THE BIOLOGY MODEL EXAMINATION FOR GRADE 12 IN 2008/2016

DIRECTIONS: THIS BOOKLET CONTAINS BIOLOGY EXAMINATION FOR

GRADE 12 FOR NATURAL SCIENCE ONLY

THE EXAMINATION CONTAINS 100 ITEMS. THERE IS ONLY ONE BEST

ANSWER FOR EACH ITEM. CHOOSE THE BEST ANSWER FROM THE
GIVEN ALTERNATIVES AND BLACK THE CIRCLE CORRESPONDING TO
YOUR ANSWER ON THE SEPARATE ANSWER SHEET.

YOU ARE ALLOWED TO WORK ON THE EXAM FOR 2:00 HOURS.

1. What is genetic engineering?

A. The study of genetic material
B. The study of microorganisms
C. The transfer of genetic information
D. The study of cells structures and functions
2. The general test to determine the presence or the absence of the
carbohydrates in a given food items is referred to as:
A. Benedict’s test C. Molisch test
B. Emulsion test D. Biuret test
3. What is the main importance of observation in the scientific method?
A. Formulation of hypothesis C. Conducting an experiments
B. Identification of problems D. Acceptance of results
4. In which of the meiosis stage, the homologous pairs line up at the equator
of the cell and attach to the spindle fibers by their centromeres?
A. Prophase I B. Metaphase I C. Anaphase I D. Telophase I
5. The outer covering of virus that made up of protein is called:
A. Plasmids B. Phagemids C. Capsids D. Cosmids
6. Which main class of enzymes changes the molecular form of the
substrates?
A. Ligases B. Lyases C. Transfererases D Isomerases

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7. Which elements have a specific function in the biological systems to

strengthen your bones, teeth and muscles?
A. Iron B. Chlorine C. Calcium D. Fluorine
8. Which enzyme is used to enhance the softness and flexibility of your
leather jacket in its industrial production process?
A. Proteases B. Lipases C. Amylases D. Nucleases
9. Which one is more dense?
A. Liquid form of water C. Gas form of water
B. Solid form of water D. Vapor form of water
10. Which of the following monosaccharide is common in the maltose,
lactose and sucrose disaccharides formation?
A. Fructose B. Glucose C. Galactose D. Ribulose
11. Which of the following is the most responsible force for holding an alpha
helix region of the secondary structure of a protein in its helical form?
A. Disulfide bonds C. Hydrogen bonds
B. Ionic bonds D. Peptide bonds
12. A person of which blood type lacks both anti- A and anti-B antibodies in
his or her blood serum?
A. Blood type A C. Blood type O
B. Blood type B D. Blood type AB
13. Sometimes, human babies are born with one extra chromosome than
normal. This condition is due to:
A. Sex- limited traits C. Non- disjunction traits
B. Sex-influenced traits D. Sex-linked traits
14. Acetobacter is industrially important microorganism in the production of:
A. Antibiotics B. Vinegar C. Insulin D. Vaccines
15. In HIV/AIDS treatment, entry inhibitor drug classes are very important
in preventing:
A. Penetration of viruses C. Attachment of viruses
B. Replication of viruses D. Assembly of viruses

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16. In our body cells, we have 46 chromosomes, half of them comes from our
mothers and the other half comes from our father. The chromosomes that
comes from our mothers are called:
A. Autosomal chromosomes C. Paternal chromosomes
B. Maternal chromosomes D. Parental chromosomes
17. Which of the ecological principles form the basis for conservation of
biodiversity in an area with the idea that it is a fundamental to conserving
species?
A. Disturbance to habitats C. Maintaining habitats

B. Climate changes D. Protection of any species

18. Pre- industrialized countries such as Ethiopia and a few remote groups
are characterized by:
A. High birth rate and high death rate
B. High birth rate and low death rate
C. Low birth rate and high death rate
D. Low birth rate and low death rate
19. In Vivo gene cloning
A. It is take places in living cell
B. It is quicker and cheaper method
C. It uses PCR machine to copy DNA
D. Mimics semi conservative DNA replication method
20. Which of the following inherited trait is sex-influenced?
A. Undescended testicles C. Breast development
B. Retinitis pigmentosa D. Pattern baldness
21. Which of the following groups of organisms are the oldest and capable of
survive in very harsh conditions on Earth?
A. Archaebacteria C. Eubacteria
B. Cyanobacteria D. Eukaryotes

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22. The types of natural selection that operates in favor of individual showing
the mean values for a features to work against the extreme one:
A. Artificial selection C. Disruptive selection
B. Directional selection D. Stabilizing selection
23. In sympatric speciation, in which isolating mechanisms, the members of
two populations reproduce at different times of the day?
A. Geographical isolation C. Temporal isolation
B. Seasonal isolation D. Behavioral isolation
24. According to John Desmond Bernal, the correct ‘Stages’ in explaining the
origin of life from non-living matter as a result of a series of biochemical
reactions are: The origin of
A. Cells→ monomers→ polymers C. Monomers→ cells → polymers
B. Monomers→ polymers → cells D. Polymers→ monomers→ cells
25. Suppose we consider four hypothetical cells, namely A, B, C and D,
having cubic shape with their sides measuring 5, 10, 15 and 20 arbitrary
units respectively. Which of this cell has the smallest surface area to
volume ratio?
A. Cell D B. Cell C C. Cell B D. Cell A
26. Sucrase catalyses the hydrolysis reaction of sucrose into glucose and
fructose. The substrate in this reaction is:
A. Sucrase B. Sucrose C. Glucose D. Fructose
27. In the systematic naming of enzymes, an enzyme with a name of EC
2.3.10.4. The second number (3) here indicate its:
A. Serial number B. Main class C. Subclass D. Sub-subclass
28. Which of the following does NOT characterize the link reaction?
A. Decarboxylation C. ATP formation
B. Dehydrogenation D. Citrate production

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29. In which stages of cellular respiration, ATP molecules are utilized and
synthesized?
A. Chemiosmosis C. Krebs cycle
B. Glycolysis D. Link reaction
30. A child graps a dog’s ear and the dog respond by biting the child. Both
behaviors are repeated once again the next day and again a day later. The
child never graps a dog’s ear again. This sequence of event is an example
of:
A. Insight learning C. Imprinting behavior
B. Latent learning D. Operant conditioning
31. Refers to the tendency of genes found on the same chromosomes to be
inherited together.
A. Genetic codes C. Generic crosses
B. Genetic diagrams D. Genetic linkage
32. Which of the following features distinguishes marine biomes from
freshwater biomes?
A. Geographic location C. Rain fall of season
B. Salt content of water D. Soil types of area
33. At high temperatures, the rate of enzyme action decreases because the
increased heat:
A. changes the PH value of the systems
B. increases the concentration the enzymes
C. alter the active site of the enzyme molecule
D. neutralizes the acids and bases in the system
34. Which of the following bacterial disease cause severe dehydration and
can lead to reduced blood pressure, rapid pulse and eventually lead to
death?
A. Cholera B. Pneumonia C. Salmonella D. Tuberculosis

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35. Holoenzymes are a combination of:

A. Apoenzymes and cofactors molecules
B. Coenzymes and mineral ions molecules
C. Competitive and non-competitive inhibitors
D. Enzymes molecules and substrates molecules
36. Which of the following enzyme use copper as mineral ion to provide
catalytic activity in the transfer of electron to oxygen during respiration?
A. Alcohol dehydrogenase C. Cytochrome oxidase
B. Carbonic anhydrase D. Salivary amylase
37. Which of the following cell organelles requires a relatively high centrifuge
speed to make it settle out in cell fractionation technique?
A. Chloroplasts B. Mitochondria C. Nucleus D. Ribosomes
38. The electron transport system produces _________ATP from each NADH
and/or _________ ATP from each FADH entering the system.
A. 4:2 B. 3:2 C. 2:4 D. 2:3
39. Where does fixation of CO2 in C3 plants and C4 plants take place?
A. Bundle sheath cells C. Palisade cells
B. Mesophyll cells D. Spongy cells
40. The concept of lock and key model refers to:
A. the fit of coenzymes to apoenzymes
B. the matching of the enzyme with substrates
C. regeneration of the ATP from ADP molecule
D. the influence of inhibitors on enzymes activity
41. Which of the following stages of the aerobic respiration responsible for
production of both FADH and NADH?
A. the glycolysis C. the Krebs cycle
B. the link reaction D. the chemiosmosis
42. The correct pair for purine nitrogen containing bases of Nucleotides are:
A. Thymine and Uracil C. Cytosine and Guanine
B. Guanine and Adenine D. Adenine and Thymine

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43. Which of the following cultivated crops have NO their center of genetic
diversity in our country?
A. Anchote B. Barley C. Coffee D. Maize
44. What is the similarity between the facilitated diffusion and active
transport processes?
A. the use of the carrier transport proteins molecules
B. the requirement for ATP molecules to drive the transport
C. the influence of concentration from low regions to high regions
D. the transport of very large particles across plasma membranes
45. What direct pressures are there for young people to become sexually
active? Select exception.
A. Pressure from peer C. Alcohol and drug use
B. Male circumcision D. Influence from media

Question number 46 and 47 are to be answered based on the following

information of report writing format.

1. Title 5. Procedure
2. Results 6. Hypothesis
3. Evaluation 7. Acknowledgments
4. Conclusion 8. Prediction
46. Among the above report writing format, in which it is helpful to
summarize in graphs, charts and tables?
A. Conclusion B. Evaluation C. Procedure D. Results
47. Based on the report writing format listed above, choose alternative that
shows the correct sequence in reporting the results of research in
scientific journals?
A. 7, 8, 6, 3, 5, 4, 1, 2 C. 1, 6, 8, 5, 2, 4, 3, 7
B. 1, 5, 3, 6, 8, 7, 2, 4 D. 7, 3, 4, 2, 5, 8, 6, 1

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48. The most important activities of human that affect the environment is:
A. Improper waste disposal C. Plants species cultivation
B. Animals domestication D. Sustainable utilization of resources
49. An enzyme that hydrolyzes protein will NOT act upon starch. This fact is
an indication that enzyme are:
A. Catalytic B. Hydrolytic C. Specific D. Synthetic
50. Which of the following enzymes assembles free DNA nucleotides into new
strand alongside each of the template strands in semi-conservative DNA
replication methods?
A. DNA helicase C. DNA polymerase
B. DNA ligase D. RNA polymerase
51. Which one of the following molecules functionally links the Glycolysis
and the Krebs cycle stages in aerobic respiration of glucose?
A. Citrate B. Pyruvate C. Acetyl CoA D. Oxaloacetate
52. In which types of dominance, the heterozygote has the characteristics of
both parents?
A. Complete dominance C. Co-dominance
B. Incomplete dominance D. Over dominance
53. Which type of dance is performed by the worker bees to obtain
information about both the distance and direction of hives and a source of
nectar?
A. Horizontal dance C. Round dance
B. Vertical dance D. Waggle dance
54. Obviously humans are a different species from chimpanzee, but why the
different races of humans are all members of the same species? Because
they:
A. interbreed to produce a fertile offsprings
B. reproduce in greater number than others
C. best adapted to their external environments
D. pass on their advantageous alleles to their offspring

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55. Which of the following an item of field equipment is incorrectly

matched with its function?
A. Balances- measuring the mass of a given objects
B. Quadrat- estimation of the abundance of organisms
C. Theodolite- measuring the height of slopes in the area
D. Data logger- used to measure the rate of flow of water
56. Which fields of biology study about the possibilities of the life on the
other planets such as Mars?
A. Astrobiology C. Microbiology
B. Neurobiology D. Paleobiology
57. If a certain married couple had four girls in a row, what would be the
chance of that their next child will be a boy?
A. 25% B. 50% D. 75% D. 100%
58. How many water molecules can be produced from 4 monosaccharide
molecules joined to form polysaccharides by condensation reaction?
A. 1 B. 2 C. 3 D. 4
59. The process in which RuBP combine with oxygen instead of carbon
dioxide is called:
A. Cellular respiration C. Photophosphorylation
B. CAM photosynthesis D. Photorespiration
60. A researcher on the improved barley food varieties, use periodic
discharges of loud sound to scare birds away from their fruit trees. After
several days birds can be seen ignoring the sounds due to what kind of
behavior?
A. Conditioning B. Instinct C. Imprinting D. Habituation

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61. Some nitrogenous waste products or organic remains of organisms are

decomposed by soil bacteria and fungi. The bacteria and fungi use the
amino acids for their own growth and in turn, release the excess in the
form of NH3 or NH4+. This process is called:
A. Ammonification C. Denitrification
B. Biosynthesis D. Nitrification
62. A chromosomes gene sequence that was ABCDEFGH before damage and
ABFEDCGH after. This is an example of which mutation.
A. Deletion C. Inversion
B. Duplication D. Translocation
63. Which of the following process is the raw material for the formation of
the new species and responsible to produce new genetic materials?
A. Crossing over C. Mutation
B. Segregation D. Evolution
64. Which theory of evolution, states that at some stages, some supreme
being created life on earth?
A. Biochemical origins theory C. Cosmozoan theory
B. Special creation theory D. Eternity of life theory
65. Which of the following RNA molecules collect and transport free amino
acids from the cytoplasm to the ribosomes in the protein synthesis
process?
A. mRNA B. rRNA C. tRNA D. siRNA
66. According to the Charles Darwin theory of natural selection core idea,
the reason why ‘straggle for existence’ between the members of species is:
A. resource limitation and better adaptation
B. over reproduction and resource limitation
C. better adaptation and variation in the offspring
D. over reproduction and variation among the offspring

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67. Which of the following does NOT cause mutation?

A. Carbon monoxide C. Nicotine
B. Natural selection D. Nitrous acid
68. A complex behavioral pattern designed to stimulate organisms to sexual
activity in mating and reproduction to recognize each other is?
A. Altruistic behavior C. Courtship behavior
B. Social behavior D. Territorial behavior
69. Which of the following active transport process is responsible for the
secretion of enzymes and hormones?
A. Endocytosis C. Pinocytosis
B. Exocytosis D. Phagocytosis
70. The painkiller aspirin is an example of a(an)
A. Activator substances C. Irreversible inhibitors
B. Competitive inhibitors D. Non-Competitive inhibitors
71. Which is incorrect about RNA molecules? RNA
A. allows the production of proteins from DNA
B. found both in the cytoplasm and the nucleus
C. smaller and single stranded molecules in cells
D. stores the genetic instructions of living organisms
72. Which of the following mutations is much bigger events, occur at
crossing over in prophase I and result in the death of a cell?
A. Genes mutations C. Frame shift mutation
B. Chromosomes mutation D. Point mutation
73. According to Aleksander Oparins theory of biochemical evolution, which
is NOT the simple organic compound that undergoes a series of reaction
leading to synthesis of more complex molecules?
A. Amino acids C. Sugars
B. Fatty acids D. Nucleotides

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74. The millennium assessment (MA) finding suggests that biodiversity loss
affects the well being of rural communities. It may
A. increasing vulnerability C. increasing insecurity of food supply
B. lower material wealth D. more freedom for choice and action
75. How can one carry genetical researches to produce maps showing the
relative positions of genes on the chromosomes? By
A. chromosomal theory of inheritance C. laws of dominance
B. calculating cross over frequencies D. laws of segregation

Question number 76 is to be answered based on the following diagram

76. What processes belong in the box of the diagram?

A. 1 transpiration; 2 respiration
B. 1 photosynthesis; 2 respiration
C. 1 respiration; 2 photosynthesis
D. 1 chemosynthesis; 2 photosynthesis
77. Which of the following of are the results of a cross between pea plants
homozygous for wrinkled and heterozygous for roundness in monohybrid
cross of complete dominance?
A. 25% round, 75% wrinkled C. 50% round, 50% wrinkled
B. 75% round, 25% wrinkled D. 100% round only

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78. Hybrid yellow pea plants we let to self pollinate and produce 1,200
seeds. How many of them do you expect to be pure yellow?
A. 300 B. 400 C. 600 D. 900
79. Suppose a man with blood group of hybrid A(AO) married a woman with
blood group AB. What will be the possible blood type of their children?
A. 50% A , 50% AB C. 50% A, 25% AB, 25% B
B. 50% AB, 25% A, 25% B D. 50% B, 25% A, 25% AB
80. In pea plants tall (T) is dominant over short (t). Tall pea plants were self
pollinated and produce 200 tall and 50 short pea plants. The parent was
probably?
A. TTxtt C. TtxTT
B. Ttxtt D. Ttx Tt
81. What is the parental genotype in the 1:1:1:1 phenotypic ratio of a
dihybrid crosses?
A. AAbb x aaBB C. AaBb x aabb
B. AABB x aabb D. AaBb x AaBb
82. The starting and ending compound in Calvin cycle is:
A. Carbon dioxide C. Glycerate phosphate
B. Triose phosphate D. Ribulose bisphosphate
83. Refers to an organism with different alleles for a particular trait on each
of homologues pairs of chromosomes?
A. Genotype C. Homozygous
B. Phenotype D. Heterozygous
84. Regions of the ocean where no light penetrates:
A. Oceanic pelagic C. Coral reef
B. Oceanic abyssal D. Littoral zone

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85. Which of the following molecules have a capable of mutations?

A. Lipids C. Nucleic acids
B. Proteins D. Carbohydrate
86. Which of the following is NOT one of the principles of heredity proposed
by Gregor Mendel?
A. Laws of dominance C. laws of incomplete dominance
B. Laws of segregations D. laws of independent assortment
87. Biodiversity refers to:
A. the natural resources on the planet Earth
B. the sustainable use of biological resources
C. the variability of living things on the planet Earth
D. the identification of species on the planet Earth
88. The reason why a vaccine against HIV is NOT successful is because?
A. HIV changes its surface antigen at very fast rate
B. Vaccine will become effective in very short time
C. HIV have different form of life cycle from other viruses
D. HIV contain protective coat to prevent the entry of vaccine
89. Rough endoplasmic reticulum differs from smooth endoplasmic
reticulum in having:
A. ribosomes on its surface
B. no ribosomes on its surface
C. active role in lipids synthesis
D. active role in carbohydrate metabolism
90. Which of the following laboratory tools take in and expel a precise
volume of liquid or gas?
A. Altimeter C. Pipettes
B. Autoclave D. Syringe
91. Hepatitis is the disease condition of which organ that considered as the
chemical laboratory of human body?
A. Brain B. Liver C. Kidneys D. Lungs

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92. Which is NOT the field work in the biological investigation?

A. Investigating study areas
B.Conducting an experiments
C. Taking samples of representatives
D.Observing organisms in their natural habitats
93. TAA,TGA and TAG are:
A. overlap codon C. anti-codon
B. B. initial codon D. stop codon
94. Lamarck used one of the following structures as an example to illustrate
what might happen to a structure with disuse?
A. the forelimb of mammals C. the toes of water birds
B. the neck of the giraffes D. the wings of penguins
95. The sex of a child is determined by:
A. Chromosomes of father C. Chromosomes of child itself
B. Chromosomes of mother D. Chromosomes of grandmother
96. Which of the following DNA technology is used to identify individuals?
A. DNA amplification C. DNA labeling
B. DNA fingerprinting D. DNA sequencing
97. Without the presence of the enzymes, the reactions necessary to sustain
life would require one of the following in order to occur?
A. Higher temperature C. Higher enzyme concentration
B. Higher PH value D. Higher substrate concentration
98. Which populations control measures will help to reduce the rapid
increase in population growth that characterizes Ethiopia at the moment?
A. Good health alongside education
B. Free contraception and sex education
C. Discourage more than one child per family
D. Compulsory contraception before a marriage

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99. Locus is
A. the location of a gene on a chromosome
B. the sequence of amino acids in a protein
C. half of a gene that occupies specific location
D. the point of crossing over between two chromosomes
100.In order to determine whether the parental organisms is heterozygous or
homozygous dominant what can you do? The parental organisms crossed
with a:
A. Homozygous recessive C. Heterozygous
B. Homozygous dominant D. F1 offspring

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