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Grade 12 Biology national exam, 2009 E.C. (2017 G.C.)
97 questions · 120 minutes. The first 5 answers are shown with explanations; sit the whole paper timed in the app to get your score and the textbook page behind every question.
- 1.The word science comes from the Latin word 'Scientia' meaning what ?
- A. Study
- B. Experiment
- C. Life
- D. Knowledge
Answer: D. The question tests the meaning of the Latin word “Scientia.” “Scientia” means knowledge. “Study” (A), “experiment” (B), and “life” (C) are not its meaning. Textbook: Grade 10, unit 1 · section 1.2. - 2.Which of the following substance can be used over and over again in an enzyme catalyzed reaction?
- A. Enzyme -substrate complex
- B. Substrate
- C. Enzyme
- D. Reaction product
Answer: C. The key idea is that an enzyme can work repeatedly in a reaction. The enzyme helps change the substrate into product without being used up, so C is correct. A is wrong because the enzyme-substrate complex is a temporary state; B is wrong because the substrate is changed into product; D is wrong because the product is formed by the reaction. Textbook: Grade 11, unit 3 · section 3.2.1. - 3.What is the intermediate compound that is formed during an enzyme catalyzed reaction?
- A. Reaction
- B. Substrate
- C. Product
- D. Enzyme-substance complex
Answer: D. An enzyme and its substrate form a temporary enzyme-substrate complex during a reaction. This intermediate forms when the substrate binds to the enzyme. A is wrong because a reaction is a process, not the intermediate; B is wrong because the substrate is the starting material; C is wrong because the product is formed after the reaction. Textbook: Grade 11, unit 3 · section 3.11. - 4.Which of the following microorganisms are prokaryotic?
- A. Bacteria
- B. Protozoa
- C. Yeast
- D. Algae
Answer: A. Prokaryotic cells have no nucleus enclosed by a membrane. Bacteria are prokaryotic, while protozoa, yeast, and algae are eukaryotic. B is eukaryotic; C is eukaryotic; D is generally eukaryotic. Textbook: Grade 12, unit 2 · section 2.4.1. - 5.Which of the following laboratory tools is LEAST accurate to measure 1 ml of liquid?
- A. Pipette
- C. Burett
- B. Measuring cylinder
- D. Beaker
Answer: D. The key idea is that a beaker is the least accurate tool for measuring a small volume such as $1\,\mathrm{mL}$. A beaker gives only a rough estimate of liquid volume. A is wrong because a pipette is designed to measure and transfer small volumes accurately. B is wrong because a measuring cylinder is more accurate than a beaker. C is wrong because a burette measures delivered liquid volume more accurately than a beaker. Textbook: Grade 12, unit 3 · section 3.4.3. - 6.From which of the following diseases can one be protected by sleeping under the cover of a mosquito net?
- A. Sleeping sickness
- B. AIDS
- C. Malaria
- D. Athlete's foot
Answer, explanation and textbook page: open in the app. - 7.Which of the following parts of the flower did Mendel remove from young flowers to prevent self-population ?
- A. Stamens
- B. Sepals
- C. Petals
- D. Ovaries
Answer, explanation and textbook page: open in the app. - 8.What do we call the place where organisms live in their ecosystem ?
- A. Abiotic
- B. Biotic
- C. Habitat
- D. Niche
Answer, explanation and textbook page: open in the app. - 9.Which of the following is the sex chromosome constitution of human males?
- A. XX
- B. XY
- C. ZZ
- D. ZW
Answer, explanation and textbook page: open in the app. - 10.Which of the following plants use CAM photosynthesis?
- A. Sugarcane
- B. Sorghum
- C. Maize
- D. Cactus
Answer, explanation and textbook page: open in the app. - 11.Which of the following bases is NOT found in RNA?
- A. Adenine
- B. Guanine
- C. Cytosine
- D. Thymine
Answer, explanation and textbook page: open in the app. - 12.In a report of the scientific experiment description of which of the following comes before all the others?
- A. Procedure
- B. Results
- C. Hypothesis
- D. Conclusion
Answer, explanation and textbook page: open in the app. - 13.Which one of the following is different from the other three?
- A. Starch
- B. Glycogen
- C. Cellulose
- D. Maltose
Answer, explanation and textbook page: open in the app. - 14.What happens when a plant cell absorbs in more water?
- A. It shrinks
- B. It becomes turgid
- C. It becomes wilted
- D. It swells and bursts
Answer, explanation and textbook page: open in the app. - 15.Which level of protein structural organization involves two or more polypeptide?
- A. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Answer, explanation and textbook page: open in the app. - 16.Which of the following do biologists consider ancestral to the higher organisms of today?
- A. Plantae
- B. Animalia
- C. Fungi
- D. Protista
Answer, explanation and textbook page: open in the app. - 17.Which type of fatty acids is healthier when used as a human food source?
- A. Saturated fatty acids
- B. Mono unsaturated fatty acids
- C. Polyunsaturated fatty acid
- D. Fatty acids in animal products
Answer, explanation and textbook page: open in the app. - 18.Which of the following is NOT recycled in the ecosystem?
- A. Sulphur
- B. Energy
- C. Carbon
- D. Phosphorus
Answer, explanation and textbook page: open in the app. - 19.What kind of cross is performed to determine whether the parent was homozygous or heterozygous ?
- A. Mono hybrid cross
- B. Di-hybrid cross
- C. Back cross
- D. Double cross
Answer, explanation and textbook page: open in the app. - 20.Which type of animal behavior happens with out learning?
- A. Innate
- B. Latent
- C. Insight
- D. Conditioned
Answer, explanation and textbook page: open in the app. - 21.Which drop of iodine solution is added to a solution of a foodstuff and the foodstuff turns dark blue what dose the foodstuff contain
- A. Reducing sugar
- B. Disaccharide
- C. Glucose
- D. Starch
Answer, explanation and textbook page: open in the app. - 22.Which of the following has the highest risk of HIV transmission?
- A. Hand shaking
- B. Needle sharing
- C. Towel Sharing
- D. Toilet Sharing
Answer, explanation and textbook page: open in the app. - 23.Which of the following organelles is common to both plant and animal cells?
- A. Cell wall
- B. Chloroplast
- C. Mitochondria
- D. Central vaculie
Answer, explanation and textbook page: open in the app. - 24.Among the following organic molecules, identify the one that dose not contain nitrogen.
- A. Starch
- B. Protein
- C. DNA
- D. RNA
Answer, explanation and textbook page: open in the app. - 25.If a cell fails to form lysosomes, which of the following cellular functions will get disturbed first?
- A. Protein synthesis
- B. Chromosome replication
- C. Removal of cellular debris
- D. Transport across cell membrane
Answer, explanation and textbook page: open in the app. - 26.Most co-enzymes are the derivatives of which of the following enzymes would one use?
- A. Proteins
- B. Vitamins
- C. Carbohydrates
- D. Fats
Answer, explanation and textbook page: open in the app. - 27.To produce from starch, which of the following enzymes would one use?
- A. Isomerases
- B. Lyases
- C. Hydrolases
- D. Ligases
Answer, explanation and textbook page: open in the app. - 28.Which class of enzyme inhibitors has similar shape as that of the normal substrate?
- A. Allosteric
- B. Competive
- C. Denaturing
- D. Irreversible
Answer, explanation and textbook page: open in the app. - 29.Fore a substance to easily pass arose the cell membrane by simple diffusion which of the following properties should it possess?
- A. Large size
- B. Ability to dissolve in lipid
- C. Positive charge
- D. Negative charge
Answer, explanation and textbook page: open in the app. - 30.Among the following factors that affect enzyme activity, which one dose NOT cause enzyme denaturation?
- A. High pH
- B. Low pH
- C. High temperature
- D. Competitive inhibitor
Answer, explanation and textbook page: open in the app. - 31.Which of the following is a type of ecological succession that starts from a cleared forest area?
- A. Hydrosere
- B. Primary
- C. Secondary
- D. Pioneer
Answer, explanation and textbook page: open in the app. - 32.Which of the following stage of photosynthesis can take place in the dark?
- A. Photolysis of water
- B. Photosystem I
- C. Photosystem II
- D. Calvin cycle
Answer, explanation and textbook page: open in the app. - 33.Which of the following is the major role-played by bacteria and fungi in the ecosystem?
- A. Causing diseases
- B. Nutrient recycling
- C. Fixing carbon dioxide
- D. Producing antibiotice
Answer, explanation and textbook page: open in the app. - 34.If a heterozygous tall pea plant (Tt) is crossed with a short pea plant(tt) ,what percentage of the progeny is expected to be short?
- A. 100%
- B. 75%
- C. 50%
- D. 25%
Answer, explanation and textbook page: open in the app. - 35.Which of the following human cell types is attacked by HIV?
- A. Red blood cells
- B. White
- C. T- lymphocytes
- D. Leukocytes
Answer, explanation and textbook page: open in the app. - 36.Which of the following processes is most important to release nutrients from dead organic matter in to the soil?
- A. Fixation
- B. Decomposition
- C. Excretion
- D. Respiration
Answer, explanation and textbook page: open in the app. - 37.Which of the following biomes supports the highest diversity of plant and animal life?
- A. Tropical rain forest
- B. Deciduous forest
- C. Grassland
- D. African savannah
Answer, explanation and textbook page: open in the app. - 38.Which of the following demographic factors can increase the size of the world population?
- A. Natality
- B. Migration
- C. Emigration
- D. Immigration
Answer, explanation and textbook page: open in the app. - 39.When Mendel crossed a tall pea plant with a short plant the progeny were all tall what did he obtain when he made the reciprocal cross?
- A. Short plants
- B. Tall plants
- C. Extra-tall plants
- D. Plants of average height
Answer, explanation and textbook page: open in the app. - 40.Among the following ABO blood group genotype, which one produces two types which one produces two types of antigens?
- A. $I^{A}I^{O}$
- B. $I^{B}I^{O}$
- C. $I^{A}I^{B}$
- D. $I^{B}I^{B}$
Answer, explanation and textbook page: open in the app. - 41.Which of the following methods do animal breeders use to produce domestic animals with hybrid vigor?
- A. Feeding with natritive food
- B. Mating together related animals
- C. Giving proper veterinary care
- D. Crossbreeding their animals
Answer, explanation and textbook page: open in the app. - 42.Which of the following groups are believed to be the first photosynthetic organisms to evolve on earth?
- A. Green plants
- B. Green algae
- C. Blue green algae
- D. Lichens
Answer, explanation and textbook page: open in the app. - 43.Which of the following factors brings about changes during both evolution and breeding of plants and animals?
- A. Limited resources
- B. Production of excess progeny
- C. Selection
- D. Competition
Answer, explanation and textbook page: open in the app. - 44.Among the following which one is held most responsible for the present fast depletion of the world biodiversity ?
- A. Herbivores
- B. Carnivores
- C. Grazers
- D. Humans
Answer, explanation and textbook page: open in the app. - 45.Which of the following reproductive isolating mechanisms keeps the horse and donkey as two independent species?
- A. Hybrid inviability
- B. Hybrid infertility
- C. Ecological isolation
- D. Habitat isolation
Answer, explanation and textbook page: open in the app. - 46.Which of the following activities of an organism do we call a behavior ?
- A. Reception of external stimulus
- B. Responding of internal stimulus
- C. Responding of stimulus
- D. Lack of receptors to receive stimulus
Answer, explanation and textbook page: open in the app. - 47.A reflex that involves internal organs such as the heart is referred to as:
- A. Somatic reflex
- B. External reflex
- C. Spinal reflex
- D. Autonomic reflex
Answer, explanation and textbook page: open in the app. - 48.At which of the following generation of crosses between dominant and recessive homozygote parents are all the progeny heterozygote?
- A. $P_1$ generation ?
- B. $F_1$ generation
- C. $F_2$ generation
- D. $F_3$ generation
Answer, explanation and textbook page: open in the app. - 49.Which of the following organs serves as a coordinating system in a reflex action?
- A. Spinal cord
- B. Dehydrogenase
- C. Nerve cells
- D. Oxidoreductase
Answer, explanation and textbook page: open in the app. - 50.Which type of enzyme catalyzes the joining of two molecules by the formation of new bonds?
- A. Decarboxylase
- B. Dehydrogenase
- C. Ligase
- D. Oxidoreductase
Answer, explanation and textbook page: open in the app. - 51.Which of the following statement about enzyme is NOT correct?
- A. Enzymes speed up on a chemical reaction
- B. Enzymes are very specific in their reaction
- C. The presence of an enzyme will change the outcome of a reaction
- D. Enzymes lower the energy of activation for a reaction to occur
Answer, explanation and textbook page: open in the app. - 52.Glycolysis occurs in the
- A. Cytoplasm
- B. Mitochondrion
- C. Nucleus
- D. Chloroplast
Answer, explanation and textbook page: open in the app. - 53.Anaerobic metabolism refers to the generation of ATP:
- A. Without the involvement of ADP
- B. Without the use of glycogen
- C. Without the use of oxygen
- D. by the conversion of pyruvate to lactate
Answer, explanation and textbook page: open in the app. - 54.The conversion of one molecule of glucose to two molecule of pyruvate results in the net formation of:
- A. Two molecule of ATP
- B. Six molecules of water
- C. Three molecules of ATP
- D. Thirty -eight molecules of ATP
Answer, explanation and textbook page: open in the app. - 55.During alcohol fermentation pyruvic acid in the presence of pyruvate decarboxylase is first converted to .
- A. Glucose
- B. Lactose
- C. Lactic acid
- D. Acetaldehyde
Answer, explanation and textbook page: open in the app. - 56.The total amount of living tissue within a given trophic level is called:
- A. Organic mass
- B. Energy mass
- C. Trophic mass
- D. Biomass
Answer, explanation and textbook page: open in the app. - 57.Biomes where trees predominant are called
- A. Polar biomes
- B. desert biomes
- C. Trophic mass
- D. Grassland biomes
Answer, explanation and textbook page: open in the app. - 58.The goals of biodiversity conservation include all of the following EXCEPT
- A. Protecting individual species
- B. Introducing exotic species in to new environments efforts
- C. Preserving habitats and ecosystem
- D. making sure local people benefit from conservation efforts
Answer, explanation and textbook page: open in the app. - 59.The maximum population growth rate characteristic of a species is called
- A. limiting factor
- B. biotic potential
- C. carrying capacity
- D. exponential growth pattern
Answer, explanation and textbook page: open in the app. - 60.from among the following choice the field which is a branch or a part of biotechnology.
- A. parasitology
- B. Immunology
- C. Phycology
- D. Genetic engineering
Answer, explanation and textbook page: open in the app. - 61.which of the following is publicly an UNDESIRED research activity
- A. breeding a new crop variety
- B. synthesis of a new vaccine
- C. manufacture of a new effective medicine
- D. breeding a new pathogeinc microoganism
Answer, explanation and textbook page: open in the app. - 62.which of the following alternatives contain ONLY organic molecule?
- A. calcium carbonate, glucose, methane
- B. carbon dioxide, sodium chloride, lysine
- C. linoleic acid, glycine, methane
- D. water, carbon dioxide, calcium carbonate
Answer, explanation and textbook page: open in the app. - 63.which test is suitable for checking the presence of lipids in foodstuffs ?
- A. buiret test
- B. bendect's test
- C. emulsion test
- D. lodine test
Answer, explanation and textbook page: open in the app. - 64.How do heavy metal ions reduce the reaction rate of enzymes?
- A. by distroying the 3- dimensional shape of the enzymes active site
- B. by raising the temperature above the optimum level for the enzyme
- C. by dropping the PH well below the optimum level for the enzyme
- D. by inducing mutation that disrupt the functioning of the enzyme
Answer, explanation and textbook page: open in the app. - 65.What happens when enzymes become denatured?
- A. They can normally catalyzed the reductions
- B. their active sites are changed
- C. rate of the reaction increase
- D. bonds holding amino acids are unaffected
Answer, explanation and textbook page: open in the app. - 66.What happens when human red blood cell are kept in a hypertonic solution ?
- A. the same net gain and loss of water
- B. more water gets into the cell than leaving it
- C. more water goes out of the cell then getting in
- D. the cell prevent water from getting in or leaving out
Answer, explanation and textbook page: open in the app. - 67.Among the following which one best describes the cell of bacteria?
- A. Eukaryotic
- B. Prokaryotic
- C. Both eukaryotic and prokaryotic
- D. Neither prokaryotic nor eukaryotic
Answer, explanation and textbook page: open in the app. - 68.Which of the following nitrogenous bases of nucleic acids is a purine base?
- A. Adenine
- B. Cytosine
- C. Thymine
- D. Uracil
Answer, explanation and textbook page: open in the app. - 69.Which of the plants with the following genotype is hetrozygyous?
- A. BBYY
- B. BbYb
- C. bbyy
- D. YYBB
Answer, explanation and textbook page: open in the app. - 70.Which of the following groups of viruses copy their RNA to DNA?
- A. Bacteriphages
- B. DNA viruses
- C. RNA viruses
- D. Retroviruses
Answer, explanation and textbook page: open in the app. - 71.During the Krebs cycle, to which of the following molecule is most of the energy released from food transferred?
- A. ATP
- B. NAD
- C. ADP
- D. AMP
Answer, explanation and textbook page: open in the app. - 72.During which stage of aerobic respiration dose oxidative phosphorylatuion occur?
- A. Glycolysis
- B. Krebs cycle
- C. Link reaction
- D. Chemiosmosis
Answer, explanation and textbook page: open in the app. - 73.What mode of feeding do soil organisms that release nutrients from dead organic matter in to the soil have?
- A. Photoautotrophic
- B. Saprophytic
- C. Chemoautotrophic
- D. Parasitic
Answer, explanation and textbook page: open in the app. - 74.When farmers are using fewer and fewer number of crop verities, what would happen to the genetic diversity of our crop plants?
- A. It would get eroded
- B. It would be more conserved
- C. It would be more diverse
- D. Nothing would happen to it
Answer, explanation and textbook page: open in the app. - 75.During anaerobic respiration, what is the gross number of ATP molecules that are produced per glucose molecule?
- A. Two
- B. Three
- C. Four
- D. Six
Answer, explanation and textbook page: open in the app. - 76.Among the following four processes, identify the one that probably evolved before all the other three.
- A. Aerobic respiration
- B. Anaerobic respiration
- C. Oxidizing atmospher
- D. Photosynthesis
Answer, explanation and textbook page: open in the app. - 77.Which of the following is NOT a learned behavior?
- A. Imprinting
- B. Habituation
- C. Conditioning
- D. Trial and error
Answer, explanation and textbook page: open in the app. - 78.If an actively growing seedling is kept horizontally, which of the following would eventually happen to the seedling?
- A. The shoot would bend upward
- B. The root would bend upward
- C. The seeding would stop growing
- D. The seedling would grow horizontally
Answer, explanation and textbook page: open in the app. - 79.Which of the following was the most possible mode of evolution by which the many species of Darwin's finches evolved on the Galapagos Islandeds?
- A. Phyletic evolution
- B. Divergent evolution
- C. Convergent evolution
- D. Sympatric evolution
Answer, explanation and textbook page: open in the app. - 80.For which of the following processes is ATP NOT required?
- A. Diffusion of oxygen in to cells
- B. Synthesis of molecules
- C. Active transport of molecules from one site to another
- D. Muscle contraction
Answer, explanation and textbook page: open in the app. - 81.Mutation may be described as:
- A. Phenotypic change
- B. Change in gene structure
- C. Continuous variation
- D. Change due to hybridization
Answer, explanation and textbook page: open in the app. - 82.Which of the following is the most UNLIKELY action that would be expected from Ethiopians who have been given adequated biological literacy?
- A. Engagement in activities resulting in biodiversity loss
- B. Supporting activities concerned with food security
- C. Awareness about climate change and its problem
- D. Engagement in biological resources conservation
Answer, explanation and textbook page: open in the app. - 83.Which form of mutation is responsible for the diseases known as leukemia?
- A. Duplication
- B. Insertion
- C. Inversion
- D. Deletion
Answer, explanation and textbook page: open in the app. - 84.Which of the following characteristic can show the evolutionary relationships among organisms?
- A. Structure having similar functions
- B. Presence of analogous structures
- C. Presence of homologous structures
- D. Structure having different origins
Answer, explanation and textbook page: open in the app. - 85.Which of the following species isolating processes could lead to the evolution of a new species by the mechanisms known as sympatric speciation?
- A. A river that change its course for many years
- B. A new mountain range that was created many years
- C. population of a species having different breeding seasons
- D. A land mass that separated two water bodies for many years
Answer, explanation and textbook page: open in the app. - 86.What is an apoenzyme?
- A. A protein molecule
- B. An active enzyme
- C. A non- protein molecule
- D. A non- protein cofactor
Answer, explanation and textbook page: open in the app. - 87.For which of the following can divergent evolution be taken as an alternative name?
- A. Allopatric speculation
- B. Adaptive radiation
- C. Stabilizing selection
- D. A non- protein cofactor
Answer, explanation and textbook page: open in the app. - 88.Which one of the following is the result of the similarity observed between the wings of a bird and a pterodactyl?
- A. Convergent evolution
- B. Directional selection
- C. Stabilizing selection
- D. Divergent evolution
Answer, explanation and textbook page: open in the app. - 89.Which of the following played an important role in the evolution of human being?
- A. Emergency of wings in addition to limbs
- B. Development of even toes in the forearms
- C. Development of feathers and hallow bones
- D. Development of opposable thumb to grasp
Answer, explanation and textbook page: open in the app. - 90.In which one of the following do we use genetically modified bacteria for purpose other than human health?
- A. Production of insulin
- B. Production of antibiotics
- C. Production of herbicides
- D. Production of vaccines
Answer, explanation and textbook page: open in the app. - 91.which knowledge about cell biology scientists discover after all the others?
- A. The first understanding that all living things are made of cells
- B. Knowledge about how chromosomes behave during mitosis
- C. First understanding about the double helix structure of DNA
- D. First understanding about the DNA sequence in human genome
Answer, explanation and textbook page: open in the app. - 92.Which of the following statements can be considered as the better definition of the biological concept of behavior?
- A. The reaction of a person or an animal in response to an external or internal stimulus
- B. The responses or reactions or movements that a living plant makes in any situation
- C. A system of coordinated response by an organism to an external or internal stimulus
- D. A receptor of some kind of stimulus that an organism has which produces a response
Answer, explanation and textbook page: open in the app. - 93.To which category of behavior does the human behavior that involves the strengthening of existing responses or the formation of new responses to existing stimuli that occur because of practice or repetition belong?
- A. Learned behavior
- B. Instinctive behavior
- C. Innate behavior
- D. Inborn behavior
Answer, explanation and textbook page: open in the app. - 94.Which of the following is NOT grouped under genetically pre-programmed pattern of behavior?
- A. Reflex actions in humans
- B. Orientation behavior
- C. Conditioned behavior
- D. Instinctive behaviors
Answer, explanation and textbook page: open in the app. - 95.Which group of bacteria reduces nitrate to nitrogen gas in th nitrogen cycle?
- A. Nitrogen fixing bacteria
- B. Ammonium ion forming
- C. Denitrifying bacteria
- D. photosynthetic bacteria
Answer, explanation and textbook page: open in the app. - 96.The main factors that determine the types of terrestrial biomes in a certain geographical area are:
- A. Soil and vegetation
- B. Soil and biological diversity
- C. Complexity in ecological succession
- D. Precipitation & temperature
Answer, explanation and textbook page: open in the app. - 97.In which parts of Ethiopian are Lions, Elephants, & Giraffes found more community?
- A. In the afroalpine and subafroalpine zones
- B. In the highland areas of northern Ethiopian
- C. In the grasslands of southwestern Ethiopian
- D. In central and northern parts of the rift valley
Answer, explanation and textbook page: open in the app.