All Free Biology MCQs with Answers

1811. Cytoplasmic strands that extend through pores in adjacent cell walls are known as___________?

• A. Pseudopods
• B. Symplasts
• C. Plasmodesmata
• D. Pili

Explanation: Plasmodesmata are microscopic channels passing through adjacent plant cell walls and connecting the cytoplasm of neighbouring cells. Symplasts refer to the interconnected cytoplasmic system reached through plasmodesmata, so students may choose b by confusing the channels with the system they create.

1812. The membrane of vacuoles is known as__________?

• A. Vacuoloplast
• B. Tonoplast
• C. Tanoplast
• D. All of these

Explanation: The tonoplast is the selectively permeable membrane surrounding a plant-cell vacuole and controls movement of substances into and out of the vacuole. Students may choose a or c because those words resemble membrane names, but neither is the standard biological term.

1813. mitochondria in ear lobe cells are nearly____________?

• A. 40
• B. 50
• C. 55
• D. 60

Explanation: An ear-lobe cell is relatively inactive compared with a muscle cell, so it contains approximately 50 mitochondria in the textbook estimate used here. Students may choose 40 because mitochondrial numbers vary between cells, but the expected rounded value in this question is 50.

1814. mitochondria in heart muscles are nearly_____________?

• A. 400
• B. 375
• C. 350
• D. 325

Explanation: Heart muscle cells require continuous ATP for contraction and therefore contain many mitochondria, approximately 350 in the stated textbook estimate. The likely distractor is 375, which reflects the same general idea but is not the expected approximate value.

1815. Membranes of the grane are sites where?

• A. Oxygen is stored
• B. Food is stored
• C. Sunlight is trapped
• D. CO2 is stored.

Explanation: The membranes of grana contain chlorophyll and other photosynthetic pigments arranged in photosystems. These pigments absorb sunlight and convert its energy into chemical energy during the light-dependent reactions. Students may choose b because chloroplasts ultimately help make food, but food production is not the direct function of the grana membranes.

1816. Cellular digestion is associated with which organelle__________?

• A. Mitochondria
• B. Golgi bodies
• C. Plastids
• D. Lysosomes

Explanation: Lysosomes contain hydrolytic enzymes that digest worn-out cell parts, foreign material and food particles inside the cell. Students may choose mitochondria because they are major organelles, but mitochondria produce ATP and are not the main organelles for intracellular digestion.

1817. During digesting the phagocytosed food particles vesicles formed from fusion of phagocytic vacuole with the enzymes secreted by Golgi apparantus are called_______?

• A. Lysosomes
• B. Primary lysosomes
• C. Secondary lysosomes
• D. Food vacuole

Explanation: When a primary lysosome fuses with a phagocytic or food vacuole, its digestive enzymes act on the engulfed material and the resulting structure is called a secondary lysosome, or phagolysosome. A primary lysosome is still unfused and contains inactive digestive enzymes. Students often choose food vacuole because it contains the engulfed particles, but fusion with a lysosome gives the combined compartment its secondary-lysosome identity.

1818. Which of the following impart a red colour to Rose petals?

• A. Chloroplast
• B. Chlorophyll
• C. Chromoplast
• D. Leucoplast

Explanation: Chromoplasts contain pigments such as carotenoids and can give flowers red, yellow or orange colours. Chloroplasts contain chlorophyll and give green colour, while leucoplasts are generally colourless. Students most likely choose chlorophyll because it is a well-known plant pigment, but chlorophyll produces green rather than red colour.

1819. Ribosomes + m-RNA?

• A. Polysome
• B. Phlosome
• C. Polosome
• D. None of these

Explanation: A polysome, or polyribosome, is a group of ribosomes attached to a single mRNA molecule and translating it simultaneously. This arrangement allows many copies of the same polypeptide to be produced efficiently. Students may choose one of the invented terms such as polosome because they sound similar, but polysome is the established biological term.

1820. Which of the following statement is incorrect about Glyoxisomes?

• A. They contain enzymes which help in conversion of fatty acids into carbohydrate
• B. They are abundant in soyabeans but absent in pea.
• C. They are present through out life of a plant and provide them whth energy through Glyoxylate cycle.
• D. They are signle membranous organelles

Explanation: Glyoxysomes are single-membrane organelles found especially in germinating oil-rich seeds, where their enzymes convert fatty acids into substances that can be used to form carbohydrates. They are not present throughout the entire life of a plant, and their abundance changes with development. Students may choose option b because it gives a specific distribution claim, but the major incorrect statement is c, which incorrectly describes their lifelong presence.