Question 1

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

Accepted Answer

Actin filaments slide past myosin filaments, shortening the sarcomere and causing muscle contraction.

Question 2

During a muscle contraction, which sequence correctly describes the order of events after a nerve impulse reaches the neuromuscular junction?

Accepted Answer

Release of acetylcholine $$\rightarrow$$ depolarization of sarcolemma $$\rightarrow$$ release of calcium ions $$\rightarrow$$ cross-bridge formation

Question 3

Which muscle type is primarily responsible for generating most of the body's heat during shivering?

Accepted Answer

Skeletal muscle

Question 4

Which of the following best distinguishes isotonic from isometric muscle contractions?

Accepted Answer

Isotonic contractions change muscle length, while isometric contractions do not change muscle length.

Question 5

Which structure separates the thoracic cavity from the abdominal cavity and plays a key role in respiration?

Accepted Answer

Diaphragm

Question 6

During inhalation, what happens to the pressure inside the lungs relative to atmospheric pressure?

Accepted Answer

Lung pressure decreases below atmospheric pressure, causing air to flow in.

Question 7

Which of the following correctly traces the path of oxygen-rich blood through the heart?

Accepted Answer

Pulmonary veins $$\rightarrow$$ left atrium $$\rightarrow$$ left ventricle $$\rightarrow$$ aorta

Question 8

Which of the following is NOT a function of the upper respiratory system?

Accepted Answer

Gas exchange between air and blood

Question 9

Which digestive organ is primarily responsible for nutrient absorption due to its large surface area?

Accepted Answer

Small intestine

Question 10

Which enzyme is produced in the salivary glands and begins the chemical digestion of carbohydrates?

Accepted Answer

Amylase

Question 11

What is the main function of peristalsis in the digestive system?

Accepted Answer

To propel food through the digestive tract via coordinated muscle contractions

Question 12

Which of the following best defines a gene?

Accepted Answer

A segment of DNA that codes for a specific protein

Question 13

If a child inherits one dominant allele (A) and one recessive allele (a) for a trait, what is the child's genotype and phenotype?

Accepted Answer

Genotype: Aa; Phenotype: displays the dominant trait

Question 14

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

Accepted Answer

Alleles of different genes are distributed independently of one another during gamete formation.

Question 15

A woman who is a carrier for a sex-linked recessive disorder (X$$^NX$^n) $$and a man who does not have the disorder (X$$^NY) $$have a child. What is the probability their son will have the disorder?

Accepted Answer

$$50\%$$

Question 16

Which of the following is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 17

Which process during meiosis increases genetic variation by creating new combinations of alleles?

Accepted Answer

Crossing over

Question 18

A karyotype is most useful for which of the following purposes?

Accepted Answer

Detecting chromosomal abnormalities such as trisomy 21

Question 19

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 20

Which of the following best describes nondisjunction and its consequence?

Accepted Answer

Failure of chromosomes to separate during meiosis, resulting in gametes with abnormal chromosome numbers

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

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