Animal Physiology Important PYQs | CSIR NET Life Science

Animal Physiology is one of the most scoring and concept-driven areas in CSIR NET Life Sciences examination. A strong command over physiological mechanisms, organ system functions, hormones, enzymes, and signal transduction pathways is essential to solve both conceptual and match-the-following questions. It helps aspirants identify high-frequency topics, understand examiner trends, and improve accuracy in competitive exams like CSIR NET Life Science.

Animal Physiology 

Animal Physiology is the branch of biology that studies how the body of animals works. It explains the functions of organs, tissues, cells, and systems and how they work together to keep the animal alive and healthy. Animal physiology helps us understand:

• How food is digested and nutrients are absorbed

• How breathing and respiration supply oxygen

• How blood circulates and transports substances

• How the nervous system controls body activities

• How hormones regulate growth, metabolism, and reproduction

• How muscles contract and allow movement

• How waste products are removed from the body

Previous Year Questions (PYQs) - Animal Physiology 

A review of questions from past papers to understand the pattern and difficulty level.

Question 1: Amylase and Carbohydrate Digestion

Question: The enzyme amylase can break alpha-glycosidic linkages between glucose monomers. Hence, amylase can digest which one of the following carbohydrates? (Options: Starch, Cellulose, Xylan, Chitin)

Explanation: Amylase (e.g., salivary alpha-amylase, pancreatic alpha-amylase) specifically breaks alpha-glycosidic bonds. Starch is a polymer of glucose linked by alpha-glycosidic bonds, thus amylase digests starch. Digestion begins in the oral cavity. Amylase cannot digest cellulose, xylan, or chitin due to different bond types (e.g., beta-1,4 glycosidic bonds in cellulose).

Answer: Starch

Question 2: Blood Group Genetics

Question: A woman with blood group A gives birth to a baby with blood group AB. What would be the blood group of the father?

Explanation: The mother has blood group A (genotype IᴬIᴬ or Iᴬi). The baby has blood group AB (genotype IᴬIᴮ). For the baby to inherit the Iᴮ allele, it must come from the father. Therefore, the father's blood group must contain the Iᴮ allele, meaning his blood group could be B (genotype IᴮIᴮ or Iᴮi) or AB (genotype IᴬIᴮ).

Answer: The father's blood group could be B or AB.

Question 3: Germ Layer Origins

Question: Cardiac and cerebral tissues are derived from which of the following germ layers, respectively?

Explanation: Cardiac tissue, part of the circulatory system, is mesodermal in origin. Cerebral tissue, part of the Central Nervous System (CNS), is ectodermal in origin.

Answer: Mesoderm and Ectoderm

Question 4: Location of Bowman's Capsule

Question: Bowman's capsules are present in which one of the following organs or tissues? (Options included Renal Cortex, Renal Medulla)

Explanation: The Bowman's capsule is part of a nephron, the functional unit of the kidney. It is located in the outer renal cortex of the kidney, along with the glomerulus, forming the Malpighian body.

Answer: Renal Cortex

Question 5: Function of Lung Surfactant

Question: What is the primary function of lung surfactant?

Explanation: The fluid lining alveoli creates surface tension, which tends to cause alveolar collapse during exhalation. Lung surfactant reduces this surface tension, thereby preventing the alveoli from collapsing and making breathing easier.

Answer: To prevent alveoli from collapsing by decreasing surface tension.

Question 6: Matching Vitamins and Related Proteins 

Question: Match the vitamins in Column 1 with their related proteins/functions in Column 2.

Explanation:

• Vitamin A (Retinol) is a crucial component of Rhodopsin, a visual pigment in the retina.

• Vitamin K is essential for blood coagulation and is linked to clotting factors like Thrombin.

• Vitamin C acts as a cofactor for Prolyl hydroxylase.

• Vitamin B1 (Thiamine) is a cofactor for Pyruvate dehydrogenase.

Question 7: Matching Hormones and Physiological Effects

Question: Match the hormones in Column 1 to their respective physiological effects in Column 2.

Explanation:

• Melatonin, secreted by the pineal gland, regulates the circadian rhythm (sleep-wake cycle).

• Oxytocin stimulates uterine contractions and promotes milk ejection.

• Prolactin is responsible for milk synthesis.

• Somatostatin is an inhibitory hormone, inhibiting hormones like growth hormone.

• Cholecystokinin (CCK) stimulates pancreatic enzyme secretion.

Question 8: Precursor for Corticosteroids

Question: Which one of the following is the precursor molecule for corticosteroids?

Explanation: Corticosteroids are steroid hormones synthesized from cholesterol. The first step is cholesterol's conversion to pregnenolone by cholesterol desmolase. Pregnenolone is the common precursor for all adrenal cortex hormones.

Answer: Pregnenolone

Question 9: Secondary Messenger in Visual Signal Transduction (M.Sc. Level)

Question: The visual signal transduction cascade is activated by rhodopsin and involves the degradation, rather than synthesis, of which one of the following secondary messenger molecules? (Options: cAMP, IP₃, cGMP, DAG)

Explanation: Light activates Rhodopsin, which activates Transducin (a G-protein). Activated Transducin then activates cGMP phosphodiesterase, which degrades cGMP into 5'-GMP. The decrease in cGMP concentration closes cGMP-gated sodium channels, leading to hyperpolarization and signal transmission.

Answer: cGMP

Question 10: Matching Anatomical Components with Organs 

Question: Match the components in Column 1 with their respective organs in Column 2.

Explanation: This involves matching anatomical structures to their locations: Endolymph is in the inner ear; Vitreous humor fills the eye; Vas deferens carries sperm from the testis; Corpus luteum forms in the ovary.

Question 11: Matching Proteins with Organs of Expression 

Question: Match the proteins in Column 1 with the organ in which they are maximally expressed in Column 2.

Explanation: Keratin is in skin; Surfactant proteins are produced in lungs; Procarboxypeptidase is a pancreatic zymogen; Albumin is synthesized in the liver.

Question 12: Matching Hormones, Sources, and Targets (3 Columns)

Question: Match the hormone (Column 1) with its source (Column 2) and primary target (Column 3).

Explanation: TRH is from hypothalamus to pituitary; Calcitonin from thyroid to bones; Prolactin from anterior pituitary to mammary glands (or pigeon's crop); Epinephrine from adrenal medulla targets the heart.

Question 13: Matching Hormones/Precursors, Chemical Type, and Origin (3 Columns)

Question: Match the hormone/precursor (Column 1) with its chemical type (Column 2) and tissue of origin (Column 3).

Explanation: Melatonin is a Tryptophan derivative from the Pineal gland. Glucagon is a peptide from the pancreas; Pregnenolone is a steroid precursor from adrenal cortex; FSH is a glycoprotein from the anterior pituitary.

Question 14: Identifying Fat-Soluble Vitamins 

Question: Choose the correct group of fat-soluble vitamins.

Explanation: Vitamins are either water-soluble or fat-soluble. The fat-soluble vitamins are A, D, E, and K. Their chemical names are Retinol (A), Calciferol (D), Tocopherol (E), and Phylloquinone/Menadione (K). Water-soluble vitamins include the Vitamin B complex and Vitamin C.

Classification of Vitamins: Fat-Soluble vs. Water-Soluble

This section addresses the identification of fat-soluble vitamins based on their chemical names, which is crucial for competitive exams. Understanding both the classification and corresponding chemical names is essential.

Comparative Structure: Fat-Soluble vs. Water-Soluble Vitamins

1. Fat-Soluble Vitamins:
   These vitamins dissolve in fat.

• Vitamin A (Retinol)

• Vitamin D (Calciferol)

• Vitamin E (Tocopherol)

• Vitamin K (Phylloquinone, Menaquinone, Menadione)
  (Memory Tip: A common mnemonic to remember the fat-soluble vitamins is ADEK.)

2. Water-Soluble Vitamins:
   All other vitamins are water-soluble. This category primarily includes:

• Vitamin B Complex (e.g., B1, B2, B3, etc.)

• Vitamin C (Ascorbic Acid)

In multiple-choice questions, any option including a B-complex vitamin can be eliminated when asked for fat-soluble vitamins. The correct answer will consist of chemical names for vitamins A, D, E, or K. Specifically, Vitamin D is also known as Cholecalciferol/Calciferol, Vitamin E as Tocopherol, and Vitamin K as Menadione.

Functions of Key Proteins

This section breaks down the functions of several proteins, a common format in "match the following" exam questions.

• Insulin: Facilitates the uptake of glucose by cells.

• Transferrin: Binds to iron and is responsible for iron transport in the body.

• Fibronectin: Serves as a substrate for cell attachment in the extracellular matrix.

• Alpha-macroglobulin: Functions as a proteinase inhibitor.