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.

Question 2

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

Accepted Answer

Acetylcholine is released, triggering depolarization of the muscle fiber membrane.

Question 3

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

Accepted Answer

Muscle contractions involve ATP hydrolysis, 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

Which of the following statements about isotonic and isometric muscle contractions is correct?

Accepted Answer

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

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

Accepted Answer

Nasal cavity

Question 8

What is the primary function of the intercostal muscles during respiration?

Accepted Answer

They assist the diaphragm in expanding and contracting the thoracic cavity.

Question 9

Which of the following best describes the flow of oxygen-rich blood through the heart?

Accepted Answer

Pulmonary veins → left atrium → left ventricle → aorta

Question 10

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

Accepted Answer

Small intestine

Question 11

Which enzyme is produced in the pancreas and is essential for the digestion of proteins in the small intestine?

Accepted Answer

Trypsin

Question 12

What is the main difference between basal metabolic rate (BMR) and standard metabolic rate (SMR)?

Accepted Answer

BMR is measured under strict resting and fasting conditions, while SMR may include variable activity or temperature.

Question 13

Which of the following best describes the Law of Segregation in genetics?

Accepted Answer

Each individual has two alleles for each gene, which separate during gamete formation.

Question 14

A woman with genotype $$X^N X^n ($$where $$N is $$normal vision and $$n is $$colorblindness) and a man with genotype $$X^n Y$$ have a child. What is the probability that their son will be colorblind?

Accepted Answer

$$50\%$$

Question 15

Which of the following is an example of codominance?

Accepted Answer

A person with AB blood type expressing both A and B antigens equally.

Question 16

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

Accepted Answer

Crossing over between homologous chromosomes

Question 17

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

Accepted Answer

Detecting chromosomal abnormalities such as trisomy 21

Question 18

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

Accepted Answer

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

Question 19

Which of the following scenarios best illustrates polygenic inheritance?

Accepted Answer

Human skin color, which is influenced by multiple genes.

Question 20

Which event during meiosis can lead to nondisjunction, and what is a possible outcome?

Accepted Answer

Failure of homologous chromosomes to separate during anaphase I, resulting in gametes with abnormal chromosome numbers.

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

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