) Gastrointestinal tract, kidney and heart also produce hormones.
(b) Pars distalis produces six trophic hormones.
(c) B-lymphocytes provide cell-mediated immunity.
(d) Insulin resistance results in a disease called diabetes mellitus.
Ans. (a) Gastrointestinal tract, kidney and heart also produce hormones other than endocrine glands hence, the statement is True. GI tract secretes hormones such as gastrin,
secretin, cholecysto kienin etc., Kidney secretes renin and erythropectin. Heart secretes anti-natriuretic factor
(b) Pars distalis produces six trophic hormones, i.e., Growth Hormone (GH) Prolactin (PRL), Thyroid Stimulating Hormone (TSH), Adrinocortico Trophic Hormone (ACTH), Luteinising Hormone (LH) and Follicle Stimulating Hormone (FSH) hence, the statement is True.
(c) T-lymphocytes are involved in providing cell-mediated immunity not B-lymphocytes hence, the statement is False.
(d) The Insulin Dependent Diabetes Mellitus (IDDM) is caused by the failure of beta cells to produce adequate amount of insulin hence, results in a disease called diabetes mellitus. So, the statement is True.
Short Answer Type Questions:
Question. George comes on a vacation to India from US. The long journey disturbs his biological system and he suffers from jet lag. What is the cause of his discomfort?
Ans. Jet lag is caused by the disruption of the body clock as it is out of synchronisation because of the unfamiliar time zone of the destination. The body experiences different patterns of light and dark conditions than it is normally used to, which disrupts the natural sleep-wake cycle.
Melatonin is a hormone that plays a key role in body rhythms and causes jet lag. After the sun sets, eyes perceive darkness and alert the hypothalamus to begin releasing melatonin, which promotes sleep. Conversely, when the eyes perceive sunlight, they tell the hypothalamus to withhold melatonin production.
However, the hypothalamus can not readjust its schedule instantly and it may take several days, to overcome this problem.
Question. On an educational trip to Uttaranchal, Ketki and her friends observe that many local people were having swollen necks, Please help Ketki and her friends to find out the solutions to the following questions.
(a) which probable disease are these people suffering from?
(b) How is it caused?
(c) What effect does this condition have on pregnancy?
Ans. (a) People with swollen necks are suffering from goitre due to deficiency of iodine in the their bodies.
(b) Iodine is essential for the synthesis of thyroid hormones-T3 and T4 which are iodinated forms of tyroxine. Deficiency of iodine in our diet results in hypothyroidism and enlargement of the thyroid gland occurs place.
(c) Hypothyroidism during pregnancy causes defective development and abnormalities in growing baby like stunted growth (cretinism) mental retardation, low intelligence quotient (IQ) abnormal skin, deafmutism, etc.
Question. Mention the difference between hypothyroidism and hyperthyroidism.
Ans. Differences between hypothyroidism and hyperthyroidism are as follows
Question. Old people have weak immune system. What could be the reasons?
Ans. The thymus gland is a lobular structure located on the dorsal side of the heart and the aorta. It is derived from the endoderm of the embryo. Thymus secretes a hormone named thymosin which stimulates the development of White Blood Cells (WBCs), involved in producing immunity.
Thymus is degenerated in old individuals, resulting in decreased production of thymosin.
As result the immune system becomes weak, in old people.
Question. Inflammatory responses can be controlled by a certain steroid. Name the steroid, its source and also its other important functions.
Ans. Glucocorticoids, particularly cortisol, produce anti-inflammatory reactions and suppress the immune response. The source for glucocorticoids is the middle zone, which is the widest of three zones, in adrenal cortex called zona fasciculata.
The functions of glucocorticoids as the name suggests they is that they affect carbohydrate metabolism and metabolism of proteins and fats. They stimulate gluconeogenesis, lipolysis and proteolysis.
They also inhibit cellular uptake and utilisation of amino acids. Cortisol is also called stress hormone as it copes with stress.
Question. What are the effects of hypothyroidism (observed during pregnancy) on the development and maturation of a growing baby?
Ans. Hypothyroidism during pregnancy cause defective development and maturation of the growing baby leading to a stunted growth (cretinism), mental retardation, low intelligence Quotient (IQ), abnormal skin, deafmutism, etc.
Question. What is the role-played by luteinising hormones in males and females respectively?
Ans. In males, luteinising hormone (LH) stimulates the synthesis and secretion of hormones called androgens from testis. Androgens along with FSH (Follicle Stimulating Hormone) regulate spermatogenesis.
In females, LH induces ovulation of fully mature follicles (Graafian follicles) and maintains the corpus luteum, formed from the remnants of the Graafian follicles after ovulation. Which secretes progesterone.
Long Answer Type Questions:
Question. Hypothalamus is a super master endocrine gland. Elaborate.
Ans. Hypothalamus is a very small but extremely important part of the diencephalon that is involved in the mediation of endocrine, autonomic and behavioural function.
It contains several groups of neurosecretory cells called nuclei which produce hormones.
Hypothalamus provides anatomical connection between the nervous and endocrine system.
It controls the release of major hormones by the hypophysis which are summarised below
(i) Adrenocorticotrophic Releasing Hormone (ARH) It stimulates the anterior lobe of pituitary gland to secrete Adrenocorticotropic Hormone (ACTH). ACTH stimulates the synthesis and secretion of steroid hormones called glucocorticoids by adrenal glands.
(ii) Thyrotropin Releasing Hormone (TRH) It stimulates the anterior lobe of pituitary gland to release Thyroid Stimulating Hormone (TSH).
(iii) Growth Hormone Releasing Hormone It stimulates the anterior lobe of the pituitary gland to release growth hormone or somatostatin.
(iv) Gonadotropin Releasing Hormone It stimulates the anterior lobe of the pituitary gland to release gonadotropic hormones (FSH and LH).
(v) Prolactin Releasing Hormone (PRH) It stimulates the anterior lobe of the pituitary gland to secrete prolactin.
(vi) MSH Releasing Hormone It stimulates the intermediate lobe of the pituitary gland to secrete Melanocyte Stimulating Hormone (MSH)
These hormones released from hypothalamus are involved in the process like temperature regulation, control of water balance in body, sexual behaviour and reproduction, control of daily cycles in physiological state, behaviour and mediation of emotional responses. Hence, hypothalamus is called as super master endocrine gland of body.
Question. Illustrate the differences between the mechanism of action of a protein and a steroid hormone.
Ans. Differences between the mechanism of action of a peptide and a steroid hormone are as follows
Question. A milkman is very upset one morning as his cow refuses to give any milk.
The milkman’s wife gets the calf from the shed. On feeding by the calf, the cow gave sufficient milk. Describe the role of endocrine gland and pathway associated with this response?
Ans. Suckling by the calf creates a neuroendocrine reflex which results in increase of oxytocin from the neurohypophysis. Oxytocin is synthesised in the hypothalamus in specific nuclei, the paraventricular nucleus and the supra optic nucleus (a cluster of nerve cells in the brain is often called a nucleus).
Neurons in this region (hypothalamic nuclei) synthesise the oxytocin precursor and package it into vesicles. The oxytocin concentration in the blood normally, gets increased within 1-2 min, after the udder stimulation.
It brings about contraction of smooth muscles of the udder resulting in the milk flow. A direct intra-udder function of oxytocin like hormone would do the same function.
It can be summarised as follows
Udder (suckling stimulus) → Brain (hypothalamus) → Neurohypophysis → Blood (oxytocin) → Udder (smooth muscles) → Milk flow.
Question. Calcium plays a very important role in the formation of bones. Write on the role of endocrine glands and hormones responsible for maintaining calcium homeostasis.
Ans. The endocrine glands and hormones that are responsible for maintaining calcium homeostasis, are thyroid and parathyroid glands and their associated hormones are calcitonin and Parathyroid Hormone (PTH).
(i) Parathyroid glands are the glands developed from the endoderm of the embryo.
The cells of parathyroid glands are of two types, i.e., chief cells and oxyphil cells. The chief cells of the parathyroid glands secrete parathyroid hormone (PTH).
This hormone (PTH) is involved in regulating calcium and phosphate balance between the blood and other tissue. It mobilises the release of calcium into the blood from bones. PTH increases calcium reabsorption by the body organs like intestine and kidneys.
(ii) Thyroidgland is the largest endocrine gland located anterior to the thyroid cartilage of the larynx in the neck. This gland plays a vital role in maintaining calcium homeostasis.
It releases thyrocalcitonin hormone produced by the parafollicular cells, also called ‘C’ cells.
This hormone is secreted when the calcium level in blood gets high. It is a 32 amino acid peptide hormone that lowers the calcium level by suppressing release of calcium ions from the bones. Thus, calcitonin has an action opposite to that of the parathyroid hormone on calcium homeostasis.
Question. A sample of urine was diagnosed to contain high content of glucose and ketone bodies. Based on this observation, answer the following
(a) which endocrine gland and hormone is related to this condition?
(b) name the cells on which this hormone acts
(c) what is the condition called and how can it rectified?
Ans. (a) The pancreas is associated with this condition and the related hormone is insulin.
The pancreas consists of ‘islets of Langerhans. The two main type of cells in islets of Langerhans are a-cells and b-cells. µ-cells secrete glucagon while b-cell secrete insulin.
Insulin is a peptide hormone, which plays a major role in the regulation of glucose homeostasis. It decreases the level of glucose in blood by increasing the rate at which glucose is transported out of blood and into the cell.
When insulin is dysfunctional or not produced adequately glucose uptake is hampered‘ and hence glucose appear in urine along with ketone bodies.
(b) Insulin hormone mainly acts on hepatocytes (liver cells) and adipocytes (cells of adipose tissue) and enhances cellular glucose up take and utilisation.
(c) Prolonged hyperglycemic condition leads to a complex disorder called diabetes mellitus which is associated with loss of glucose through urine and formation of harmful compounds known as ketone bodies due to protein metabolism.
Diabetic patients are successfully treated with insulin therapy. It lowers the blood glucose levels and give relief to the patients.