Question 1

Which of the following best describes the role of calcium ions ($$\mathrm{Ca$$^{2+}$$}) in $$muscle contraction according to the sliding filament theory?

Accepted Answer

They allow myosin to attach to actin, enabling contraction.

Question 2

A patient is unable to move their diaphragm due to nerve damage. Which of the following physiological changes would most likely occur during attempted inspiration?

Accepted Answer

Lung volume would decrease and pressure would increase, preventing air from entering the lungs.

Question 3

Which of the following best explains why shivering increases body temperature?

Accepted Answer

Shivering causes muscle contractions, which generate heat as a byproduct of energy use.

Question 4

A person is holding a heavy box without moving their arms. Which type of muscle contraction is primarily occurring in their biceps?

Accepted Answer

Isometric contraction

Question 5

Which structure is responsible for storing and releasing calcium ions ($$\mathrm{Ca$$^{2+}$$}) in $$muscle cells during contraction?

Accepted Answer

Sarcoplasmic reticulum

Question 6

During an asthma attack, which of the following best describes what happens in the respiratory system?

Accepted Answer

The airways become narrow and inflamed, making breathing difficult.

Question 7

Which of the following correctly traces the path of oxygen-rich blood from the lungs to the body?

Accepted Answer

Lungs → pulmonary veins → left atrium → left ventricle → aorta → body

Question 8

A person with emphysema has difficulty absorbing enough oxygen. Which structure is most directly affected by this disorder?

Accepted Answer

Alveoli

Question 9

Which enzyme is responsible for beginning the breakdown of starch in the mouth?

Accepted Answer

Amylase

Question 10

If the small intestine did not have villi and microvilli, which of the following would most likely occur?

Accepted Answer

Nutrient absorption would decrease due to reduced surface area.

Question 11

Which of the following best describes the function of the gallbladder?

Accepted Answer

It stores and releases bile into the small intestine.

Question 12

A genetic cross between two heterozygous individuals ($$Bb 	imes Bb) $$for a trait controlled by simple dominance results in which expected phenotypic ratio?

Accepted Answer

$$3:1 ($$dominant:recessive)

Question 13

Which of the following scenarios is an example of incomplete dominance?

Accepted Answer

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

Question 14

A male inherits an X-linked recessive allele for red-green color blindness. What is the probability he will express the trait?

Accepted Answer

100%, because males have only one X chromosome.

Question 15

Which process during meiosis increases genetic variation by exchanging DNA between homologous chromosomes?

Accepted Answer

Crossing over

Question 16

A karyotype of a human cell shows 47 chromosomes, including three copies of chromosome 21. Which condition does this indicate?

Accepted Answer

Down syndrome (trisomy 21)

Question 17

Which of the following best explains why recessive genetic disorders can remain common in a population?

Accepted Answer

Carriers with one copy of the allele do not show symptoms.

Question 18

Which of the following is an example of polygenic inheritance?

Accepted Answer

Height in humans

Question 19

If a person’s environment changes (e.g., improved nutrition), which of the following is most likely to be affected?

Accepted Answer

Their phenotype

Question 20

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

Accepted Answer

Different genes are usually inherited independently, creating new combinations.

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

Study Guide - Practice Questions

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