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

A patient is unable to generate enough heat to maintain body temperature in a cold environment. Which system is most likely impaired?

Accepted Answer

Muscular system

Question 3

During inhalation, which of the following best describes the change in pressure inside the lungs?

Accepted Answer

The pressure inside the lungs decreases below atmospheric pressure, causing air to flow in.

Question 4

Which of the following best explains the function of the intercostal muscles during breathing?

Accepted Answer

They contract to elevate the rib cage during inhalation and relax during exhalation.

Question 5

Which of the following is a correct sequence of events leading to muscle contraction after a nerve impulse?

Accepted Answer

Action potential → Calcium release from sarcoplasmic reticulum → Binding of calcium to troponin → Cross-bridge formation

Question 6

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

Accepted Answer

Isotonic contractions produce movement by changing muscle length, while isometric contractions generate force without changing muscle length.

Question 7

Which structure is responsible for separating the thoracic and abdominal cavities in humans?

Accepted Answer

Diaphragm

Question 8

Which of the following best describes the function of enzymes in the human digestive system?

Accepted Answer

They catalyze the breakdown of macromolecules into absorbable units.

Question 9

A person has a mutation in a gene coding for a digestive enzyme produced in the pancreas. Which process is most likely impaired?

Accepted Answer

Chemical digestion of macromolecules in the small intestine

Question 10

Which of the following best explains why a large surface area is important in the small intestine?

Accepted Answer

It increases the rate of nutrient absorption.

Question 11

Which of the following best describes the Law of Segregation?

Accepted Answer

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

Question 12

A woman with genotype $$Aa$$ for a trait and a man with genotype $$aa$$ have a child. What is the probability that the child will have the $$aa$$ genotype?

Accepted Answer

$$50\%$$

Question 13

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote expresses a phenotype intermediate between the two homozygotes.

Question 14

Which of the following is an example of codominance?

Accepted Answer

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

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

A child is born with Down syndrome, which is caused by trisomy 21. Which meiotic event most likely led to this condition?

Accepted Answer

Nondisjunction during meiosis

Question 17

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes contribute to a single trait, resulting in a range of phenotypes.

Question 18

Which of the following best explains how linked genes are inherited?

Accepted Answer

They tend to be inherited together because they are located close to each other on the same chromosome.

Question 19

Which of the following best describes the function of a Punnett Square?

Accepted Answer

It predicts the probability of offspring genotypes based on parental alleles.

Question 20

A man with genotype $$X^Y$$ and a woman with genotype $$X^X^* ($$where $$X^* is a $$recessive allele for color blindness) have a son. What is the probability that the son will be color blind?

Accepted Answer

$$50\%$$

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

Study Guide - Practice Questions

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