2011 IMSO Science test II
Section A Each question is followed by four answers. Choose the correct answer. 40%( 2% for each)
C1. Which project is most likely tointerest a scientist working at abiotechnology company?
A) study and reconstruction offossilized bones
B) conservation of key species withinecosystems
C) development of geneticallymodified corn plants
D) prevention of sewage leaking intowater supplies
B2.Which is most likely responsible forthe formation of cancer cells?
A) an antibiotic
B) a mutagen
C) a bacterium
D) a parasite
A 3.How is the cell membrane importantto the process of osmosis?
A) It allows water to move into thecell.
B) It allows all materials from theoutside environment to move intothe cell.
C) It traps water and nutrients thatwould otherwise be unable tomove into the cell.
D) It collects nutrients from water inthe outside environment andmoves them into the cell.
C 4. Information about the heredity of acell is stored in which organelle?
A) flagellum
B) mitochondrion
C) nucleus
D) vacuole
D 5.Why were some pesticides such asDDT removed from public use?
A) They can cause heart disease.
B) They can cause diabetes.
C) They can cause meningitis.
D) They can cause cancer.
D 6.The population density of marine lifeis greater along the shorelines of theocean than farther out in the deepwaters of the ocean. Which statementprovides the best reason for thissituation?
A) Ocean currents prevent manysmaller marine organisms fromliving in deep water.
B) The shallow waters have fewerpredators.
C) Coastal waters are less pollutedthan the deeper waters of theocean.
D) There are more nutrients inshallow waters.
A7. Which statement best explains the reason muscle cells have more mitochondria than skin cells?
A) Muscle cells use more energy than skin cells.
B) Muscle cells have fewer proteins than skin cells.
C) Muscle cells have a smaller nucleus than skin cells.
D) Muscle cells have more excess water than skin cells.
B 8.The figure1 shows the path of a light ray through three different media. Rank the media in order of their refractive indices.
A) n1＞n2＞n3.
B) n3＞n1＞n2.
C) n3＞n2＞n1.
D) n2＞n1＞n3.
B 9. Ball A is at rest on a level floor. Ball B head-on collides elastically with Ball A, and the two move off separately, but in the same direction. What can you conclude about the masses of the two balls?
A) Ball A and Ball B have the same mass.
B) Ball B has a greater mass than Ball A.
C) Ball A has a greater mass than Ball B.
D) can not conclude anything.
D 10.Two identical sound producers producesound at the same time will sound,
A) twice as loud as just one.
B) the same loud as just one.
C) half as loud as just one.
D) may be louder, or may be less loud than as just one.
C 11.Which of the following is moving at the highest speed related to one fixed start far away??
A) an airplane.
B) a rocket
C) the earth.
D) aracecar.
A 12. Someone bring a pot of water to boil at the high mountain. What is right in the right about its temperature ?
A) less than 1000C.
B) greater than 1000C.
C) equal to 1000C.
D) all of above are possible.
C 13.Where would you place an object so that its real image is the same size as the object, as in the right figure?
A) At the mirror’s focal length.
B) At half the mirror’s center of curvature.
C) At the mirror’s center of curvature
D) At twice the mirror’s center of curvature.
D14.Why is water important to our bodies? Please choose one of the following (A, B. C or D) to answer this question.
I)Our bodies are made mostly of water
II)Water can dissolve a lot of substances, allowing the dissolved substances to pass through cell membranes
III)Diffusion of dissolved substances needs water
IV)Water is needed for blood flow
A)I, II, and IV
B)II, III, and IV
C)II and IV
D)I, II, III, and IV
D15.To survive, animal cells need to produce energy, mostly in the form of ATP. Glucose is a common substrate for producing ATP, and it needs to go through many metabolic pathways before ATP is produced. Which of the following metabolic pathwaysis not needed to produce ATP from glucose in animal cells?
A)Glycolysis
B)Krebs cycle
C)Electron transport chain
D)The Calvin Cycle
B16.When we fry an egg, the egg white turns into a white solid. Why?
A)DNA is mutated
B)Protein is denatured
C)DNA is cleaved
D)Lipid if formed
A17.Why is the element phosphorus important to life?
A)It is a component of DNA
B)It is a component of vitamins
C)It is a component of lipids
D)It is a component of carbohydrates
C18.After the Japan earthquake and tsunami that happened this year, the radioactive material from the nuclear power plant continues toenter the sea.The radioactive material may be harmful to the marine life because:
A)It changes the migration pattern of the fish
B)It causes all the plants in the sea to stop photosynthesis
C)It causes mutation in DNA of the organisms
D)It increases the growth rate of bacteria in the sea
A19.The picture below shows a drawing of a bacterium.
Which of the following is right?
A)A- flagellum; B- cell membrane; E: chromosome
B)A- pilus; B- cell membrane; G- ribosome
C)F- cytoplasm; C- cell membrane; G- capsule
D)C- cell wall; E- protein; A- flagellum
D20.Which of the following structures is needed for photosynthesis?
A)Mitochondria
B)Golgi body
C)Nucleus
D)Chloroplast
Section BAnswer the following questions. 40% (4% for each)
Mr. Jimoh Bello was 17 years old when he had a deep cut on his left leg and bled excessively without blood clot. Under normal conditions, when a tissue is wounded blood flows from it, and coagulates to form a blood clot. The clot then prevents further blood loss and entry of pathogenic microorganisms and the process of clotting depends on some clotting factors working in harmony with each other. Further investigation showed that Jimoh’s blood would not clot. The conditions in which individual’s blood does not clot is usually seen only in males and it is an inheritable gene mutation transmitted on an X chromosome and it is recessive to the normal allele. Jimoh’s father’s mother is not a carrier of the recessive gene for bleeding. Use the above information to answer questions 1 and 2.
1. The above information shows that,
I. Mr. Jimoh’s father had the gene that predisposes one to excessive blood loss.
II. Jimoh’s mother was a carrier of the gene that predisposes one to excessive blood loss.
Which of the above statements is correct?Give your explanation. II, The X chromosome of males is inherited from mother.
2. If Jimoh marries a normal woman that is not a carrier of the abnormal allele, what is the probability that they will give birth to a son that will produce excessive bleeding? 0
3. In an ecological study, Petersen method is the simplest mark-recapture for estimating absolute animal population size. The basic procedure is to mark a number of individuals over a short time, release them, and then recapture individuals to check for marks. The second sample must be a random sample for this method to be valid; that is, all individuals must have an equal chance of being captured in the second sample regardless of whether they are marked or not. The data to be obtained are; N= MC/R
M = Number of individuals marked in the first sample
C = Total number of individuals captured in the second sample.
R = Number of individuals in second sample that are marked.
From these three variables, we can obtain an estimate of population size (N) at the time
of marking. Therefore,
Catfish (Clarias gariepinus) is a common fish species in Nigeria and it is a relished source of animal protein in the diet of many urban dwellers. A group of students carried out an ecological investigation in a small lake (approximately 100m x 60 m) to estimate the size of the population of catfish ( Clarias sp. ) that would be subject to fishing during a proposed fishing expedition. They marked 110 catfish and in a second sample, a few days later, they caught 180 fish of which 120 fish were not marked. What is the number of the catfishin this lake? (110*180)/60=330
4.Flowering of plants are influenced by the relative lengths of day and night. Some plants are called short-day (long-night) plants. They flower when the night exceeds a certain critical period. Others are long-day (short-night) plants. They flower when the night is shorter than a certain critical period.
The picture below show the normal condition of short-day (long-night) plants and long-day (short-night) plants.
(A)If we give a shaft of light to both plants, which plant will flower?long-day or short-night plants
(B) If we give a shaft of dark to both plants, which plant will flower?short-day or long-night plants
5. Arctic sea ice melting as a result of global warning. Does this process contribute to the sea level rise? Explain the reason why.
6. A wrong report, “a new power plant will produce energy 50 megawatts per hour” on a local news paper. What is wrong with this statement? How shall you correct it?
5.Answer,
No. When floating, the ice displace a mass of equal in volume to its submerged portion- which is less than the ice’s total volume by the ice-to-water density ratio. When the ice melts, it shrinks by the same factor, so it continues to displace the same volume.
6.Answer,
There is a wrong unit of energy. 50 megawatts per hour is a wrong unit of power.
“ a new power plant will produce energy with a power, 50 megawatts per hour”
7. The following two pictures represent an animal cell and a plant cell.
Please write down 2 structural differences between animal and plant cells
- Animal cells don’t have cell wall and plant cells do
- Plant cells have chloroplasts but animal cells don’t
8. Please fill in the gaps in the paragraph below.
Photosynthesis is a process in plants that useslightenergy to convert a gas called carbon dioxide into food especially carbohydrates/glucose. During the process, another gas called oxygen is released.
9. Please fill in the gaps in the paragraph below.
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA, composed of a long chain of nucleotides. There are 4 types of nucleotides.
10. Some of our glands or organs or cells can secrete a chemical called hormone. What do hormones do?
Hormones can send out messages to affect cells in other parts of the organism.
Section C Experiment 40%(10% for each)
EX 1. ESTIMATION OF GLUCOSE CONCENTRATION IN EXTRACTS OF FRUITS
The aim of this experiment is to determine the concentration of glucose in the extracts of these fruits. You are to determine the glucose concentration in a variety of solutions of known values and draw a Standard Curve from which the estimate of the glucose concentration in the extracts of fruits will be determined.You are to measure the time taken for the purple colour of potassium tetraoxomanganate (VII) to disappear.
Glucose(C6H12O6) is a monosaccharide reducing sugar. In a chemical reaction with potassium tetraoxomanganate (VII), the glucose molecules can cause the tetraoxomanganate(VII) to change colour. The purplesolution of tetraoxomanganate(VII) (MnO4-)is reduced to a colourless solution of manganate ions (Mn2+) as in Plate 2. The rate of decolourization of the tetraoxomanganate (VII)solution will be directly related to the concentration of glucose present in the mixture. Accuracy of timing and use of clean glasswares and materials are some oftheimportant factors that may affect the results of this experiment.(Graph paper required)
Glucose Concentration and Time Taken to Decolourise
Test Tube number / Glucose Conc (%) / Time (mins)G1 / 2 / 4.7
G2 / 6 / 8.5
G3 / 10 / 13.9
G4 / 14 / 17.5
G5 / 16 / 20.2
Sample A / ? / 12
Sample B / ? / 15
Questions 1. Plot a graph of the results of G1 – G5 on the graph paper provided with time on the Y (vertical) axis and the concentration of glucose on the X (horizontal)
Questions 2.From the graph plotted, determine the concentration of glucose in samples A and B.
2.Car factory
Make a car by using the following materials. The only driven force must be produced by the balloon. Keep refine you car in order to run longer distance on lawn, grasslands.
straw
string,
pens,
a knife,
a rule.
a scissor
pearl board (thin Styrofoam)
tape
balloon
bamboo sticks
(a).What kind of the driven force in you design? Is it possible there are some other different kinds?
(b).Describe at three most important improvements you made. Explain the reasons why.
(a) answer
driven force-1 氣球用吸管連接吹氣，氣體噴出的反作用力。
driven force-2 利用氣球彈力彈出車子。
driven force-1 將氣球捲曲成麻髮捲作為橡皮筋，以橡皮筋纏繞當成動力。
(b) answer for example,
improvement-1 用珍珠板剪成輪子。
improvement-2 用2個以上的氣球當動力。
improvement-3 用吸管和竹籤組合成輪軸裝置，讓輪子轉動順暢。
Others, 輪子加大、調整車子平衡、減輕重量、讓車子流線型….
3. The Straw spring
Make a spring by using a straw then measure weight of the sample byusing following materials.
straws
plastic beads with a standard weight 1 gram
samples to be measured
strings,
plastic bags
drawing pens,
papersheets,
a knife,
ascissors
a rule.
tape
(a).Describe how to make your own straw spring and why it can be work as a spring.
(b).Write the procedures for those experiments.
(a) answer
將吸管剪成螺線形拉長後具有彈性。
將吸管壓扁當成紙條交互彎曲成彈簧。
(b) answer
將吸管剪成螺線形拉長後具有彈性，或將吸管壓扁當成紙條交互彎曲成彈簧。
將吸管彈簧ㄧ端用線綁著垂吊，另外用線穿過塑膠帶當秤盤。
等重之塑膠方塊當法碼，將1塊放入秤盤，紀錄吸管彈簧伸長量。
取出法碼等候吸管彈簧恢復原長，將2塊塑膠方塊放入秤盤，紀錄吸管彈簧伸長量。
重複以上測量，每次增加1塊塑膠方塊。
放入待測物體秤重，量出伸長量，紀錄並與塑膠方塊數據對照。
4. Amylase is an enzyme that catalyzes the breakdown of starch into maltose, which can then be broken into glucose. Enzyme activity is closely associated with the structure of an enzyme, so any change in the secondary or tertiary structure leads to a change in enzyme activity. Enzymes are proteins, so their secondary and tertiary structures are affected by many factors such as temperature.
To detect the presence of starch, iodine (I2) solution (yellow in color) is used, because iodine can react with starch to form a dark blue complex.
Aim of the experiment and hypothesis
A student called Mary has hypothesized that amylase’s activity is faster at room temperature than at 0 ℃, and slowest at 100 ℃. She has designed an experiment in step-by-step format to prove her hypothesis:
1.Label three test tubes as “0”, “room temperature” and “100”. Into each test tube place 2.5 ml of starch solution and 2.5 ml of distilled water.
2.Place the test tube marked “0” into the 0℃water bath, the one marked “room temperature” leave at room temperature, and the one marked “100” into a 100℃water bath.
3.Place 1 ml of freshly prepared amylase solution into each of three new test tubes. Put one of these into the 0℃water bath, another left at room temperature, the third into the 100℃water bath.
4.After 5 minutes, remove the test tube containing the starch and the test tube containing the enzyme from the 0℃water bath and pour the enzyme solution into the starch solution and mix well. Record the time and call this starting time 0.
5.Remove 4 drops of the mixed solution from the test tube onto a spot in a spot plate that contains 1 drop of iodine solution. Record the color.
6.Place the test tube back into the 0℃water bath.
7.Repeat steps 4-6 for test tubes from 100℃water bath and from room temperature.
8.After 2 minutes, remove another 4 drops of the solution from each test tube to a clean spot in the spot plates that contains 1 drop of iodine each. Record the color as before.
9.Repeat step 8 for each test tube at 4, 6, and 8 minute.
Q1: Based on the experimental procedure designed above, please describe the results Mary should get to prove her hypothesis? I.e. how the color changed over time (0 – 8 min) and how fast was the color change for 0℃, room temperature and 100℃? You may draw a table to describe your results or write in sentences.
Ans
-0C: the color should change from dark blue (lots of starch) to light blue (some starch broke down) then to yellow (no starch left) slowly.
-Room temperature: the color should change from dark blue to light blue then to yellow quickly.
-100C: the color should stay dark blue over time (no starch was broken down).
OR
Time (min) / 0C / room temperature / 100C0 / Dark blue / Dark blue / Dark blue
2 / Dark blue / Light Blue / Dark blue
4 / Blue / Yellow / Dark blue
6 / Light blue / Yellow / Dark blue
8 / Yellow / Yellow / Dark blue
Q2:In science, it is important to discuss why you get a particular result. Assuming Mary’s hypothesis is right, please explain why is amylase enzyme activity slowest at 100℃?
Ans
At 100℃, amylase is denatured, so it loses its secondary and tertiary structure and cannot catalyze the reaction anymore.
Q3: Please explain why amylase enzyme activity at 0℃is slower than at room temperature?
Ans
-Enzyme activity rates are generally slower at 0℃.
-Amylase works best at room temperature.