Which one of the following plant plastids stores starch, oil and protein granules?
- A.Chloroplast
- B.Leucoplast
- C.Chromoplast
- D.Xanthoplast
Correct answer
Explanation
The correct answer is B, Leucoplast. Leucoplasts are colourless plastids that store food: starch, oils and proteins.
Plastids are found only in plant cells and some algae, and they are of three main kinds. Leucoplasts have no pigment and are common in roots, seeds and tubers. They are named by what they store: amyloplasts store starch (as in potato), elaioplasts store oils and fats (as in oilseeds), and aleuroplasts store proteins (as in the aleurone layer of cereal grains). Chloroplasts make food, chromoplasts give colour, and leucoplasts keep the reserve.
A is wrong because chloroplasts carry chlorophyll and make food by photosynthesis rather than store these reserves.
C is wrong because chromoplasts hold carotenoid pigments that colour fruits and petals, such as red tomatoes and orange carrots.
D is wrong because xanthoplasts are yellow chromoplasts holding xanthophyll; they colour, they do not store food.
Exam tip: amyloplast – starch, elaioplast – oil, aleuroplast – protein; all three are leucoplasts.
Practice Questions
View allWhich one of the following cell organelles contains DNA?
- A.Golgi apparatus
- B.Mitochondrion
- C.Lysosome
- D.Endoplasmic reticulum
Show answer
Mitochondria carry their own small, circular DNA and their own ribosomes. Mitochondria are the powerhouses of the cell, where aerobic respiration makes ATP.
Read the full explanation →Which set of vegetables is underground stem or modified stem of a plant?
- A.Potato, artichoke, round gourd
- B.Onion, garlic, carrot
- C.Potato, onion, garlic
- D.Potato, garlic, turnip
Show answer
All three are underground modified stems: the potato is a stem tuber, and onion and garlic are bulbs. A stem can be told from a root by its nodes and buds.
Read the full explanation →A sound wave having frequency of 300 Hz is travelling in an unknown medium. Its wavelength is not known. It travels a distance equal to 150 times its wavelength in time t. The value of t is :
- A.0.5 s
- B.1 s
- C.1.5 s
- D.2 s
Show answer
A wave moves forward by one wavelength in each cycle, so 150 wavelengths take 150 cycles, and 150 cycles at 300 per second take half a second.
Read the full explanation →A body floats in a liquid if the buoyant force is :
- A.equal to its weight.
- B.less than its weight.
- C.greater than its weight.
- D.zero.
Show answer
A floating body is in equilibrium, so the upward buoyant force exactly balances its weight. By Archimedes' principle, a body in a liquid is pushed up by a force equal to the weight of the liquid it displaces.
Read the full explanation →Which of the following are the different parts of a human brain ?
- A.Forefront brain, Standard brain and Hind brain
- B.Fore brain, Median brain and Rear brain
- C.Fore brain, Mid brain and Hind brain
- D.Precursor brain, Mean brain and Hind brain
Show answer
These are the three main divisions of the human brain. The fore brain is the largest part.
Read the full explanation →