WGU D312 Anatomy and Physiology I - Objective
Assessment Practice Questions
Question 1
A patient presents with loss of sensation over the lateral aspect of the forearm and thumb,
along with weakness in wrist extension. Which nerve is most likely damaged?
A) Median nerve
B) Radial nerve
C) Ulnar nerve
D) Musculocutaneous nerve
Correct Answer: B) Radial nerve
Rationale: The radial nerve innervates the posterior compartment of the arm and forearm,
providing sensation to the lateral forearm and dorsal hand (thumb side) and motor
innervation to wrist and finger extensors. Damage to this nerve produces wrist drop and
sensory loss over the lateral forearm, matching the clinical presentation described. The
median nerve affects thumb opposition and sensation to the palmar side; the ulnar nerve
affects intrinsic hand muscles and sensation to the medial hand .
Question 2
During mitosis, which event occurs during anaphase?
A) Chromosomes align at the metaphase plate
B) Sister chromatids separate and move toward opposite poles
C) Nuclear envelope breaks down
D) Chromosomes decondense and nuclear envelope reforms
Correct Answer: B) Sister chromatids separate and move toward opposite poles
Rationale: During anaphase, cohesin proteins holding sister chromatids together are cleaved,
allowing the separated chromatids (now individual chromosomes) to be pulled toward
opposite poles of the cell by shortening kinetochore microtubules. Chromosome alignment
occurs in metaphase, nuclear envelope breakdown in prophase, and decondensation in
telophase .
Question 3
A histology slide shows a tissue with multiple layers of cells where the surface cells are flat
and scale-like. This tissue is best classified as:
,A) Stratified squamous epithelium
B) Pseudostratified columnar epithelium
C) Simple squamous epithelium
D) Transitional epithelium
Correct Answer: A) Stratified squamous epithelium
Rationale: Stratified squamous epithelium is characterized by multiple cell layers with the
apical (surface) cells being flat (squamous) in shape, providing protection against abrasion.
This tissue is found in areas subject to mechanical stress such as the epidermis, oral cavity,
and esophagus. Simple squamous has only one layer, pseudostratified appears layered but
all cells contact the basement membrane, and transitional epithelium changes shape with
stretching .
Question 4
Which type of muscle fiber is best suited for maintaining posture over extended periods?
A) Type IIb fibers
B) Type I fibers
C) Type IIa fibers
D) Type IIx fibers
Correct Answer: B) Type I fibers
Rationale: Type I (slow oxidative) muscle fibers are rich in mitochondria, myoglobin, and
capillaries, giving them a red appearance and high fatigue resistance ideal for sustained, low-
intensity activities like postural maintenance. Type IIb/IIx fibers are fast glycolytic and fatigue
rapidly, while Type IIa are intermediate fast oxidative-glycolytic fibers suited for moderate-
duration activities .
Question 5
A 45-year-old patient suffers a deep partial-thickness burn affecting the epidermis and upper
dermis. Which clinical finding is most expected?
A) Charred, painless skin requiring grafting
B) Blistering with severe pain
C) Redness and pain without blistering
D) White, leathery skin with no sensation
Correct Answer: B) Blistering with severe pain
Rationale: Second-degree (partial-thickness) burns destroy the epidermis and extend into
the dermis, damaging nerve endings enough to cause severe pain while also damaging the
dermal-epidermal junction, leading to fluid accumulation and blister formation. First-degree
,burns cause redness and pain without blistering; third-degree burns are full-thickness,
painless, and require grafting; fourth-degree extends to muscle and bone .
Question 6
Which organelle is primarily responsible for ATP production through oxidative
phosphorylation?
A) Smooth endoplasmic reticulum
B) Mitochondria
C) Golgi apparatus
D) Lysosomes
Correct Answer: B) Mitochondria
Rationale: Mitochondria are the primary site of aerobic cellular respiration, where the
electron transport chain and ATP synthase on the inner mitochondrial membrane (cristae)
generate the majority of cellular ATP through oxidative phosphorylation. The smooth ER
synthesizes lipids and detoxifies, the Golgi packages and sorts proteins, and lysosomes
perform intracellular digestion .
Question 7
What is the most abundant chemical compound found in the human body?
A) Protein
B) Carbohydrate
C) Water
D) Lipid
Correct Answer: C) Water
Rationale: Water makes up approximately 60-70% of the human body by weight, serving as
the primary solvent for biochemical reactions, a medium for transport, and a temperature
regulator throughout the body .
Question 8
Which type of bond holds water molecules together through hydrogen bonding?
A) Ionic bond
B) Covalent bond
C) Hydrogen bond
D) Peptide bond
Correct Answer: C) Hydrogen bond
, Rationale: Hydrogen bonds form between the slightly positive hydrogen atom of one water
molecule and the slightly negative oxygen of another. These bonds give water its unique
cohesive, adhesive, and thermal properties .
Question 9
A solution with a pH of 3 compared to a solution with a pH of 5 is:
A) 2 times more acidic
B) 10 times more acidic
C) 100 times more acidic
D) 2 times more basic
Correct Answer: C) 100 times more acidic
Rationale: The pH scale is logarithmic. Each unit change in pH represents a 10-fold change in
hydrogen ion concentration. Therefore, a difference of 2 pH units means a 10² = 100-fold
difference in acidity .
Question 10
The cell membrane is composed primarily of a bilayer of molecules that serve as a barrier to
most water-soluble substances. What are these primary structural molecules called?
A) Carbohydrates
B) Proteins
C) Phospholipids
D) Cholesterol
Correct Answer: C) Phospholipids
Rationale: The cell (plasma) membrane is fundamentally composed of a phospholipid
bilayer. Phospholipids are amphipathic molecules with hydrophilic (water-loving) head
groups and hydrophobic (water-fearing) fatty acid tails. This arrangement creates a
semipermeable barrier that allows the membrane to control which substances enter and
exit the cell. While proteins are embedded in and attached to the membrane, and
cholesterol is interspersed within it, phospholipids are the primary structural component .
Question 11
A patient has damage to the lysosomal membranes in their cells. What consequence would
MOST likely result from this damage?
A) Increased protein synthesis
B) Accumulation of undigested materials and cell death
C) Enhanced ATP production
D) Improved calcium storage
Assessment Practice Questions
Question 1
A patient presents with loss of sensation over the lateral aspect of the forearm and thumb,
along with weakness in wrist extension. Which nerve is most likely damaged?
A) Median nerve
B) Radial nerve
C) Ulnar nerve
D) Musculocutaneous nerve
Correct Answer: B) Radial nerve
Rationale: The radial nerve innervates the posterior compartment of the arm and forearm,
providing sensation to the lateral forearm and dorsal hand (thumb side) and motor
innervation to wrist and finger extensors. Damage to this nerve produces wrist drop and
sensory loss over the lateral forearm, matching the clinical presentation described. The
median nerve affects thumb opposition and sensation to the palmar side; the ulnar nerve
affects intrinsic hand muscles and sensation to the medial hand .
Question 2
During mitosis, which event occurs during anaphase?
A) Chromosomes align at the metaphase plate
B) Sister chromatids separate and move toward opposite poles
C) Nuclear envelope breaks down
D) Chromosomes decondense and nuclear envelope reforms
Correct Answer: B) Sister chromatids separate and move toward opposite poles
Rationale: During anaphase, cohesin proteins holding sister chromatids together are cleaved,
allowing the separated chromatids (now individual chromosomes) to be pulled toward
opposite poles of the cell by shortening kinetochore microtubules. Chromosome alignment
occurs in metaphase, nuclear envelope breakdown in prophase, and decondensation in
telophase .
Question 3
A histology slide shows a tissue with multiple layers of cells where the surface cells are flat
and scale-like. This tissue is best classified as:
,A) Stratified squamous epithelium
B) Pseudostratified columnar epithelium
C) Simple squamous epithelium
D) Transitional epithelium
Correct Answer: A) Stratified squamous epithelium
Rationale: Stratified squamous epithelium is characterized by multiple cell layers with the
apical (surface) cells being flat (squamous) in shape, providing protection against abrasion.
This tissue is found in areas subject to mechanical stress such as the epidermis, oral cavity,
and esophagus. Simple squamous has only one layer, pseudostratified appears layered but
all cells contact the basement membrane, and transitional epithelium changes shape with
stretching .
Question 4
Which type of muscle fiber is best suited for maintaining posture over extended periods?
A) Type IIb fibers
B) Type I fibers
C) Type IIa fibers
D) Type IIx fibers
Correct Answer: B) Type I fibers
Rationale: Type I (slow oxidative) muscle fibers are rich in mitochondria, myoglobin, and
capillaries, giving them a red appearance and high fatigue resistance ideal for sustained, low-
intensity activities like postural maintenance. Type IIb/IIx fibers are fast glycolytic and fatigue
rapidly, while Type IIa are intermediate fast oxidative-glycolytic fibers suited for moderate-
duration activities .
Question 5
A 45-year-old patient suffers a deep partial-thickness burn affecting the epidermis and upper
dermis. Which clinical finding is most expected?
A) Charred, painless skin requiring grafting
B) Blistering with severe pain
C) Redness and pain without blistering
D) White, leathery skin with no sensation
Correct Answer: B) Blistering with severe pain
Rationale: Second-degree (partial-thickness) burns destroy the epidermis and extend into
the dermis, damaging nerve endings enough to cause severe pain while also damaging the
dermal-epidermal junction, leading to fluid accumulation and blister formation. First-degree
,burns cause redness and pain without blistering; third-degree burns are full-thickness,
painless, and require grafting; fourth-degree extends to muscle and bone .
Question 6
Which organelle is primarily responsible for ATP production through oxidative
phosphorylation?
A) Smooth endoplasmic reticulum
B) Mitochondria
C) Golgi apparatus
D) Lysosomes
Correct Answer: B) Mitochondria
Rationale: Mitochondria are the primary site of aerobic cellular respiration, where the
electron transport chain and ATP synthase on the inner mitochondrial membrane (cristae)
generate the majority of cellular ATP through oxidative phosphorylation. The smooth ER
synthesizes lipids and detoxifies, the Golgi packages and sorts proteins, and lysosomes
perform intracellular digestion .
Question 7
What is the most abundant chemical compound found in the human body?
A) Protein
B) Carbohydrate
C) Water
D) Lipid
Correct Answer: C) Water
Rationale: Water makes up approximately 60-70% of the human body by weight, serving as
the primary solvent for biochemical reactions, a medium for transport, and a temperature
regulator throughout the body .
Question 8
Which type of bond holds water molecules together through hydrogen bonding?
A) Ionic bond
B) Covalent bond
C) Hydrogen bond
D) Peptide bond
Correct Answer: C) Hydrogen bond
, Rationale: Hydrogen bonds form between the slightly positive hydrogen atom of one water
molecule and the slightly negative oxygen of another. These bonds give water its unique
cohesive, adhesive, and thermal properties .
Question 9
A solution with a pH of 3 compared to a solution with a pH of 5 is:
A) 2 times more acidic
B) 10 times more acidic
C) 100 times more acidic
D) 2 times more basic
Correct Answer: C) 100 times more acidic
Rationale: The pH scale is logarithmic. Each unit change in pH represents a 10-fold change in
hydrogen ion concentration. Therefore, a difference of 2 pH units means a 10² = 100-fold
difference in acidity .
Question 10
The cell membrane is composed primarily of a bilayer of molecules that serve as a barrier to
most water-soluble substances. What are these primary structural molecules called?
A) Carbohydrates
B) Proteins
C) Phospholipids
D) Cholesterol
Correct Answer: C) Phospholipids
Rationale: The cell (plasma) membrane is fundamentally composed of a phospholipid
bilayer. Phospholipids are amphipathic molecules with hydrophilic (water-loving) head
groups and hydrophobic (water-fearing) fatty acid tails. This arrangement creates a
semipermeable barrier that allows the membrane to control which substances enter and
exit the cell. While proteins are embedded in and attached to the membrane, and
cholesterol is interspersed within it, phospholipids are the primary structural component .
Question 11
A patient has damage to the lysosomal membranes in their cells. What consequence would
MOST likely result from this damage?
A) Increased protein synthesis
B) Accumulation of undigested materials and cell death
C) Enhanced ATP production
D) Improved calcium storage
