Cell: The Unit of Life' For NEET
Test 2

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which sequence correctly represents the layers of a typical bacterial cell envelope from the outermost to the innermost side?

Cell wall → glycocalyx → plasma membrane
Plasma membrane → cell wall → glycocalyx
Glycocalyx → cell wall → plasma membrane
Glycocalyx → plasma membrane → cell wall
3

The bacterial cell envelope is a tightly bound three-layered structure. Its outermost layer is the glycocalyx, followed by the cell wall and then the plasma membrane.

Which statement correctly distinguishes bacterial fimbriae from bacterial flagella?

Fimbriae may help bacteria attach to surfaces, whereas flagella are associated with motility.
Fimbriae contain the bacterial chromosome, whereas flagella contain plasmids.
Fimbriae synthesise proteins, whereas flagella synthesise lipids.
Fimbriae are membrane-bound organelles, whereas flagella are inclusion bodies.
1

Fimbriae are small bristle-like surface structures that may help bacteria attach to rocks or host tissues. Bacterial flagella are filamentous extensions associated with motility.

Which combination correctly describes inclusion bodies in prokaryotic cells?

Membrane-bound structures involved in intracellular digestion
Infoldings of the plasma membrane involved in respiration
Tubular structures involved in bacterial attachment
Non-membrane-bound structures that store reserve materials in the cytoplasm
4

Inclusion bodies store reserve materials in prokaryotic cells. They are not surrounded by a membrane and lie freely in the cytoplasm; examples include phosphate, cyanophycean and glycogen granules.

A substance is transported across the plasma membrane from a region of lower concentration to a region of higher concentration. Which statement best describes this process?

It is osmosis and involves only the movement of water.
It is active transport and requires energy supplied through ATP.
It is simple diffusion and does not require energy.
It is passive transport occurring along the concentration gradient.
2

Movement against a concentration gradient, from lower to higher concentration, is active transport. It is an energy-dependent process in which ATP is utilised; the Na+/K+ pump is an example.

What is the structural significance of cristae in a mitochondrion?

They increase the surface area of the inner mitochondrial membrane.
They enclose the mitochondrial DNA within a nuclear membrane.
They connect neighbouring mitochondria through cytoplasmic channels.
They form the continuous outer boundary of the mitochondrion.
1

Cristae are infoldings of the inner mitochondrial membrane that project towards the matrix. These infoldings increase the surface area of the inner membrane.

Which option correctly matches a type of leucoplast with the material it stores?

Amyloplast — proteins
Elaioplast — starch
Aleuroplast — proteins
Chromoplast — oils and fats
3

Aleuroplasts are colourless plastids that store proteins. Amyloplasts store carbohydrates such as starch, whereas elaioplasts store oils and fats.

Which chloroplast structure connects the thylakoids of different grana?

Cristae
Stroma lamellae
Tonoplast
Middle lamella
2

Stroma lamellae are flat membranous tubules that connect the thylakoids of different grana. Grana are stacks of thylakoids located within the chloroplast stroma.

Which arrangement of microtubules is usually present in the axoneme of a eukaryotic cilium or flagellum?

Nine peripheral triplets without central microtubules
Eight peripheral doublets and two central microtubules
Nine peripheral singlets and one central microtubule
Nine peripheral doublets and two central microtubules
4

The axoneme usually contains nine radially arranged peripheral microtubule doublets and a pair of centrally located microtubules. This organisation is called the 9+2 array.

Which statement correctly describes the arrangement of centrioles in a centrosome?

The two centrioles lie parallel to each other and contain nine peripheral doublets.
The two centrioles lie perpendicular to each other and each has a cartwheel-like organisation.
A centrosome contains a single centriole surrounded by a membrane.
The centrioles are joined end to end and contain a central pair of microtubules.
2

A centrosome usually contains two cylindrical centrioles lying perpendicular to each other. Each centriole has a cartwheel-like organisation with nine evenly spaced peripheral fibrils.

Which of the following is not listed as a function of mesosomes in prokaryotic cells?

Assisting in cell-wall formation
Synthesising proteins on attached ribosomes
Helping in DNA replication and its distribution to daughter cells
Increasing the surface area and enzymatic content of the plasma membrane
2

Mesosomes are plasma-membrane infoldings associated with cell-wall formation, DNA replication and distribution, respiration, secretion, and increased membrane surface area. Protein synthesis occurs on ribosomes, not on mesosomes.

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