A major breakthrough in the studies of cells came with the development of electron microscope. This is because :
(a) the resolution power of the electron microscope is much higher than that of the light microscope
(b) the resolving power of the electron microscope is 200 - 350 nm as compared to 0.1 - 0.2 nm for the light microscope
(c) electron beam can pass through thick materials, whereas light microscopy requires thin sections
(d) the electron microscope is more powerful than the light microscope as it uses a beam of
electrons which has wavelength much longer than that of photons
Which of the following statements regarding cilia is not correct ?
(a) The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane
(b) Cilia are hair-like cellular appendages
(c) Microtubules of cilia are composed of tubulin
(d) Cilia contain an outer ring of nine doublet microtubules surrounding two single microtubules
Which one of the following phenomena is commonly referred as 'cell drinking?
If a chloroplast of plant is isolated and studied in a test tube the investigation is described as
(a) in vivo
(b) in vitro
(c) in situ
(d) none of these.
An organelle present in plant cells but absent from those of animals is
(d) Both a and c
Primary cell wall consists of a loose network of cellulose microfibrils impregnated with a matrix of
(a) glycoprotein and flavoprotein
(b) hemicellulose and flavoprotein
(c) hemicellulose and pectin
(d) flavoprotein and pectin.
Which of the following is not a true subcellular organelle ?
Golgi body is associated with
(a) packaging and storage of material
(b) cell wall formation
(c) transport of enzyme
(d) all of the above
Which of the following cytoskelelal components of an eukaryotic cell play a major role in protoplasmic streaming?
(c) Intermediate filaments
(d) None of these
Free radicals in our body have been implicated in
(b) certain degenerative disorders
(d) all the above