NEET MCQs Practice on Cell : The Unit of Life Class-XI Biology, Free unlimited practice on Cell : The Unit of Life Class-XI Biology Mcqs

Question 51 of 100

📘 CLASS XI

Select the correct statements regarding plastid classification:

I. Classified into chloroplasts, chromoplasts, and leucoplasts based on pigments.
II. Chloroplasts contain chlorophyll and carotenoids.
III. Chromoplasts contain water-soluble anthocyanin pigments only.
IV. Leucoplasts are colourless plastids storing nutrients.

Which statements are correct?

Plastids are classified into chloroplasts, chromoplasts, and leucoplasts. Chloroplasts contain chlorophyll and carotenoid pigments, while leucoplasts are colourless storage plastids. Statement III is incorrect because chromoplasts contain fat-soluble carotenoid pigments such as carotene and xanthophylls, not anthocyanins.

Question 52 of 100

📘 CLASS XI

Read statements regarding leucoplast types:

I. Amyloplasts store carbohydrates/starch.
II. Elaioplasts store oils and fats.
III. Aleuroplasts store proteins.
IV. Amyloplasts store proteins in aleurone layer of seeds.

Which statements are correct?

Amyloplasts store starch, elaioplasts store oils and fats, and aleuroplasts store proteins. Statement IV is incorrect because amyloplasts specifically store carbohydrates rather than proteins.

Question 53 of 100

📘 CLASS XI

Consider statements regarding chloroplast dimensions and location:

I. Majority of green plant chloroplasts are in mesophyll cells.
II. Length ranges from 5 to 10 μm and width 2 to 4 μm.
III. Chlamydomonas has 20-40 chloroplasts per cell.
IV. Mesophyll cells have 20-40 chloroplasts per cell.

Which options are correct?

Most chloroplasts of green plants are present in mesophyll cells. They are about 5–10 μm long and 2–4 μm wide. Mesophyll cells generally contain 20–40 chloroplasts, whereas Chlamydomonas possesses a single chloroplast. Hence Statement III is incorrect.

Question 54 of 100

📘 CLASS XI

Which statements about chloroplast membranes and stroma are correct?

I. Chloroplast is double membrane-bound.
II. Inner chloroplast membrane is relatively less permeable than outer membrane.
III. Space limited by inner membrane is called stroma.
IV. Stroma lacks DNA and ribosomes.

Which statements are correct?

Chloroplasts possess double membranes, with the inner membrane being less permeable than the outer membrane. The space enclosed by the inner membrane is called the stroma. Statement IV is incorrect because the stroma contains circular DNA, RNA, 70S ribosomes, and enzymes.

Question 55 of 100

📘 CLASS XI

Read statements regarding thylakoid arrangement in chloroplasts:

I. Thylakoids are flattened membranous sacs in stroma.
II. Arranged in stacks like piles of coins called grana.
III. Stroma lamellae connect thylakoids of different grana.
IV. Chlorophyll pigments are present in stroma matrix outside thylakoids.

Which statement combination is correct?

Thylakoids are flattened membranous sacs arranged into stacks called grana, and different grana are interconnected by stroma lamellae. Statement IV is incorrect because chlorophyll pigments are embedded in the thylakoid membranes, not free in the stroma.

Question 56 of 100

📘 CLASS XI

Select the correct statements regarding ribosome discovery and subunits:

I. Discovered by George Palade in 1953.
II. Prokaryotic 70S ribosomes consist of 50S and 30S subunits.
III. Eukaryotic 80S ribosomes consist of 60S and 40S subunits.
IV. Subunits sum mathematically (50 + 30 = 80, 60 + 40 = 100).

Which statements are correct?

George Palade first observed ribosomes in 1953. Prokaryotic ribosomes are 70S (50S + 30S), while eukaryotic ribosomes are 80S (60S + 40S). Statement IV is incorrect because Svedberg units are sedimentation coefficients and are not additive.

Question 57 of 100

📘 CLASS XI

Consider statements regarding eukaryotic vs organellar ribosomes:

I. Cytoplasmic ribosomes of eukaryotes are 80S.
II. Chloroplast ribosomes are 70S.
III. Mitochondrial ribosomes are 70S.
IV. All organellar ribosomes are 80S.

Which statements are correct?

Eukaryotic cytoplasm contains 80S ribosomes, whereas mitochondria and chloroplasts possess 70S ribosomes. Statement IV is incorrect because organellar ribosomes are 70S rather than 80S.

Question 58 of 100

📘 CLASS XI

Read statements regarding eukaryotic locomotory structures:

I. Cilia are small oar-like structures causing cell or fluid movement.
II. Flagella are longer and responsible for cell movement.
III. Eukaryotic flagella are structurally identical to prokaryotic flagella.
IV. Both cilia and flagella emerge from centriole-like basal bodies.

Which option is correct?

Cilia are short, oar-like structures, whereas flagella are longer and propel cells. Both arise from basal bodies. Statement III is incorrect because prokaryotic flagella differ structurally from eukaryotic flagella.

Question 59 of 100

📘 CLASS XI

Consider statements regarding centriole cartwheel structure:

I. Centriole consists of 9 peripheral tubulin triplets.
II. Central proteinaceous region is called hub.
III. Hub is connected to peripheral triplets by proteinaceous radial spokes.
IV. Centrioles contain a central pair of microtubules (9+2).

Which statements are correct?

Centrioles possess a cartwheel structure with nine peripheral triplet microtubules surrounding a central hub connected by radial spokes. Statement IV is incorrect because the 9+2 arrangement is characteristic of cilia and flagella, not centrioles.

Question 60 of 100

📘 CLASS XI

Select the correct statements regarding chromatin chemical composition:

I. Contains double-stranded DNA.
II. Contains basic proteins called histones.
III. Contains non-histone proteins.
IV. Contains RNA.

Which statements are correct?

Chromatin is composed of double-stranded DNA, histone proteins, non-histone proteins, and RNA. All four statements are correct.

Cell the Unit of Life MCQs