1.
- All of these are true about " electron configuration" EXCEPT:
Correct Answer
E. None of the above
Explanation
The electron configuration of an atom determines the kind of bonds that an atom will form with other atoms, the number of bonds that an atom will form with other atoms, and it is the key to an atom's chemical characteristics. It also determines the number of valence electrons. Therefore, all of the statements are true about electron configuration.
2.
Carbon chains Could have all of these forms(shapes) except:
Correct Answer
C. Random chain
Explanation
A random chain is not a valid form of carbon chains. Carbon chains can exist in various forms such as open (straight) chains, ring chains, or branched chains. However, a random chain does not have a specific structure or pattern and is not commonly observed in carbon compounds. Therefore, it is the only form that is not possible for carbon chains.
3.
Saturated fats have cis double bonds
Correct Answer
B. False
Explanation
Saturated fats do not have cis double bonds. Saturated fats are composed of single bonds only, which means that all carbon atoms are bonded to hydrogen atoms and there are no double bonds present. The absence of double bonds makes saturated fats solid at room temperature and they are typically found in animal products such as meat and dairy.
4.
One of these is an example of a disaccharides:
Correct Answer
D. Lactose
Explanation
Lactose is an example of a disaccharide because it is composed of two monosaccharides, glucose and galactose, joined together by a glycosidic bond. Disaccharides are carbohydrates made up of two sugar molecules and are formed through a condensation reaction where a molecule of water is released. Starch and amylose are polysaccharides, which are made up of many monosaccharide units bonded together, while galactose is a monosaccharide, a single sugar molecule. Therefore, lactose is the only option that fits the definition of a disaccharide.
5.
One of theses isn't a frequent bonding partner of Carbo
Correct Answer
B. Sulfur
Explanation
Sulfur is not a frequent bonding partner of carbon because it has a larger atomic radius and a lower electronegativity compared to carbon. Carbon typically forms covalent bonds with elements that have similar electronegativities, such as hydrogen, nitrogen, and oxygen. However, sulfur's larger size and lower electronegativity make it less likely to form strong covalent bonds with carbon. Therefore, sulfur is not a frequent bonding partner of carbon.
6.
The structural level of a protein least affected by a disruption in hydrogen bonding is the
Correct Answer
A. Primary level
Explanation
The primary level of protein structure is least affected by a disruption in hydrogen bonding because hydrogen bonds primarily contribute to the stability and folding of secondary, tertiary, and quaternary structures. The primary structure refers to the linear sequence of amino acids in a protein, which is determined by the sequence of nucleotides in the gene that codes for the protein. Hydrogen bonding plays a minimal role in maintaining the primary structure, as it is primarily stabilized by covalent peptide bonds between amino acids.
7.
Carbon can make organic compounds that vary in:
Correct Answer
E. All of the above
Explanation
Carbon is unique in its ability to form covalent bonds with other carbon atoms, allowing for the formation of long chains of carbon atoms. This flexibility allows for the creation of organic compounds with varying lengths of carbon chains. Additionally, carbon can form bonds with other elements such as hydrogen, oxygen, and nitrogen, resulting in different shapes of organic compounds. Carbon can also form double bonds with other carbon atoms, and the number and location of these double bonds can vary, leading to a wide range of organic compounds. Therefore, all of the given options are correct.
8.
One of these is wrong about fats:
Correct Answer
C. Are macromolecules
9.
Which of the following statements is true regarding the molecule illustrated in that Figure
Correct Answer
D. A and B
Explanation
The molecule illustrated in the figure is a saturated fatty acid, which means that it contains only single bonds between carbon atoms. A diet rich in this molecule may contribute to atherosclerosis, a condition characterized by the buildup of plaque in the arteries. This is because saturated fats can increase levels of LDL cholesterol, which is associated with the development of atherosclerosis. However, the statement about the molecule being usually liquid at room temperature is not necessarily true for all saturated fatty acids, as some can be solid at room temperature.
10.
If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other
Correct Answer
B. 3'TAACGT5'
Explanation
The correct answer is 3'TAACGT5'. In DNA, the two strands are complementary to each other, meaning that the sequence of bases on one strand determines the sequence on the other strand. Adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Therefore, the complementary strand to 5'ATTGCA3' would be 3'TAACGT5', as it follows the base pairing rules.
11.
If a polymer with 741 monomers is broken by hydrolysis , this will give us :
Correct Answer
D. None of the above
Explanation
The correct answer is None of the above. When a polymer with 741 monomers is broken by hydrolysis, it will result in the formation of 741 monomers and 740 water molecules. Hydrolysis breaks the polymer into its individual monomer units by breaking the covalent bonds between them and adding a water molecule to each bond. Therefore, the number of monomers formed will be the same as the number of monomers in the original polymer, and one less water molecule will be produced.
12.
All of these are characteristics of hydrocarbons(such as fats and gasoline) except:
Correct Answer
A. Dissolve in water
Explanation
Hydrocarbons, such as fats and gasoline, are known to be hydrophobic compounds because their bonds are mostly nonpolar carbon to hydrogen linkages. This means that they do not dissolve in water, making the statement "Dissolve in water" incorrect. Hydrocarbons can undergo reactions that release a relatively large amount of energy, which is why they are used as fuels. Therefore, the correct answer is "Dissolve in water."
13.
Which bonds are created during the formation of the primary structure of a protein?
Correct Answer
A. Peptide bonds
Explanation
During the formation of the primary structure of a protein, peptide bonds are created. Peptide bonds are formed through a condensation reaction between the carboxyl group of one amino acid and the amino group of another amino acid. This bond links the amino acids together to form a polypeptide chain, which is the basis of the primary structure of a protein. Hydrogen bonds, disulfide bonds, and phosphodiester bonds are not involved in the formation of the primary structure of a protein.
14.
The best describes the relation between amylose and amylopectin is:
Correct Answer
D. Potato tubers and grains are the major sources of them
Explanation
The correct answer is "Potato tubers and grains are the major sources of them." This answer is correct because amylose and amylopectin are both types of starch, and potato tubers and grains are the primary sources of starch in plants. Starch is a complex carbohydrate that serves as a storage form of energy in plants, and both amylose and amylopectin are present in starch.
15.
The two compounds in that figure are related as:
Correct Answer
D. None of the above
Explanation
The two compounds in the figure cannot be classified as geometric isomers, structural isomers, or enantiomers because they do not have the same connectivity of atoms or the same arrangement of atoms in space. Geometric isomers have the same connectivity but differ in the arrangement of atoms around a double bond, while structural isomers have the same molecular formula but differ in the connectivity of atoms. Enantiomers are non-superimposable mirror images of each other. Therefore, since none of these classifications apply to the given compounds, the correct answer is "None of the above".
16.
When phospholipids are added to water they self-assemble into double-layered structures called:
Correct Answer
B. Bilayer
Explanation
When phospholipids are added to water, they have a unique property that allows them to self-assemble into a double-layered structure. This structure is called a bilayer. The hydrophilic heads of the phospholipids are attracted to the water molecules, while the hydrophobic tails are repelled by water and orient themselves towards each other, forming the inner layer of the bilayer. This arrangement creates a stable structure that is commonly found in cell membranes. Therefore, the correct answer is bilayer.
17.
Which type of interaction stabilizes the alpha (α) helix and the beta (β) pleated sheet structures of proteins?
Correct Answer
A. Hydrogen bonds
Explanation
Hydrogen bonds are responsible for stabilizing the alpha helix and beta pleated sheet structures of proteins. These bonds form between the hydrogen atom of one amino acid and the oxygen or nitrogen atom of another amino acid. The hydrogen bond creates a strong electrostatic attraction, which helps to hold the secondary structures of proteins in place. This allows the protein to maintain its three-dimensional shape and function properly. Hydrophobic interactions, nonpolar covalent bonds, and ionic bonds do not play a significant role in stabilizing these structures.
18.
Starch and cellulose differ in:
Correct Answer
E. All of the above
Explanation
Starch and cellulose differ in all of the above aspects. They have different functions, with starch being used as a storage form of energy in plants and cellulose providing structural support. They also have different glycosidic linkages, with starch having alpha linkages and cellulose having beta linkages. Additionally, they have different three-dimensional shapes, with starch forming helical structures and cellulose forming straight chains. Therefore, the correct answer is that they differ in all of the above aspects.
19.
One of these isn't an example of Steroids:
Correct Answer
D. Atherosclerosis
Explanation
Atherosclerosis is not an example of steroids because it is a condition characterized by the buildup of plaque in the arteries, leading to restricted blood flow. Steroids, on the other hand, are a class of hormones that include cholesterol, estradiol, and testosterone. Cholesterol is a type of steroid that is essential for the production of hormones and cell membranes, while estradiol and testosterone are sex hormones. Therefore, atherosclerosis does not fit into the category of steroids.
20.
The major components of petroleum are:
Correct Answer
B. Hydrocarbons
Explanation
Petroleum is a complex mixture of hydrocarbons, which are organic compounds made up of hydrogen and carbon atoms. These hydrocarbons can vary in size and structure, ranging from small molecules like methane to larger ones like octane or even complex compounds like aromatic hydrocarbons. Enantiomers are stereoisomers that have the same molecular formula but differ in their spatial arrangement, and amino acids are organic compounds that are the building blocks of proteins. Therefore, the major components of petroleum are hydrocarbons, making them the correct answer.
21.
One of these statements is TRUE about that figure:
Correct Answer
E. Two of the above
Explanation
The given figure can make enantiomers, which means it can produce molecules that are mirror images of each other. This is indicated by the presence of asymmetric carbons. Additionally, the figure can make structural isomers, which means it can produce molecules with the same molecular formula but different structural arrangements. Therefore, the correct answer is "It can make enantiomers and asymmetric carbons are (b&c)" or "Two of the above."
22.
One of these is not true about an Carbon atom:
Correct Answer
D. It forms hydrogen bounds by sharing it's 4 electrons
Explanation
The statement "It forms hydrogen bounds by sharing its 4 electrons" is not true about a carbon atom. Carbon atoms do not typically form hydrogen bonds, which are a specific type of bond that occurs between a hydrogen atom and an electronegative atom such as oxygen, nitrogen, or fluorine. Carbon atoms are more likely to form covalent bonds by sharing electrons with other atoms, including other carbon atoms.
23.
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
Correct Answer
D. C60H102O51
Explanation
When ten glucose molecules are linked together by dehydration reactions, a water molecule is eliminated for each linkage. Since there are 10 linkages, 10 water molecules are eliminated. The molecular formula for glucose is C6H12O6, so for 10 glucose molecules, the total number of carbon atoms would be 6 x 10 = 60, the total number of hydrogen atoms would be 12 x 10 = 120, and the total number of oxygen atoms would be 6 x 10 = 60. However, since 10 water molecules are eliminated, the total number of oxygen atoms would be reduced by 10, resulting in C60H102O51.
24.
β glucose mean that OH group attached to second carbon are above the plane of the glucose ring
Correct Answer
B. False
Explanation
The statement is false because β glucose refers to the configuration of the hydroxyl group attached to the first carbon, not the second carbon. In β glucose, the hydroxyl group is below the plane of the glucose ring, not above it.
25.
Which one is a peptide bond?
Correct Answer
C. C
26.
The one true about relation between Glucose and Fructose is:
Correct Answer
E. Two of the above
Explanation
The correct answer is "Two of the above." This is because both glucose and fructose are aldoses and they are structural isomers. They have the same molecular formula (C6H12O6) and are both hexoses.
27.
How many different types of polypeptides ,each composed of 110 amino acids, could be synthesized using 20 common amino acids
Correct Answer
B. 20^(110)
Explanation
The correct answer is 20^(110). This is because there are 20 different common amino acids that can be used to compose each of the 110 amino acids in the polypeptide. Each amino acid can be chosen independently, so the total number of possible combinations is equal to 20 raised to the power of 110.
28.
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
Correct Answer
C. 40%
Explanation
If a DNA sample is composed of 10% thymine, it means that the complementary base, adenine, would also be present in 10% since they pair up in equal amounts. Since guanine pairs up with cytosine, and the total percentage of all bases in DNA should add up to 100%, the percentage of guanine would also be 40%.
29.
Ovalbumin is an example of:
Correct Answer
C. Storage proteins
Explanation
Ovalbumin is a protein found in egg whites and is considered a storage protein. Storage proteins are responsible for storing amino acids and other essential nutrients in organisms. They serve as a reserve of nutrients that can be used during periods of fasting or when the organism requires additional resources for growth and development. Ovalbumin specifically acts as a source of nutrients for the developing embryo inside the egg.
30.
Cow harbors can digest cellulose by it's enzymes
Correct Answer
A. True
Explanation
Cow harbors have specialized enzymes in their digestive system that allow them to break down cellulose, a complex carbohydrate found in plant cell walls. These enzymes, such as cellulase, help in the digestion and extraction of nutrients from plant material. This enables cows to derive energy from cellulose, which is otherwise indigestible by humans and many other animals. Therefore, the statement is true.
31.
When a Carbon forms 4 single bounds the arrangement of these bounds will be:
Correct Answer
B. Tetrahedral shape with 109.5 bond angles
Explanation
When a carbon forms 4 single bonds, it adopts a tetrahedral shape with bond angles of 109.5 degrees. This is because the carbon atom has 4 valence electrons and it wants to minimize repulsion between these electrons. The tetrahedral shape allows the bonds to be as far apart as possible, resulting in the optimal bond angle of 109.5 degrees. This arrangement is commonly observed in molecules such as methane (CH4) where the carbon atom is bonded to four hydrogen atoms.
32.
Carbon dioxide is often considered inorganic because:
Correct Answer
E. Two of the above
Explanation
Carbon dioxide is often considered inorganic because it lacks nitrogen and hydrogen, which are typically found in organic molecules. Additionally, carbon dioxide is a very simple molecule composed of only carbon and oxygen atoms. It does not have single bonds, but this is not a defining characteristic for categorizing it as inorganic. Therefore, the correct answer is that carbon dioxide is considered inorganic due to the combination of lacking nitrogen and hydrogen.
33.
Amino group is characterized by:
Correct Answer
E. Two of the above
Explanation
The amino group is characterized by two of the given options. It is charged by (-1) in ionized form and includes a nitrogen atom. It acts as a base rather than an acid and can pick up H+ from the water in living organisms.
34.
"insoluble fiber" refers mainly to:
Correct Answer
C. Cellulose
Explanation
Insoluble fiber refers mainly to cellulose. Cellulose is a type of complex carbohydrate found in plant cell walls that cannot be broken down by human digestive enzymes. It adds bulk to the stool and helps promote regular bowel movements. Chitin is a similar compound found in the exoskeletons of insects and crustaceans, while the cytoskeleton is a network of protein filaments inside cells that provides structural support. Therefore, neither chitin nor cytoskeleton are correct answers for the term "insoluble fiber".
35.
Starch is found in planet cells in a structures called "plastids"
Correct Answer
A. True
Explanation
Starch is indeed found in plant cells in structures called "plastids." Plastids are organelles found in plant cells that are responsible for various functions, including the synthesis and storage of starch. Starch serves as a major energy storage molecule in plants and is stored in plastids such as chloroplasts and amyloplasts. Therefore, the statement that starch is found in plant cells in plastids is correct.
36.
Compounds that have the same numbers of atoms of the same elements (same molecular formula) but different structures , is the definition of:
Correct Answer
D. All of the above
Explanation
The correct answer is "All of the above." This is because structural isomers, cis-trans isomers, and enantiomers all refer to compounds that have the same molecular formula but different structures. Structural isomers have different connectivity of atoms, cis-trans isomers have different spatial arrangements around a double bond, and enantiomers are mirror images of each other. Therefore, all three terms describe compounds with the same numbers of atoms of the same elements but different structures.
37.
Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct?
Correct Answer
B. The 5' end has a pHospHate group attached to the number 5 carbon of pentose
Explanation
The 5' end of a polynucleotide strand of DNA has a phosphate group attached to the number 5 carbon of pentose. This is because the phosphate group is covalently bonded to the 5' carbon of the sugar molecule (pentose) in the DNA backbone. The phosphate group plays a crucial role in forming the phosphodiester bonds between nucleotides, which are essential for the stability and structure of the DNA molecule.
38.
Carbohydrates macromolecules are:
Correct Answer
C. Polymers called polysaccharides composed of many monosaccharides joined by glycosidic linkage
Explanation
Carbohydrate macromolecules are polymers called polysaccharides composed of many monosaccharides joined by glycosidic linkage. This means that multiple monosaccharide units are connected together through a specific type of covalent bond called a glycosidic linkage. This arrangement allows for the formation of complex carbohydrate structures, such as starch and cellulose, which serve as important sources of energy and structural components in living organisms.
39.
The function of each protein is a consequence of its specific shape. What is the term used for a change in a protein's three-dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, or ionic bonds?
Correct Answer
C. Denaturation
Explanation
Denaturation refers to a change in a protein's three-dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, or ionic bonds. This disruption can be caused by factors such as heat, pH changes, or exposure to certain chemicals. Denaturation often leads to loss of protein function as the altered shape may no longer be able to carry out its specific biological role. Hydrolysis refers to a chemical reaction involving the breaking of a covalent bond by the addition of a water molecule. Stabilization refers to the process of making something more stable or less likely to change. Dehydration refers to the removal of water molecules.
40.
Organic compounds with a sulfhydryl group are known as:
Correct Answer
D. Thiols
Explanation
Organic compounds with a sulfhydryl group are known as thiols. The sulfhydryl group, also known as the thiol group, consists of a sulfur atom bonded to a hydrogen atom. Thiols are characterized by their distinct odor and are commonly found in garlic, onions, and skunks. They are used in various chemical reactions and have important biological functions, such as protein structure and enzymatic activity. Therefore, thiols are the correct answer for this question.
41.
Which type of organelle or structure is primarily in the synthesis of oils, phospholipids and steroids?
Correct Answer
C. Smooth endoplasmic reticulum (SER)
Explanation
The smooth endoplasmic reticulum (SER) is primarily involved in the synthesis of oils, phospholipids, and steroids. This organelle lacks ribosomes on its surface, unlike the rough endoplasmic reticulum (RER), which is involved in protein synthesis. The SER plays a crucial role in lipid metabolism, detoxification of drugs and toxins, and regulation of calcium levels in the cell. Therefore, it is the correct answer for this question.
42.
The liver is involved in detoxification of many poisons and drugs, which of the following structure is primarily involved in this process and therefore abundant in liver cell?
Correct Answer
B. SER
Explanation
The smooth endoplasmic reticulum (SER) is primarily involved in the detoxification of poisons and drugs in liver cells. It contains enzymes that help in the metabolism and breakdown of these substances. The abundance of SER in the liver allows for efficient detoxification processes to occur. The rough endoplasmic reticulum (rough ER) is involved in protein synthesis, the Golgi apparatus is responsible for modifying and packaging proteins, and the nuclear envelope is a double membrane that surrounds the nucleus. Transport vesicles are involved in the transportation of molecules within the cell.
43.
Which structure is the site of the synthesis of proteins that maybe exported from the cell?
Correct Answer
A. RER
Explanation
The correct answer is RER (rough endoplasmic reticulum). The RER is a network of membrane-bound sacs and tubules that is studded with ribosomes. It is involved in the synthesis of proteins that are destined to be exported from the cell. The ribosomes on the RER synthesize these proteins, which are then modified and packaged into vesicles for transport to the Golgi apparatus. From there, the proteins can be further modified and sorted for export out of the cell.
44.
Which of the following contain 9+2 arrangement of microtubules, consisting of nine doubles of microtubules surrounding a pair of single microtubules?
Correct Answer
C. both flagella and motile cilia
45.
Cells require which of the following to form cilia and flagella?
Correct Answer
A. Centrosomes
Explanation
Centrosomes are required for the formation of cilia and flagella in cells. Cilia and flagella are hair-like structures that extend from the surface of cells and are involved in various cellular processes such as movement and sensory perception. Centrosomes play a crucial role in organizing the microtubules that make up the structure of cilia and flagella. They serve as a microtubule organizing center and help in the assembly and positioning of microtubules, which are essential for the formation and function of cilia and flagella.
46.
Which of the following are built from actin:
Correct Answer
B. Microfilaments
Explanation
Microfilaments are built from actin. Actin is a protein that forms long, thin fibers, which are known as microfilaments. These microfilaments play a crucial role in cell structure and movement. They are involved in various cellular processes such as cell division, cell signaling, and cell migration. Microtubules, on the other hand, are built from tubulin protein, while intermediate filaments are built from various types of proteins depending on the cell type. Therefore, the correct answer is Microfilaments.
47.
What do the cell walls of plants and the extracellular matrix of animal cells have in common?
Correct Answer
E. They have functional connections with Cytoskeleton inside the cell.
Explanation
The cell walls of plants and the extracellular matrix of animal cells have functional connections with the cytoskeleton inside the cell. This means that both structures interact with the cytoskeleton, which provides support and stability to the cell. The cytoskeleton helps maintain the shape of the cell and allows for cellular movement and communication. This functional connection is important for the overall structure and function of both plant cell walls and animal extracellular matrix.