All 16 questions from the Post-UTME Screening (Post-UTME) Biology 2010 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.
Which of the following is the direct consequence of transferring energy from one trophic level to another?
A. an increase in biomass
B. a decrease in the efficiency of energy conversionCorrect
C. an increase in the total numbers of resulting individuals
D. a decrease in the resulting biomass
Explanation
Energy transfer between trophic levels is inefficient (much energy is lost as heat/respiration), so each transfer results in a lower efficiency of energy conversion/less available energy.
The sequence of the biomes in Nigeria from Port Harcourt to Damaturu is
A. estuarine, rain forest, Guinea savannah, sahel savannahCorrect
B. rain forest, Guinea savannah, estuarine, desert
C. estuarine, Guinea savannah, rain forest, sahel savannah
D. rain forest, estuarine, Guinea savannah, desert
Explanation
Moving north from the coast (Port Harcourt) to the far north (Damaturu), Nigeria's vegetation transitions through estuarine/mangrove, rainforest, Guinea savannah, and sahel savannah zones.
Which of the following groups of diseases are associated with water? I. onchocerciasis II. Schistosomiasis III. Dracunculiasis IV. Elephantiasis V. Taeniasis
A. I, II and IIICorrect
B. II, IV and V
C. II, III and IV
D. I, II and V
Explanation
Onchocerciasis (transmitted by blackflies breeding in fast-flowing rivers), Schistosomiasis (water snails) and Dracunculiasis (guinea worm, via contaminated drinking water) are all closely associated with water sources.
One of the ways in which body cells differ from gamete cells is in the
A. type of centromeres they contain
B. number of chromosome pairs they containCorrect
C. type of chromatin they contain
D. number of chromosomeres they contain
Explanation
Body (somatic) cells are diploid, containing pairs of chromosomes, while gamete cells are haploid, containing only single sets - this is the key distinguishing feature.
Agglutination (clumping) during an incompatible blood transfusion occurs when red blood cell antigens react with corresponding antibodies in the recipient's plasma; the reaction is driven by incompatible antigen types meeting.
Parasitic forms are well documented among nematodes, annelids (e.g. leeches) and platyhelminths (e.g. tapeworms); parasitism is comparatively rare among molluscs.