Science: Life Science Practice Test Flashcards

Which of the following is NOT a function of the skeletal system?

Answer: Regulating blood glucose levels

Blood glucose regulation is a function of the endocrine system (insulin/glucagon), not the skeletal system.

What happens during the light-dependent reactions of photosynthesis?

Answer: Light energy is used to split water and produce ATP and NADPH

Light-dependent reactions capture solar energy to split water molecules, releasing oxygen and producing ATP and NADPH for the Calvin cycle.

A scientist discovers a new organism that has no nucleus, no membrane-bound organelles, and a single circular chromosome. This organism is best classified as:

Answer: A prokaryote

Prokaryotes lack a membrane-bound nucleus and organelles and typically have a single circular chromosome.

Which hormone is responsible for stimulating the fight-or-flight response in the human body?

Answer: Adrenaline (epinephrine)

Adrenaline (epinephrine) is released by the adrenal glands in response to stress, triggering increased heart rate, blood flow, and alertness.

What evidence best supports the theory that all modern species share a common ancestor?

Answer: All organisms share a nearly universal genetic code (DNA/RNA)

The near-universal genetic code (DNA → RNA → protein) shared by all life strongly supports descent from a common ancestor.

In an experiment, root tips are treated with a chemical that prevents spindle fiber formation. Which cellular process would be most directly disrupted?

Answer: Cell division (mitosis)

Spindle fibers pull chromosomes apart during mitosis; without them, chromosomes cannot separate and cell division fails.

Which of the following best explains why biodiversity is important for ecosystem stability?

Answer: Diverse ecosystems have more redundancy, so the loss of one species has less overall impact

Biodiversity provides functional redundancy — if one species disappears, others can fulfill similar roles, making the ecosystem more resilient.