Exam 3 Review (BIO)

Which structure in the lungs is primarily responsible for gas exchange?

• Bronchi

• Alveoli

• Trachea

• Diaphragm

Answer explanation

The alveoli are tiny air sacs in the lungs where gas exchange occurs. They allow oxygen to enter the blood and carbon dioxide to be expelled, making them the primary site for this essential process.

Tags

NGSS.HS-LS2-3

NGSS.HS-LS2-5

What is the basic functional unit of the nervous system?

• Neuron

• Muscle fiber

• Red blood cell

• Platelet

Answer explanation

The basic functional unit of the nervous system is the neuron. Neurons are specialized cells that transmit nerve impulses, making them essential for communication within the nervous system.

Which part of the nervous system is responsible for carrying sensory information to the central nervous system?

• Efferent division

• Afferent division

• Parasympathetic division

• Sympathetic division

Answer explanation

The afferent division of the nervous system is responsible for transmitting sensory information from the body to the central nervous system, making it the correct choice for this question.

Which of the following best describes genetic drift?

• Change in allele frequencies due to random events

• Change in traits due to natural selection

• Movement of genes between populations

• Mutation in DNA sequence

Answer explanation

Genetic drift refers to changes in allele frequencies within a population due to random events, rather than natural selection or other factors. This makes 'Change in allele frequencies due to random events' the correct description.

Tags

NGSS.HS-LS4-2

Which division of the autonomic nervous system is responsible for the "fight or flight" response?

• Parasympathetic

• Sympathetic

• Somatic

• Afferent

Answer explanation

The sympathetic division of the autonomic nervous system triggers the "fight or flight" response, preparing the body for stressful situations by increasing heart rate, dilating pupils, and redirecting blood flow to muscles.

What is the main role of synapses in the nervous system?

• To store oxygen

• To transmit signals between neurons

• To produce hormones

• To digest nutrients

Answer explanation

The main role of synapses in the nervous system is to transmit signals between neurons. They facilitate communication by allowing neurotransmitters to pass from one neuron to another, enabling the flow of information.

Which of the following is an example of gene flow?

• Migration of individuals from one population to another, introducing new alleles

• A mutation occurring in a single organism

• A population bottleneck event

• Natural selection favoring a specific trait

Answer explanation

Gene flow occurs when individuals migrate between populations, introducing new alleles. This process increases genetic diversity, making the correct choice "Migration of individuals from one population to another, introducing new alleles."

Emma is running a race and her brain sends signals to her leg muscles to move faster. Which of the following best describes the function of the efferent division of the nervous system in this scenario?

• Carrying sensory information to the brain

• Carrying motor commands from the brain to muscles

• Regulating blood sugar levels

• Filtering waste from the blood

Answer explanation

In this scenario, the efferent division of the nervous system is responsible for carrying motor commands from the brain to the leg muscles, enabling Emma to run faster. This is the correct function described.

In a forest, a population of beetles comes in two colors: green and brown. Birds can spot green beetles more easily, so brown beetles are more likely to survive and reproduce. Which of the following best describes what is happening in this scenario?

• The random change in allele frequencies

• The process by which organisms better adapted to their environment tend to survive and reproduce

• The movement of genes between populations

• The duplication of DNA

Answer explanation

This scenario illustrates natural selection, where brown beetles survive better due to their color, leading to increased reproduction. This process describes how organisms better adapted to their environment tend to survive and reproduce.

Tags

NGSS.HS-LS4-2

NGSS.HS-LS4-4

Which of the following is an example of genetic drift in a population?

• A flood randomly kills a large portion of a population, changing allele frequencies

• Individuals with a certain trait are more likely to survive

• New individuals migrate into a population

• A gene mutates to a new form

Answer explanation

The correct choice illustrates genetic drift, as the flood randomly alters allele frequencies by killing individuals regardless of their traits, leading to a change in the population's genetic makeup.