Biology Midterm Review 24-25

Front

Which of the following is a density-independent limiting factor?

• natural disaster
• predation
• disease
• parasitism

Back

natural disaster

Answer explanation

A natural disaster is a density-independent limiting factor because it affects populations regardless of their density. In contrast, predation, disease, and parasitism are density-dependent factors, as their impact varies with population size.

Front

What is the primary role of photosynthesis in the carbon cycle?

Back

To convert carbon dioxide to organic compounds

Answer explanation

The primary role of photosynthesis in the carbon cycle is to convert carbon dioxide into organic compounds, which are essential for plant growth and serve as the foundation of the food chain.

Front

What impact do resources such as sunlight and water have on a forest ecosystem?

Back

They limit the carrying capacity of the ecosystem.

Answer explanation

Resources like sunlight and water are crucial as they limit the carrying capacity of the ecosystem. Insufficient resources can restrict the number of organisms that can thrive, affecting biodiversity and ecosystem health.

Front

What is the best conclusion for the graph?

Back

The population is increasing because of unlimited food and shelter.

Answer explanation

The correct choice indicates that the population is increasing due to unlimited food and shelter, suggesting favorable conditions for growth, unlike the other options which imply limitations or competition.

Front

How is nitrogen "fixed" into a usable form for plants?

Back

through action of bacteria & lightning

Answer explanation

Nitrogen is fixed into a usable form for plants through the action of bacteria in the soil and by lightning, which converts atmospheric nitrogen into compounds that plants can absorb. Thus, the correct answer is through action of bacteria & lightning.

Front

The cell wall of organisms from this kingdom is made up of chitin.

Back

Fungi

Answer explanation

The cell wall of fungi is composed of chitin, distinguishing them from plants (cellulose), animals (no cell wall), and protists (varied). Therefore, the correct answer is Fungi.

Front

What happens in the lysogenic cycle?

Back

Virus injects the nucleic acid into the host cell, and the nucleic acid integrates into the host cell DNA, and stays dormant for a long time.

Answer explanation

In the lysogenic cycle, the virus injects its nucleic acid into the host cell, which then integrates into the host's DNA and remains dormant for an extended period, allowing the host cell to replicate the viral DNA without immediate destruction.

Front

What is shown here? Options: Lysogenic Cycle, Lytic Cycle, Binary Fission, Conjugation

Back

Lytic Cycle

Answer explanation

The Lytic Cycle is a viral replication process where the virus infects a host cell, replicates, and causes the cell to burst, releasing new viruses. This distinguishes it from the Lysogenic Cycle, which integrates viral DNA into the host's genome.

Front

What is facilitated diffusion?

Back

Movement of molecules across cell membranes through protein channels without energy

Answer explanation

Facilitated diffusion is the process where molecules move across cell membranes via protein channels without the use of energy, making the first answer choice the correct description.

Front

An illustration and a dichotomous key are given. What is the correct classification for this organism? Class Insecta, Order Amblygygi, Order Araneae, Order Scorpiones

Back

Order Araneae

Answer explanation

The organism is classified as Order Araneae because it exhibits characteristics typical of spiders, such as having eight legs and a body divided into two segments, distinguishing it from other orders listed.