1. We can continue asking in the same way, what type of organic compounds
are found in living organisms? How does one go about finding the answer?
To get an answer, one has to perform a ____.
Correct Answer: C
1. Living organisms contain many organic compounds. 2. To identify these compounds, we need a proper method. 3. Chemical analysis helps in identifying substances present in a sample. 4. It separates and detects different organic molecules. 5. Physical or microscopic methods cannot fully identify chemical composition. 6. Therefore, chemical analysis is required. 7. Hence, the correct answer is chemical analysis.
2. We can take any
living tissue (a vegetable or a piece of liver, etc.) and grind it in ___ using a mortar and a pestle. We obtain a thick slurry. If
we were to strain this through a cheesecloth or cotton we would obtain two
fractions. One is called the filtrate or more technically, the ___
pool, and the second, the retentate or the ___ fraction.
Correct Answer: B
1. Living tissue is ground in trichloroacetic acid (Cl3CCOOH). 2. This produces a thick slurry. 3. The mixture is filtered through cloth or cotton. 4. The filtrate is called acid-soluble pool. 5. The retentate is called acid-insoluble fraction. 6. Hence correct answer is option (b).
3. Scientists have found ____ in the acid-soluble pool.
Correct Answer: C
1. Acid-soluble pool contains small molecules. 2. These include sugars, amino acids, nucleotides, etc. 3. Scientists studied this fraction carefully. 4. They discovered a very large number of compounds. 5. These are organic in nature. 6. The number runs into thousands. 7. Hence, the correct answer is thousands of organic compounds.
4. To identify a particular organic compound from a living tissue, one must extract it, apply separation techniques, then ____ the compound before analysing its molecular formula and structure. or In higher classes you will learn about how
to analyse a living tissue sample and identify a
particular organic compound. It will suffice to
say here that one extracts the compounds, then
subjects the extract to various separation
techniques till one has separated a compound
from all other compounds. In other words, one
____ a compound. Analytical
techniques, when applied to the compound give
us an idea of the molecular formula and the
probable structure of the compound.
Correct Answer: B
1. First, compounds are extracted from the tissue. 2. Then separation techniques are applied to separate different compounds. 3. The target compound must be obtained alone. 4. This process is called isolation. 5. Further cleaning is done, called purification. 6. After isolation and purification, analysis is performed. 7. Analytical techniques reveal molecular formula and structure. 8. Hence, the correct answer is isolate and purify.
5. All the carbon compounds obtained from living tissues are called ____.
Correct Answer: C
1. Living tissues contain many carbon-based compounds. 2. These compounds include proteins, carbohydrates, lipids, etc. 3. Such carbon compounds found in living organisms are given a specific name. 4. They are called biomolecules. 5. The term 'bio' means life. 6. Hence, biomolecules are molecules of living systems. 7. Therefore, the correct answer is biomolecules.
6. However, living organisms have also got ____ in them.
Correct Answer: C
1. Living organisms mainly contain biomolecules (organic compounds). 2. But they are not made of only organic substances. 3. They also contain inorganic substances. 4. Examples include water, minerals, and ions. 5. These are essential for life processes. 6. Hence, living organisms have inorganic elements and compounds. 7. Therefore, the correct answer is inorganic elements and compounds.
7. In an experiment, a living tissue is weighed (wet weight), dried (dry weight), and then fully burnt. The remaining material after complete burning is called ____ and it contains ____.
Correct Answer: B
1. First, the tissue is weighed as wet weight. 2. After drying, water evaporates giving dry weight. 3. On complete burning, all carbon compounds are oxidised to CO2 and water vapour. 4. These gaseous products are lost. 5. The remaining solid is called ash. 6. Ash contains inorganic elements like calcium and magnesium. 7. Hence, the correct answer is ash and inorganic elements.
8. Inorganic compounds like sulphate,
phosphate, etc., are also seen in the ____.
Correct Answer: B
1. After tissue is ground and filtered, two fractions are obtained. 2. The filtrate is called the acid-soluble fraction. 3. It contains small molecules. 4. These include inorganic compounds like sulphate and phosphate. 5. Acid-insoluble fraction contains larger molecules. 6. Hence, the correct answer is acid-soluble fraction.
9. Therefore Elemental analysis gives the elemental composition of living tissues in the form of ____.
Correct Answer: C
1. Elemental analysis identifies basic elements present in a sample. 2. It does not directly show complex biomolecules. 3. Instead, it shows elements like hydrogen, oxygen, carbon, chlorine, etc. 4. These elements form the building blocks of living matter. 5. Hence, the composition is expressed in terms of elements. 6. Therefore, the correct answer is elements like hydrogen, oxygen, chlorine, carbon.
10. Analysis for compounds gives an idea of the ____ present in living tissues.
Correct Answer: B
1. Compound analysis studies different molecules present in tissues. 2. It identifies both organic compounds like proteins, lipids, carbohydrates. 3. It also identifies inorganic constituents like salts and minerals. 4. Unlike elemental analysis, it focuses on types of compounds. 5. Hence, it gives idea about organic and inorganic constituents. 6. Therefore, correct answer is kind of organic and inorganic constituents.
11. From a chemistry point of view, compounds are identified as ____ while from a biological point of view, they are classified into ____.
Correct Answer: B
1. Chemistry classifies compounds based on functional groups. 2. Examples include aldehydes, ketones, and aromatic compounds. 3. Biology classifies them based on their role in living systems. 4. Examples include amino acids, nucleotide bases, and fatty acids. 5. Thus, the same compounds are viewed differently in chemistry and biology. 6. Hence, the correct answer is option (b).
12. Amino acids are organic compounds containing an ____ and an ____ as substituents on the same carbon (α-carbon), hence they are called ____.
Correct Answer: B
1. Amino acids are organic compounds present in living organisms. 2. They contain an amino group (-NH2). 3. They also contain an acidic (carboxyl) group (-COOH). 4. Both groups are attached to the same carbon atom. 5. This carbon is called α-carbon. 6. Because of this arrangement, they are called α-amino acids. 7. Hence, the correct answer is option (b).
13. Amino acids are considered substituted methane because the central carbon has ____ occupying its four valency positions.
Correct Answer: C
1. Amino acids have a central carbon atom called α-carbon. 2. This carbon is similar to methane carbon (CH4). 3. Methane has four valency positions. 4. In amino acids, all four positions are occupied. 5. These are amino group, carboxyl group, hydrogen, and R group. 6. Hence, amino acids are called substituted methanes. 7. Therefore, four substituent groups occupy the positions. 8. Correct answer is four substituent groups.
14. In amino acids, the four substituent groups attached to the α-carbon are hydrogen, amino group, carboxyl group, and ____.
Correct Answer: C
1. Amino acids have a central α-carbon. 2. This carbon is bonded to four groups. 3. These are hydrogen (H), amino group (-NH2), and carboxyl group (-COOH). 4. The fourth group is a variable group called R group. 5. The R group differs in each amino acid. 6. It determines the properties of amino acids. 7. Hence, the correct answer is variable R group.
15. Based on the nature of the R group, there are many ____.
Correct Answer: C
1. Amino acids have a variable R group. 2. This R group differs from one amino acid to another. 3. The variation in R group leads to different types. 4. Hence, many amino acids exist based on R group nature. 5. These differences affect properties like charge and polarity. 6. Therefore, the correct answer is amino acids.
16. However, the amino acids that occur in proteins are only of ____ types.
Correct Answer: B
1. Many amino acids exist in nature. 2. They differ based on their R group. 3. However, not all are used in proteins. 4. Proteins are made from a specific set. 5. Only 20 amino acids are commonly found in proteins. 6. These are called standard amino acids. 7. Hence, the correct answer is twenty.
17. In proteinaceous amino acids, if the R group is hydrogen, methyl, and hydroxymethyl, the amino acids are called ____ respectively.
Correct Answer: B
1. The R group determines the type of amino acid. 2. If R = hydrogen, the amino acid is glycine. 3. If R = methyl group (-CH3), it is alanine. 4. If R = hydroxymethyl group (-CH2OH), it is serine. 5. These are examples of proteinaceous amino acids. 6. Hence, the correct sequence is glycine, alanine, serine. 7. Therefore, option (b) is correct.
18. The chemical and physical properties of amino acids are essentially due to the ____.
Correct Answer: A
1. Amino acids contain three important functional parts. 2. These are amino group (-NH2), carboxyl group (-COOH), and R group. 3. The amino group gives basic nature. 4. The carboxyl group gives acidic nature. 5. The R group determines specific properties. 6. Together they decide chemical and physical behavior. 7. Hence, correct answer is amino, carboxyl, and R group.
19. Based on the number of amino and carboxyl groups, amino acids are classified as ____ and aromatic amino acids include ____.
Correct Answer: A
1. Amino acids can be classified based on number of amino and carboxyl groups. 2. They are acidic, basic, and neutral types. 3. Acidic example: glutamic acid. 4. Basic example: lysine. 5. Neutral example: valine. 6. Another classification is based on structure. 7. Aromatic amino acids contain ring structures. 8. Examples include tyrosine, phenylalanine, tryptophan. 9. Hence, option (a) is correct.
20. A particular property of amino acids is the ____ nature of –NH2 and –COOH groups, hence their structure changes in solutions of different ____.
Correct Answer: B
1. Amino acids contain –NH2 (amino) and –COOH (carboxyl) groups. 2. These groups can gain or lose protons. 3. Hence, they are ionizable in nature. 4. The ionization depends on the surrounding pH. 5. In acidic or basic solutions, their charge changes. 6. This leads to structural changes in amino acids. 7. Therefore, correct answer is ionizable and pH.
21. Lipids are generally ____.
Correct Answer: B
1. Lipids include fats and oils. 2. They are non-polar molecules. 3. Water is a polar solvent. 4. Non-polar substances do not dissolve in polar solvents. 5. Hence, lipids do not dissolve in water. 6. They are called hydrophobic substances. 7. Therefore, the correct answer is water insoluble.
22. Lipids could be simple ____.
Correct Answer: B
1. Lipids are a group of organic compounds. 2. They include fats, oils, and related substances. 3. The simplest form of lipids are fatty acids. 4. Fatty acids consist of long hydrocarbon chains. 5. These chains may be saturated or unsaturated. 6. Hence, lipids could be simple fatty acids. 7. Therefore, the correct answer is fatty acids.
23. A fatty acid has a ____ group attached to an R group.
Correct Answer: B
1. Fatty acids are simple lipids. 2. They consist of a long hydrocarbon chain (R group). 3. One end of this chain has a functional group. 4. This functional group is the carboxyl group (-COOH). 5. Hence, a fatty acid has a carboxyl group attached to an R group. 6. Therefore, the correct answer is carboxyl group.
24. In fatty acids, the R group could be ____.
Correct Answer: A
1. Fatty acids have a carboxyl group attached to an R group. 2. The R group is a hydrocarbon chain. 3. It can be very small like methyl (–CH3). 4. It can also be ethyl (–C2H5). 5. In many fatty acids, it is a long chain of –CH2 groups. 6. These chains can range from 1 to 19 carbon atoms. 7. Hence, the correct answer is option (a).
25. For example, Palmitic acid has ____ carbon atoms including the carboxyl carbon.
Correct Answer: C
1. Fatty acids are long-chain hydrocarbons with a carboxyl group. 2. The total number of carbons includes the carboxyl carbon. 3. Palmitic acid is a common saturated fatty acid. 4. It contains 16 carbon atoms in total. 5. Hence, the correct answer is 16.
26. Arachidonic acid has ____ carbon atoms including the carboxyl carbon.
Correct Answer: C
1. Fatty acids are long-chain hydrocarbons with a carboxyl group. 2. The total number of carbons includes the carboxyl carbon. 3. Arachidonic acid is a polyunsaturated fatty acid. 4. It contains 20 carbon atoms in total. 5. Hence, the correct answer is 20.
27. Fatty acids are classified as saturated and unsaturated based on the presence or absence of ____.
Correct Answer: C
1. Fatty acids have hydrocarbon chains. 2. These chains may or may not contain double bonds. 3. Saturated fatty acids have no C=C double bonds. 4. Unsaturated fatty acids have one or more C=C double bonds. 5. This difference affects their physical properties. 6. Hence, classification is based on presence of C=C double bonds. 7. Therefore, the correct answer is C=C double bonds.
28. Glycerol is a simple lipid which is chemically known as ____.
Correct Answer: B
1. Glycerol is a simple lipid molecule. 2. It contains three carbon atoms (propane backbone). 3. Each carbon has a hydroxyl (-OH) group attached. 4. Hence, it has three hydroxyl groups. 5. Therefore, it is called trihydroxy propane. 6. Thus, the correct answer is trihydroxy propane.
29. Many lipids are composed of both ____ and ____.
Correct Answer: B
1. Lipids are a group of organic compounds. 2. Many lipids are formed by combining glycerol and fatty acids. 3. Glycerol acts as a backbone molecule. 4. Fatty acids attach to glycerol. 5. This forms structures like fats and oils. 6. Hence, the correct answer is glycerol and fatty acids.
30. In many lipids, fatty acids are found ____ with glycerol.
Correct Answer: B
1. Lipids often consist of glycerol and fatty acids. 2. Fatty acids attach to glycerol through chemical bonds. 3. This bond formation is called esterification. 4. It involves reaction between carboxyl group of fatty acid and hydroxyl group of glycerol. 5. The product formed is called ester bond. 6. Hence, fatty acids are esterified with glycerol. 7. Therefore, the correct answer is esterified.
31. Lipids formed by esterification of glycerol with fatty acids can be classified as ____.
Correct Answer: A
1. Glycerol has three hydroxyl (-OH) groups. 2. Each can form an ester bond with a fatty acid. 3. If one fatty acid is attached, it is a monoglyceride. 4. If two are attached, it is a diglyceride. 5. If three are attached, it is a triglyceride. 6. Hence, lipids are classified into monoglycerides, diglycerides, and triglycerides. 7. Therefore, the correct answer is option (a).
32. Monoglycerides, diglycerides and triglycerides are also called fats and oils based on their ____.
Correct Answer: B
1. Lipids like mono-, di-, and triglycerides are common in food. 2. They are classified as fats or oils. 3. This classification depends on their physical state. 4. Physical state depends on melting point. 5. Fats are solid at room temperature (higher melting point). 6. Oils are liquid at room temperature (lower melting point). 7. Hence, the correct answer is melting point.
33. Oils have ____ melting point and hence remain as oil/liquid (e.g., gingelly oil) even in winters.
Correct Answer: B
1. Lipids are classified as fats and oils based on melting point. 2. Oils have lower melting point compared to fats. 3. Because of this, oils do not solidify easily. 4. They remain liquid even at low temperatures. 5. Example: gingelly oil stays liquid in winters. 6. Hence, the correct answer is lower.
34. Lipids that contain phosphorus and a phosphorylated organic compound are called ____ and they are found in ____.
Correct Answer: B
1. Some lipids contain phosphorus in their structure. 2. These lipids also have a phosphorylated organic compound. 3. Such lipids are called phospholipids. 4. Phospholipids are major components of cell membranes. 5. They form the lipid bilayer structure. 6. Hence, correct answer is phospholipids and cell membrane.
35. Lecithin is an example of ____.
Correct Answer: B
1. Lecithin is a type of lipid. 2. It contains phosphorus in its structure. 3. Such lipids are called phospholipids. 4. Phospholipids are components of cell membranes. 5. Lecithin is a common example of phospholipid. 6. Hence, the correct answer is phospholipid.
36. Some tissues, especially neural tissues, contain lipids with ____.
Correct Answer: C
1. Lipids vary in their structure and complexity. 2. Simple lipids include fatty acids and glycerides. 3. Some tissues like neural tissues have special requirements. 4. They contain lipids with more complex structures. 5. These complex lipids help in nerve function. 6. Hence, the correct answer is more complex structures.
37. Living organisms have many carbon compounds in which ____ can be found.
Correct Answer: B
1. Carbon compounds in living organisms are diverse. 2. Some of these compounds form ring structures. 3. When the ring contains atoms other than carbon, it is called heterocyclic. 4. These are common in biomolecules like nucleotides and vitamins. 5. Hence, heterocyclic rings are present in many biological compounds. 6. Therefore, the correct answer is heterocyclic rings.
38. Some heterocyclic compounds in living organisms are nitrogen bases such as ____.
Correct Answer: B
1. Some biomolecules contain heterocyclic rings with nitrogen. 2. These are called nitrogen bases. 3. They are important components of nucleic acids. 4. Examples include adenine and guanine. 5. Also cytosine, uracil, and thymine. 6. These bases form DNA and RNA structures. 7. Hence, correct answer is adenine, guanine, cytosine, uracil, thymine.
39. When nitrogen bases are attached to a sugar, they are called ____.
Correct Answer: B
1. Nitrogen bases include adenine, guanine, cytosine, etc. 2. These bases can combine with a sugar molecule. 3. The sugar is usually ribose or deoxyribose. 4. When base + sugar combine, the compound is called nucleoside. 5. No phosphate group is present in nucleoside. 6. Hence, the correct answer is nucleosides.
40. If a phosphate group is also esterified to the sugar of a nucleoside, it is called a ____.
Correct Answer: C
1. A nucleoside consists of a nitrogen base and a sugar. 2. When a phosphate group is added to the sugar, it forms a new compound. 3. This addition occurs through esterification. 4. The resulting molecule is called a nucleotide. 5. Nucleotides are building blocks of DNA and RNA. 6. Hence, the correct answer is nucleotide.
41. Which of the following are nucleosides?
Correct Answer: A
1. Nucleosides consist of a nitrogen base attached to a sugar. 2. They do not contain a phosphate group. 3. Examples include adenosine and guanosine. 4. Also thymidine, uridine, and cytidine. 5. These are derived from nitrogen bases + sugar. 6. Option (b) lists only nitrogen bases, not nucleosides. 7. Hence, the correct answer is option (a).
42. Which of the following are nucleotides?
Correct Answer: A
1. Nucleotides consist of a nitrogen base, a sugar, and a phosphate group. 2. They are formed when a nucleoside is esterified with a phosphate group. 3. Examples include adenylic acid and thymidylic acid. 4. Also guanylic acid, uridylic acid, and cytidylic acid. 5. These are building blocks of nucleic acids like DNA and RNA. 6. Option (b) lists nucleosides, not nucleotides. 7. Hence, the correct answer is option (a).
43. Nucleic acids like DNA and RNA consist of ____.
Correct Answer: C
1. DNA and RNA are nucleic acids. 2. They are long chain polymers. 3. The basic unit of these polymers is nucleotide. 4. Each nucleotide contains a base, sugar, and phosphate. 5. These nucleotides link together to form DNA and RNA. 6. Hence, nucleic acids consist of nucleotides. 7. Therefore, the correct answer is nucleotides.
44. DNA and RNA function as ____.
Correct Answer: B
1. DNA and RNA are nucleic acids. 2. They store and transmit genetic information. 3. DNA carries hereditary information from parents to offspring. 4. RNA helps in protein synthesis. 5. Together, they function as genetic material. 6. Hence, the correct answer is genetic material.