Biology Waec 2017

Biology Waec 2017 (Essay & Objective) Answers Available Here

BIOLOGY OBJ
PROFAKOBUNDU
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                    1ai)
Classifications of living things consists of placing together in categories those living things that resembles each other. It involves placing living things into groups that have certain features in common which distinguish them from other groups
     1aii) Car von Linnè Also known as Carolus Linnaeus
1aiii)-Classification is important because it allows scientists to identify the organisms
-Classification is important because it makes it easy for scientists to group the organisms.
- It is also good to properly name organisms via a standardized system

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1aiv)
-Kingdom
- Phylum(Animal) or division (Plant)
-Class
-Order
-Family
-Genus
-Species
1bi)
-Vírus can reproduce when present in another living cell
-It possesses characteristics which can be transmitted from one generation to the next
1bii)
-When a virus is extracted from a living cell and placed in a non living medium, it assumes a crystalline form and thus become non-living
-Virus cannot respire, excrete or respond to stimuli
1ci)
-Rosette disease
- Cassava mosaic disease
1cii)
-Chicken Pox
-Polio
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2a)
i) They catalyse reactions by lowering the activation energy of a reaction
ii). They are regenerated after each reaction
iii). They are substrate specific, hence only molecules which are complementary to their shape can bind to it.
iii). They aid in metabolism (anabolism and catabolism)
2bi)
-Pancreatic lipase
- Amylase
2bii)-Fats and oil
-Starch Maltose
2biii) -It converts fat and oils to fatty acids and glycerol
-It converts starch to maltose
2ci)
Chlorophyll is necessary to absorb the radiant energy of the sun to synthesize sugar during photosynthesis
2cii)
-Magnessium
-Iron
2ciii)
Magnessium --->Ye-llowing of leaves and poor growth
-Iron--->Ye-llowing of leaves and poor growth
2d)
STEPS TO TEST PRESENCE OF STARCH IN THE LEAF
1. Boil pieces of leaves in a beaker of water TO KILL THE CELLS AND BREAK THE WALL OF LEAF CELL
Fresh leaves
Boiling the leaves
2. Heat the pieces of leaf in alcohol for few minutes TO REMOVE CHLOROPHYLL
Alcohol turns to green color- chlorophyll is removed
3. Soak the pieces of leaf in hot water for a little while TO SOFTEN THE LEAF
4. Using a dropper, add a few drops of iodine solution onto the pieces of leaf TO TEST FOR STARCH
Finally, LEAVES THAT CONTAINS STARCH TURN TO DARK BLUE COLOUR
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6a)
The odorous molecules come into contact with the olfactory epithelium at the top of the nasal cavity and stimulate multiple chemically cell receptors and thus the odour is transmitted to the brain. There after the brain interprets the type of smell.
6b)
i)Shell
ii)Membranes
iii)Airspace
iv)Albumen
v)Yolk
vi)Chalaza
6ci)
autotrophs are organisms that can synthesizes food from inorganic substances by using chemical energy or light
6cii)
i)Bacteria
ii)Unicellular algae
6d)
i)providing leadership on matters critical to health
ii)shaping the research agenda and stimulating the generation
iii)translation and dissemination of valuable knowledge
iv)setting norms and standards
v)promoting and monitoring their implementation
6e)
i)plants: Water Wisteria and Java Moss.
ii)Animals: catfish and earthworm
6f) Tabulate
Skin of mamma:
-Epidemis is multi-layered
-Waterproof
-Opeque
Epidemis of leaf:
-Epidemis is single layered
-Forous water can seep through
-Transparent
6gi) Plot A: Intra-species or intra-specific competition
ii) Plot B: Inter-species or inter-specific competition
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