Human Anatomy and Physiology 16th Edition by Elaine N.
Marieb and Katja Hoehn (Welsh Adaptation) Study Guide,
Workbook & Exam Prep Resource | Comprehensive Body
Systems Review, Clinical Terminology Mastery, and Nursing
& Health Science Success Guide
Question 1: Which of the following best describes the anatomical position?
A. Body lying face down with arms extended
B. Body standing erect, feet parallel, arms at sides with palms facing forward
C. Body sitting with legs crossed and hands on knees
D. Body standing with feet apart and arms raised overhead
CORRECT ANSWER: B. Body standing erect, feet parallel, arms at sides with palms facing
forward
Rationale: The anatomical position is the standardized reference position used in anatomy to
describe body structures and their relationships. It is defined as the body standing upright, feet
parallel and on the floor, head level and eyes facing forward, with arms at the sides and palms
facing anteriorly. This position ensures consistent directional terminology regardless of the
body's actual position.
Question 2: What is the primary function of negative feedback mechanisms in homeostasis?
A. To amplify physiological changes to achieve a rapid response
B. To initiate positive reinforcement of a stimulus
C. To reverse a change and return conditions to a set point
D. To maintain a constant state without any regulatory input
CORRECT ANSWER: C. To reverse a change and return conditions to a set point
Rationale: Negative feedback mechanisms are the primary regulatory processes in homeostasis.
They detect deviations from a set point and initiate responses that counteract the change,
thereby restoring equilibrium. For example, when body temperature rises, negative feedback
triggers sweating and vasodilation to cool the body back to its normal range.
Question 3: Which plane divides the body into equal right and left halves?
A. Frontal plane
B. Transverse plane
C. Midsagittal plane
D. Oblique plane
CORRECT ANSWER: C. Midsagittal plane
Rationale: The midsagittal (or median) plane is a vertical plane that passes through the midline
of the body, dividing it into equal right and left portions. The frontal plane divides the body into
anterior and posterior sections, the transverse plane creates superior and inferior sections, and
oblique planes cut at angles other than 90 degrees to the vertical or horizontal axes.
Question 4: Which body cavity contains the heart and lungs?
A. Abdominal cavity
B. Pelvic cavity
C. Thoracic cavity
D. Cranial cavity
CORRECT ANSWER: C. Thoracic cavity
,Rationale: The thoracic cavity, protected by the rib cage and separated from the abdominal
cavity by the diaphragm, houses the heart within the pericardial sac and the lungs within the
pleural cavities. The mediastinum, located between the lungs, contains the heart, great vessels,
trachea, and esophagus.
Question 5: What is the most abundant chemical element in the human body by mass?
A. Carbon
B. Hydrogen
C. Oxygen
D. Nitrogen
CORRECT ANSWER: C. Oxygen
Rationale: Oxygen constitutes approximately 65% of the human body by mass, primarily
because it is a major component of water (H₂O), which makes up about 60% of body weight,
and is also present in organic molecules such as carbohydrates, lipids, proteins, and nucleic
acids.
Question 6: Which type of chemical bond involves the sharing of electron pairs between
atoms?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Van der Waals force
CORRECT ANSWER: C. Covalent bond
Rationale: Covalent bonds form when two atoms share one or more pairs of electrons to
achieve stable electron configurations. This type of bond is fundamental in forming organic
molecules, including the backbone of DNA, proteins, and carbohydrates. Ionic bonds involve
electron transfer, hydrogen bonds are weak attractions involving hydrogen, and Van der Waals
forces are transient intermolecular attractions.
Question 7: What is the pH of a neutral solution at 25°C?
A. 5.5
B. 7.0
C. 8.5
D. 10.0
CORRECT ANSWER: B. 7.0
Rationale: A neutral solution has equal concentrations of hydrogen ions (H⁺) and hydroxide ions
(OH⁻), resulting in a pH of 7.0 at standard temperature (25°C). Solutions with pH below 7 are
acidic (higher H⁺ concentration), while those above 7 are basic or alkaline (higher OH⁻
concentration).
Question 8: Which organic molecule serves as the primary structural component of cell
membranes?
A. Carbohydrates
B. Proteins
C. Phospholipids
D. Nucleic acids
,CORRECT ANSWER: C. Phospholipids
Rationale: Phospholipids form the fundamental bilayer structure of cell membranes. Their
amphipathic nature—hydrophilic phosphate heads and hydrophobic fatty acid tails—allows
them to spontaneously arrange into a bilayer in aqueous environments, creating a selectively
permeable barrier that separates intracellular and extracellular compartments.
Question 9: What is the monomeric unit of proteins?
A. Monosaccharides
B. Nucleotides
C. Amino acids
D. Fatty acids
CORRECT ANSWER: C. Amino acids
Rationale: Proteins are polymers composed of amino acid monomers linked by peptide bonds.
There are 20 standard amino acids, each containing an amino group, a carboxyl group, and a
unique side chain. The sequence of amino acids determines a protein's three-dimensional
structure and biological function.
Question 10: Which cellular organelle is responsible for ATP production through aerobic
respiration?
A. Ribosome
B. Golgi apparatus
C. Mitochondrion
D. Lysosome
CORRECT ANSWER: C. Mitochondrion
Rationale: Mitochondria are often called the "powerhouses" of the cell because they generate
most of the cell's supply of adenosine triphosphate (ATP) through oxidative phosphorylation.
This process occurs in the inner mitochondrial membrane and requires oxygen, making it the
primary site of aerobic cellular respiration.
Question 11: What is the function of ribosomes in the cell?
A. Synthesis of lipids
B. Degradation of cellular waste
C. Protein synthesis
D. Packaging and sorting of proteins
CORRECT ANSWER: C. Protein synthesis
Rationale: Ribosomes are the cellular machinery responsible for translating messenger RNA
(mRNA) into polypeptide chains during protein synthesis. They can be found free in the
cytoplasm or attached to the rough endoplasmic reticulum, where they facilitate the assembly
of amino acids into proteins according to genetic instructions.
Question 12: Which process describes the movement of water across a selectively permeable
membrane from an area of lower solute concentration to higher solute concentration?
A. Diffusion
B. Active transport
C. Osmosis
D. Facilitated diffusion
, CORRECT ANSWER: C. Osmosis
Rationale: Osmosis is the passive movement of water molecules through a selectively
permeable membrane from a region of lower solute concentration (higher water
concentration) to a region of higher solute concentration (lower water concentration). This
process is critical for maintaining cellular hydration and turgor pressure without requiring
energy expenditure.
Question 13: During which phase of the cell cycle does DNA replication occur?
A. G₁ phase
B. S phase
C. G₂ phase
D. M phase
CORRECT ANSWER: B. S phase
Rationale: The S (synthesis) phase of interphase is when DNA replication takes place. During
this phase, the cell's entire genome is duplicated, ensuring that each daughter cell will receive a
complete set of genetic information. The G₁ and G₂ phases involve cell growth and preparation,
while the M phase encompasses mitosis and cytokinesis.
Question 14: What is the primary function of the Golgi apparatus?
A. Synthesis of steroid hormones
B. Modification, sorting, and packaging of proteins for secretion
C. Breakdown of macromolecules using hydrolytic enzymes
D. Production of ribosomal RNA
CORRECT ANSWER: B. Modification, sorting, and packaging of proteins for secretion
Rationale: The Golgi apparatus receives proteins and lipids from the endoplasmic reticulum,
modifies them (e.g., by adding carbohydrate groups), sorts them according to their destination,
and packages them into vesicles for transport to the plasma membrane, lysosomes, or
secretion outside the cell.
Question 15: Which type of cell junction prevents the passage of materials between adjacent
epithelial cells?
A. Gap junction
B. Desmosome
C. Tight junction
D. Adherens junction
CORRECT ANSWER: C. Tight junction
Rationale: Tight junctions form virtually impermeable seals between adjacent epithelial cells by
fusing their plasma membranes. This prevents the paracellular passage of substances, ensuring
that materials must pass through cells (transcellular route) where they can be selectively
regulated, which is essential for barrier functions in tissues like the intestinal epithelium.
Question 16: What is the term for programmed cell death that occurs in a controlled, energy-
dependent manner?
A. Necrosis
B. Apoptosis
Marieb and Katja Hoehn (Welsh Adaptation) Study Guide,
Workbook & Exam Prep Resource | Comprehensive Body
Systems Review, Clinical Terminology Mastery, and Nursing
& Health Science Success Guide
Question 1: Which of the following best describes the anatomical position?
A. Body lying face down with arms extended
B. Body standing erect, feet parallel, arms at sides with palms facing forward
C. Body sitting with legs crossed and hands on knees
D. Body standing with feet apart and arms raised overhead
CORRECT ANSWER: B. Body standing erect, feet parallel, arms at sides with palms facing
forward
Rationale: The anatomical position is the standardized reference position used in anatomy to
describe body structures and their relationships. It is defined as the body standing upright, feet
parallel and on the floor, head level and eyes facing forward, with arms at the sides and palms
facing anteriorly. This position ensures consistent directional terminology regardless of the
body's actual position.
Question 2: What is the primary function of negative feedback mechanisms in homeostasis?
A. To amplify physiological changes to achieve a rapid response
B. To initiate positive reinforcement of a stimulus
C. To reverse a change and return conditions to a set point
D. To maintain a constant state without any regulatory input
CORRECT ANSWER: C. To reverse a change and return conditions to a set point
Rationale: Negative feedback mechanisms are the primary regulatory processes in homeostasis.
They detect deviations from a set point and initiate responses that counteract the change,
thereby restoring equilibrium. For example, when body temperature rises, negative feedback
triggers sweating and vasodilation to cool the body back to its normal range.
Question 3: Which plane divides the body into equal right and left halves?
A. Frontal plane
B. Transverse plane
C. Midsagittal plane
D. Oblique plane
CORRECT ANSWER: C. Midsagittal plane
Rationale: The midsagittal (or median) plane is a vertical plane that passes through the midline
of the body, dividing it into equal right and left portions. The frontal plane divides the body into
anterior and posterior sections, the transverse plane creates superior and inferior sections, and
oblique planes cut at angles other than 90 degrees to the vertical or horizontal axes.
Question 4: Which body cavity contains the heart and lungs?
A. Abdominal cavity
B. Pelvic cavity
C. Thoracic cavity
D. Cranial cavity
CORRECT ANSWER: C. Thoracic cavity
,Rationale: The thoracic cavity, protected by the rib cage and separated from the abdominal
cavity by the diaphragm, houses the heart within the pericardial sac and the lungs within the
pleural cavities. The mediastinum, located between the lungs, contains the heart, great vessels,
trachea, and esophagus.
Question 5: What is the most abundant chemical element in the human body by mass?
A. Carbon
B. Hydrogen
C. Oxygen
D. Nitrogen
CORRECT ANSWER: C. Oxygen
Rationale: Oxygen constitutes approximately 65% of the human body by mass, primarily
because it is a major component of water (H₂O), which makes up about 60% of body weight,
and is also present in organic molecules such as carbohydrates, lipids, proteins, and nucleic
acids.
Question 6: Which type of chemical bond involves the sharing of electron pairs between
atoms?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Van der Waals force
CORRECT ANSWER: C. Covalent bond
Rationale: Covalent bonds form when two atoms share one or more pairs of electrons to
achieve stable electron configurations. This type of bond is fundamental in forming organic
molecules, including the backbone of DNA, proteins, and carbohydrates. Ionic bonds involve
electron transfer, hydrogen bonds are weak attractions involving hydrogen, and Van der Waals
forces are transient intermolecular attractions.
Question 7: What is the pH of a neutral solution at 25°C?
A. 5.5
B. 7.0
C. 8.5
D. 10.0
CORRECT ANSWER: B. 7.0
Rationale: A neutral solution has equal concentrations of hydrogen ions (H⁺) and hydroxide ions
(OH⁻), resulting in a pH of 7.0 at standard temperature (25°C). Solutions with pH below 7 are
acidic (higher H⁺ concentration), while those above 7 are basic or alkaline (higher OH⁻
concentration).
Question 8: Which organic molecule serves as the primary structural component of cell
membranes?
A. Carbohydrates
B. Proteins
C. Phospholipids
D. Nucleic acids
,CORRECT ANSWER: C. Phospholipids
Rationale: Phospholipids form the fundamental bilayer structure of cell membranes. Their
amphipathic nature—hydrophilic phosphate heads and hydrophobic fatty acid tails—allows
them to spontaneously arrange into a bilayer in aqueous environments, creating a selectively
permeable barrier that separates intracellular and extracellular compartments.
Question 9: What is the monomeric unit of proteins?
A. Monosaccharides
B. Nucleotides
C. Amino acids
D. Fatty acids
CORRECT ANSWER: C. Amino acids
Rationale: Proteins are polymers composed of amino acid monomers linked by peptide bonds.
There are 20 standard amino acids, each containing an amino group, a carboxyl group, and a
unique side chain. The sequence of amino acids determines a protein's three-dimensional
structure and biological function.
Question 10: Which cellular organelle is responsible for ATP production through aerobic
respiration?
A. Ribosome
B. Golgi apparatus
C. Mitochondrion
D. Lysosome
CORRECT ANSWER: C. Mitochondrion
Rationale: Mitochondria are often called the "powerhouses" of the cell because they generate
most of the cell's supply of adenosine triphosphate (ATP) through oxidative phosphorylation.
This process occurs in the inner mitochondrial membrane and requires oxygen, making it the
primary site of aerobic cellular respiration.
Question 11: What is the function of ribosomes in the cell?
A. Synthesis of lipids
B. Degradation of cellular waste
C. Protein synthesis
D. Packaging and sorting of proteins
CORRECT ANSWER: C. Protein synthesis
Rationale: Ribosomes are the cellular machinery responsible for translating messenger RNA
(mRNA) into polypeptide chains during protein synthesis. They can be found free in the
cytoplasm or attached to the rough endoplasmic reticulum, where they facilitate the assembly
of amino acids into proteins according to genetic instructions.
Question 12: Which process describes the movement of water across a selectively permeable
membrane from an area of lower solute concentration to higher solute concentration?
A. Diffusion
B. Active transport
C. Osmosis
D. Facilitated diffusion
, CORRECT ANSWER: C. Osmosis
Rationale: Osmosis is the passive movement of water molecules through a selectively
permeable membrane from a region of lower solute concentration (higher water
concentration) to a region of higher solute concentration (lower water concentration). This
process is critical for maintaining cellular hydration and turgor pressure without requiring
energy expenditure.
Question 13: During which phase of the cell cycle does DNA replication occur?
A. G₁ phase
B. S phase
C. G₂ phase
D. M phase
CORRECT ANSWER: B. S phase
Rationale: The S (synthesis) phase of interphase is when DNA replication takes place. During
this phase, the cell's entire genome is duplicated, ensuring that each daughter cell will receive a
complete set of genetic information. The G₁ and G₂ phases involve cell growth and preparation,
while the M phase encompasses mitosis and cytokinesis.
Question 14: What is the primary function of the Golgi apparatus?
A. Synthesis of steroid hormones
B. Modification, sorting, and packaging of proteins for secretion
C. Breakdown of macromolecules using hydrolytic enzymes
D. Production of ribosomal RNA
CORRECT ANSWER: B. Modification, sorting, and packaging of proteins for secretion
Rationale: The Golgi apparatus receives proteins and lipids from the endoplasmic reticulum,
modifies them (e.g., by adding carbohydrate groups), sorts them according to their destination,
and packages them into vesicles for transport to the plasma membrane, lysosomes, or
secretion outside the cell.
Question 15: Which type of cell junction prevents the passage of materials between adjacent
epithelial cells?
A. Gap junction
B. Desmosome
C. Tight junction
D. Adherens junction
CORRECT ANSWER: C. Tight junction
Rationale: Tight junctions form virtually impermeable seals between adjacent epithelial cells by
fusing their plasma membranes. This prevents the paracellular passage of substances, ensuring
that materials must pass through cells (transcellular route) where they can be selectively
regulated, which is essential for barrier functions in tissues like the intestinal epithelium.
Question 16: What is the term for programmed cell death that occurs in a controlled, energy-
dependent manner?
A. Necrosis
B. Apoptosis
