Home / IB DP Biology- A2.2 Cell structure -FA 2025- IB Style Questions For HL Paper 1

IB DP Biology- A2.2 Cell structure -FA 2025- IB Style Questions For HL Paper 1

Question

Which feature shared by both types of cells – aseptate fungal hyphae and striated muscle cell makes them atypical?

A. Both have cell walls.

B. Both have several nuclei.

C. Both lack membrane-bound organelles.

D. Both are divided into compartments.

▶️Answer/Explanation

Ans. B

Atypical cells are cells that are not normal but are not necessarily cancerous: 

Causes

Atypical cells can be caused by a number of factors, including inflammation, infection, and aging. 

Treatment

Atypical cells can change back to normal cells if the underlying cause is treated. This can happen naturally or through treatment. 

Follow-up

If your doctor identifies atypical cells, you should have close follow-up to monitor the cells and make sure they don’t become cancerous. 

Examples

Atypical cells can occur in the breast, urine, or blood: 

Atypical hyperplasia: A non-cancerous condition that occurs when breast cells increase in number and develop an unusual shape. 

 Atypical cells in urine: Atypical cells in urine can be a sign of high or low grade papillary urothelial carcinoma. 

Atypical circulating tumor cells: These cells can be found in the blood of cancer patients and can present as single cells, clusters of cells, or giant cells. 

 The feature shared by both aseptate fungal hyphae and striated muscle cells that makes them atypical is the presence of multiple nuclei within a single cell. In aseptate fungal hyphae, this occurs because the cell walls (septa) are absent, allowing cytoplasm and nuclei to flow freely along the length of the hyphae. In striated muscle cells, multinucleation occurs due to the fusion of multiple precursor cells during development, resulting in long, multinucleated fibers. This multinucleation is unusual because most cells contain only one nucleus.

Question

Chlorella and Paramecium are both unicellular eukaryotic organisms living in freshwater. Chlorella is photosynthetic and has a cell wall. Which organelle will be found in Paramecium but not in Chlorella?

A. Chloroplast

B. Contractile vacuole

C. Rough endoplasmic reticulum

D. Mitochondrion

▶️Answer/Explanation

Ans:B

Question

Which function is accomplished by structures X and Y in the Paramecium?

▶️Answer/Explanation

Ans:A

Question

The image shows an electron micrograph of a fungus, Candida albicans.

Which terms identify the structures labelled I and II in the image?

▶️Answer/Explanation

Ans:C