1. It is a pure substance that cannot be broken down to other types of substances
a. Isotope
b. Compound
c. Element
d. Isomer
2. Atoms with the same number of protons but differing numbers of neutrons
a. Element
b. Isotope
c. Isomer
d. Compound
3. Substance resulting from a combination of two or more different chemical elements
a. Isotope
b. Isomer
c. Element
d. Compound
4. In ionic bonding, cation is
a. A negatively charged ion
b. A neutral charge molecule
c. A positively charged ion
d. Has a partial positive and negative charge
5. Electronegativity is defined as
a. Transfer of electrons between atoms, leaving some with fewer electrons and others with more electrons
b. It is when one atom has more electrons than another
c. Power of an atom to attract electrons toward itself
d. It is when atoms have similar physical and chemical properties
6. What name is given to organic structures where hydrogens are omitted for clarity and carbons are represented by corners or kink
a. Bond line structures
b. Isomerism structures
c. Structure of atoms
d. None of the above
7. The branches or substituents which are derived from the names of the parent hydrocarbons are also known as
a. Functional groups
b. Structural groups
c. Alkyl groups
d. All of the above
8. When one carbon atom has branched from the carbon parent chain, the substituent name is called
a. Ethyl group
b. Methyl group
c. Propyl group
d. Phenyl group
9. The following are examples of structural isomers
a. Geometrical isomers
b. Ring chain isomers
c. Optical isomers
d. Stereoisomers
10. When a molecular formular of a compound represents two or more chemical structures, it is
a. Isotope
b. Covalent double or triple bond
c. Functional isomerism
d. Isomer
11. Stereoisomers include
a. Cis-trans isomers
b. Chain isomers
c. Superimposable isomers
d. All of the above
12. The following is true about isomers
a. Share similar properties when they have the same functional groups
b. Do not contain the same number of atoms of each element
c. Have the similar positions of protons and electrons
d. None of the above
13. When isomers are non-superimposable mirror images of each other, it is called.
a. Structural isomers
b. Enantiomers
c. Ring isomers
d. None of the above
14. A stock solution is
a. A solution of higher concentration than is needed for a procedure
b. A desired solution for a procedure
c. Smallest possible structure that has less than three carbon atoms
d. None of the above
15. The volume occupied by 1 mole of gas at Room Temperature and Pressure is
a. 22.4 liters of gas
b. 24 liters of gas
c. 24.4 liters of gas
d. All of the above
16. By a chemical definition carbohydrates are also known as
a. Aldehydes
b. Ketoses
c. Polyhydroxyl
d. Carbonyls
17. The following are the possible functional groups of carbohydrates
a. Aldehyde group
b. Keto group
c. Monosaccharide group
d. A and B
18. They are the simplest form of carbohydrates
a. Aldoses
b. Ketoses
c. Monosaccharides
d. Disaccharides
19. It is an example of a monosaccharide
a. Fructose
b. Sucrose
c. Maltose
d. Lactose
20. It is a carbohydrate with three to ten monosaccharides
a. Disaccharide
b. Oligosaccharide
c. Polysaccharide
d. Heteropolysaccharides
21. Glucose oxidation in aerobic conditions produces
a. 2 ATP
b. 8 ATP
c. 38 ATP
d. 28 ATP
22. Synthesis of glucose from non-carbohydrates compounds is called
a. Gluconeogenesis
b. Bioenergetics
c. Enolase
d. None of the above
23. Hyperglycemia could be, except
a. Increased hepatic production of glucose via gluconeogenesis
b. Decreased peripheral utilization of glucose
c. Increased mobilization of fatty acids
d. Muscle or adipose tissue having insulin insensitive glucose transporter GLUT-4
24. The following are chronic complications of diabetes, except
a. Atherosclerosis
b. Retinopathy
c. Nephropathy
d. Sorbitol
25. It is the storage form of glucose
a. Glucagon
b. Glycogen
c. Insulin
d. Pyruvate
26. The following are the nitrogenous bases in DNA
a. Guanine and Pentose sugar
b. Cytosine and Phosphate group
c. Adenine and Uracil
d. Guanine and Cytosine
27. It’s nitrogen base that is only found in ribonucleic acid
a. Thymine
b. Guanine
c. Cytosine
d. Uracil
28. It is a triplet of bases along the mRNA that codes for a particular amino acid
a. Codon
b. Anti-codon
c. Pyrimidines
d. Purines
29. It is an example of water-soluble vitamin
a. Niacin
b. Retinol
c. Tocopherol
d. Cholecalciferol
30. It is one of the causes of vitamin D deficiency
a. Immunosuppression
b. Impaired ossification
c. Lack of UV irradiation
d. All of the above
31. The following are the signs or symptoms of vitamin E deficiency, except
a. Neurological problems
b. Impaired vision
c. Eye muscle paralysis
d. Osteomalacia
32. Ataxia is a sign of which vitamin deficiency
a. Vitamin A
b. Vitamin D
c. Vitamin B1
d. Vitamin K
33. A serious deficiency of niacin could lead into
a. Pellagra
b. Rashes
c. Fatigue
d. Irritability
34. Which of the following vitamin when in deficiency in pregnant women can lead to birth defects?
a. Vitamin B1
b. Folic acid
c. Vitamin C
d. Vitamin K
TRUE OR FALSE QUESTIONS
1. Dynamic equilibrium in a reversible reaction is when the forwards reaction and the backwards reaction are occurring at the same rate. _______________
2. Isotopes of hydrogen element have nearly identical chemical properties because the number of neutrons has a significant effect on the size of the hydrogen nucleus_______
3. A compound is different from a mixture because bonding among the atoms of the constituent substances does not occur in a mixture. ____________
4. The physical properties of isotopes are different from each other because they often depend on mass. _____________
5. A hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. ___________
6. All hydrocarbons are straight chains. _________
7. The names of the substituents or alkyl groups are derived from the names of the parent hydrocarbons chain. _______________
8. An alkane called pentane has seven carbon atoms in its parent chain. ___________
9. It is common to represent organic molecules using bond-line structures, where hydrogens are omitted for clarity, and carbons are represented by a corner or “kink” in the line. _________
10. If an aliphatic chain attached to a benzene ring has more carbons, the benzene ring is treated as a substituent and is given the name phenyl. __________
11. A mole consists of a number of molecules or atoms which is known as the Avogadro's number. The Avogadro’s number is 6.02×1026. ______________
12. The volume of a gas is sensitive to both pressure and temperature. _________________
13. Standard temperature and pressure is 0° C and 1 atmosphere, while Room temperature and pressure is 25° C and 1 atmosphere, respectively. ____________
14. The volume occupied by 1 mole of gas at Room Temperature and Pressure is 22.4 liters of gas. ____________
15. Positional isomerism is when the same functional group is located on different positions. ______
16. Geometrical isomers are also known as Cis-trans isomers. _________
17. Carbohydrates with an aldehyde as their carbonyl group are called aldoses_________
18. Carbohydrates are not the primary source of energy in the cell__________
19. When an enzyme of a metabolic pathway is absent or deficient, the entire pathway becomes abnormal___________
20. Ribonucleic Acid has two types, that is, mRNA and tRNA_______
21. DNA base pairing is always antiparallel from 5’end to 3’ end carbons_________
22. The stop codon signals the start of the peptide chain_________________
23. The first step in translation of the genetic code is the activation of the tRNA___________
24. On the mRNA, the start codon (AUG) binds to a tRNA with methionine_____________
25. There is no tRNA with an anticodon for the “stop” codons_______________
26. Initiation of protein synthesis does not occurs when a mRNA attaches to a ribosome____________
27. The vitamin B complex is divided into energy releasing and hematopoietic groups___________
28. Vitamins do not build resistance against diseases in the body_____________
29. vitamin A deficiency could lead to blindness
30. Vitamin K deficiency could lead to blood clotting disorders___________
31. Vitamin B5 deficiency can never lead to Paresthesia___________
32.
SHORT ANSWER QUESTIONS
1. Define an element?
2. Explain how a compound is formed.
3. What are organic compounds?
4. Explain how polar covalent bonds are formed.
5. Give two examples of the body structures where we can find the hydrogen bonds.
6. Explain the hydrogen bonding.
7. Mention two types of covalent bonding.
8. Define molar volume?
9. You have a stock solution of 99% ethanol. Your procedure requires 50 mL solution of 70% ethanol. Show your working.
i. How much initial volume of the stock solution would you need?
10. How much volume of distilled water would you add to the initial volume?
11. How would you prepare the 50ml of 70% ethanol solution needed by dilution?
12. Calculate the volume of carbon dioxide gas, CO2, occupied by 5 moles of the gas at Standard Temperature and Pressure. Show your working.
13. Calculate the number of moles of ammonia gas, NH3, in a volume of 80 L of the gas measured at Room Temperature and Pressure. Show your working.
14. With example, define optical isomerism?
15. Define metamerism?
16. Differentiate chain isomerism from functional isomerism
17. In brief explain the IUPAC nomenclature for the naming of branching hydrocarbons structures.
18. Name the compound below.
19. Draw the alkene structure of the molecular formular 2,4-dimethylhept-3-ene.
20. Explain why carbon is able to make large molecules.
21. Define glycolysis?
22. What does polyhydroxyl mean in carbohydrates naming?
23. Mention two functional groups of the carbohydrates.
24. Explain how carbohydrates can be classified.
25. Differentiate between homopolysaccharides and heteropolysaccharides.
26. Mention the stages of a glycolysis reaction.
27. Glycolysis reaction is very important for cell metabolic processes since it provides energy and several enzymes are involved.
a. Mention three key enzymes of glycolysis.
b. Why are the above mentioned enzymes identified as key enzymes?
28. What is a pentose phosphate pathway?
29. Outline two phases of pentose phosphate pathway.
30. Why does diabetic cataract develop in diabetic mellitus patients?
31. Explain how vitamins are classified.
32. What are the two classes of vitamins?
33. Mention any two examples of fat-soluble vitamins.
34. Explain any two functions of vitamins.
35. Explain beriberi a disease which is a result of vitamin B1 deficiency.
36. A serious deficiency of niacin could lead into pellagra, what are four results of pellagra?
37. Mention two classes of nucleic acids.
38. Outline three components of the nucleotide.
39. Who developed the double helix model of the DNA?
40. Explain the functions of the following Ribonucleic acids.
a. Messenger RNA
b. Transfer RNA
41. What do you understand the term Gene Expression? (2 marks)
42. Briefly explain the process of genetic information transfer. (4 marks)
1. An element is a pure substance that cannot be broken down to other types of substances.
2. A compound is formed when two or more different elements chemically combine in a fixed ratio.
3. Organic compounds are compounds that contain carbon and are typically found in living organisms.
4. Polar covalent bonds are formed when two atoms share electrons unequally, resulting in a slightly positive charge on one atom and a slightly negative charge on the other.
5. Hydrogen bonds can be found in DNA, where they help hold the double helix structure together, and in proteins, where they help stabilize the structure.
6. Hydrogen bonding occurs when a hydrogen atom bonded to an electronegative atom is attracted to another electronegative atom. It is a weak attraction, but can have significant effects on the properties of molecules.
7. Two types of covalent bonding are polar covalent bonding, where electrons are shared unequally between atoms, and nonpolar covalent bonding, where electrons are shared equally.
8. Molar volume is the volume occupied by one mole of a substance.
9. To obtain 50 mL of 70% ethanol from a stock solution of 99% ethanol, you would need to calculate the amount of ethanol needed. 70% of 50 mL is 35 mL, so you would need to take 35 mL of the stock solution.
10. You would add the initial volume (35 mL) to the volume of distilled water required to obtain a total volume of 50 mL.
11. To prepare the 50 mL of 70% ethanol solution, you would mix the calculated volumes of the stock solution and distilled water together.
12. The molar volume of a gas at standard temperature and pressure (STP) is 22.4 liters/mol. Therefore, the volume of carbon dioxide gas occupied by 5 moles would be 5 x 22.4 = 112 liters.
13. The number of moles of a gas can be calculated using the ideal gas law equation: PV = nRT. Rearranging the equation to solve for n, you would divide the given volume (80 L) by the ideal gas law constant (R = 0.0821 L·atm/(mol·K)) and the given temperature in Kelvin.
14. Optical isomerism occurs when a molecule has a chiral carbon (a carbon atom bonded to four different groups) and exists in two non-superimposable mirror-image forms called enantiomers.
15. Metamerism is a type of isomerism where the molecular formula of compounds is the same, but the arrangement of atoms is different due to a different position of the functional group.
16. Chain isomerism refers to isomers that have the same molecular formula but differ in the arrangement of the carbon chain, while functional isomerism refers to isomers that have the same molecular formula but differ in the functional group present.
17. The IUPAC nomenclature for naming branching hydrocarbon structures involves numbering the carbon chain to give the substituent the lowest possible number, and then naming the substituent and indicating its position on the parent chain using prefixes such as di-, tri-, or tetra-.
18. The compound shown is 2-methylbutane.
19. The alkene structure of 2,4-dimethylhept-3-ene would have a double bond between the 3rd and 4th carbon atoms, and methyl groups attached to the 2nd and 4th carbon atoms.
20. Carbon is able to make large molecules because it can form four covalent bonds with other atoms, allowing for the formation of complex and diverse structures.
21. Glycolysis is the metabolic pathway that converts glucose into pyruvate, releasing energy in the form of ATP and NADH.
22. Polyhydroxyl means that carbohydrates contain multiple hydroxyl (OH) groups.
23. The functional groups of carbohydrates include hydroxyl groups and carbonyl groups.
24. Carbohydrates can be classified as monosaccharides, disaccharides, and polysaccharides based on the number of sugar units they contain.
25. Homopolysaccharides are composed of the same type of monosaccharide units, while heteropolysaccharides are composed of different types of monosaccharide units.
26. The stages of glycolysis are energy investment phase and energy payoff phase.
27. a. Three key enzymes of glycolysis are hexokinase, phosphofructokinase, and pyruvate kinase.
b. These enzymes are identified as key enzymes because they catalyze irreversible steps in the glycolysis pathway and play a crucial role in regulating the overall rate of glycolysis.
28. The pentose phosphate pathway is an alternative metabolic pathway that can occur alongside glycolysis to generate NADPH and ribose-5-phosphate.
29. The pentose phosphate pathway consists of an oxidative phase, where glucose-6-phosphate is oxidized to generate NADPH, and a non-oxidative phase, where multiple reactions occur to convert intermediates and regenerate glucose-6-phosphate.
30. Diabetic cataract develops in diabetic mellitus patients due to the accumulation of sorbitol, a sugar alcohol formed from the metabolism of glucose in high glucose concentrations. Sorbitol buildup can cause osmotic stress and damage to lens cells, leading to cataract formation.
31. Vitamins are classified into two groups: water-soluble vitamins, which are not stored in the body and need to be consumed regularly, and fat-soluble vitamins, which are stored in the body's fatty tissues and liver.
32. The two classes of vitamins are energy-releasing vitamins, which include B vitamins and vitamin C, and hematopoietic vitamins, which include vitamins A, D, E, and K.
33. Examples of fat-soluble vitamins are
1. c. Element - A pure substance that cannot be broken down into other types of substances is called an element. It consists of only one type of atom.
2. b. Isotope - Atoms with the same number of protons but differing numbers of neutrons are called isotopes. They have the same atomic number but different atomic masses.
3. d. Compound - A substance resulting from a combination of two or more different chemical elements is called a compound. It is made up of atoms of different elements chemically bonded together.
4. c. A positively charged ion - In ionic bonding, a cation is a positively charged ion that is formed by losing one or more electrons.
5. c. Power of an atom to attract electrons toward itself - Electronegativity is defined as the power of an atom to attract electrons towards itself in a chemical bond.
6. a. Bond line structures - The organic structures where hydrogens are omitted for clarity and carbons are represented by corners or kinks in the lines are called bond line structures. They are commonly used to represent organic molecules.
7. c. Alkyl groups - The branches or substituents derived from the names of the parent hydrocarbon chains are also known as alkyl groups.
8. c. Propyl group - When one carbon atom has branched from the carbon parent chain, the substituent name is called a propyl group. It consists of a three-carbon chain.
9. b. Ring chain isomers - Examples of structural isomers include ring chain isomers, which have different arrangements of carbon atoms in a cyclic structure.
10. c. Functional isomerism - When a molecular formula of a compound represents two or more chemical structures, it is called functional isomerism. These isomers have different functional groups.
11. a. Cis-trans isomers - Stereoisomers include cis-trans isomers, which have the same connectivity but differ in the spatial arrangement around a double bond or a ring.
12. a. Share similar properties when they have the same functional groups - Isomers share similar properties when they have the same functional groups, as the functional groups determine the chemical behavior of the compound.
13. b. Enantiomers - When isomers are non-superimposable mirror images of each other, they are called enantiomers. They have the same connectivity but differ in their spatial arrangement.
14. a. A solution of higher concentration than is needed for a procedure - A stock solution is a solution of higher concentration than is needed for a procedure. It is diluted to obtain the desired concentration.
15. a. 22.4 liters of gas - The volume occupied by 1 mole of gas at Standard Temperature and Pressure (STP) is 22.4 liters of gas.
16. c. Polyhydroxyl - By a chemical definition, carbohydrates are also known as polyhydroxyl compounds due to their multiple hydroxyl (OH) groups.
17. d. A and B - The possible functional groups of carbohydrates include both an aldehyde group and a keto group. These functional groups determine the classification of carbohydrates as aldoses or ketoses.
18. c. Monosaccharides - The simplest form of carbohydrates are monosaccharides, which are single sugar units. Examples include glucose, fructose, and galactose.
19. a. Fructose - Fructose is an example of a monosaccharide. It is a simple sugar found in fruits and honey.
20. b. Oligosaccharide - A carbohydrate with three to ten monosaccharides is called an oligosaccharide. Examples include maltose and lactose.
21. c. 38 ATP - Glucose oxidation in aerobic conditions produces a net gain of 38 ATP molecules.
22. a. Gluconeogenesis - Synthesis of glucose from non-carbohydrate compounds is called gluconeogenesis. It occurs primarily in the liver and kidneys.
23. d. Muscle or adipose tissue having insulin insensitive glucose transporter GLUT-4 - Hyperglycemia can be caused by decreased peripheral utilization of glucose, increased hepatic production of glucose via gluconeogenesis, and increased mobilization of fatty acids. Muscle or adipose tissue having insulin insensitive glucose transporter GLUT-4 can contribute to insulin resistance and hyperglycemia.
24. d. Sorbitol - Sorbitol is not a chronic complication of diabetes. It is a sugar alcohol that can be converted from glucose and can accumulate in tissues, leading to osmotic damage.
25. b. Glycogen - Glycogen is the storage form of glucose in animals. It is a polysaccharide composed of multiple glucose units linked together.
26. d. Guanine and Cytosine - The nitrogenous bases in DNA are guanine and cytosine. They form hydrogen bonds with each other, contributing to the stability of the DNA double helix structure.
27. d. Uracil - Uracil is a nitrogen base that is only found in ribonucleic acid (RNA). It replaces thymine, which is found in DNA.
28. a. Codon - A codon is a triplet of bases along the mRNA that codes for a particular amino acid during protein synthesis.
29. a. Niacin - Niacin is an example of a water-soluble vitamin. It is also known as vitamin B3.
30. c. Lack of UV irradiation - Vitamin D deficiency can occur as a result of inadequate exposure to UV radiation from sunlight, which is necessary for the synthesis of vitamin D in the skin.
31. d. Osteomalacia - Osteomalacia is not one of the signs or symptoms of vitamin E deficiency. Vitamin E deficiency can cause neurological problems, impaired vision, and eye muscle paralysis.
32. c. Vitamin B1 - Ataxia is a sign