Solution Authoring Guidelines Version 9.4 September 2016

Size: px

Start display at page:

Download "Solution Authoring Guidelines Version 9.4 September 2016"

Christal May
5 years ago
Views:

1 Solution Authoring Guidelines Version 9.4 September 2016

2 Subject-specific Guidelines- Biology Table of Contents B1. Technology... 3 B2. Special points/others... 3 List of changes made over Version 9.1 Removed B1. Content and B4. Conceptual questions.. Page no.3 List of changes made over Version 9.2 Modified the point (b) in B2.Special points/others..... Page no.3 List of changes made over Version 9.3 Modified B2(b).Page no. 3 2

3 B1. Technology a. Use ChemBio/ChemDraw for Chemical structures. b. Use CorelDraw or Serif DrawPlus for other diagrams. c. Should you wish to use a different program, please check first with your Territory Manager. B2. Special points/others a. Names of Species and genes should be in italics. b. The correct option(s) in match the following type questions should be boxed. c. The symbols for males ( ) and females ( ) should be used for solutions of genetic books. The symbol for males can be created by holding down ALT and pressing 11, while the symbol for females can be created by holding down ALT and pressing 12. Back 3

4 Sample solutions Biology List of changes made over Version 9.2 Sample example 3-MCQ type has been added..page no. 7 Sample example 4-Fill in the blank type has been added..page no. 8 Sample example 5-True or False type has been added...page no.9 Sample example 7- New Very Short Answer Type has been added...page no.12 List of changes made over Version 9.3 Sample example 1- Calculation based has been modified..page no.5 4

5 Biology Example 1: Calculation based Question: Normal human hemoglobin has an isoelectric point of A mutant variety of hemoglobin, known as sickle-cell hemoglobin, has an isoelectric point of The titration curve of hemoglobin indicates that, in this ph range, 13 groups change ionization states per unit change in ph range. Calculate the difference in ionic charge between molecules of normal and sickle-cell hemoglobin. Solution: Calculate the difference in the charges between sickle-cell hemoglobin and normal hemoglobin using the following formula: z n ph Here, the number of charged groups is n, the change in ph is ΔpH, and the charge is z. Number of charged groups in Normal hemoglobin, n is 13. The isoelectric point of the normal hemoglobin is 6.87 The isoelectric point of sickle-cell hemoglobin is Substitute the values in the formula. Δz nδph = 2.86 or 3 Thus, the difference of the charges between sickle-cell hemoglobin and normal hemoglobin is three approximately. Therefore, sickle-cell hemoglobin is three ionic charges less or negative than normal hemoglobin. 5

Biology Example 2: Conceptual Question: What are the three economically important members of the Moraceae? Solution: Moraceae is one of the four Urticalean Rosid families.

6 Biology Example 2: Conceptual Question: What are the three economically important members of the Moraceae? Solution: Moraceae is one of the four Urticalean Rosid families. These families were first a part of the order Utricales. They are now included in the order Rosales. Moraceae is generally known as the mulberry family. It consists of monoecious and dioecious trees, shrubs, lianas, and herbs. Economically important members of Moraceae include the following: The latex from the bark of Ficus elastica is used to manufacture rubber. The fruits from the plant Artocarpus altilis is edible and is called the jack fruit or the breadfruit. Edible figs are obtained from Ficus carica. The leaves of Moringa are used as food for the silkmoth. They also have the nutritive value and can be used as food for humans. The fruits of Moringa are used as vegetables. Morus alba or mulberry is used in the manufacture of silk. The bark of paper mulberry is used for obtaining fibers, which are used in the cloth manufacturing industry. Match the following questions: Match the following questions contain two different or related options, which should be matched with each other. All the correct options should be boxed. Example: 6

7 Biology Example 3: Multiple Choice Question Type Question Prolonged muscle inactivity as in siting causes a(n) a) Increase in blood lipids b) Increase in calories burned c) Decrease in blood glucose d) All the above Solution Sitting inactive for prolonged periods would allow our body to accumulate various compounds in our body. In specific, there is only one compound that accumulates faster than any other. Observe this condition option by option in the following steps: The burning of calories requires enhanced activity but not prolonged inactive state that results in storage of energy. Hence, the option (b) is not the correct answer. Decreased muscle activity leads to under-utilization of the available glucose, increasing its content in the blood. Hence, the option (c) is not the correct answer. As decreased muscle activity increases blood lipids, decreases the number of calories burned, and increases blood glucose levels. Thus, only the option (a) is correct and all the other options are not correct. Thus, the option (d) is also incorrect. Inactivity of the muscles for extended durations results in the accumulation of excess energy as lipids. Prolonged sitting is hazardous. During this time, leg muscles relax and decrease the production of lipoprotein lipase (LPL). LPL is essential for uptake of lipids from the blood and for production of HDL. As the production of LPL decreases, accumulation of lipids in the blood increases. Hence, the correct answer is Option a. 7

8 Biology Example 4: Fill in the blank Type Question: A common type of knee injury seen in football, usually caused by a hard blow to the lateral side of the knee while the foot is fixed on the ground, involves the rupture of the and tearing of the and the and is also known as unhappy triad. Solution: A general type of knee injury, which produces swelling and leakage of blood from injured blood vessels, is also responsible for the ruptures of the closed areas near to injury. The damaged regions around the injured blood vessels are synovial membrane, collateral ligament, anterior cruciate ligament and menisci. Tearing of ligament produces tearing of the meniscus. Tearing of ligaments is observed in football and rugby when the knee experiences a hit from the lateral side when the foot is at rest. When the three parts of the knee joint get injured along with the injury of medial meniscus, anterior cruciate ligament, and tibial collateral ligament, it is termed as unhappy triad. So, first blank can be filled with anterior cruciate ligament. The second blank can be filled with ligament and the third blank can be filled with Meniscus. 8

9 Biology Example 5: True or False Type Question Provide correct answer for the following statement, whether it is true/false The major cause of intellectual disability is a neurologic disease. Solution Intellectual disability refers to significant limitation in intellectual functioning and adaptive behaviour. The factors are prenatal factors, environmental factors, and neurological diseases (like Down syndrome, Fragile X syndrome, and Fetal Alcohol Spectrum Disorder (FASD)). These factors may alter the cognitive function that results in mental retardation. Profound intellectual disability is caused due to neurological diseases which occur in 2% of the cases. So, neurological disease cannot be considered as major cause of intellectual disability. Hence, the above statement is false. 9

10 Biology Example 6: Structure based Question: Explain how MIT, DIT, T3, and T4 relate to each other structurally? Solution: MIT is the monoiodotyrosine. It is the precursor of thyroid hormone. It is formed when iodine is added to the tyrosine molecule, and has the following structure: DIT is the diiodotyrosine. It is formed by addition of two atoms of iodine to the tyrosine or by addition of iodine to MIT. DIT has the following structure: 10

11 T 4 or thyroxine is synthesized when two DIT molecules combine. Two iodines on each DIT molecule add to a total of four iodines to the T 4 molecule. T 3 or triiodothyronine is formed when one molecule of MIT combines with one molecule of DIT. Therefore, T3, on the whole contains 3 iodines in its structure. Therefore, by observing the structures of MIT, DIT, T3, and T4, it can be inferred that all of them are the derivatives of the amino acid, tyrosine. Also, MIT and DIT are the main precursors of the hormone, thyroxine. 11

12 Biology Example 7: Very Short answer Type Question: Protein synthesis takes place much more slowly in eukaryotes than in prokaryotes. Give a reason why. Solution: Protein synthesis takes place much more slowly in eukaryotes than in prokaryotes because of the following reasons: Translation in prokaryotes is coupled with transcription which indicates that as soon as the mrna is transcribed, ribosomes attach to it and start the process of translation. This simultaneous process of transcription and translation occurs because there is no defined nucleus in prokaryotes. In eukaryotes, the mrna is produced in the nucleus, which then undergoes modification, and finally enters the cytoplasm where protein synthesis occurs. This separation of transcription and translation occurs in space and time. 12

13 Biology Example 8: Diagrammatic Question: Explain how the cellular and subcellular structure of skeletal muscle relates to the sliding filament theory of muscle contraction. Solution: A sarcomere is the fundamental unit of skeletal muscle and includes repeating segments of the proteins actin and myosin. The sarcomere is the cellular structure of the skeletal muscle, while the actin and myosin filaments are the subcellular structures. The following diagram represents the sarcomere: The sliding filament theory of skeletal muscle contraction was based on observable differences made between contracted and relaxed muscle tissue. To understand the filament theory, it is necessary to know the anatomy of a muscle cell. Muscle cells, also known as muscle fibers, are made up of bundles of cylindrical organelles called myofibrils. Myofibrils are surrounded by other organelles such as the sarcoplasmic reticulum, mitochondria, granules, and a plasma membrane (sarcolemma). Myofibrils contain two rod-shaped proteins called actin and myosin that lie parallel to each other in an overlapping pattern. Actin and myosin are also called thin and thick filaments respectively, because of their relative thickness (that is, actin is thin and myosin is thick). Actin filaments are joined together at a structure called the Z-line, also known as the Z-disk. In the middle of the myosin is the M-line, which is also the anchor point for myosin. The repeating pattern from the Z-line of one actin filament to the Z-line of an adjacent actin filament is defined as a sarcomere. The sarcomere is the fundamental unit of skeletal muscle tissue. The area of a sarcomere, where myosin is not overlapping with actin is called the H-zone and is observably lighter in color than the rest of the sarcomere under a microscope. This is what gives the skeletal muscle, its striated or banded appearance. The area that spans the length of the myosin filament is called the A-band. The area where actin is not overlapping with myosin is called the I-band. 13

14 The sliding filament theory of skeletal muscle contraction was developed, when scientists observed that a contracted sarcomere had different length, than a sarcomere at rest. In a contracted muscle fiber, the H-zone decreased to almost nothing, the I-band decreased in size, and the Z-lines and A-bands were closer together. The sliding filament theory is that the interaction between actin and myosin filaments during contraction caused the sarcomere to decrease in size, as adjacent actin and myosin filaments pulled closer together. The anatomy of actin and myosin filaments further demonstrates the sliding filament theory. Each myosin filament contains numerous strands of myosin molecules with globular heads. The myosin heads have a site for ATP (adenosine triphosphate), the ability to break down ATP for energy, and a site for binding with actin filament. Actin filaments have sites for binding with the myosin heads and structures that cover these binding sites to prevent interaction with myosin heads when at rest. When actin and myosin are bound together, a cross-bridge is formed and then energy from the use of ATP is used to slide the actin filaments closer together. Back 14

According to the diagram, which of the following is NOT true?

According to the diagram, which of the following is NOT true? Instructions: Review Chapter 44 on muscular-skeletal systems and locomotion, and then complete the following Blackboard activity. This activity will introduce topics that will be covered in the next few