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Archive for the ‘Biology’ Category

Biology-1996

Q.1 Which of the movable joint makes the hip joint ?
Ans1. Ball and socket joint.

Q.2 Write the full form of tRNA.
Ans2. Transfer Ribosenucleic Acid.

Q.3 Mention any two factors by which the environment or the nature checks the pollution size.
Ans3. (i) Competition and struggle.
(ii) Drought and flood.

Q.4 Give two examples of analogous organs from animals.
Ans4. Wings of :
(i) an insect,
(ii) a bird, and
(iii)a bat are analogous organs.

Q.5 Mention one difference in the structure of chlorophyll-a and chlorophyll-b.
Ans5. Chlorophyll-a has a methyl (-CH3) group whereas chlorophyll-b has an aldehyde (-CHO) group.

Q.6 Name the source glands of glucagon and parathormone.
Ans6. Glucagon : Islets of Langerhans in Pancreas
Parathormone: Parathyroid gland

Q.7 Mention one difference between benign tumour and malignant tumour.
Ans7. A malignant tumour is different from a benign tumour in the formers capacity to undergo metastasis.

Q.8 Name any two structures in our body, which bear ciliated epithilium.
Ans8. (i) Kidney tubules, and
(ii) Fallopian tubes

Biology-1997

Q1. At what stage the embryo is implanted in the uterus of the mother in case of a test tube baby?
Ans1. 32-celled Morula.

Q2. Human heart is Myogenic yet a parasympathetic nerve can reduce the heart rate. Name the nerve.
Ans2. Vagus Nerve.

Q3. Which of the following diseases could be avoided by analysing the pedegree of parents – Klinefelter’s syndrome, Haemophilia, Amoebiasis.
Ans3. Haemophilia.

Q4. Name the functional contractile unit of the muscle.
Ans4. Sarcomere.

Q5. Name any two synthetic auxins used in agriculture.
Ans5. (i) NAA (naphthaleneacetic acid)

(ii) 2,4 D (2,4-dichlorophenoxyacetic acid)

Q6. What is pulvinus?
Ans6. Pulvinus is the swollen base of the leaf in many members of the bean family. It is responsible for sleep movements.

Q7. Name the fluid in which membranous labyrinth of the inner ear floats.
Ans7. Perilymph.

Biology-1998

Q1. What induces parthenocarpy in grapes?
Ans1. Auxins.

Q2. What is the term used for the regions of a gene which become part of mRNA and code for the different regions of the proteins?
Ans2. Exons.

Q3. The venous blood in the lung has a PCO2 of 46 mm Hg. Should the alveolar PCO2 exceed or be less than 46 mm Hg to result in diffusion of CO2 from the blood into the alveolus?
Ans3. It should be less than 46 mm Hg.

Q4. Which part of the plant leaf is modified to form spines of Acacia and the sheath covering the leaf of Ficus elastica.
Ans4. Stipules.

Q5. Name the enzyme that can break and reseal one strand of DNA.
Ans5. Topoisomerase.

Q6. What does J-shaped growth curve of a population indicate?
Ans6. The J-shaped curve indicates that the factors of environmental
resistance do not produce zero growth to contain the exponential growth.

Q7. What forms the cambial ring in a dicot stem during the secondary growth?
Ans7. The cambial rings are formed by alternately forming secondary xylem.

Q8. Name the principal mineral anion in the extracellular fluid.
Ans8. Ca2+.

Biology -1999

Q1. Name the process in which bacteriophage picks-up a piece of DNA from one bacterial cell and transfers the same to another bacterial cell on infection.
Ans1. Transduction.

Q2. Which fraction of soil water is readily available to plants for absorption.
Ans2. Capillary water fraction .

Q3. What protects nitrogenase?
Ans3. ‘Leghemoglobin’ combines with oxygen and maintains anaerobic environment to protect nitrogenase.

Q4. Name two plants that produce rhizomes.
Ans4. Ginger, Turmeric.

Q5. Why is oxytocin called as ‘Birth Hormone’?
Ans5. Oxytocin helps in uterine contraction and the onset of labour at the time of child-birth.

Q6. From which germ layers do the following organs differentiate :
(i) Kidney
(ii) Urinary bladder

Ans6. Kidney and the urinary bladder differentiate from mesoderm.

Q7. What provided energy for abiotic synthesis on the primitive earth?
Ans7. ‘Lightning and solar radiation’ provided energy for abiotic synthesis on the primitive earth.

Q8. Name the two curable sexually transmitted diseases.
Ans8.
(i) Syphilis, and
(ii) gonorrhoea are curable sexually transmitted diseases.

Biology-2000

Q 1. What is meant by trisomic condition? (1 mark)
Ans1. Trisomy is the presence of an extra chromosome i.e., so that a particular chromosome is present in three copies.

Q 2. State the presence or absence of sinus venous in a fish and a mammal. (1 mark)
Ans2. Fish and mammals do not have sinus venosus because a sufficiently high blood pressure cannot be maintained in the open spaces.

Q 3. Which type of cartilage is present between vertebrae to allow limited movement? (1 mark)
Ans3. White fibrocartilage

Q 4. Name any two breeds of wild rock pigeon that have been developed through artificial selection. (1 mark)
Ans4. (i) Pouter, and
(ii) Jacobin.

Q 5. Which chromosomes are called autosomes? (1 mark)
Ans5. Autosome is any chromosome other than a sex chromosome. In humans they are 22 pairs.

Q 6. When is a tumour referred to as malignant? (1 mark)
Ans6. A tumour is called malignant, if it has the capacity to undergo metastasis.

Q 7. What are the two factors that contribute for the dissociation of oxyhaemoglobin in the arterial blood to release molecular oxygen in an active tissue? (1 mark)
Ans7. PO2 in the tissues lower than arterial blood, and PCO2 in the tissues higher than arterial blood.

Q 8. Which one of the following is fatal unless oral rehydration therapy is administered :
(i) Whooping cough (ii) Cholera (iii) Tetanus (1 mark)

Ans8. Cholera