Question 1

Which of the following best describes the sliding filament mechanism in skeletal muscle contraction?

Accepted Answer

Myosin heads bind to actin, pulling actin filaments toward the center of the sarcomere, resulting in muscle contraction.

Question 2

During a muscle contraction, which sequence of events occurs immediately after an action potential reaches the neuromuscular junction?

Accepted Answer

Calcium ions are released from the sarcoplasmic reticulum, allowing myosin to bind to actin.

Question 3

Which of the following best explains why most human body heat is generated by the muscular system?

Accepted Answer

Muscle contractions involve the breakdown of ATP, which releases energy as heat.

Question 4

Which muscle type is primarily responsible for separating the thoracic and abdominal cavities in humans?

Accepted Answer

Diaphragm

Question 5

A patient is unable to perform isotonic contractions but can still generate muscle tension. Which of the following best describes their condition?

Accepted Answer

They can perform isometric contractions, where muscle length does not change but tension increases.

Question 6

Which of the following best describes the role of the intercostal muscles during inhalation?

Accepted Answer

They contract to elevate the rib cage, increasing thoracic volume and decreasing lung pressure.

Question 7

During inspiration, which of the following pressure changes occurs in the lungs?

Accepted Answer

Intrapulmonary pressure decreases below atmospheric pressure, allowing air to flow in.

Question 8

Which structure in the human respiratory system is primarily responsible for warming, humidifying, and filtering incoming air?

Accepted Answer

Nasal cavity

Question 9

A person with a blocked pancreatic duct would have difficulty digesting which macromolecules, and why?

Accepted Answer

Proteins, carbohydrates, and fats, because pancreatic enzymes are essential for their breakdown.

Question 10

Which of the following best explains the importance of a large surface area in the small intestine?

Accepted Answer

It increases nutrient absorption by maximizing contact between digested food and absorptive cells.

Question 11

Which of the following best describes the difference between basal metabolic rate (BMR) and standard metabolic rate (SMR)?

Accepted Answer

BMR is measured under strict resting, fasting, and thermoneutral conditions, while SMR is measured under less controlled conditions.

Question 12

Which of the following best describes the function of peristalsis in the digestive system?

Accepted Answer

Coordinated contractions of smooth muscle that propel food through the digestive tract.

Question 13

A child inherits one allele for brown eyes (B) and one for blue eyes (b) from their parents. If brown is dominant, what is the child's genotype and phenotype?

Accepted Answer

Genotype: Bb; Phenotype: Brown eyes

Question 14

Which of the following best describes the Law of Independent Assortment?

Accepted Answer

Alleles of different genes assort independently during gamete formation.

Question 15

A woman who is a carrier for a sex-linked recessive disorder (X	extsuperscript{N}X	extsuperscript{n}) and a man who is unaffected (X	extsuperscript{N}Y) have a son. What is the probability that their son will have the disorder?

Accepted Answer

$$\displaystyle \frac{1}{2}$$

Question 16

Which of the following scenarios best illustrates incomplete dominance?

Accepted Answer

A cross between red-flowered and white-flowered plants produces pink-flowered offspring.

Question 17

Which of the following best explains why some recessive genetic disorders remain prevalent in human populations?

Accepted Answer

Carriers do not express the disorder and can pass the allele to offspring.

Question 18

Which of the following best describes nondisjunction and its consequences?

Accepted Answer

Failure of homologous chromosomes or sister chromatids to separate during meiosis, resulting in gametes with abnormal chromosome numbers.

Question 19

Which of the following best explains how polygenic inheritance differs from Mendelian inheritance?

Accepted Answer

Polygenic traits are influenced by multiple genes, resulting in a continuous range of phenotypes.

Human Biology Exam 2 Study Guide: Muscular, Respiratory, Digestive Systems & Genetics

Study Guide - Practice Questions

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