Cell: The Unit of Life' For NEET
Test 3

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which observation best illustrates the relationship between the shape of a cell and the function it performs?

All cells of a multicellular organism have the same shape.
A cell retains one fixed shape regardless of its activity.
Cells differ only in size, while their shapes remain identical.
Cells may be disc-like, columnar, thread-like or irregular according to their functions.
4

Cells vary greatly in shape and may be disc-like, polygonal, columnar, cuboid, thread-like or irregular. Their shape may vary according to the function they perform.

A bacterium possesses a small circular DNA molecule in addition to its genomic DNA. Which conclusion is correct?

It is a plasmid that may confer a characteristic such as antibiotic resistance.
It is a nucleolus responsible for ribosomal RNA synthesis.
It is a lysosome containing hydrolytic enzymes.
It is a chromosome enclosed by a nuclear membrane.
1

Plasmids are small circular DNA molecules present outside the genomic DNA in many bacteria. They may confer distinctive phenotypic characters, such as resistance to antibiotics.

On what basis are bacteria classified as Gram-positive or Gram-negative?

The number and arrangement of their flagella
Differences in their cell envelopes and their response to Gram staining
The presence or absence of plasmid DNA
The shape and size of their ribosomes
2

Bacteria are classified according to differences in their cell envelopes and their response to the Gram staining procedure. Those that take up the stain are Gram-positive; the others are Gram-negative.

Which option correctly distinguishes the two forms of bacterial glycocalyx?

The slime layer is thick and tough, whereas the capsule is loose.
The slime layer contains ribosomes, whereas the capsule contains DNA.
The slime layer is a loose sheath, whereas the capsule is thick and tough.
The slime layer is the plasma membrane, whereas the capsule is the cell wall.
3

The glycocalyx varies in composition and thickness. In some bacteria it occurs as a loose sheath called the slime layer, while in others it forms a thick and tough capsule.

Which structure contains pigments in prokaryotes such as cyanobacteria?

Chromatophores
Mesosomes
Fimbriae
Inclusion granules
1

Chromatophores are membranous extensions into the cytoplasm of some prokaryotes, such as cyanobacteria. These structures contain pigments.

Several ribosomes attached to a single messenger RNA form a chain. What is this arrangement called?

Centrosome
Nucleosome
Polysome
Chromatophore
3

Several ribosomes may attach to a single mRNA to form a polyribosome or polysome. The ribosomes of the polysome translate the mRNA into protein.

Which group contains only components of the endomembrane system?

Endoplasmic reticulum, Golgi apparatus, lysosomes and vacuoles
Endoplasmic reticulum, mitochondria, chloroplasts and lysosomes
Golgi apparatus, ribosomes, peroxisomes and vacuoles
Mitochondria, chloroplasts, peroxisomes and centrosome
1

The endomembrane system includes the endoplasmic reticulum, Golgi apparatus, lysosomes and vacuoles because their functions are coordinated. Mitochondria, chloroplasts and peroxisomes are excluded.

Why may the concentration of certain ions be significantly higher inside a plant vacuole than in the cytoplasm?

The vacuole synthesises ions from water.
The tonoplast facilitates their transport into the vacuole against concentration gradients.
The cell wall actively pumps ions into the vacuole.
The vacuole lacks a surrounding membrane.
2

The tonoplast is the membrane surrounding the vacuole. It facilitates the transport of several ions and other materials into the vacuole against their concentration gradients.

Which combination is present in the mitochondrial matrix?

Linear DNA, 80S ribosomes and cellulose
Chromatin, nucleoli and nuclear pores
Thylakoids, grana and chlorophyll
Circular DNA, RNA molecules, 70S ribosomes and components for protein synthesis
4

The mitochondrial matrix contains a single circular DNA molecule, a few RNA molecules, 70S ribosomes and the components required for protein synthesis.

A chromosome has its centromere close to one end, producing one extremely short arm and one very long arm. How is this chromosome classified?

Metacentric
Submetacentric
Telocentric
Acrocentric
4

An acrocentric chromosome has its centromere close to one end, producing one extremely short arm and one very long arm. A telocentric chromosome has a terminal centromere.

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