Welcome to your GRADE 12 BIOLOGY MODEL EXAMINATIONS 2015
CHOOSE THE CORRECT ANSEWR FORM THE GIVEN QUESTIONS
1.
Suppose you have submitted a laboratory report for your teacher. The teacher returned it back saying that you didn‟t‟ properly explain the cause and effect relationships in your particular topic in the report. In which section of the report should you include this information?
2.
Which one of the following is used as an input to formulate a hypothesis about the particular observed problem?
3.
Identify the biological tool that used by ecologist to measure the distribution and abundance of slowly moving or non-moving organisms in the given ecological area?
4.
Which discipline of biology concerned with collection, storage, and analysis of biological data, mainly DNA and protein sequences?
5.
Which tools of biologist is more suitable for monitoring growing conditions in the agricultural industry?
6.
Data loggers are electronic devices used to continuously monitor and record environmental conditions such as temperature, humidity, and light intensity, which are crucial for optimal plant growth in agriculture.
7.
Biological knowledge is relevant in Ethiopia to address all of the following issues EXCEPT?
8.
Biologists have been striving to produce a vaccine against HIV based on the study of:
9.
A grade 12 student hypothesized that high concentration of copper dissolved in the water in the soil seriously affects the growth rate of plants. To test his hypothesis, he assigned plants as group “A” and group “B”. Group “A” plants were given different concentration of copper and group “B” plants were given moderate amount of copper. Each group has the same amount of soil, water, temperature and number of seeds. In this experiment, the number of seeds assigned in the experimental group is:
10.
The concentration of copper is the manipulated variable (independent variable) in the experiment, as it is intentionally changed to observe its effect on plant growth.
11.
Which chemical element is frequently found in living organisms with high percentage as compared to others?
12.
Carbon is the fundamental building block of organic molecules and is the most abundant element in living organisms.
13.
Which characteristics of carbohydrates distinguish them from protein and lipids?
14.
When 100 amino acids joined together through condensation reaction, how many peptide bonds are formed and water molecules are released respectively?
15.
When glucose and galactose molecules are joined together by glycosidic bond through condensation reaction, the expected molecular formula of the disaccharide will be:
16.
Which property of water helps to it to move through the xylem vascular bundle of plants during Passive transport system?
17.
A food gives a positive result when tested with the Emulision test, and an initial negative result when tested with Bendict‟s solution. Following acid hydrolysis and neutralization, the food gave a negative test with Benedict‟s solution. The food contains:
18.
If AIDS patients are given antiretroviral drugs that are targeted against the integrase enzyme, which one of the following stages of HIV life cycle would be inhibited?
19.
Why several different enzymes are involved to catalyze the metabolic system of human. This is because:
20.
Esters of fatty acids with long chain monohydric alcohol, found on the feather of birds and the fur of some animals which serve as a water repellent is refers to:
21.
Which one of the following is the functional role of co-enzymes?
22.
Cystic fibrosis is an inherited disease in which the body makes very thick, sticky mucus and results in breathing problems. Which enzyme is used to treat the person having this disease?
23.
Pulmozyme is a medication containing the enzyme DNase, which helps break down the thick mucus in the lungs of people with cystic fibrosis.
24.
Why biologists now prefer the induced-fit model over the lock and key model? Because it explains:
25.
In competitive inhibition, which one of the following factors determines the rate of inhibition?
26.
Which one of the following statement is best to describe the effect of PH on the activity of enzymes?
27.
Suppose a metabolic pathway consisting of five enzymes that are involved in the synthesis of the amino acid, isoleucine from amino acid, threonine. When a cell contains enough isoleucine, the synthesis is stopped by:
28.
Which one of the following human digestive enzymes works most effectively in acidic medium?
29.
If other conditions were to remain constant, which one of the following changes would explain a reduced rate of activity in an enzyme-controlled reaction?
30.
Which enzyme has been named based on the reaction that it catalyses?
31.
Sucrase is an enzyme that specifically catalyzes the hydrolysis of sucrose into glucose and fructose.
32.
According to the endosymbiont theory a large, anaerobic, heterotrophic prokaryote ingested a small, aerobic prokaryote, the aerobic endosymbiont has evolved into:
33.
The endosymbiotic theory proposes that mitochondria originated from free-living aerobic bacteria that were engulfed by a larger host cell.
34.
Which one of the following is found in both prokaryotic and eukaryotic cells?
35.
Ribosomes are found in all living cells, both prokaryotic and eukaryotic, and are responsible for protein synthesis.
36.
Which organelles are works together in the production, packaging, and distribution of proteins?
37.
When physicians perform an organ transplant, they choose a donor whose tissues match those of the recipient as closely as possible. Which of the following cell components are being matched?
38.
Which one of the following transport system is used as a mode of feeding mechanism for amoeba and protective mechanism of most animal cells?
39.
Identify the chemical component of cell membrane that functions as “temperature buffer,” stabilize the cell membrane at higher or lower temperature?
40.
All of the following features are shared by both prokaryotic and eukaryotic cells EXCEPT?
41.
In eukaryotic cells like plants, where citric acid cycle take place?
42.
Identify the correct statement regarding glycolysis metabolic pathway?
43.
In which mechanism C4 and CAM plants minimize photorespiration and optimize Calvin cycle?
44.
Why are carbohydrates and fats considered as high energy substrates for respiration?
45.
Which one of the following is the primary function of light dependent reaction of photosynthesis?
46.
Lactic acid fermentation is a metabolic process by which glucose is converted into cellular energy and metabolic lactate. When human aerobically respire, where is lactic acid converted back to pyruvic acid and then to glucose?
47.
A scientist suspects that a particular plant contains chloroplasts that lack photosystem II (PSII), even though it is able to live. How could the scientist determine if PSII is missing from the plant's chloroplasts?
48.
Which of the events listed below occur in the light independent reactions of photosynthesis?
49.
A grade 12 student conducted an experiment to separate and identify the photosynthetic pigments in spinach leaves using chromatography paper. He took a strip of chromatography paper and marked with a pencil line about 3 cm from one end and placed a small circular spot of pigment extract on the pencil line then, hang the strip inside the jar with specified solvent. The solvent carries the dissolved pigments as it moves up the paper. Which pigment molecule would travel the greatest distance?
50.
Which structure of bacteria enabling them to adhere to host tissue surfaces?
51.
Why Gram positive bacteria retain the blue or purple color of crystal violet in the gram stain after washing with decolonization reagent (alcohol)? Because they:
52.
To which of the following groups do those bacteriophages that integrate their DNA into the chromosome of their bacterial host belong?
53.
To prevent the transmission of infectious diseases, which element of transmission cycle of a disease should be controlled?
54.
Which one of the following disease is correctly matched with its causative agent?
55.
Some biologists say that, strictly, viruses are not microorganisms. This because viruses are/have
56.
Suppose Abebe suffers in drained of all energy with no apparent reason and the simplest task can be an extreme effort for him. This disease most probably associated with :
57.
Which one of the following is NOT the role of bacterial in industrial process?
58.
Which one of the following is NOT the common property of all virus particles?
59.
One of the following statements is true regarding lysogenic reproductive cycle of virus?
60.
Which of the following is NOT usually true as an ecological succession progresses to advanced seral stages?
61.
As ecological succession progresses, the ecosystem becomes more complex, with increased biodiversity and a greater number of species supported.
62.
Species richness refers to the number of different species present in a given area or community.
63.
Which of the following statements is true about matter and energy in the ecosystem?
64.
In nitrogen cycle, which of the following process decreases the available nitrogen in the soil?
65.
The part of water ecosystem that contains a mixture of fresh water and salt water and serve as marine nurseries for many juvenile organisms especially fishes is refers to:
66.
Which one of the following is the most possible suggestion of low value of index of diversity?
67.
Among the following practices, which one has indirect effect/impact on the biodiversity?
68.
In sulfur cycle, which bacteria degrade dead organic matter in an aerobic condition to released sulfur in the form of H2S?
69.
Of the following Ethiopian biomes, which one has been recognized as a hotspot for biodiversity conservation?
70.
Which of the following can create strong inter-species competition if shared by two or more species? Which of the following can create strong inter-species competition if shared by two or more species?
71.
Which event might happen to population if their number exceeded the carrying capacity of their environment?
72.
Suppose gene X, Y, and Z are located on the same chromosome and have Crossover Frequency values between X and Y, 26%, between Y and Z, 10% and between X and Z, 36%. Based on this information which statement will be your possible conclusion?
73.
Crossover frequency is directly proportional to the distance between genes on a chromosome. Since the crossover frequency between X and Z is higher than between X and Y or Y and Z, genes X and Z are likely further apart on the chromosome.
74.
Which one of the following is NOT the feature of sex-linked traits determined by recessive alleles on the X- chromosome?
75.
Suppose 50% children‟s have blood group “A” genotype, 25% of children‟s have blood group “AB” and “B” genotypes, in which pair or mating you would get such conditions?
76.
Which one of the following is a true statement about the semi-conservative replication of DNA?
77.
Semi-conservative replication means that each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.
78.
When going from simple to complex, which of the following is the proper order for DNA structure organization?
79.
Which one of the following is true about protein synthesis in prokaryotic cell?
80.
In prokaryotes, transcription and translation occur simultaneously, and mRNA does not undergo extensive post-transcriptional modifications like in eukaryotes.
81.
Which one of the following is best represents Lamarck's ideas on the evolutionary process?
82.
Which evolutionary theory about the origin of life proposed that life comes from another planet through cosmic dust or meteorites?
83.
Which process is used by bacteria to transfer antibiotic resistant gene from mutated bacterial plasmid to new species plasmid using viruses as vehicle?
84.
Which of the following genetic disorders and its consequences is correctly matched?
85.
Suppose some palm trees were survived well in volcanic acidic soils whereas others better in calcareous alkaline soil, natural selection removes the palm trees that grow on neutral soil. Which of the following mode of selection is in operation?
86.
Which evolution can takes place when different species occupy the similar niche and faced the same selection pressure gradually evolve similar structures that adapted for the same function?
87.
If the amount of C14 relative to C12 in a sample is 1/8 of in living organism at
present. Determine the estimated age of the fossil?
88.
In which geologic period does the fossil record shows the major extinctions and more diversity of reptiles?
89.
During human evolution from the earliest hominid to modern human, which one is the major trend (changes) that happens on their appearance?
90.
In which phase of meiotic nuclear division, non-disjunction of sex chromosomes occurs?
91.
Which one of the following is an example of instinctive behavior?
92.
Which caste of the honey bee maintains the social structure of the nest by secreting powerful pheromones within the nest that control the behaviour of the workers at different stages of their development?
93.
All of the following are the main features of eusocial behavior of insects EXCEPT?
94.
In Ivan Pavlov experiment on dog, which one was considers as unconditional stimulus?
95.
A new born human grasping a rope strongly enough so that he can be lifted it. This is an example of:
96.
Which one of the following do honey bees use to inform other bees about the location and distance of a new source of nectar they discover?
97.
Which one of the following is an innate mechanism of controlling the rhythmic physiological activities of an organism?
98.
Suppose your mathematics teacher gave you a word problem, you have puzzled over a problem for several days or weeks, and suddenly the answer flashes into your mind. This type of learning behavior is :
99.
Suppose a girl, after watching her mother making „enjera‟ on several occasions, successfully did it herself, what type of learning is this?
100.
Artificial breeding experiments on the plants and animals provides evidence to evolution because it :
