One of the following biomes in Africa is supporting large wild mammals such as elephants, giraffes and lions.

The rain forest of western Ethiopia

Grade 12 Biology national exam, 2005 E.C. (2013 G.C.)

95 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.

Sit this paper (timed)Practice mode

1.Which one of the following is the main constituent of biological membranes?
- A. Phospholipids
- B. Glycoproteins
- C. Glycolipids
- D. Cholesterol
Answer: A. Every biological membrane is built as a double sheet of phospholipids. Each phospholipid has a water loving head and two water hating tails, so in water the molecules line up automatically with the tails facing inward and the heads facing out. That bilayer is the sheet itself, and everything else sits inside it. Cholesterol is tempting because animal membranes really do contain it, but it is a small amount tucked between the phospholipids to control how stiff the membrane is, not the material the membrane is made from. Textbook: Grade 10, unit 3 · section 3.1.3.
2.One of the following biomes in Africa is supporting large wild mammals such as elephants, giraffes and lions.
- A. The Congo rain forest
- B. The rain forest of western Ethiopia
- C. The savanna grassland
- D. The Sahara desert
Answer: C. The savanna is open grassland with scattered trees and a long dry season. Grass grows back fast after rain and after grazing, so it can feed huge herds of elephants, giraffes and zebras, and those herds in turn feed lions and other big predators. The Congo rain forest is tempting because it holds more species than any other African biome, but its closed canopy leaves little food at ground level, so its large mammals are scattered forest animals rather than the big open plains herds. Textbook: Grade 9, unit 6 · section 6.1.5.
3.Which of the following steps in the scientific method comes following observation?
- A. Predication
- B. Hypothesis
- C. Experiment
- D. Theory
Answer: B. The scientific method starts when you notice something, then you offer a possible explanation for what you noticed. That proposed explanation is the hypothesis, and it is what the rest of the work tests. Prediction is tempting, but a prediction is what you work out from a hypothesis you already have: without the hypothesis first, there is nothing to predict from. Textbook: Grade 12, unit 4 · section 4.1.1.
4.The main components of the plant cell wall are ____________?
- A. Starch
- B. Cellulose
- C. protein
- D. chitin
Answer: B. The plant cell wall is made mainly of cellulose, long unbranched chains of glucose that lie side by side and bond to each other to form tough fibres. Those fibres give the wall its strength and keep the cell from bursting when water enters. Starch is tempting because it is also made of glucose, but starch chains coil into grains stored inside the cell as food, and they carry no structural strength. Chitin does build a wall, but in fungi rather than plants. Textbook: Grade 10, unit 3 · section 3.1.3.
5.Which of the following classes of enzymes digests carbohydrates?
- A. Amylases
- B. Lipases
- C. Proteases
- D. Nucleases
Answer: A. Amylases are the carbohydrate digesting enzymes. The name comes from amylum, the Latin word for starch, and salivary and pancreatic amylase both break starch down into maltose and then to glucose. Enzymes are usually named after what they act on, which is the quickest way to sort this list. Proteases are tempting only if the naming rule is missed: they act on proteins, not on sugars. Textbook: Grade 10, unit 5 · section 5.1.
6.Which of the following kingdoms of life is consisting of prokaryotic organisms?
- A. Fungi
- B. Monera
- C. Protista
- D. Plantae
Answer, explanation and textbook page: open in the app.
7.Which component of soil fertility is improved when farmers grow legumes in crop rotation ?
- A. Phosphorus
- B. Nitrogen
- C. Sulfur
- D. Carbon
Answer, explanation and textbook page: open in the app.
8.Which one of the following do bees use to inform other bees about location and distance of a new source of nectar they discover?
- A. Pheromones
- B. Waggle dance
- C. Buzzing noise
- D. vibration of wings
Answer, explanation and textbook page: open in the app.
9.What are the specialists in biology called if he/she studies fossils to generate new knowledge on the origin and evolution of living things of past geologic periods?
- A. Geneticist
- B. Ecologist
- C. Paleontogist
- D. comparative Biochemist
Answer, explanation and textbook page: open in the app.
10.All proteins contain carbon, hydrogen, oxygen and what other element?
- A. Chlorine
- B. Fluorine
- C. Nitrogen
- D. Sulphur
Answer, explanation and textbook page: open in the app.
11.Which of the following is the correct $F_2$ phenotypic ratio of a monohybrid cross?
- A. 1:2
- B. 1:1
- C. 3:1
- D. 2:2
Answer, explanation and textbook page: open in the app.
12.How many carbon atoms are there in one disaccharide molecule?
- A. 6
- B. 12
- C. 18
- D. 24
Answer, explanation and textbook page: open in the app.
13.Which unit is best to use for measuring the smallest cells and organelles?
- A. Micrometer
- B. Milliliter
- C. Millimeter
- D. Nanometer
Answer, explanation and textbook page: open in the app.
14.Which energy rich organic compound contains adenine in its molecule ?
- A. Lipid
- B. Carbohydrate
- C. Glucose
- D. ATP
Answer, explanation and textbook page: open in the app.
15.What are the most frequent causative agents of food poisoning?
- A. Bachteria
- B. Protozoa
- C. viruses
- D. Worms
Answer, explanation and textbook page: open in the app.
16.What are the most likely causes of variations within species?
- A. Mitosis and a sexual reproduction.
- B. Overpopulation and overproduction.
- C. Vegetative propagation and cloning.
- D. Mutations and sexual reproduction.
Answer, explanation and textbook page: open in the app.
17.In which hominid species did scientists find the smallest brain size (cranial capacity)?
- A. Homo Sapiens
- B. Homo Habilis
- C. Homo erectus
- D. Homo neanderthalensis
Answer, explanation and textbook page: open in the app.
18.Which of the following is NOT classified as a learned behavior?
- A. Insight
- B. Innate
- C. Latent
- D. Conditioned
Answer, explanation and textbook page: open in the app.
19.In which one of the following aspects is the tropical rain forest biome poor?
- A. Species diversity
- B. amount of sunlight
- C. Annual precipitation
- D. Soil fertility
Answer, explanation and textbook page: open in the app.
20.If the size of a cell increase, which one of the following gets smaller?
- A. The volume of the cell
- B. The surface area of the cell
- C. surface area to volume ratio of cell
- D. volume to surface ratio of the cell
Answer, explanation and textbook page: open in the app.
21.What makes unsaturated fatty acids different from saturated fatty acids?
- A. The presence of long chain of carbon
- B. The presence of one or more double bonds
- C. The presence of large number of hydrogen atoms
- D. Their occurrence as solid at room temperature
Answer, explanation and textbook page: open in the app.
22.Which of the following pairs of molecule are known to have catalytic activity?
- A. Lipids and proteins
- B. carbohydrate and proteins
- C. protein and RNAs
- D. protein and DNAs
Answer, explanation and textbook page: open in the app.
23.If a suspension of a mixture of cellular organelle is spun in a centrifuge, which organelle settles to the bottom first?
- A. Mitochondria
- B. Nuclei
- C. Chloroplasts
- D. Ribosomes
Answer, explanation and textbook page: open in the app.
24.During chemiosmosis, what substance diffuses from one side to the other side of the membrane?
- A. Water molecules
- B. protons
- C. Electrons
- D. ATP molecules
Answer, explanation and textbook page: open in the app.
25.Which of the following human diseases can be prevented by taking proper diets?
- A. Degenerative diseases
- B. Genetic diseases
- C. Social diseases
- D. Deficiency diseases
Answer, explanation and textbook page: open in the app.
26.When two species are compared ,which of the following sources of evidence is least informative about the degree of relationships between the species?
- A. Nucleotide sequence of DNAs
- B. Amino acid sequence of proteins
- C. Gluscose sequence of polysaccharides
- D. DNA-DNA hybridization
Answer, explanation and textbook page: open in the app.
27.Which of the following practices dose NOT normally transmit HIV?
- A. Sexual intercourse through anus
- B. sharing injection needles
- C. Blood transfusion
- D. shaking hands
Answer, explanation and textbook page: open in the app.
28.What is the important role played by microorganism such as bacteria and fungi in the ecosystem?
- A. ?Antibiotic production
- B. Recycling of nutrients
- C. Forming organic substance
- D. Supplying energy to the ecosystem
Answer, explanation and textbook page: open in the app.
29.Which of the following theories explains evolutionary changes of living things in terms of changes in their allele frequencies?
- A. Darwin's natural selection
- B. Spontaneous generation
- C. Inheritance of acquired characteristics
- D. Neo-Darwinism
Answer, explanation and textbook page: open in the app.
30.Which of the following is an important function of the Golgi apparatus?
- A. Protein synthesis
- B. packaging of proteins
- C. Removing of ᓼdebris from cell
- D. Storage of waste materials not needed by the cell
Answer, explanation and textbook page: open in the app.
31.Which of the following is NOT usually true as an ecological succession progresses to advanced seral stages ?
- A. More ecological niches are formed
- B. Species become more diverse
- C. The depth of the soil increase
- D. Less population is supported
Answer, explanation and textbook page: open in the app.
32.One of the following is an important cause of gene of gene mutation.
- A. Old age
- B. Alcoholic drinks
- C. Smoking
- D. Radiation
Answer, explanation and textbook page: open in the app.
33.What is the reproductive isolating mechanism called if two species of forgs do not interbreed because they cannot understand the mating calls of one another
- A. Seasonal isolation
- B. Behavioral isolation
- C. Temporal isolation
- D. isolation by distance
Answer, explanation and textbook page: open in the app.
34.How many chromosomes do humans inherit from each of their parents?
- A. 23 chromosome
- B. 23 pairs of chromosome
- C. 46 chromosome
- D. 46 pairs of chromosome
Answer, explanation and textbook page: open in the app.
35.In which one of the four phases of population growth is the number of the population the highest ?
- A. Lag phase
- B. log phase
- C. Constant phase
- D. Decline phase
Answer, explanation and textbook page: open in the app.
36.Which of the following is NOT true abut the gene called SRY?
- A. It is found on the Y-chromosome.
- B. It determines maleness.
- C. Testes develop in its presence.
- D. Female have two copies of this gene.
Answer, explanation and textbook page: open in the app.
37.To which of the following groups do those bacterio phages that integrate their DNA in to the chromosome of their bacterial host belong?
- A. Virulent viruses
- B. Lytic viruses
- C. Lysogenic viruses
- D. Non-parasitic viruses
Answer, explanation and textbook page: open in the app.
38.What do we call the learned behavior if a mouse that had just escaped from the mouth of a cat jumped violemy at a slight touch by a trivial object?
- A. Latent learning
- B. Sensitization
- C. Conditioning
- D. Imprinting
Answer, explanation and textbook page: open in the app.
39.In which of the following features are eukaryotic cells distinguished from prokaryotic cells?
- A. They have mitochondria
- B. ᓼTheir nuclei lack membrane
- C. They have no DNA
- D. They have smallest ribosomes
Answer, explanation and textbook page: open in the app.
40.What will happen if human red biood cells are kept in a hypotonic solution
- A. Lose water by osmosis and burst
- B. Lose water by osmosis and shrink
- C. Take in water by osmosis ,swell and burst
- D. Take in water by osmosis ,swell and remain turgid
Answer, explanation and textbook page: open in the app.
41.Which of the following field equipment is used to detrmine an exact location of a place?
- A. Theodolite
- B. Global positioning system
- C. Field microscope
- D. Field PH kit
Answer, explanation and textbook page: open in the app.
42.The sheep 'dolly' is an example of which biotechnological manipulation of animals by human?
- A. Transgenic animal
- B. Genetically engineered animal
- C. Cloned animal
- D. Hybrid animal
Answer, explanation and textbook page: open in the app.
43.Among the following ,which one is the best criterion to show that two population belong to same species?
- A. Morphological similarity
- B. Physiologically similarity
- C. Inhabiting the same geographic area
- D. Production of fertile offspring
Answer, explanation and textbook page: open in the app.
44.In the process of the evolution of life on earth , which of the following four processes evolved last?
- A. Photosynthesis
- B. Aerobic respiration
- C. chemosynthesis
- D. Photo-autotrophism
Answer, explanation and textbook page: open in the app.
45.What is a theory in biology?
- A. The outcome of an experiment
- B. A proof that shows the hypothesis is true
- C. A hypothesis supported by experiments and/or observations.
- D. An opinion or educated guess resulting from observations.
Answer, explanation and textbook page: open in the app.
46.For which of the following is a theodolite used in biology education?
- A. Measuring the height of trees
- B. Recording positions where a species is found
- C. Measuring the rate of flow of water in a cell.
- D. Measuring the PH of water or soil.
Answer, explanation and textbook page: open in the app.
47.What is the name of the suger found in milk?
- A. Glucose
- B. Lactose
- C. Maltose
- D. Sucrose
Answer, explanation and textbook page: open in the app.
48.To which class of enzymes do the digestive enzymes belongs?
- A. Esterases
- B. Transferases
- C. Hydrolyses
- D. Isomerases
Answer, explanation and textbook page: open in the app.
49.Which of the following crops is considered to be the best choice for a better balance of essential amino aides as a human diet?
- A. Maize
- B. Quinoa
- C. Rice
- D. Wheat
Answer, explanation and textbook page: open in the app.
50.What is the main reason fore the high species richness of pants and mammals observed in Ethiopia?
- A. Lack of predators
- B. Lack of disturbance
- C. Presence of several becomes within the country
- D. Efficient management of the ecological resources
Answer, explanation and textbook page: open in the app.
51.In which type of solution is the water potential more negative than in the cells?
- A. Hypotonic
- B. hyper-tonic
- C. Isotonic
- D. equal solute and solvent concentration
Answer, explanation and textbook page: open in the app.
52.Which of the following paired organelle are membrane-bound?
- A. Ribosomes and peroxisomes
- B. Chloroplasts and ribosomes
- C. Mitochondria and ribosome
- D. chloroplasts and mitochondria
Answer, explanation and textbook page: open in the app.
53.Most cell membrane are primarily composed of which compounds
- A. Proteins and lipids
- B. DNA and ATP
- C. Chitin and starch
- D. Nucleotides and amino acids
Answer, explanation and textbook page: open in the app.
54.Which group of micro-organisms cause the diseases known as athletes foot?
- A. Bacteria
- B. Fungi
- C. Protozoa
- D. Viruses
Answer, explanation and textbook page: open in the app.
55.Choose the one that is different from all the others.
- A. Genetically modified organisms
- B. Genetically engineered organisms
- C. Pathogenic organisms
- D. Transgenic organisms
Answer, explanation and textbook page: open in the app.
56.Under which of the following groups can the fungi be more conveniently placed?
- A. Autotrophs
- B. Heterotrophs
- C. Prokaryotes
- D. Plants
Answer, explanation and textbook page: open in the app.
57.What is the type of community called when it has reached the final and most complex stage of a succession
- A. Pioneer community
- B. seral community
- C. Climax community
- D. secondary community
Answer, explanation and textbook page: open in the app.
58.Which of the following is an ecosystem
- A. A Tropical Rain forest
- B. The African continent
- C. All the organisms in a given area
- D. The non-living components of an environment
Answer, explanation and textbook page: open in the app.
59.Which of the following characteristics can show the evolutionary relationships among organism?
- A. Structures having similar function
- B. structures having same size
- C. structure having common origin
- D. structure having different origin
Answer, explanation and textbook page: open in the app.
60.The group of the Ethiopian wolf does NOT contribute to territory marking with their urine containing pheromones is __________.
- A. Adult males
- B. Adult females
- C. sub-adult males
- D. Sub-adult females
Answer, explanation and textbook page: open in the app.
61.In which of the following are flowers and fruits found?
- A. Ferns and relative
- B. Gymnosperms and ferns
- C. Mosses and conifers
- D. monocots and dicots
Answer, explanation and textbook page: open in the app.
62.In a cross between heterozygous what proportion is expected to be homozygous recessive?
- A. 25%
- B. 50%
- C. 75%
- D. 100%
Answer, explanation and textbook page: open in the app.
63.Gene silencing is the function of one of the following molecules.
- A. dsRNA
- B. mRNA
- C. siRNA
- D. tRNA
Answer, explanation and textbook page: open in the app.
64.Which processes is held responsible for chronic myelogenous leukemia?
- A. Translocation
- B. Translation
- C. Transcription
- D. Duplication
Answer, explanation and textbook page: open in the app.
65.Two parents of genotype Aa are cross-bred .The alleles show complete dominance. What proportion of the offspring will phenotypically look like their parents?
- A. 0
- B. 1/4
- C. 1/2
- D. 3/4
Answer, explanation and textbook page: open in the app.
66.Which one of the following concepts contains all the other ?
- A. Species
- B. Genus
- C. population
- D. community
Answer, explanation and textbook page: open in the app.
67.Choose the one that is NOT a requirement of all living things.
- A. Ability to think
- B. organization of parts
- C. Response to the stimuli
- D. Maintenance of internal constancy
Answer, explanation and textbook page: open in the app.
68.What is the advantage of using HAART (highly active antiretroviral therapy ) for the treatment of HIV
- A. It gives a lasting immunity to HIV
- B. It prevents mutation of HIV.
- C. It prevents re-infection by HIV.
- D. It helps to break the life cycle of HIV.
Answer, explanation and textbook page: open in the app.
69.In which of its contents RNA differs from DNA?
- A. Deoxyribose and guanine
- B. Ribose and uracil
- C. Ribose and uracil
- D. Phosphate and adenine
Answer, explanation and textbook page: open in the app.
70.Which of the following cell types can be rich in lysosomes?
- A. Red blood cells
- B. Nerve cells
- C. Phagocytic cells
- D. Muscle cells
Answer, explanation and textbook page: open in the app.
71.What can one conclude about the contents of the food stuff if a mixture of Benedict solution and foodstuff remain blue after heating ?
- A. It contains proteins
- B. It lacks starch
- C. It contains fats
- D. It lacks reducing sugar
Answer, explanation and textbook page: open in the app.
72.Which of the following types of enzyme inhibitions can be removed when the end product of the metabolic pathway is depleted?
- A. Allosteric inhibition
- B. Non-reversible inhibition
- C. competitive inhibition
- D. Reversible competitive inhibition
Answer, explanation and textbook page: open in the app.
73.If red blood cells shrink when placed in a certain solution ,what is the strength of the solution relative to the strength of the protoplasm of the cells?
- A. Hypotonic
- B. Isotonic
- C. Hyper tonic
- D. Isoosmotic
Answer, explanation and textbook page: open in the app.
74.Which of the following is NOT true about photo system-II?
- A. Its reaction center molecule is P680.
- B. Its passes its excited electrons to photo system-I
- C. The energy lost from its excited electrons reduces NADP
- D. It replenishes its lost electrons from photolysis of water.
Answer, explanation and textbook page: open in the app.
75.On which one of the following principle are most of the anti-HIV drugs currently in use working?
- A. Inhibition of enzyme action
- B. Degradation of viral RNA
- C. Digesting of viral particles
- D. Phagocytosis of the virus
Answer, explanation and textbook page: open in the app.
76.Among the following mating, where the ABO blood genotype of the partners are shown, identify the mating in which all the children will have the same blood type.
- A. AO x BO
- B. AA x OO
- C. AB x BO
- D. BB x AO
Answer, explanation and textbook page: open in the app.
77.If a new mutant allele arises in a certain population, which of the following factors determines if the allele is going to b adaptive or non- adaptive
- A. The environment in which the population lives.
- B. The rate at which the gene mutates.
- C. The population in which the gene is found
- D. The use and disuse of the gene by the population
Answer, explanation and textbook page: open in the app.
78.Which of the following is the correct route that connects a stimulus and a response?
- A. Receptor --> coordinator --> effector
- B. Coordinator-->receptor--> effector
- C. Receptor--> effector --> coordinator
- D. Effector--> receptor --> coordinator
Answer, explanation and textbook page: open in the app.
79.In which of the following compound are both members of the pair are polymers of carbohydrates that naturally occur in plants only?
- A. Starch and chitin
- B. Starch and cellulose
- C. Glycogen and cellulose
- D. Glycogen and chitin
Answer, explanation and textbook page: open in the app.
80.Which of the following is generally expected to give better health benefits when presence in human diet?
- A. Animal fat
- B. Mono unsaturated fatty acid
- C. Saturated fatty acid
- D. Polyunsaturated fatty acid
Answer, explanation and textbook page: open in the app.
82.Suppose the amino acid coding region in a mRNAis 1200 nucleotides long, how long is the protein in terms of amino acid number?
- A. 1200 amino acids
- B. 600 amino acids
- C. 400 amino acids
- D. 300 amino acids
Answer, explanation and textbook page: open in the app.
83.If a new anti-HIV drug is to be developed to prevent the virus form entering the host cell, which one of the following processes should the drug target?
- A. Reverse transcription
- B. Binding of Gp120 and CD4
- C. Integration of viral DNA in to host DNA
- D. Assembly of viral parts in to a whole virus
Answer, explanation and textbook page: open in the app.
84.Which one of the following factors is NOT important for evolutionary change of a population
- A. Over reproduction
- B. Insufficiency of natural resource
- C. Existence of heritable variations
- D. Survival of all that are born
Answer, explanation and textbook page: open in the app.
85.One of the following would be harder to see under the ordinary light microscope that is more likely to be available in school laboratories .
- A. Nucleus
- B. A bacterium
- C. A mitochondrion
- D. A ribosome
Answer, explanation and textbook page: open in the app.
86.In some human liver cells there are 92 chromosome per cell. What is the ploidy level of such cells?
- A. Haploid
- B. Diploid
- C. Tetraploid
- D. Hexaploid
Answer, explanation and textbook page: open in the app.
87.Which of the following groups of substance are all inorganic?
- A. Water ,sugar, calcium, carbonate
- B. sugar , fatty acid , amino acid
- C. Water ,calcium carbonate,carbon dioxide
- D. Carbon dioxide ,amino acid, fatty acid
Answer, explanation and textbook page: open in the app.
88.To what kind of animal behavior can the spinning of a web by a spider be classified?
- A. Learned behavior
- B. Experiential behavior
- C. Instinctive behavior
- D. Accidental behavior
Answer, explanation and textbook page: open in the app.
89.Which of the following is a recently developed active area of research in biology today?
- A. Taxonomic study
- B. study about the cell theory
- C. Ecological research
- D. stem cell research
Answer, explanation and textbook page: open in the app.
90.Where dose the light dependent reaction of photosynthesis occur in the chloroplast?
- A. In the thylakoid ?membrane
- B. In the fluid of the stroma
- C. In all parts of the chloroplast
- D. In the stomatal opening
Answer, explanation and textbook page: open in the app.
91.In which process is ATP generated during short distance hight speed running ?
- A. Aerobic respiration
- B. Mitochondrial energy transformation
- C. Anaerobic respiration
- D. The krebs cycle
Answer, explanation and textbook page: open in the app.
92.Which one of the following choices shows the end products of a mitotic cell division?
- A. Gametes and ordinary cells
- B. Four genetically different cells
- C. Two genetically different cells
- D. Two genetically identical cells
Answer, explanation and textbook page: open in the app.
93.What exactly happens during a substitution mutation?
- A. One base is replaced by a different base.
- B. An extra base is added during DNA replication
- C. A base is missed out during DNA replication
- D. Change occur in the arrangement or structure of a chromosome
Answer, explanation and textbook page: open in the app.
94.During the course of evolution, which of the following events came before all the others?
- A. Origin of dinosaurs and other reptiles.
- B. Availability of free oxygen in the atmospare
- C. Origin of the oldest eukaryotic organism
- D. origin of the first multicellular animals and plants.
Answer, explanation and textbook page: open in the app.
95.What kind of natural selection is at work in a situation where individual at both extreme ends of the range get better survival advantages that those around the middle?
- A. Stabilizing selection
- B. Direction selection extremes
- C. Disruptive selection
- D. Selection that removes the
Answer, explanation and textbook page: open in the app.
96.In which geologic period does the fossil record show more diverse and relatively higher forms of organism?
- A. Devonian
- B. Cretaceous
- C. Jurassic
- D. Permian
Answer, explanation and textbook page: open in the app.

Other Biology years: 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006