51.

Vacuole in a plant cell

• is membrane-bound and contains storage

• is membrane-bound and contains water and excretory substances

• lacks membrane and contains air

• lacks membrane and contains air

The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated?

• Deletion of non-essential genes

• Super-coiling in nucelosomes

• DNAse digestion

• DNAse digestion

Which one of the following is not a constituent of cell membrane?

• Cholesterol

• Glycolipids

• Proline

• Proline

During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has which type of electric change?

• First negative, then positive and again back to negative.

• First positive, then negative and continue to be negative

• First negative, then positive and continue to be positive

• First negative, then positive and continue to be positive

Select the wrong statement from the following:

• Both chloroplasts and mitochondria contain an inner and an outer membrane

• Both chloroplasts and mitochondria have an internal compartment, the thylakoid space bounded by teh thylakoid membrane

• Both chloroplasts and mitochondria contain DNA

• Both chloroplasts and mitochondria contain DNA

If you are asked to classify the various algae into distinct groups, which of the following characters you should choose?

• types of pigments present in the cell

• nature of stored food materials in the cell

• structural organization of thallus

• structural organization of thallus

A major breakthrough in the studies of cells came with the development of electron microscope. This is because

• the resolution power of the electron microscope is much higher than that of the light microscope

• the resolving power of the electron microscope is 200 – 350 nm as compared to 0.1 – 0.2 nm for the light microscope

• electron beam can pass through thick materials, whereas light microscopy requires thin sections

• electron beam can pass through thick materials, whereas light microscopy requires thin sections

Which of the following statements regarding cilia is not correct?

• The organized beating of cilia is controlled by fluxes of Ca²⁺ across the membrane

• Cilia are hair-like cellular appendages

• Microtubules of cilia are composed of tubulin

• Microtubules of cilia are composed of tubulin

Cri-du-chat syndrome in humans is caused by the

• fertilization of an XX egg by a normal Y-bearing sperm

• loss of half of the short arm of chromosome 5

• loss of half of the long arm of chromosome 5

• loss of half of the long arm of chromosome 5

Which of the following RNAs should be most abundant in animal cell?

• r-RNA

• t-RNA

• m-RNA

• m-RNA