C) Development of plants without fusion of gametes.
D) Inability to perceive stimulus for flowering.
2. Name the phenomenon because of which crystals of KMnO4 added to water make it purple.
A) Imbibition
B) Plasmolysis
C) Osmosis
D) Diffusion
3. Which of the following is an initiation codon?
A) UAG
B) UAA
C) AUG
D) AAG
4. Identify an oviparous mammal?
A) Duck-billed platypus
B) Kangaroo
C) Bat
D) Penguin
5. Water chestnut shows two different types of leaves on the same plant. This condition is known as:
A) Heterotropic
B) Biparous
C) Phyllotaxy
D) Heterophylly
6. Approximately how many bacteria may be obtained from one bacterium in an hour under favourable conditions?
A) 64
B) 8
C) 32
D) Infinite number
7. For which of the following diseases bioengineered vaccine has not been developed?
A) Rabies
B) Marasmus
C) Herpes
D) Hepatitis B
8. Hypervitaminosis is caused due to excessive intake of which of the following:
A) Vit. D
B) Vit. B
C) Folic acid
D) Vit. C
2 MARKS QUESTIONS
9. Distinguish between multiple alleles and Codominance, giving suitable examples.
Ans: The existence of more than one gene controlling the same trait is called a multiple allele. Codominance is the expression of a trait due to the presence of two dominant genes.
10. a) List any three advantages of Bio-diesel.
b) Name a common Petro-Plant.
Ans:
Advantages of Biodiesel
It is an agriculture-based fuel substitute.
It can be made from both vegetable oil and animal fats.
It can be used without major modifications in engines.
It does not need a separate infrastructure for storage and delivery
Jatropha curcus
11. Explain Kranz anatomy.
Ans: In C4 plants, the vascular bundles have a sheath of large parenchyma cells around them in the form of a wreath, thus the name Kranz anatomy. Kranz means wreath and thus the name. They also have dimorphic chloroplasts.
12. State any four reasons for the degradation of water.
Ans:
Depletion of the volume of water to meet the needs of an increasing population.
Use by humans and animals makes water unfit.
Wastewater from industries flows into water bodies.
Agricultural waste containing manure, fertilisers and pesticides enters the water
13. State any four significances of transpiration.
Ans: Significance of transpiration
Absorption of water. Transpiration pull affects the rate of water absorption from the soil.
Water movement. By transpiration, water moves upwards and as it passes into the cell vacuoles, it makes the cells turgid. This gives a form and shape to the cells and to the plants as a whole.
Mineral salt transport. The water stream moving upwards also carries the dissolved minerals required for the development of the plant. Transpiration also helps in distributing these minerals throughout the plant body.
Cooling. The evaporation of water during transpiration cools the leaves.
Protection from heat injury. Some plants, like Cacti, retain water by reducing transpiration. This saves the plants from high temperatures and strong sunlight.
14. Draw a neat and labelled diagram of the Androecium and Gynoecium in an Angiosperm flower.
Ans:
15. Distinguish between actively acquired immunity and passively acquired immunity.
Ans:
By infection, so that antibodies are produced against the infective agent and by deliberate artificial immunisation. This is termed as actively acquired immunity.
By transfer from an actively immunised individual through blood, serum component, etc. This is called passively acquired immunity.
16. Distinguish between tropic movements and nastic movements in plants?
Ans:
Movement in plants or in any part of the plants towards or away from some environmental factors is known as tropic movement. Phototropism of shoots, geotropism of roots, thigmotropism seen in twining tendrils of climbers, hydrotropism of roots, etc, are examples.
The nastic movements are the growth movements resulting from to difference in the rate of growth on opposite sides of an organ, e.g., opening of petals, coiling of leaves, etc. When the upper side of the organ grows faster than the lower side, it is called epinasty. If it is the lower part that grows faster than the upper part, it is called hyponasty.
17. a) Mention any two functions of Auxin.
b) Which two hormones are essential for vascular tissue differentiation?
Ans:
Functions of auxin
Promotes cell elongation.
Delays the fall of leaves
Auxin and cytokinin are essential for vascular tissue differentiation.
18. Draw a neat diagram of the male reproductive system of a Cockroach. Label testis and ejaculatory duct in it.
Ans:
19. What is a Food chain? Give a suitable example. What are different steps of a food chain known as?
Ans: Transfer of food from the plants (producers) through a series of organisms with repeated eating and being eaten is called a food chain. Eg., Grasses → Grasshopper → Frogs → Snakes → Hawk/Eagle.
Each step in the food chain is called a trophic level.
20. Name the two basic strategies for conservation of biodiversity and define them with suitable examples.
Ans:
In situ (on-site) conservation includes the protection of plants and animals within their natural habitats or in protected areas. E.g.. Wildlife Sanctuaries.
Ex situ (off-site) conservation is the conservation of plants and animals outside their natural habitats. Eg. Zoo
4 MARKS QUESTIONS
21. a) How are the heart sounds Lubb and Dubb produced during heartbeat?
b) What is the role of S.A. node (Sinu Atrial Node) in the heart? Where is it situated?
Ans:
The beating of the heart goes on by itself as long as one is alive. Each heartbeat consists of the steps mentioned below and makes two sounds – Lubb and Dubb during each beat. The heartbeat starts with the contraction or systole of the atria, followed by relaxation or diastole. The lubb sound or 1st heart sound occurs due to the closure of atrioventricular valves, the atrial systole.
Since the Sinu-atrial Node initiates and regularises the heartbeat, it is also called the pacemaker. It is located in the upper corner of the right atrium.
22. a) What do you understand by the following terms:
i) Implantation
ii) Colostrum
iii) Artificial Insemination
b) Name the hormone:
i) Produced by the placenta.
ii) Responsible for uterine contractions for childbirth
Ans:
Implantation: The fixing of the embryo in the wall of the uterus is called implantation.
Colostrum: The first secretion that comes out from the mammary glands of the mother, just after childbirth, is called colostrum.
Artificial Insemination is the introduction of human semen into a woman using a syringe during ovulation.
Hormone Produced by the Placenta: Progesterone
Hormone Responsible for uterine contractions for childbirth: Oxytocin
23. a) Draw a diagrammatic representation of an antibody.
b) Define the terms:
i) Immunity
ii) Genetic Engineering
Ans:
Antibody structure
Definition of,
Immunity: Immunity is the capacity of the body to recognise materials as foreign to itself and to neutralise, eliminate or metabolise them with or without injury to its own tissues.
Genetic Engineering: The process of obtaining multiple copies of a gene using recombinant DNA technology is called genetic engineering.
24. Draw neat and labelled diagrams of:
a) A mushroom
b) Venation in dicot and monocot leaves.
Ans:
Mushroom
Venation in a dicot leaf
Venation in a monocot leaf
25. a) List any four reasons as to why roughage should be included in our diet?
b) Name the diseases and any two symptoms of each of the following:
i) excessive intake of Iron
ii) deficiency of Iodine
Ans:
Importance of roughage
It helps with bowel movement.
It cleans our digestive tracts and protects the body from digestive ailments.
It prevents constipation.
It helps in retaining water in the body.
It helps in maintaining optimum levels of blood sugar and cholesterol.
Diseases and symptoms
Hemosiderosis: Heartburn, nausea, constipation.
Cretinism: Stunted growth and delayed puberty
26. With the help of a flow chart, explain the chromosomal basis of sex determination in humans.
Ans:
6 MARKS QUESTIONS
27. a) Draw a neat diagram of the double helical structure of DNA.
b) Who proposed this structure?
c) Draw a diagrammatic representation of an RNA showing anticodon and codon pairing?
Ans:
Double helical structure of DNA
Franklin and Wilkins proposed this structure.
RNA
28. Draw a neat diagram to show the location of the eight principal endocrine glands in the human body.
Ans:
29. a) Mention any two special features of the meristematic cells, and also mention any two locations they are present.
b) Name the complex tissues of plants and state their main functions.
c) Give two suitable examples of each of the following:
i) Plasma Proteins
ii) Contractile proteins
Ans:
Meristematic cells
Apical meristem: Root tip and shoot tip
Lateral meristem: Cambium between xylem and phloem.
Complex tissues in plants are xylem and phloem
Xylem: Xylem conducts water and salts upward from roots to leaves.
Phloem: Phloem conducts the metabolites (food) synthesised in the leaves to different parts of the plant.
Examples
Plasma proteins: Fibrinogen
Contractile proteins: Tubulin
30. a) Distinguish between Biological and Abiological Nitrogen Fixation.
b) Where do photochemical and biosynthetic pathways in photosynthesis take place? What are the products formed in each case?
c) Define the following:
i) Principle of Limiting Factor
ii) Compensation Point
Ans:
Biological nitrogen fixation is the reduction of molecular nitrogen to ammonia by a living cell in the presence of enzymes called nitrogenases. In abiological nitrogen fixation, the nitrogen is reduced to ammonia without involving any living cell.
Photochemical reactions take place in the thylakoids of chloroplasts in green leaves. It produces ATP, NADPH2 and oxygen. The biosynthetic pathway takes place in the stroma of the chloroplast. The end product here is glucose.
Define
Principle of Limiting Factor: When a process is affected by various factors, the rate of the process depends upon the pace of the slowest factor.
Compensation Point: At a certain light intensity, the amount of CO2 used in photosynthesis and the amount of CO2 produced in respiration are the same. This point of light intensity is known as the compensation point.