NEET Biology Cell The Unit of Life MCQs Set 37

Answer: (c) Centrioles

Explanation:
1. Animal cells have centrioles for spindle formation, but they are absent in prokaryotes and in higher plant cells.

Teacher's Note:
1. Ribosomes are present in all three cell types.
2. Mesosomes are found only in prokaryotes.

Answer: (d) A, B, C and E

Explanation:
1. Both cell types have cytoplasm, a selectively permeable plasma membrane, 70S ribosomes (eukaryotes have them in organelles) and DNA.

Teacher's Note:
1. A membrane bound nucleus is absent in prokaryotes, and chromatophores are found only in prokaryotes.
2. So A, B, C and E are common.

Answer: (d) Primary wall

Explanation:
1. In growing meristematic cells only the middle lamella and the primary wall are present, and the primary wall lies next to the plasma membrane.

Teacher's Note:
1. The secondary wall forms later, inside the primary wall, in mature cells.
2. The middle lamella is the outermost layer.

Answer: (c) Chromatophores

Explanation:
1. In photosynthetic bacteria, pigments lie in membranous extensions of the plasma membrane called chromatophores.

Teacher's Note:
1. Mesosomes help in respiration and cell wall formation.
2. Cyanophycean granules are food reserves.

Answer: (d) (i) ER, (ii) forming face, (iii) trans face

Explanation:
1. Vesicles from the ER fuse with the forming (cis) face of the Golgi and the material moves through the cisternae to the maturing (trans) face.

Teacher's Note:
1. The cis face is convex and the trans face is concave.
2. Products leave the trans face.

Answer: (c) The vacuole is bound by a pair of membranes called tonoplast

Explanation:
1. The vacuole is bound by a single membrane, the tonoplast.

Teacher's Note:
1. The other statements are correct.
2. Lysosomal enzymes work best at acidic pH.

Answer: (c) Mitochondria

Explanation:
1. Prokaryotic cells have no mitochondria, so it is not present in all cells.

Teacher's Note:
1. Cytoplasm, genetic material and the plasma membrane are universal.
2. Mitochondria are found only in eukaryotes.

Answer: (a) By active transport

Explanation:
1. A polar molecule cannot cross the lipid bilayer by simple diffusion, and movement against a concentration gradient needs energy.

Teacher's Note:
1. So it enters by active transport with a carrier protein.
2. Facilitated diffusion works only down the gradient.

Answer: (b) Rough ER, Golgi body, plasma membrane

Explanation:
1. Proteins are made on ribosomes of the rough ER, sent in vesicles to the Golgi body for packaging and then to the plasma membrane for secretion.

Teacher's Note:
1. Smooth ER makes lipids, not proteins.

Answer: (d) They are monomorphic and uniform in structure and function

Explanation:
1. Lysosomes are polymorphic, which means they differ in size, shape and function (primary, secondary, residual and autophagic).

Teacher's Note:
1. The other statements are true.
2. Lysosomes are called suicide bags.

Answer: (b) All living plant cells and in Euglenoids

Explanation:
1. Plastids are found in plant cells and in euglenoids.

Teacher's Note:
1. They are absent in animals and fungi.
2. Plastids are of three kinds: chloroplasts, chromoplasts and leucoplasts.

Answer: (d) b and d

Explanation:
1. The cytoskeleton of microtubules, microfilaments and intermediate filaments gives mechanical support, motility and maintains cell shape.
2. It does not control transport across the membrane, which is the job of membrane proteins.

Teacher's Note:
1. Attachment to any surface is a function of other structures.
2. So b and d are correct.

Answer: (a) Fusion of its two membranes

Explanation:
1. The two membranes of the nuclear envelope fuse at places to form nuclear pores.

Teacher's Note:
1. Through them RNA and protein molecules pass in both directions.
2. The pores are lined with nuclear pore complexes.

Answer: (a) Both plant and animal cells

Explanation:
1. Microbodies such as peroxisomes and glyoxysomes are found in both plant and animal cells.

Teacher's Note:
1. They are absent in prokaryotes.
2. They carry out oxidative reactions.

Answer: (c) Chromatin, nucleoplasm and nucleolus

Explanation:
1. In interphase the nucleus has the nucleoplasm, a nucleolus and thread-like chromatin, since chromosomes are visible only during cell division.

Teacher's Note:
1. The nuclear envelope surrounds them.

Answer: (a) A hair-like outgrowth of the plasma membrane

Explanation:
1. Cilia and flagella are hair-like outgrowths of the cell membrane and are covered by it.

Teacher's Note:
1. They have an axoneme of 9 + 2 microtubules arising from a basal body.

Answer: (a) b and c

Explanation:
1. The stroma has enzymes for the dark reaction and 70S ribosomes, similar to those of mitochondria.

Teacher's Note:
1. It has a circular DNA, which differs from nuclear DNA.
2. Krebs cycle enzymes are in the mitochondrial matrix.

Answer: (c) It is equal to half of the S of the large subunit of 80S ribosome

Explanation:
1. ER ribosomes are 80S with a 60S large subunit, and chloroplast ribosomes are 70S with a 30S small subunit.
2. The difference is 60 - 30 = 30, which is half of 60S.

Teacher's Note:
1. The others give 40, 15 and 50.
2. Hence option 3 is correct.

Answer: (a) 1, 2 and 3 are correct

Explanation:
1. A karyotype is defined by the chromosome number, their length and the position of the centromere.

Teacher's Note:
1. It is shown as an idiogram.
2. Chromosome banding is also used.