Chapter 8: Cell: The Unit of Life Assertion-Reason Questions | biology Class 11 CBSE

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 1

Logic Check

Assertion (A): Ribosomes are found in both prokaryotic and eukaryotic cells. Reason (R): Ribosomes are non-membrane bound organelles that serve as the site of protein synthesis in all living cells.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 2

Logic Check

Assertion (A): Mycoplasma does not have a cell wall. Reason (R): Mycoplasma is a eukaryote and eukaryotes lack cell walls.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 3

Logic Check

Assertion (A): The fluid mosaic model describes the plasma membrane as having a quasi-fluid phospholipid bilayer. Reason (R): The fluid nature of the membrane allows lateral movement of proteins within the bilayer, which is essential for functions like endocytosis and cell division.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 4

Logic Check

Assertion (A): Mitochondria are referred to as the powerhouses of the cell. Reason (R): Mitochondria are the sites of aerobic respiration and produce ATP, the universal energy currency of the cell.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 5

Logic Check

Assertion (A): The Golgi apparatus is found in close association with the endoplasmic reticulum. Reason (R): Proteins synthesised in the nucleus are directly transferred to the Golgi apparatus for packaging.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 6

Logic Check

Assertion (A): Plant cells do not burst when placed in a hypotonic solution. Reason (R): The rigid cell wall of plant cells exerts wall pressure that counteracts the osmotic pressure, preventing cell lysis.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 7

Logic Check

Assertion (A): Chloroplasts and mitochondria contain 70S ribosomes. Reason (R): Both chloroplasts and mitochondria are membrane-bound organelles that are part of the endomembrane system.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 8

Logic Check

Assertion (A): Active transport requires energy in the form of ATP. Reason (R): Active transport moves molecules against their concentration gradient, from a region of lower to higher concentration.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 9

Logic Check

Assertion (A): Lysosomes are called the suicidal bags of the cell. Reason (R): Lysosomes contain hydrolytic enzymes capable of digesting all types of macromolecules and can digest the cell itself under certain conditions.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 10

Logic Check

Assertion (A): Cilia and flagella both have the 9+2 arrangement of microtubules in their axoneme. Reason (R): Cilia and flagella emerge from centriole-like basal bodies and are covered by the plasma membrane.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 11

Logic Check

Assertion (A): The nucleolus is a membrane-bound structure within the nucleus. Reason (R): The nucleolus is the site of ribosomal RNA synthesis and is therefore important for ribosome biogenesis.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): Prokaryotic cells lack membrane-bound organelles. Reason (R): Prokaryotic cells are more primitive organisms and have not evolved the complexity seen in eukaryotic cells.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 13

Logic Check

Assertion (A): The cell wall of bacteria is absent in Mycoplasma. Reason (R): Mycoplasma is classified as a prokaryote but represents an exception to the general rule that prokaryotes possess a cell wall.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 14

Logic Check

Assertion (A): Smooth endoplasmic reticulum (SER) is the site of lipid synthesis in cells. Reason (R): SER lacks ribosomes on its surface and therefore cannot synthesise proteins.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 15

Logic Check

Assertion (A): In plant cells, the vacuole can occupy up to 90 per cent of the cell volume. Reason (R): The tonoplast actively transports ions into the vacuole against their concentration gradient, increasing the osmotic concentration inside.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 16

Logic Check

Assertion (A): Polar molecules cannot pass through the plasma membrane by simple diffusion. Reason (R): The interior of the phospholipid bilayer is nonpolar, creating a hydrophobic barrier that polar molecules cannot cross unaided.

Reasoning Options

ByteNotes

Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 17

Logic Check

Assertion (A): Metacentric chromosomes have two equal arms. Reason (R): In metacentric chromosomes, the centromere is located exactly in the middle of the chromosome.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 18

Logic Check

Assertion (A): Prokaryotic flagella and eukaryotic flagella both have the 9+2 microtubule arrangement. Reason (R): Both types of flagella serve the same function of providing motility to the cell.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 19

Logic Check

Assertion (A): The rough endoplasmic reticulum is extensively developed in secretory cells. Reason (R): RER bears ribosomes on its surface and is the major site for synthesis and secretion of proteins.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 20

Logic Check

Assertion (A): The inner compartment of the mitochondrion is filled with a dense substance called the matrix. Reason (R): The matrix contains enzymes, circular DNA, RNA, and 70S ribosomes needed for mitochondrial function and semi-autonomous replication.

Reasoning Options

ByteNotes

Chapter sections

Chapter 8: Cell: The Unit of Life | Assertion-Reason

Assertion (A): Ribosomes are found in both prokaryotic and eukaryotic cells. Reason (R): Ribosomes are non-membrane bound organelles that serve as the site of protein synthesis in all living cells.

Assertion (A): Mycoplasma does not have a cell wall. Reason (R): Mycoplasma is a eukaryote and eukaryotes lack cell walls.

Assertion (A): The fluid mosaic model describes the plasma membrane as having a quasi-fluid phospholipid bilayer. Reason (R): The fluid nature of the membrane allows lateral movement of proteins within the bilayer, which is essential for functions like endocytosis and cell division.

Assertion (A): Mitochondria are referred to as the powerhouses of the cell. Reason (R): Mitochondria are the sites of aerobic respiration and produce ATP, the universal energy currency of the cell.

Assertion (A): The Golgi apparatus is found in close association with the endoplasmic reticulum. Reason (R): Proteins synthesised in the nucleus are directly transferred to the Golgi apparatus for packaging.

Assertion (A): Plant cells do not burst when placed in a hypotonic solution. Reason (R): The rigid cell wall of plant cells exerts wall pressure that counteracts the osmotic pressure, preventing cell lysis.

Assertion (A): Chloroplasts and mitochondria contain 70S ribosomes. Reason (R): Both chloroplasts and mitochondria are membrane-bound organelles that are part of the endomembrane system.

Assertion (A): Active transport requires energy in the form of ATP. Reason (R): Active transport moves molecules against their concentration gradient, from a region of lower to higher concentration.

Assertion (A): Lysosomes are called the suicidal bags of the cell. Reason (R): Lysosomes contain hydrolytic enzymes capable of digesting all types of macromolecules and can digest the cell itself under certain conditions.

Assertion (A): Cilia and flagella both have the 9+2 arrangement of microtubules in their axoneme. Reason (R): Cilia and flagella emerge from centriole-like basal bodies and are covered by the plasma membrane.

Assertion (A): The nucleolus is a membrane-bound structure within the nucleus. Reason (R): The nucleolus is the site of ribosomal RNA synthesis and is therefore important for ribosome biogenesis.

Assertion (A): Prokaryotic cells lack membrane-bound organelles. Reason (R): Prokaryotic cells are more primitive organisms and have not evolved the complexity seen in eukaryotic cells.

Assertion (A): The cell wall of bacteria is absent in Mycoplasma. Reason (R): Mycoplasma is classified as a prokaryote but represents an exception to the general rule that prokaryotes possess a cell wall.

Assertion (A): Smooth endoplasmic reticulum (SER) is the site of lipid synthesis in cells. Reason (R): SER lacks ribosomes on its surface and therefore cannot synthesise proteins.

Assertion (A): In plant cells, the vacuole can occupy up to 90 per cent of the cell volume. Reason (R): The tonoplast actively transports ions into the vacuole against their concentration gradient, increasing the osmotic concentration inside.

Assertion (A): Polar molecules cannot pass through the plasma membrane by simple diffusion. Reason (R): The interior of the phospholipid bilayer is nonpolar, creating a hydrophobic barrier that polar molecules cannot cross unaided.

Assertion (A): Metacentric chromosomes have two equal arms. Reason (R): In metacentric chromosomes, the centromere is located exactly in the middle of the chromosome.

Assertion (A): Prokaryotic flagella and eukaryotic flagella both have the 9+2 microtubule arrangement. Reason (R): Both types of flagella serve the same function of providing motility to the cell.

Assertion (A): The rough endoplasmic reticulum is extensively developed in secretory cells. Reason (R): RER bears ribosomes on its surface and is the major site for synthesis and secretion of proteins.

Assertion (A): The inner compartment of the mitochondrion is filled with a dense substance called the matrix. Reason (R): The matrix contains enzymes, circular DNA, RNA, and 70S ribosomes needed for mitochondrial function and semi-autonomous replication.

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