Cell the Unit of Life | Class XI Biology

Question 21 of 31

🟢 Re NEET 2026 📘 CLASS XI

Endomembrane system includes _______.

The endomembrane system comprises the endoplasmic reticulum, Golgi apparatus, lysosomes and vacuoles.

Question 22 of 31

🟢 Re NEET 2026 📘 CLASS XI

Smooth endoplasmic reticulum _______.

Smooth endoplasmic reticulum lacks ribosomes and is primarily responsible for lipid synthesis and detoxification.

Question 23 of 31

🟢 Re NEET 2026 📘 CLASS XI

Cell theory was formulated by ________.

Matthias Schleiden and Theodor Schwann proposed the cell theory. Rudolf Virchow later modified it by stating that all cells arise from pre-existing cells.

Question 24 of 31

🟢 Re NEET 2026 📘 CLASS XI

Which of the following are characteristics of prokaryotic cells?

(a) Ribosomes are made of 50S and 30S subunits
(b) They can have plasmids
(c) They contain mesosomes
(d) They have peroxisomes

Choose the correct answer from the options given below:

Prokaryotes possess 70S ribosomes (50S + 30S), plasmids and mesosomes, but they lack membrane-bound organelles such as peroxisomes.

Question 25 of 31

🟢 Re NEET 2026 📘 CLASS XI

Mitochondrial inner membrane encloses _________.

The inner mitochondrial membrane encloses the mitochondrial matrix, which contains enzymes of the Krebs cycle, mitochondrial DNA and ribosomes.

Question 26 of 31

🟢 Re NEET 2026 📘 CLASS XI

Match List-I with List-II:

List-I	List-II
A. Cristae	I. Flat membrane sacs in stroma of chloroplast
B. Cisternae	II. Infoldings in mitochondria
C. Thylakoids	III. Cell membrane
D. Phospholipid	IV. Disc-shaped sacs in the Golgi apparatus

Cristae are infoldings of the inner mitochondrial membrane. Cisternae are flattened sacs of the Golgi apparatus. Thylakoids are membrane sacs in chloroplasts. Phospholipids are major components of cell membranes.

Question 27 of 31

🟢 Re NEET 2026 📘 CLASS XI

The plastid that stores xanthophyll is known as

Chromoplasts contain carotenoid pigments such as carotene and xanthophyll, giving yellow, orange and red colours to plant parts.

Question 28 of 31

🟢 NEET 2026 📘 CLASS XI

Which one of the following is the site for active ribosomal RNA synthesis?

The nucleolus is the site of ribosomal RNA (rRNA) synthesis and ribosome assembly.

Question 29 of 31

🟢 NEET 2026 📘 CLASS XI

Non-membrane bound cell organelles found in both prokaryotic and eukaryotic cells are _________.

Ribosomes are non-membrane-bound organelles present in both prokaryotic and eukaryotic cells where protein synthesis occurs.

Question 30 of 31

🟢 NEET 2026 📘 CLASS XI

Select the correct statements regarding cell membrane in eukaryotic cell.

(A) Membrane of human RBCs has approximately 52% protein.
(B) Major phospholipids are arranged in a bilayer.
(C) Extensions of the plasma membrane into the cell form mesosomes.
(D) Tails towards the inner part of lipids are hydrophobic and thus protected from aqueous medium.
(E) Glycocalyx is present on the outer surface of the plasma membrane.

Choose the correct answer from the options given below:

Human RBC membrane contains about 52% protein. Phospholipids form a bilayer with hydrophobic tails inward, glycocalyx is present externally, whereas mesosomes are found only in prokaryotes.

Cell the Unit of Life| PYQs