Question
A plant cell is viewed using a microscope with a magnification of 500. The image of the cell has a width of 20 mm.
What is the actual width of the cell?
(A) 0.04 mm
(B) 0.2 mm
(C) 4 mm
(D) 25 mm
▶️Answer/Explanation
Ans: A
The correct answer is A (0.04mm), because:
Magnification = (original size) ÷ (actual size)
500 = (20) ÷ (actual size)
Actual size = 20 ÷ 500 = 0.04 mm
Question
A cell was viewed under a microscope. The actual length of the cell is 0.025 mm. The magnification of the image is ×400.
What is the length of the cell in the image?
(A) 10 mm
(B) 100 mm
(C) 1600 mm
(D) 16 000 mm
▶️Answer/Explanation
Ans : A
The correct answer is A (10mm), because :
Magnification = (original size) ÷ (actual size)
400 = (original size) ÷ (0.025 mm)
original size = 400 × 0.025 mm = 10mm
Question
Root hair cells are found on plant roots.
Which feature is present in a root hair cell but not in a sperm cell?
(A) cell membrane
(B) cell wall
(C) chloroplasts
(D) cytoplasm
▶️Answer/Explanation
Ans: B
The correct answer is B (cell wall), because :
Root hair cells are related to plants and it will have the cell wall whereas, sperm cell is related to animal.
- Cell membrane is seen in both root hair cells (plant) and sperm cells (animal).
- Chloroplasts are not found in root hair cells as they don’t make food.
- Cytoplasm is common in both the root hair cell and sperm cell.
Question
What is an example of a tissue?
(A) a chloroplast
(B) the palisade mesophyll
(C) a neurone
(D) the pancreas
▶️Answer/Explanation
Ans: B
The correct answer is B (Palisade mesophyll), because :
Tissue is defined as a group of similar cells carrying out the same job.
Palisade mesophyll is a composition of tightly packed cells responsible for photosynthesis, hence it is tissue.
- Chloroplast is a single cell organelle present in plant cells but not tissue.
- Neurone is a single nerve cell, so not a tissue.
- Pancreas is an organ, which is complex than tissue as it contain various tissues.