Sub. code 2021
NEB — GRADE XII
2081
Old Question
Biology Question Paper 2081 (Old Question)
The candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.
Pass Marks : 32
सबै प्रश्नको उत्तर दिनुहोस् । (Attempt All Questions)
This old question question paper is for Class 12 Biology, 2081 (subject code 2021), carrying full marks of 75 with a pass mark of 32, to be completed within 3hrs. Answers with step-by-step solutions are available for every question below.
Group A (Botany)
Rewrite the correct option of each question in your answer sheet.
Which of the following type of artificial vegetative propagation in which root is induced while it is still attached to the parent plant and it is particularly suitable for plants having soft branches lying near to soil?
Air layering
Grafting
Soil layering
Cutting
What causes cell elongation in the internodal regions of plants?
Indole acetic acid
Gibberellins
Abscisic acid
Cytokinins
Which of the following genotypes represents monosomy, a type of aneuploidy?
What is the primary function of the cambium in perennial dicot vascular plants?
To produce lateral roots
To provide structural support
To produce new xylem and phloem
To regulate transpiration
How does plasmolysis alter the osmotic process across the cell membrane?
Alters solute equilibrium, promoting water withdrawal from the cell
Blocks water exit, causing water accumulation within the cell
Disturbs solute balance, causing water to enter the cell
Increases solute diffusion across the membrane, leading to osmotic equilibrium
Group B (Botany)
short answer question
Draw a labelled diagram of T.S. of a typical dicot stem and mention any two anatomical characteristics of its vascular bundles.
Look at the figure related to the sexual reproduction of angiosperms and answer the following questions:
What is the figure about, and why is it important?
Label the parts marked as A and B.
Describe the different phases of female gametophyte development using labelled diagrams.
In which cross, the genotypic and phenotypic ratio are same? Explain it with reference to Mirabilis jalapa.
Apply your understanding of various processes involved in the ascent of sap in cohesion tension theory for the maximum uptake of water in plants.
How do organic fertilizers contribute to sustainable agricultural practices compared to chemical fertilizers, and why is prioritizing their use advantageous?
Group C (Botany)
long answer question
How does aerobic respiration differ from anaerobic respiration? Describe the cycle that involves breakdown of two carbon compound Acetyl CoA in aerobic respiration with necessary diagram.
“Genes are inherited in new combination due to crossing over in the gametes.” Interpret this statement with its mechanism and necessary diagrams. Write the significance also
Briefly discuss the Watson and Crick’s model of DNA with the help of a neat and labelled diagram. Give three points of differences between DNA and RNA in their structure, composition and function.
Group A (Zoology)
Rewrite the correct option in your answer sheet
Which of the following epithelium forms the inner lining of vagina?
Columnar
Cuboidal
Stratified keratinized squamous
Stratified non-keratinized squamous
Which is the correct sequence in embryonic development of frog?
Morula, blastula, gastrula
Blastula, morula, gastrula
Morula, gastrula, blastula
Blastula, gastrula, morula
What would happen, if the oxyntic cells of gastric glands become non-functional due to some reasons?
Lipase enzyme becomes more active
Protein digestion does not take place
pH of stomach falls
Pepsin is not secreted
Show the correct path for the flow of urine.
Renal pelvis, ureter, urinary bladder, urethra
Renal pelvis, ureter, urethra, urinary bladder
Renal pelvis, urinary bladder, urethra, ureter
Renal pelvis, urethra, ureter, urinary bladder
If the person has puffy appearance, moon face, low body temperature and has intolerance to cold, what do you think he is suffering from?
Grave's disease
Conn's disease
Myxoedema
Hashimoto's disease
What is the substance sampled during amniocentesis?
Placental cells
Amniotic fluid
Maternal blood
Umbilical cord tissue
Group B (Zoology)
short answer question
Compare and contrast between simple and compound epithelium.
What is blastula? How is blastula formed during development of frog? Why micromeres divide faster than the macromeres?
Explain the basic steps involved in IVF. Mention any two potential risks or complications associated with IVF.
Study the given figure and answer the following questions.
Label the parts C and D
What is the difference between the parts A and B? (any two)
Mention the function of part C.
“Tobacco smoking is injurious to health.” Identify some of the health hazards of tobacco smoking and suggest some preventive measures of smoking
Group C (Zoology)
long answer question
Name the causative agent of AIDS. Mention its mode of transmission, symptoms and preventive measures. Why is it prevalent among intravenous drug users?
Human alimentary canal is a complete tube designed for ingestion, digestion, absorption, assimilation and egestion process. Draw a labelled diagram of human digestive system and explain the parts of alimentary canal. What would happen if the bile duct becomes blocked?
Human ear is concerned with hearing and equilibrium. With the help of a labelled diagram, explain the structure of human ear. What would happen if the opening of Eustachian tube becomes blocked?