Board Paper of Class 12-Science 2007 Biology Delhi(SET 1) - Solutions
(i) All questions are compulsory.
(ii) This question paper consists of four sections A, B, C and D.
Section A contains 5 questions of one mark each.
Section B is of 10 questions of two marks each.
Section C is of 10 questions of three marks each and
Section D is of 3 questions of five marks each.
(iii) There is no overall choice. However, an internal choice has been provided.
(iv) Wherever necessary, the diagrams drawn should be neat and properly labelled.
- Question 1
What is the importance of the epiglottis in human body?VIEW SOLUTION
- Question 2
What happens to the glycogen concentration in the liver cells when the level of adrenaline increases in the blood stream of humans?VIEW SOLUTION
- Question 3
Mention the scientific term used for modified form of reproduction in which seeds are formed without fusion of gametes.VIEW SOLUTION
- Question 4
What does ecological niche of an organism represent?VIEW SOLUTION
- Question 5
It was diagnosed by a specialist that the immune system of the body of a patient has been suppressed. Name the disease the patient has been suffering from and its causative agent.VIEW SOLUTION
- Question 6
Where are casparian strips located in a plant body and what are they made up of? Mention its function.
What is respiration quotient (RQ)? Under what conditions will the value of RQ be 1? Explain.VIEW SOLUTION
- Question 7
What is resting membrane potential of a neuron? What is the role of sodium potassium pumps in maintaining it?VIEW SOLUTION
- Question 8
Draw a diagram of external view of a human brain. Label the frontal lobe, temporal lobe, occipital lobe and cerebellum.VIEW SOLUTION
- Question 9
How is the milk production regulated by hormones in human female? Explain.VIEW SOLUTION
- Question 10
Explain the significance of the auxin / cytokinin ratio in plant tissue culture.VIEW SOLUTION
- Question 11
What does S-shaped pattern of population growth represent? How is J-shaped pattern different from it and why?VIEW SOLUTION
- Question 12
What does secondary productivity in an ecosystem indicate? List any two factors by which productivity is limited in aquatic ecosystems.VIEW SOLUTION
- Question 13
How do viruses enter plant body and spread to long distances within it? Mention any two ways by which viruses spread from one plant to another.VIEW SOLUTION
- Question 14
In what form do plants absorb calcium from the soil? List any two calcium deficiency symptoms in plants.VIEW SOLUTION
- Question 15
What is vernalisation? How is the process of vernalisation advantageous to plants?VIEW SOLUTION
- Question 16
Explain the theory of capillarity of water translocation in plants. Can the theory explain translocation of water in 100 m tall trees? Give one reason.VIEW SOLUTION
- Question 17
What is symbiotic nitrogen fixation? Name the two protein components needed for this process. Explain their role.
List the various modes of heterotrophic nutrition in plants. Explain any two modes giving one example of each.VIEW SOLUTION
- Question 18
What is biological magnification? Explain how DDT as a water pollutant undergoes biological magnification.VIEW SOLUTION
- Question 19
What are exotic species? Explain with the help of two examples how the exotic species disturb the native species of an ecosystem.VIEW SOLUTION
- Question 20
In what forms are nitrogenous wastes excreted in birds, humans and aquatic turtles respectively? Why so, explain?VIEW SOLUTION
- Question 21
A patient was complaining of frequent urination, excessive thirst and dehydration. His fasting glucose level was found to be normal. Name the disease and its cause. Explain why such symptoms are occurring in this patient.VIEW SOLUTION
- Question 22
Explain with the help of a suitable example for each of the following terms: (i) morphallaxis (ii) epimorphosis and (iii) compensatory regeneration.VIEW SOLUTION
- Question 23
Describe the polygonum type of embryo sac. Why it is generally referred to as monosporic?VIEW SOLUTION
- Question 24
What is obsessive-compulsive disorder? How is it different from borderline personality disorder? What are the two most common obsessions that affect adolescents?VIEW SOLUTION
- Question 25
What is human leukocytes antigen complex? Explain its role in organ transplantation.VIEW SOLUTION
- Question 26
Why do C4plants have dimorphic chloroplasts? Explain the different steps involved in C4photosynthetic carbon cycle in such plants.
Explain the electron transport system. Where does it occur in a mitochondrion and what is the role of oxygen in it?VIEW SOLUTION
- Question 27
Explain the events that occur in the human heart during ventricular systole and ventricular diastole in a cardiac cycle. Name the heart sounds and mention how they are produced.
What is oxygen−haemoglobin dissociation curve? Describe the role of red blood cells in the transport of oxygen and carbon dioxide by blood.VIEW SOLUTION
- Question 28
Briefly explain the principle, procedure and the role of ELISA.
What is somatic hybridisation? Explain the various steps involved in the process. Mention any two uses of somatic hybridisation.VIEW SOLUTION