Quiz: Fundamentals of Living Organisms and Processes — 24 domande

1. Which statement best describes a living organism?

A. A substance that can move and change shape

B. A biological system that carries out life processes such as growth and reproduction

C. Any object made of cells and found in nature

D. A group of organisms with the same habitat

Answer: (B)

Spiegazione

A living organism is defined by carrying out life processes such as growth, reproduction, and response to stimuli. The other options describe either non-living objects or broader ecological groupings.

2. What is classification in biology?

A. Separating living things into plants and animals only

B. Naming organisms using Latin words only

C. Grouping organisms by shared features to show relationships and variety

D. Measuring the size and mass of organisms

Answer: (C)

Spiegazione

Classification groups organisms based on shared characteristics to organise variety and show relationships. It is broader than simply naming organisms or splitting them into two groups.

3. What is the correct order of biological organisation from smallest to largest?

A. Organ, tissue, cell, organ system

B. Cell, organ, tissue, organ system

C. Cell, tissue, organ, organ system

D. Tissue, cell, organ, organ system

Answer: (C)

Spiegazione

Cells form tissues, tissues form organs, and organs form organ systems. This increasing level of organisation is the standard hierarchy.

4. What is an organelle?

A. A group of similar cells working together

B. A group of organs working together

C. A structure made of different tissues

D. A specialised structure inside a cell that carries out a specific function

Answer: (D)

Spiegazione

An organelle is a specialised structure within a cell with a particular job. The other options describe a tissue, an organ, and an organ system.

5. Which structure is present in plant cells but not in animal cells?

A. Mitochondrion

B. Cell wall

C. Cell membrane

D. Cytoplasm

Answer: (B)

Spiegazione

Plant cells have a cell wall, while animal cells do not. Mitochondria, cytoplasm, and cell membranes are found in both.

6. What is the main function of mitochondria?

A. To store genetic information

B. To control what enters the cell

C. To carry out respiration and release energy

D. To make the cell wall rigid

Answer: (C)

Spiegazione

Mitochondria are the organelles where respiration releases energy, especially in aerobic conditions. Genetic information is stored in the nucleus, not in mitochondria.

7. What is diffusion?

A. The movement of substances against a concentration gradient using energy

B. The movement of water only through a partially permeable membrane

C. The random movement of all particles until they stop

D. The net movement of particles from a higher concentration to a lower concentration

Answer: (D)

Spiegazione

Diffusion is the net movement of particles down a concentration gradient, from higher to lower concentration. Osmosis and active transport are different processes.

8. When is active transport needed?

A. When substances must move against a concentration gradient

B. When particles spread from high to low concentration

C. When substances move through a fully permeable membrane

D. When water moves from dilute to concentrated solution

Answer: (A)

Spiegazione

Active transport uses energy to move substances against a concentration gradient. The other options describe osmosis or diffusion.

9. What does aerobic respiration use to release energy from food molecules?

A. Oxygen

B. Water

C. Lactic acid

D. Carbon dioxide

Answer: (A)

Spiegazione

Aerobic respiration uses oxygen to release energy from food molecules. Carbon dioxide and water are products of the process, not the reactant used.

10. Why does oxygen keep diffusing into respiring cells?

A. Because the cell membrane actively pumps oxygen in

B. Because oxygen is produced faster than it is removed

C. Because oxygen cannot pass through the membrane

D. Because oxygen is continually used inside the cell

Answer: (D)

Spiegazione

Aerobic respiration uses oxygen, keeping its concentration low inside the cell and maintaining a diffusion gradient into the cell. The membrane does allow oxygen to diffuse through.

11. In a hypotonic solution, what happens to a potato cylinder?

A. It shows no change because osmosis does not occur

B. It decreases in mass and length as water leaves by osmosis

C. It increases in mass and length as water enters by osmosis

D. It gains mass because sucrose moves into the cells

Answer: (C)

Spiegazione

A hypotonic solution has a higher water potential than the potato cells, so water moves in by osmosis. This increases both mass and length.

12. How can the reliability of a potato osmosis experiment be improved?

A. Change the potato shape after each test

B. Blot the potatoes as much as possible before weighing

C. Repeat the experiment and calculate a mean

D. Use only one potato cylinder

Answer: (C)

Spiegazione

Repeating the experiment and calculating a mean improves reliability. Excessive blotting can change the measured mass and increase error.

13. What is fertilisation?

A. The growth of a zygote into an embryo

B. The division of cells to make a tissue

C. The fusion of male and female gametes to form a zygote

D. The release of pollen from a flower

Answer: (C)

Spiegazione

Fertilisation is the joining of male and female gametes to form a zygote. Growth into an embryo happens after fertilisation.

14. What develops from a zygote in humans?

A. A seed and then a fruit

B. A pollen grain and then a flower

C. A gamete and then a chromosome

D. An embryo and then a baby

Answer: (D)

Spiegazione

In humans, the zygote divides and develops into an embryo, which then develops into a baby. Seeds and fruits are plant reproductive structures.

15. What is a gene?

A. A section of DNA that codes for a specific characteristic

B. A type of cell that makes gametes

C. An alternative version of a chromosome

D. A structure that carries many nuclei

Answer: (A)

Spiegazione

A gene is a section of DNA that codes for a specific characteristic. Chromosomes carry many genes, but a gene is not a chromosome itself.

16. How do different alleles affect inherited characteristics?

A. They prevent chromosomes from being inherited

B. They can produce different phenotypes

C. They make all individuals identical

D. They turn genes into proteins only in plants

Answer: (B)

Spiegazione

Different alleles of the same gene can lead to different traits or phenotypes. This variation comes from the different versions of genes inherited from parents.

17. What is the effect of a steeper concentration gradient on diffusion?

A. It changes diffusion into active transport

B. It increases the rate of movement

C. It stops particles from moving

D. It only affects water molecules

Answer: (B)

Spiegazione

A steeper concentration gradient increases the rate of diffusion because there is a larger difference between the two areas. Active transport and osmosis are different processes.

18. What happens to an animal cell in a hypertonic solution?

A. It remains unchanged because the membrane blocks water

B. It swells because water enters by osmosis

C. It shrinks because water leaves by osmosis

D. It bursts because active transport pushes water in

Answer: (C)

Spiegazione

In a hypertonic solution, water moves out of the cell by osmosis, so the cell shrinks or crenates. Swelling happens in a hypotonic solution.

19. What is double circulation in humans?

A. Blood flows through the heart only once before returning

B. Blood moves in the same vessel system as lymph

C. Air passes through the heart and lungs together

D. Blood passes through the heart twice in one complete circuit

Answer: (D)

Spiegazione

Double circulation means blood passes through the heart twice in one full circuit of the body. This separates oxygenated and deoxygenated blood more effectively.

20. What is the role of alveoli?

A. They are tiny air sacs where gas exchange occurs

B. They produce digestive enzymes

C. They store oxygen for later use

D. They pump blood around the body

Answer: (A)

Spiegazione

Alveoli are the tiny air sacs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out. They do not pump blood or store oxygen.

21. Why is milk pasteurised before Lactobacillus is added in yoghurt production?

A. To prevent the milk from cooling

B. To kill unwanted bacteria that could compete with Lactobacillus

C. To increase the pH of the milk

D. To turn lactose directly into ethanol

Answer: (B)

Spiegazione

Pasteurisation kills unwanted bacteria that could contaminate the milk or compete with Lactobacillus. After pasteurising, the milk is cooled before the starter bacteria are added.

22. What is the main useful product of Lactobacillus in yoghurt production?

A. Oxygen

B. Lactic acid

C. Ethanol

D. Cellulose

Answer: (B)

Spiegazione

Lactobacillus ferments lactose to form lactic acid, which lowers pH and thickens the milk. Ethanol is associated with yeast fermentation, not yoghurt production.

23. What is selective breeding?

A. Choosing parents with desired characteristics to produce offspring with those traits

B. Inserting a gene from one species into another species

C. Making identical copies of an organism in a laboratory

D. Allowing organisms to reproduce without human influence

Answer: (A)

Spiegazione

Selective breeding involves choosing parents with desired traits so the offspring are more likely to show those traits. Genetic modification and cloning are different processes.

24. Which process produces genetically identical organisms?

A. Fertilisation

B. Cloning

C. Mutation

D. Selective breeding

Answer: (B)

Spiegazione

Cloning produces genetically identical copies of an organism or cells. Selective breeding mixes traits through reproduction rather than making identical copies.