Quiz: Fundamentals of Cell Structure and Division — 12 domande

1. What happens to potato cells when they are placed in salt or sugar solution for about an hour?

A. They divide rapidly because of the extra solute

B. They stay unchanged because osmosis cannot occur

C. They swell because water enters them

D. They shrink because water leaves them

Answer: (D)

Spiegazione

In a concentrated salt or sugar solution, water moves out of the cells by osmosis, causing them to shrink. In plain water, the cells would swell instead.

2. What is the main function of ribosomes in a cell?

A. Protein synthesis

B. Lipid storage

C. DNA replication

D. Waste digestion

Answer: (A)

Spiegazione

Ribosomes are the sites of protein synthesis, either free in the cytoplasm or attached to the endoplasmic reticulum. They do not store lipids or replicate DNA.

3. Which plastid type is colourless and mainly stores starch, oils, or proteins?

A. Chromoplast

B. Leucoplast

C. Mitochondrion

D. Chloroplast

Answer: (B)

Spiegazione

Leucoplasts are colourless plastids that store food materials such as starch, oils, or proteins. Chromoplasts contain pigments, while chloroplasts carry out photosynthesis.

4. What is the main outcome of meiosis?

A. Two daughter cells formed after a single division in somatic tissue

B. Two identical body cells with the same chromosome number as the parent

C. Four gametes with half the chromosome number and genetic variation

D. One repaired cell that replaces damaged tissue

Answer: (C)

Spiegazione

Meiosis is a two-step division in reproductive organs that forms four gametes, each with half the chromosome number and increased genetic variation. The other choices describe mitosis or incorrectly reduce meiosis to one division.

5. What did Robert Hooke call the box-like compartments he observed in cork in 1665?

A. Membranes

B. Cells

C. Chromosomes

D. Tissues

Answer: (B)

Spiegazione

Hooke examined cork and named the box-like structures he saw "cells." The other options refer to different biological levels or structures.

6. What is a key function of the Golgi apparatus?

A. It stores the cell's DNA

B. It makes ATP from glucose

C. It modifies, sorts, and packages proteins or lipids

D. It carries out photosynthesis

Answer: (C)

Spiegazione

The Golgi apparatus processes and packages proteins and lipids into vesicles for transport or secretion. ATP production and DNA storage are functions of other organelles.

7. What is osmosis?

A. The movement of salts through a cell wall

B. The movement of all particles from low to high concentration

C. The diffusion of water across a selectively permeable membrane

D. The breakdown of glucose to release energy

Answer: (C)

Spiegazione

Osmosis is specifically the diffusion of water across a selectively permeable membrane. It is not the movement of all particles or the release of energy.

8. How is chromatin best described in a non-dividing cell?

A. A rod-shaped structure visible during division

B. A membrane that separates the nucleus from the cytoplasm

C. A dense round body inside the nucleus

D. An entangled mass of thread-like DNA-protein material

Answer: (D)

Spiegazione

Chromatin is the loose, thread-like DNA-protein material found when the cell is not dividing. Chromosomes are the condensed rod-shaped form seen before division.

9. What is the main role of mitochondria in cells?

A. They store chlorophyll for photosynthesis

B. They contain genes inside a nuclear membrane

C. They release energy from glucose during cellular respiration

D. They package proteins into vesicles

Answer: (C)

Spiegazione

Mitochondria release energy from glucose during cellular respiration, and that energy is stored in ATP. The other choices describe different organelles or functions.

10. What is the nucleolus mainly responsible for producing?

A. Chromosomes

B. Ribosomal subunits

C. ATP molecules

D. Cell membrane proteins

Answer: (B)

Spiegazione

The nucleolus is the site where ribosomal subunits are synthesized. These later combine to form ribosomes in the cytoplasm.

11. Which statement best describes mitosis in multicellular organisms?

A. It halves the chromosome number in the first division and restores it later

B. It produces four genetically different gametes with half the chromosomes

C. It produces two genetically identical daughter cells for growth and repair

D. It occurs only in reproductive organs to create genetic variation

Answer: (C)

Spiegazione

Mitosis produces two daughter cells that are genetically identical to the parent cell, which is why it is important for growth and repair. The other options describe meiosis or a mix-up between the two processes.

12. What is the total magnification of a light microscope using a 10× eyepiece and a 40× objective lens?

A. 100×

B. 4,000×

C. 400×

D. 50×

Answer: (C)

Spiegazione

Total magnification is calculated by multiplying eyepiece magnification by objective magnification, so 10× × 40× = 400×. This is a direct application of the microscope rule.