BioChem 210 Final Exam - Portage
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. 1: According to the module, a compound with a molecular mass of 1,000
g/mol is considered a macromolecule.
A) True
B) False
Correct answerB) False
Expert-Explanation The statement is false because the threshold for a molecule
to be classified as a macromolecule is typically much higher than 1,000 g/mol.
In the context of this course, macromolecules like proteins, nucleic acids, and
large polysaccharides usually have molecular masses exceeding 5,000 g/mol. A
compound with a mass of only 1,000 g/mol would be considered an oligomer
or a small polymer, not a true macromolecule. This distinction is important for
understanding the scale and complexity of the four major classes of biological
macromolecules.
. 2: Which element is considered the "superglue" of the chemical world due to
its ability to form stable covalent bonds with itself and other elements?
A) Hydrogen
B) Oxygen
C) Nitrogen
D) Carbon
Correct answerD) Carbon
Expert-Explanation Carbon is unique in its ability to form four stable covalent
bonds, including long chains and rings with other carbon atoms. This property
allows it to serve as the backbone for millions of organic molecules, from
simple methane to complex DNA. While hydrogen, oxygen, and nitrogen are
also crucial for life, they lack carbon's unparalleled ability to create the stable,
complex, and diverse structures necessary for biological molecules. This
versatility is why carbon is the foundational element for all known life.
,. 3: What is the fundamental similarity between all prokaryotic and eukaryotic
cells that separates life from non-life?
A) The presence of a nucleus
B) The presence of ribosomes
C) The presence of a plasma membrane
D) The presence of a cell wall
Correct answerC) The presence of a plasma membrane
Expert-Explanation While both cell types have ribosomes, the defining feature
that enables cellular life is the plasma membrane. This lipid bilayer acts as a
selective barrier, controlling the movement of substances into and out of the
cell. By maintaining an internal chemical environment different from the
external surroundings, the plasma membrane creates a distinct space where
life's processes can occur. This compartmentalization is the fundamental
characteristic that separates a living cell from a non-living collection of
molecules.
. 4: The following functional group, -NH2, is characteristic of which class of
organic compounds?
A) Alcohol
B) Carboxylic acid
C) Amine
D) Ketone
Correct answerC) Amine
Expert-Explanation The -NH2 group is known as an amino group. Compounds
containing this functional group are called amines. Amines are critically
important in biochemistry as they are a key component of amino acids, the
building blocks of proteins. Alcohols are characterized by an -OH group,
carboxylic acids by -COOH, and ketones by a carbonyl group (C=O) bonded to
two carbon atoms.
. 5: In a eukaryotic cell, which organelle is primarily responsible for digesting
macromolecules and worn-out organelles?
A) Peroxisome
B) Lysosome
C) Golgi apparatus
D) Mitochondrion
Correct answerB) Lysosome
, Expert-Explanation Lysosomes are membrane-bound vesicles that contain
powerful hydrolytic enzymes. These enzymes break down various biomolecules,
including proteins, nucleic acids, carbohydrates, and lipids. This digestive
function is essential for cellular cleanup, recycling of components, and defense
against pathogens. While peroxisomes break down hazardous molecules like
hydrogen peroxide, lysosomes are specifically responsible for the controlled
digestion of macromolecules.
. 6: Which of the following is NOT a common element found in living
organisms?
A) Carbon (C)
B) Hydrogen (H)
C) Bromine (Br)
D) Nitrogen (N)
Correct answerC) Bromine (Br)
Expert-Explanation Living organisms are primarily composed of a small subset
of elements, often remembered by the acronym CHNOPS (Carbon, Hydrogen,
Nitrogen, Oxygen, Phosphorus, Sulfur). These small elements are favored
because they form stable covalent bonds. Bromine is a larger, less common
element in biochemistry and is typically not found as a structural component of
standard biomolecules. It is more likely to be found as a trace element or in
specialized secondary metabolites in some organisms, but it is not a common
element overall.
. 7: A Kekulé structure is a chemical formula that:
A) Does not show C-H and C-C bonds
B) Shows all the atoms and all the bonds in a molecule
C) Is the simplest ratio of atoms in a compound
D) Uses lines to represent only the carbon-carbon bonds
Correct answerB) Shows all the atoms and all the bonds in a molecule
Expert-Explanation A Kekulé structure, also known as a Lewis structure, is a
representation of a molecule that shows every atom and every chemical bond
(covalent bond) between them. This includes bonds between carbon and
hydrogen, which are often omitted in condensed formulas. This type of drawing
provides a complete and unambiguous picture of a molecule's connectivity,
making it a fundamental tool for understanding organic chemistry.
Learning Questions and Ansẉers with
Expert-Verified Explanation 2026\2027
update
This Exam contains:
Guarantee passing score
questions and Ansẉers
format set of multiple-choice
Expert-Verified Explanation
, Verified ẉith trusted textbooks
───────────────────────────────────────────────────────
─
. 1: According to the module, a compound with a molecular mass of 1,000
g/mol is considered a macromolecule.
A) True
B) False
Correct answerB) False
Expert-Explanation The statement is false because the threshold for a molecule
to be classified as a macromolecule is typically much higher than 1,000 g/mol.
In the context of this course, macromolecules like proteins, nucleic acids, and
large polysaccharides usually have molecular masses exceeding 5,000 g/mol. A
compound with a mass of only 1,000 g/mol would be considered an oligomer
or a small polymer, not a true macromolecule. This distinction is important for
understanding the scale and complexity of the four major classes of biological
macromolecules.
. 2: Which element is considered the "superglue" of the chemical world due to
its ability to form stable covalent bonds with itself and other elements?
A) Hydrogen
B) Oxygen
C) Nitrogen
D) Carbon
Correct answerD) Carbon
Expert-Explanation Carbon is unique in its ability to form four stable covalent
bonds, including long chains and rings with other carbon atoms. This property
allows it to serve as the backbone for millions of organic molecules, from
simple methane to complex DNA. While hydrogen, oxygen, and nitrogen are
also crucial for life, they lack carbon's unparalleled ability to create the stable,
complex, and diverse structures necessary for biological molecules. This
versatility is why carbon is the foundational element for all known life.
,. 3: What is the fundamental similarity between all prokaryotic and eukaryotic
cells that separates life from non-life?
A) The presence of a nucleus
B) The presence of ribosomes
C) The presence of a plasma membrane
D) The presence of a cell wall
Correct answerC) The presence of a plasma membrane
Expert-Explanation While both cell types have ribosomes, the defining feature
that enables cellular life is the plasma membrane. This lipid bilayer acts as a
selective barrier, controlling the movement of substances into and out of the
cell. By maintaining an internal chemical environment different from the
external surroundings, the plasma membrane creates a distinct space where
life's processes can occur. This compartmentalization is the fundamental
characteristic that separates a living cell from a non-living collection of
molecules.
. 4: The following functional group, -NH2, is characteristic of which class of
organic compounds?
A) Alcohol
B) Carboxylic acid
C) Amine
D) Ketone
Correct answerC) Amine
Expert-Explanation The -NH2 group is known as an amino group. Compounds
containing this functional group are called amines. Amines are critically
important in biochemistry as they are a key component of amino acids, the
building blocks of proteins. Alcohols are characterized by an -OH group,
carboxylic acids by -COOH, and ketones by a carbonyl group (C=O) bonded to
two carbon atoms.
. 5: In a eukaryotic cell, which organelle is primarily responsible for digesting
macromolecules and worn-out organelles?
A) Peroxisome
B) Lysosome
C) Golgi apparatus
D) Mitochondrion
Correct answerB) Lysosome
, Expert-Explanation Lysosomes are membrane-bound vesicles that contain
powerful hydrolytic enzymes. These enzymes break down various biomolecules,
including proteins, nucleic acids, carbohydrates, and lipids. This digestive
function is essential for cellular cleanup, recycling of components, and defense
against pathogens. While peroxisomes break down hazardous molecules like
hydrogen peroxide, lysosomes are specifically responsible for the controlled
digestion of macromolecules.
. 6: Which of the following is NOT a common element found in living
organisms?
A) Carbon (C)
B) Hydrogen (H)
C) Bromine (Br)
D) Nitrogen (N)
Correct answerC) Bromine (Br)
Expert-Explanation Living organisms are primarily composed of a small subset
of elements, often remembered by the acronym CHNOPS (Carbon, Hydrogen,
Nitrogen, Oxygen, Phosphorus, Sulfur). These small elements are favored
because they form stable covalent bonds. Bromine is a larger, less common
element in biochemistry and is typically not found as a structural component of
standard biomolecules. It is more likely to be found as a trace element or in
specialized secondary metabolites in some organisms, but it is not a common
element overall.
. 7: A Kekulé structure is a chemical formula that:
A) Does not show C-H and C-C bonds
B) Shows all the atoms and all the bonds in a molecule
C) Is the simplest ratio of atoms in a compound
D) Uses lines to represent only the carbon-carbon bonds
Correct answerB) Shows all the atoms and all the bonds in a molecule
Expert-Explanation A Kekulé structure, also known as a Lewis structure, is a
representation of a molecule that shows every atom and every chemical bond
(covalent bond) between them. This includes bonds between carbon and
hydrogen, which are often omitted in condensed formulas. This type of drawing
provides a complete and unambiguous picture of a molecule's connectivity,
making it a fundamental tool for understanding organic chemistry.
