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 muscle contraction, which ion is released from the sarcoplasmic reticulum and is essential for the interaction between actin and myosin?

Accepted Answer

Calcium ions ($$\mathrm{Ca$$^{2+}$$})$$

Question 3

Which of the following best explains the difference between isotonic and isometric muscle contractions?

Accepted Answer

Isotonic contractions change muscle length, while isometric contractions maintain muscle length.

Question 4

Which muscle is primarily responsible for separating the thoracic and abdominal cavities and plays a crucial role in breathing?

Accepted Answer

Diaphragm

Question 5

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

Accepted Answer

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

Question 6

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 7

Which structure in the digestive system is primarily responsible for nutrient absorption due to its large surface area?

Accepted Answer

Small intestine

Question 8

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

Accepted Answer

To move food along the digestive tract via coordinated muscle contractions

Question 9

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

Accepted Answer

BMR is measured in endotherms at rest, while SMR is measured in ectotherms at a specific temperature.

Question 10

Which of the following statements about genes and chromosomes is correct?

Accepted Answer

Genes are segments of DNA located on chromosomes.

Question 11

A couple, both heterozygous for a dominant trait (genotype $$Aa$$), are expecting a child. What is the probability that their child will be homozygous recessive ($$aa) $$for this trait?

Accepted Answer

$$\dfrac{1}{4}$$

Question 12

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

Accepted Answer

Alleles of different genes assort independently during gamete formation.

Question 13

A woman with blood type $$AB$$ and a man with blood type $$O$$ have a child. Which blood types are possible for their child?

Accepted Answer

A or B

Question 14

Which of the following is an example of incomplete dominance?

Accepted Answer

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

Question 15

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 16

Which of the following best describes nondisjunction and its effect during meiosis?

Accepted Answer

It is the failure of homologous chromosomes to separate, resulting in gametes with abnormal chromosome numbers.

Question 17

Which of the following is an example of polygenic inheritance?

Accepted Answer

Human skin color, which is influenced by multiple genes.

Question 18

Which of the following best explains how environmental factors can influence phenotypic expression?

Accepted Answer

Environmental factors can affect gene expression, leading to different phenotypes from the same genotype.

Question 19

Which of the following best describes the function of a karyotype in genetics?

Accepted Answer

It displays the number and appearance of chromosomes in a cell.

Question 20

Which of the following best describes the function of digestive enzymes?

Accepted Answer

They catalyze the breakdown of macromolecules into absorbable units.

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

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