Life Science Quiz
Questions: 16 · 10 minutes
1. Which statement best describes the primary role of the cell membrane?
It produces most proteins used by the cell.
It stores all of the cell's genetic information.
It regulates which substances enter and leave the cell.
It converts glucose directly into DNA.
2. Why is less usable energy generally available at higher trophic levels of an ecosystem?
Producers prevent consumers from absorbing chemical energy.
Matter disappears whenever one organism eats another.
Top predators convert most food energy directly into sunlight.
Organisms use energy for metabolism, and much is released as heat.
3. A DNA substitution changes a codon, but the resulting protein contains the same amino-acid sequence as before. What best explains this result?
The mutation caused the chromosome to duplicate.
More than one codon can specify the same amino acid.
The ribosome repaired the DNA before translation.
Every DNA substitution occurs outside a gene.
4. In a eukaryotic cell, which organelle produces most ATP during aerobic cellular respiration?
Mitochondrion
Golgi apparatus
Nucleus
Lysosome
5. After a carbohydrate-rich meal, blood glucose rises. How does insulin normally help restore balance?
It causes the liver to release more glucose into the blood.
It promotes glucose uptake and storage, lowering blood glucose.
It prevents body cells from using glucose for respiration.
It converts all absorbed glucose directly into protein.
6. After repeated antibiotic exposure, a bacterial population becomes mostly antibiotic-resistant. Which explanation best fits natural selection?
Every bacterium learned to neutralize the antibiotic during exposure.
The antibiotic transformed all surviving bacteria into a new species.
Bacteria deliberately produced useful mutations because resistance was needed.
Resistant bacteria survived and reproduced more successfully than susceptible bacteria.
7. A student wants to test how light intensity affects plant growth. Which design best isolates light intensity as the independent variable?
Change both light intensity and watering frequency for each group.
Use a different plant species at each light intensity.
Vary light intensity while keeping species, soil, water, and temperature consistent.
Place all plants at one light intensity but use different fertilizers.
8. New skin cells are produced while a small cut heals. Which process creates these genetically similar replacement cells?
Fertilization
Meiosis
Mitosis
Transcription
9. Which condition is essential for a population to evolve through natural selection?
Organisms pass all acquired characteristics directly to offspring.
Every individual develops the same useful trait during life.
The environment remains completely unchanged for many generations.
Heritable variation affects survival or reproductive success.
10. Why can vaccination produce a faster immune response during later exposure to the same pathogen?
It permanently raises body temperature so pathogens cannot reproduce.
It replaces innate immunity with a pathogen-specific barrier.
It prevents the pathogen from ever entering the body.
It generates memory cells that respond rapidly to familiar antigens.
11. In a simple food web, a predator mainly eats one herbivore species. If the predator is removed, what is the most likely initial change?
The herbivore population immediately becomes extinct.
Plant biomass increases because more herbivores are feeding.
The herbivore population increases because predation decreases.
Energy transfer from plants to herbivores stops.
12. During vigorous exercise, breathing rate usually increases. What is the best biological explanation?
Working tissues need greater gas exchange to support respiration and remove carbon dioxide.
Muscles must receive nitrogen gas to produce movement.
Faster breathing lowers the body's need to circulate blood.
The lungs begin digesting stored nutrients for the muscles.
13. One DNA strand has the sequence 5′-ATGC-3′. Which sequence is complementary and antiparallel to it?
3′-TACG-5′
5′-TACG-3′
3′-UACG-5′
3′-ATGC-5′
14. For a gene with alleles A and a, an Aa parent is crossed with an aa parent. What is the probability that an offspring will have genotype aa?
25%
50%
75%
100%
15. Fertilizer runoff causes rapid algal growth in a pond. After many algae die, fish begin dying as well. What is the most direct explanation?
The dead algae make the pond water too salty for fish.
Decomposers consume dissolved oxygen while breaking down the dead algae.
Fertilizer prevents decomposers from growing in the pond.
Fish stop carrying out cellular respiration when algae are present.
16. A healthy plant cell is placed in pure water. What is most likely to happen as a result of osmosis?
Water enters the cell, increasing pressure against the cell wall.
Water leaves the cell, causing it to shrink.
Salt enters the cell until its concentration equals that of the water.
The cell wall dissolves and releases the cell contents.