National Examinations Board Grade 12 Biology — Model Question 2079 (2023)

National Examinations Board · Biology (Grade 12) · 2079 (2023) BS · Model Question — 23 questions — a free old question paper on Goodone.club’s exam-paper archive.

  1. Three German biochemists — Embden, Meyerhof and Parnas (EMP) — worked out a pathway involving the formation of pyruvic acid from a glucose molecule. Identify this pathway. Name the site where it takes place in a cell. Construct a step-by-step pathway developed by them. List the net gain of ATP in this pathway. [1+1+5+1] [8 marks]
  2. The development of an embryo from an unfertilized egg is called (A) Parthenocarpy (B) Parthenogenesis (C) Polyembryogeny (D) Polycarpy [1 marks]
  3. Define vascular bundle. What type of vascular bundle is present in a monocot root? Mention any two functions of a vascular bundle. [1+1+2] [4 marks]
  4. Which of the following tissues lacks blood supply? (A) Areolar (B) Muscular (C) Bone (D) Cartilage [1 marks]
  5. Define blastulation. Write the process of blastulation during the development of frog. [1+3] OR What is immunity? Explain its types. [1+3] [4 marks]
  6. Why is typhoid called an enteric fever? Illustrate its causative agent, mode of transmission, symptoms and preventive measures. [1+1+2+2+2] [8 marks]
  7. Which one of the following parts is not responsible for transpiration in plants? (A) Root (B) Stem (C) Leaves (D) All aerial parts [1 marks]
  8. Study the given figure carefully and answer: (i) Identify the given figure. (ii) Name the parts A to D. (iii) State the function of part D. [1+2+1] [4 marks]
  9. The semi-conservative mode of DNA replication results in two identical daughter DNA molecules. Explain the various enzymes and the mechanism involved during this process with necessary diagrams. [2+4+2] OR "Genes are inherited in new combinations due to crossing over in the gametes." Interpret this statement with its mechanism and necessary diagrams. Assess its significance also. [4+2+2] [8 marks]
  10. In frog, the coelom is derived from which embryonic layer? (A) Ectoderm (B) Mesoderm (C) Endoderm (D) Mesogloea [1 marks]
  11. Study the given figure carefully and answer: (i) Identify the gland. (ii) Where is it located? (iii) Mention any two hormones secreted by it. [1+1+2] [4 marks]
  12. A human being usually takes complex foods in the diet; however, our body needs their simpler forms. Describe how complex foods are converted into simpler forms within the alimentary canal. Draw a well-labelled diagram of the alimentary canal. What would happen to digestion if the gall bladder is removed surgically? [4+2+2] OR On oxidation of glucose in the cells, CO₂ is released as a by-product and carried to the lungs for elimination. Explain how the transport of CO₂ takes place in the human body. What is the role of the carbonic anhydrase enzyme? Mention the significance of the diaphragm in... [8 marks]
  13. If you are assigned to make a Watson and Crick model of DNA, what essential components do you apply to make the exact structure of the DNA? [2+2] OR Assuming you are provided seeds for germination, which influencing parameters do you need to follow for normal germination? What would happen when seeds are kept at low temperature? [3+1] [4 marks]
  14. Which type of mutation is caused by the addition or deletion of a single nitrogenous base? (A) Transition (B) Transversion (C) Frame shift (D) Substitution [1 marks]
  15. What kind of enzyme is needed for digestion of milk protein in human beings? (A) Rennin (B) Lactase (C) Pepsin (D) Sucrase [1 marks]
  16. Compare and contrast areolar and adipose connective tissues. [2+2] [4 marks]
  17. Biotechnology is an emerging discipline in this era. Do you think it can be used to mitigate the problem of food scarcity in the context of Nepal? Justify your opinion. [4] [4 marks]
  18. What basis would you apply to distinguish a meristematic tissue from a permanent tissue? (A) Supporting plant (B) Providing food (C) Activating cell division (D) Losing ability of cell division [1 marks]
  19. Which one of the following sets contains bacterial diseases only? (A) Hepatitis, influenza, cholera (B) Cholera, typhoid, candidiasis (C) Tuberculosis, typhoid, cholera (D) Tuberculosis, cholera, candidiasis [1 marks]
  20. Peer pressure plays a negative role in provoking smoking habits in adolescents. As a school captain, plan any two activities you would organize with the help of senior students, and any two activities you would like your school authorities to organize for students to tackle this problem. [2+2] [4 marks]
  21. Some C₄ plants possess the diagnostic feature of Kranz anatomy. Select which of the following plants contains such features. (A) Wheat (B) Maize (C) Barley (D) Oats [1 marks]
  22. If the cerebellum of a person gets injured, it will affect which of the following physiological functions? (A) Respiratory ability (B) Body movement (C) Memory function (D) Smelling power [1 marks]
  23. Vas deferens transports spermatozoa from the cauda epididymis to the ejaculatory duct. What happens when the vas deferens of a male is surgically disconnected? (A) Sperms become non-motile (B) Sperms lack nuclei (C) Seminal fluid is without sperms (D) No spermatogenesis occurs [1 marks]