Biology Quiz for Class 8
Questions: 16 · 10 minutes
1. Which cell structure releases usable energy from food during cellular respiration?
Nucleus
Mitochondrion
Vacuole
Cell wall
2. What was a major focus of biologist Ernest Everett Just's research?
How crop rotation restores nutrients to farmland
How cell surfaces and egg cells function during fertilization and development
How blood plasma can be stored for transfusion
How antibiotics prevent all genetic mutations in bacteria
3. A plant cell is placed in a concentrated salt solution and becomes smaller. What best explains the change?
Water moves into the cell by osmosis.
Salt leaves the cell by active transport.
Water moves out of the cell by osmosis.
The cell wall is broken down by enzymes.
4. In the food chain grass → grasshopper → frog → snake, the frog population suddenly decreases. What is the most likely short-term effect?
The grasshopper population increases because fewer are eaten.
The grass population decreases because snakes eat more of it.
The snake population increases because it has more food.
The grasshopper population disappears because frogs support it.
5. A bee carries pollen from the anther of one flower to the stigma of another flower of the same species. What process has occurred?
Germination
Fertilization
Seed dispersal
Pollination
6. Which scientific and medical contribution is Charles Drew best known for?
Demonstrating that microorganisms cause fermentation
Discovering the structure of DNA
Advancing the preservation and large-scale banking of blood plasma
Developing the first successful smallpox vaccine
7. Part of a plant leaf is covered so that no light reaches it. After several hours, that area does not turn blue-black in an iodine test. What does this show?
Iodine prevents water from entering leaves.
Covered leaves cannot absorb minerals from soil.
Light is needed for the leaf to produce starch.
Darkness causes all chlorophyll to disappear immediately.
8. Which contribution is most closely associated with agricultural scientist George Washington Carver?
Providing the cells that became the widely used HeLa cell line
Improving methods for preserving blood plasma and organizing blood banks
Studying fertilization and the role of the cell surface in marine organisms
Promoting crop rotation and developing uses for crops such as peanuts and sweet potatoes
9. A doctor describes a blood vessel that carries blood away from the heart. Which type of vessel is being described?
Capillary
Artery
Lymph vessel
Vein
10. A student touches a hot pan and pulls back a hand before consciously thinking about it. Which structure coordinates this rapid reflex first?
Spinal cord
Stomach
Kidney
Pituitary gland
11. Why do breathing rate and heart rate usually increase during vigorous exercise?
Muscles need more oxygen and glucose, and carbon dioxide must be removed faster.
Muscles need less blood while they are moving.
The lungs begin digesting stored food for the muscles.
The heart must prevent oxygen from reaching active cells.
12. A student argues that a bat should be classified as a bird because it has wings. Which evidence best supports classifying a bat as a mammal instead?
It can move through the air.
It has a lightweight skeleton.
It has hair and females produce milk for their young.
It is active during certain parts of the day.
13. Why have cells taken from Henrietta Lacks, known as HeLa cells, been especially important to biological research?
They were the first plant cells observed with a microscope.
They proved that all infectious diseases are inherited.
They were used to produce the first artificial blood plasma.
They could continue dividing in laboratories and were used in many areas of research.
14. A person's blood contains an unusually high amount of urea because certain organs are not filtering it effectively. Which organs are most directly involved?
Kidneys
Lungs
Salivary glands
Pancreas
15. After an antibiotic treatment, a few resistant bacteria survive and reproduce. Why can the next bacterial population contain a larger proportion of resistant bacteria?
The antibiotic teaches every bacterium how to resist it.
Bacteria choose resistance when they detect medicine.
The antibiotic changes all surviving bacteria into a new species.
Resistant bacteria survive the selection pressure and pass on their traits.
16. Yeast is mixed with warm water and sugar in a bottle, and a balloon is placed over the opening. The balloon begins to inflate. Which gas is mainly responsible?
Oxygen released from sugar
Carbon dioxide produced by yeast respiration
Nitrogen absorbed from the water
Hydrogen produced by photosynthesis