1.
Which of the following statements is untrue about macromolecules?
Correct Answer
C. Macromolecules are always found as long polymers.
Explanation
Although carbohydrates, nucleic acids, and proteins are often found as long polymers in nature, lipids are not usually polymers.
2.
This is a long molecule that is made up of repeating molecular subunits called monomers.
Correct Answer
B. Polymer
Explanation
A polymer is a long molecule made up of repeating molecular subunits called monomers. This means that the correct answer is "Polymer". A carboxyl is a functional group consisting of a carbon atom double bonded to an oxygen atom and single bonded to a hydroxyl group. Isomer refers to molecules with the same molecular formula but different structural arrangements. None of the above options accurately describe a long molecule made up of repeating subunits, so the correct answer is "Polymer".
3.
Which of the following statements is true about carbohydrates?
Correct Answer
D. All of the above.
Explanation
The statement "All of the above" is the correct answer because all three statements are true about carbohydrates. Carbohydrate chains can vary in length, biologically important carbohydrates are classified into monosaccharides, disaccharides, and polysaccharides, and carbohydrates are indeed the body's most important energy source. Therefore, all of the statements mentioned are true about carbohydrates.
4.
The type of reaction that occurs when a disaccharide is formed from two monosaccharides is called a:
Correct Answer
B. Dehydration synthesis reaction.
Explanation
In a dehydration synthesis reaction, monomers form covalent bonds to form larger molecules known as polymers. In doing so, monomers release water molecules as byproducts.
5.
Which of the following statements is false about monosaccharides?
Correct Answer
A. Monosaccharides are usually less soluble in water than polysaccharides.
Explanation
Most polysaccharides (sugar polymers) are less soluble than their monomers (simple sugars). Monosaccharides and disaccharides are small enough to dissolve readily in water while polysaccharides such as starch, glycogen and cellulose are not due to their size and polymeric character.
6.
Two monosaccharides are joined by:
Correct Answer
D. A glycosidic linkage.
Explanation
A peptide bond occurs between amino acids. Carbohydrate linkages do not exist.
Ester linkages are key components of lipids.
7.
Which of the following statements is untrue about polysaccharides?
Correct Answer
C. None of the above.
Explanation
Polysaccharides are indeed a long chain of monosaccharides bonded by glycosidic linkages. The three main types of polysaccharides are starch, cellulose, and glycogen. Therefore, the statement "None of the above" is true, as both statements are correct.
8.
Which of the following statements is true about cellulose?
Correct Answer
A. Cellulose is a major component of plant cell walls.
Explanation
Glucose monomers are linked together by 1,4 glycosidic linkages.
The human body cannot digest cellulose, but it is a necessary part of our diet. It functions to hold water in the large intestine and aids in the elimination of wastes.
9.
Which of the following is NOT a type of lipid?
Correct Answer
D. None of the above.
Explanation
There are three main groups of lipids:
1. Fats, oils, and waxes
2. Phospholipids
3. Steroids
10.
Lipids are soluble in water.
Correct Answer
B. False
Explanation
Lipids are non-polar molecules and are insoluble in water.
11.
Which of the following statements is untrue about the phosphate functional group?
Correct Answer
C. It is positively charged.
Explanation
The phosphate functional group is negatively charged.
12.
If there are only single bonds between neighbouring carbons in the hydrocarbon chain, a fatty acid is said to be:
Correct Answer
A. Saturated.
Explanation
A fat is made of two kinds of molecules: monoglyceride and fatty acids. Fats are made of long chains of carbon atoms. Some carbon atoms are linked by single bonds (saturated) and others are linked by double bonds (unsaturated).
13.
An unsaturated fat:
Correct Answer
D. All of the above.
Explanation
A fat molecule is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.
14.
Which of the following statements is untrue about triglycerides?
Correct Answer
A. Triglycerides are the least common type of lipid.
Explanation
Triglycerides are actually the most common type of lipid.
15.
Which of the following statements is untrue about nucleic acids?
Correct Answer
A. Nucleic acids are large biomolecules that are essential to all known forms of life, except bacteria.
Explanation
Nucleic acids are large biomolecules that are essential to all known forms of life!
16.
Each nucleotide is made up of three parts: a nitrogen-containing ring structure called a nitrogenous base, a five-carbon sugar, and at least one phosphate group.
Correct Answer
A. True
Explanation
The statement is true because each nucleotide consists of a nitrogenous base, a five-carbon sugar, and at least one phosphate group. These components are essential for the structure and function of nucleotides, which are the building blocks of DNA and RNA. The nitrogenous base provides the genetic information, the sugar molecule forms the backbone of the nucleotide, and the phosphate group helps to link the nucleotides together to form the DNA or RNA strand. Therefore, all three parts are necessary for the formation and function of nucleotides.
17.
What is the genetic material found in all living organisms and is typically broken up into a number of very long, linear pieces called chromosomes?
Correct Answer
C. Deoxyribonucleic acid (DNA).
Explanation
DNA, or deoxyribonucleic acid, is the genetic material found in all living organisms. It is typically broken up into a number of very long, linear pieces called chromosomes. DNA carries the instructions for the development, functioning, and reproduction of all living organisms. It is made up of nucleotides, which consist of a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). These nucleotides are arranged in a specific sequence, forming the genetic code that determines an organism's traits and characteristics. RNA, ATP, and polysaccharides are not the genetic material found in all living organisms.
18.
Ribonucleic acid (RNA) is essential in various biological roles in coding, decoding, regulation, and expression of genes.
Correct Answer
A. True
Explanation
All living organisms store genetic information using the same molecules — DNA and RNA.
19.
Which of the following captures chemical energy obtained from the breakdown of food molecules and releases it to fuel other cellular processes?
Correct Answer
B. Adenosine triphosphate (ATP).
Explanation
ATP is a small molecule used in cells as a coenzyme. It is often referred to as the "molecular unit of currency" of intracellular energy transfer.
20.
Which of the following is the name of the bond that links the 3’ carbon of one nucleotide to the 5’ carbon of another to produce strands of DNA and RNA?
Correct Answer
B. Phosphodiester linkage.
Explanation
A phosphodiester linkage is the bond between two deoxyribose or ribose sugars on adjacent nucleotides.
21.
Which of the following best describes a condensation reaction?
Correct Answer
D. Two small molecules come together/condense to form a large molecule.
Explanation
A condensation reaction involves two small molecules coming together or condensing to form a larger molecule. This process typically involves the removal of a small molecule, such as water, as a byproduct. In the given options, this is the only choice that accurately describes a condensation reaction. The other options involve different processes such as photosynthesis, hydrolysis, or neutralization reactions.
22.
The bond between amino acids is formed by dehydration synthesis and is called a peptide bond.
Correct Answer
A. True
Explanation
Amino acids form a bond through dehydration synthesis, where a water molecule is removed to join the amino group of one amino acid with the carboxyl group of another. This bond is referred to as a peptide bond. Therefore, the statement is true.
23.
Which of the following is untrue about organic molecules?
Correct Answer
D. None of the above.
Explanation
The statement "None of the above" is the correct answer because all three statements about organic molecules are true. Organic molecules are indeed normally found in living systems, they typically consist of carbon atoms in rings or long chains with other atoms attached, and carbohydrates, lipids, proteins, and nucleic acids are all important classes of organic molecules.
24.
Which of the following is true about hydrogen bonding?
Correct Answer
C. Hydrogen bonding occurs when a hydrogen atom is covalently bound to a highly electronegative atom such as nitrogen, oxygen or fluorine.
Explanation
Hydrogen bonding is a relatively strong intermolecular force. A hydrogen bond is the attractive force between the hydrogen attached to an electronegative atom (N, O, F) of one molecule and an electronegative atom (N, O, F) of a different molecule. The electronegative atom has a partial negative charge, while the hydrogen has a partial positive charge.
25.
Which of the following is untrue about proteins?
Correct Answer
B. Proteins are used primarily for energy.
Explanation
Proteins are not primarily used for energy. While proteins can be broken down and used for energy in certain situations, their primary function is not energy production. Proteins are involved in various chemical activities in the body, including building structures and new cells. They are made up of 20 different amino acids, and the specific order and number of amino acids determine the type of protein. Additionally, many enzymes and hormones in the body are proteins.
26.
Which of the following is untrue about the secondary structure of proteins?
Correct Answer
D. None of the above.
Explanation
The given correct answer is "None of the above." This means that all of the statements about the secondary structure of proteins are true. The secondary structure is indeed formed when the sequence of amino acids is linked by hydrogen bonds. The α-helix and the β pleated sheet are the most common types of secondary structures. Additionally, certain amino acids are more likely to be found in α-helices or β pleated sheets. Therefore, none of the statements are untrue about the secondary structure of proteins.
27.
Which of the following statements best describes tertiary protein structure?
Correct Answer
B. Occurs when certain attractions are present between alpha helices and pleated sheets.
Explanation
Tertiary protein structure refers to the overall three-dimensional arrangement of a single polypeptide chain. It is determined by the interactions between different regions of the chain, including the formation of alpha helices and beta pleated sheets. These secondary structures can be stabilized by hydrogen bonds and other attractions between amino acid residues. Therefore, the statement "Occurs when certain attractions are present between alpha helices and pleated sheets" best describes tertiary protein structure.
28.
Proteins do not change shape under any circumstances.
Correct Answer
B. False
Explanation
Each protein has its own unique shape. Exposing a protein to heat, radiation or changing its environment (e.g. changing pH or temperature) will alter its shape. This causes the protein to lose its three-dimensional structure and turn back into an unstructured string of amino acids. When a protein loses its higher-order structure, but not its primary sequence, it is said to be denatured. Denatured proteins are usually non-functional.
29.
A triglyceride is formed when the three hydroxyl (OH-) groups of a single glycerol molecule react with the carboxyl group (COOH-) of three fatty acids by forming ________.
Correct Answer
Ester linkages, ester bonds
Explanation
A triglyceride is formed when the three hydroxyl (OH-) groups of a single glycerol molecule react with the carboxyl group (COOH-) of three fatty acids by forming ester linkages or ester bonds.
30.
________ are the monomers that make up proteins. The order and number of these determine the type of protein.
Correct Answer
Amino acids
Explanation
Amino acids are the monomers that make up proteins. They are organic compounds that contain an amino group (-NH2) and a carboxyl group (-COOH). The order and number of amino acids determine the type and function of the protein. Proteins are formed by linking amino acids together through peptide bonds, creating a polypeptide chain. The unique sequence of amino acids in a protein determines its three-dimensional structure and ultimately its function in the body.
31.
The five-carbon sugar found in RNA is called ________
Correct Answer
Ribose
Explanation
The five-carbon sugar found in DNA is called deoxyribose.