TS Inter 2nd Year – Zoology Previous Paper 2023

PAPER – II

(English Version)
Time: 3 hours
Max. Marks: 60

SECTION-A

Note:

(i) Answer ALL Questions

(ii) Each Question carries TWO marks

(iii) All are very short answer type questions.

1. Give the dental formula of adult human beings.  

Answer:

The dental formula for adult human beings is:

I 2/2, C 1/1, PM 2/2, M 3/3

Where:

 

  • I = Incisors
  • C = Canines
  • PM = Premolars
  • M = Molars

This formula represents the number of teeth in each quadrant of the mouth (upper and lower jaws).

2. Define glomerular filtration.

Answer:

Glomerular filtration is the first step in urine formation, where blood plasma is filtered from the glomerulus (a network of capillaries) into the Bowman’s capsule in the nephron of the kidney. This process is driven by the high blood pressure within the glomerulus, which forces water and small molecules (like glucose, amino acids, ions) to pass through the filtration membrane.

3. Write the difference between actin and myosin.

Answer:

Actin and myosin are the two main contractile proteins involved in muscle contraction. Here are some key differences:

Feature Actin Myosin
Structure Thin, helical protein filament Thick, filamentous protein with a head and tail region
Role in Contraction Forms the thin filaments in the sarcomere Forms the thick filaments in the sarcomere
Interaction Myosin heads bind to actin filaments, forming cross-bridges and pulling the thin filaments towards the center of the sarcomere during muscle contraction.

4. Name the keystone bone of the cranium. Where is it located?

Answer:

The keystone bone of the cranium is the sphenoid bone.

Location: It is located at the base of the skull, forming a central wedge-shaped structure that articulates with several other cranial bones.

5. Write the names of any four mononuclear phagocytes.

Answer:

Mononuclear phagocytes are white blood cells that play a crucial role in the immune system. Here are four examples:

  • Macrophages: These are large phagocytes that engulf and digest foreign particles and cellular debris.
  • Monocytes: These are immature macrophages that circulate in the bloodstream and differentiate into macrophages in tissues.
  • Dendritic Cells: These cells are specialized antigen-presenting cells that play a key role in initiating immune responses.
  • Microglia: These are specialized macrophages found in the brain and spinal cord.

6. What is erythropoietin? What is its function?

Answer:

  • Erythropoietin (EPO): It is a hormone primarily produced by the kidneys.
  • Function: EPO stimulates the production of red blood cells (erythrocytes) in the bone marrow. It plays a crucial role in maintaining adequate oxygen-carrying capacity in the blood.

7. Define spermiogenesis and spermiation.

Answer:

  • Spermiogenesis: This is the final stage of spermatogenesis, where spermatids (immature sperm cells) differentiate into mature spermatozoa. During this process, the spermatid undergoes significant morphological changes, such as the formation of the acrosome, flagellum, and mitochondria.

  • Spermiation: This is the process by which mature spermatozoa are released from the Sertoli cells into the lumen of the seminiferous tubules.  

     

8. What is ‘amniocentesis’? Name any two disorders that can be detected by amniocentesis.

Answer:

  • Amniocentesis: It is a prenatal diagnostic procedure where a small amount of amniotic fluid is withdrawn from the amniotic sac surrounding the fetus. This fluid contains fetal cells and can be used to analyze the fetal chromosomes and detect certain genetic disorders.

  • Disorders detectable by amniocentesis:

    • Down syndrome
    • Cystic fibrosis
    • Neural tube defects (like spina bifida)

9. What is apiculture?

Answer:

Apiculture, also known as beekeeping, is the practice of managing and maintaining honey bee colonies for the production of honey and other bee products like beeswax, propolis, and royal jelly.

10. What does ADA stand for? Deficiency of ADA causes which disease?

  • ADA: Adenosine Deaminase
  • Disease: Severe Combined Immunodeficiency (SCID)

SECTION-B

Note:

(i) Answer ANY SIX questions. (ii) Each question carries FOUR marks. (iii) All are short answer type questions. (iv) Draw labelled diagrams, wherever necessary.

11. What are the functions of liver?

Answer:

The liver is a vital organ with numerous functions:

  • Detoxification: It detoxifies harmful substances like alcohol and drugs.
  • Bile Production: It produces bile, which is essential for the digestion of fats.
  • Metabolism: It plays a crucial role in carbohydrate, protein, and fat metabolism. It stores glucose as glycogen, breaks down amino acids, and synthesizes cholesterol and other lipids.
  • Storage: It stores vitamins (like vitamin A and B12), minerals (like iron and copper), and glycogen.
  • Blood Filtration: It removes old red blood cells and other cellular debris from the bloodstream.
  • Immune Function: It plays a role in immune function by removing bacteria and other foreign substances from the blood.

12. How is respiratory movements regulated in man?

Answer:

Respiratory movements in humans are primarily regulated by the nervous system, specifically the respiratory center located in the medulla oblongata of the brainstem.

  • Neural Control: The respiratory center generates rhythmic nerve impulses that stimulate the diaphragm and intercostal muscles, causing them to contract and relax, leading to inhalation and exhalation.
  • Chemoreceptors: Chemoreceptors in the medulla oblongata and carotid arteries monitor the levels of carbon dioxide and oxygen in the blood. When carbon dioxide levels rise or oxygen levels fall, these chemoreceptors send signals to the respiratory center to increase the rate and depth of breathing.
  • Higher Brain Centers: The cerebral cortex can voluntarily control breathing, such as holding your breath or breathing deeply.

13. Draw a labelled diagram of the T.S of the spinal cord of man.

Unfortunately, I cannot draw diagrams directly. However, I can describe the key features of a transverse section (T.S.) of the human spinal cord:

  • Gray Matter: A central H-shaped region containing nerve cell bodies and their dendrites. It consists of two dorsal horns (posterior horns) and two ventral horns (anterior horns).
  • White Matter: Surrounds the gray matter and consists of myelinated nerve fibers (axons) that transmit signals up and down the spinal cord.
  • Central Canal: A small canal filled with cerebrospinal fluid that runs through the center of the gray matter.
  • Dorsal Root: Contains sensory nerve fibers that carry information from the body to the spinal cord.
  • Ventral Root: Contains motor nerve fibers that carry signals from the spinal cord to muscles and glands.

14. Write a note on Addison’s disease and Cushing’s syndrome.

Answer:

  • Addison’s Disease:

    • Caused by the insufficient production of cortisol and aldosterone by the adrenal glands.
    • Symptoms include fatigue, weight loss, muscle weakness, low blood pressure, and skin pigmentation.

  • Cushing’s Syndrome:

    • Caused by excessive production of cortisol by the adrenal glands.
    • Symptoms include weight gain, high blood pressure, muscle weakness, easy bruising, and changes in body shape (moon face, buffalo hump).

15. Describe erythroblastosis foetalis.

Answer:

Erythroblastosis fetalis is a condition that develops in Rh-negative mothers who are carrying Rh-positive fetuses.

  • Mechanism: During pregnancy, some fetal red blood cells can cross the placenta and enter the mother’s bloodstream. If the mother is Rh-negative and the fetus is Rh-positive, her immune system may produce antibodies against the Rh factor on the fetal red blood cells.

  • Consequences: In subsequent pregnancies with Rh-positive fetuses, these antibodies can cross the placenta and attack the fetal red blood cells, leading 1 to their destruction. This can 2 cause anemia, jaundice, and even death in the fetus.

     

  • Prevention: Rh-negative mothers are typically given Rhogam, an anti-Rh immunoglobulin, during and after pregnancy to prevent the development of Rh antibodies.

16. What is meant by genetic drift? Explain genetic drift citing the example of Founder Effect.

Answer:

Genetic drift is the random fluctuation in the frequency of alleles in a population due to chance events. It is a significant factor in small populations.

  • Founder Effect: This is a specific type of genetic drift that occurs when a small group of individuals from a larger population colonizes a new area. The gene pool of the new population will be a subset of the original population, and it may have a different allele frequency distribution due to chance. This can lead to the loss of genetic diversity and the fixation of certain alleles in the new population.

17. Write a short note on the theory of mutations.

Answer:

The mutation theory, proposed by Hugo de Vries, states that mutations are the source of new variations and the driving force of evolution. Mutations are sudden, heritable changes in the genetic material of an organism. They can be beneficial, harmful, or neutral.

  • Beneficial mutations: Can provide an organism with an advantage in survival and reproduction.
  • Harmful mutations: Can cause genetic disorders and diseases.
  • Neutral mutations: Have no significant effect on the organism’s fitness.

Mutations introduce genetic variation into populations, which is essential for natural selection and the process of evolution.

18.question:

Discuss in brief about ‘Avian Flu’.

Answer:

Avian Influenza, commonly known as Bird Flu, is a highly contagious viral infection that primarily affects birds. It is caused by influenza A viruses, which exhibit a wide range of severity in infected birds. While primarily affecting avian species, certain strains can also infect humans, posing a significant zoonotic threat.  

Key features of Avian Flu include:

 

  • High Contagiousness: The virus spreads rapidly among birds.  
  • Varying Severity: Strains range from mild to highly pathogenic.  
  • Zoonotic Potential: Poses a risk of infection to humans.  
  • The potential for human-to-human transmission of some strains raises concerns about the emergence of pandemics.

Section: C

Marks: 2 x 8 = 16

Note:

(i) Answer ANY TWO questions. (ii) Each question carries EIGHT marks. (iii) All are long answer type questions. (iv) Draw labelled diagrams, wherever necessary.  

 

19. Describe chromosomal theory of sex determination.

Answer:

The chromosomal theory of sex determination proposes that sex is determined by specific chromosomes called sex chromosomes. In humans and many other organisms, there are two types of sex chromosomes:

  • X chromosome: Present in both males and females.
  • Y chromosome: Typically present only in males.

Sex Determination in Humans:

  • Females: Have two X chromosomes (XX)
  • Males: Have one X and one Y chromosome (XY)

The presence of the Y chromosome determines maleness. A gene on the Y chromosome called the SRY gene triggers the development of male characteristics.

Key points:

  • The chromosomal theory of sex determination explains how sex is inherited from parents to offspring.
  • It provides a mechanistic understanding of sex differentiation.
  • It has significant implications for understanding sex-linked disorders, which are caused by genes located on the sex chromosomes.

20. Describe female reproductive system of a woman with the help of a labelled diagram.

Answer:

The female reproductive system is a complex system of organs responsible for the production of eggs, the fertilization of an egg by sperm, and the development and nurturing of a fetus.  

 

Key components of the female reproductive system:

  • Ovaries: The primary female reproductive organs, responsible for the production of eggs (ova) and the secretion of hormones like estrogen and progesterone.
  • Fallopian Tubes: Two tubes that connect the ovaries to the uterus. They transport the released egg from the ovary to the uterus.
  • Uterus: A muscular organ where the fertilized egg implants and develops into a fetus.
  • Cervix: The lower, narrow part of the uterus that opens into the vagina.
  • Vagina: A muscular tube that connects the cervix to the external genitalia. It serves as the birth canal and receives the penis during intercourse.
  • External Genitalia: Includes the vulva, which consists of the labia majora, labia minora, clitoris, and vaginal opening.

Diagram:

Image of Female Reproductive System Diagram

21. Write notes on the working of the heart of man.

Answer:

The human heart is a muscular organ that pumps blood throughout the body. It is divided into four chambers:

    • Right Atrium: Receives deoxygenated blood from the body.
    • Right Ventricle: Pumps deoxygenated blood to the lungs for oxygenation.  

    • Left Atrium: Receives oxygenated blood from the lungs.
  • Left Ventricle: Pumps oxygenated blood to the rest of the body.  

Working of the Heart:

  1. Deoxygenated blood enters the right atrium from the body via the superior and inferior vena cavae.
  2. The right atrium contracts, pumping blood into the right ventricle.
  3. The right ventricle contracts, pumping blood through the pulmonary artery to the lungs for oxygenation.
  4. Oxygenated blood returns from the lungs to the left atrium via the pulmonary veins.
  5. The left atrium contracts, pumping blood into the left ventricle.
  6. The left ventricle contracts, pumping blood out of the heart through the aorta to the rest of the body.

The rhythmic contraction and relaxation of the heart chambers is controlled by the cardiac cycle, which is regulated by the sinoatrial (SA) node, the natural pacemaker of the heart.

Key Points:

  • The heart valves ensure unidirectional blood flow.
  • The heart receives blood supply from the coronary arteries.
  • The heart’s electrical activity can be monitored using an electrocardiogram (ECG).

I hope this helps! Let me know if you have any further questions or want to explore any of the topics in more detail.

Section: C

Marks: 2 x 8 = 16