In which one of the following is nitrogen not a constituent?
Pepsin
idioblast
Bacteriochlorophyll
Invertase
Flagella of prokaryotic and eukaryotic cells differ in
Type of movement and placement in cell
Location in cell and mode of functioning
Microtubular organization and type of movement
Microtubulart organization and function
in chloroplasts, chlorophyll is present in the
outer membrane
inner membrane
thylakoids
stroma
In the somatic cell cycle
In G1 phase DNA content is double the amount of DNA present in the original cell
DNA replication takes place in S- phase
A short interphase is followed by a along term mitotic phase
G2 phase follows mitotic phase
If you are provided with root –tips of onion in your class and are asked to count the chromosomes, which of the following stages can you most conveniently look into?
Metaphase
Telophase
Anaphase
Prophase
Which one of the following precedes re-formation of the nuclear envelope during M phase of the cell cycle
Decondensation from chromosomes, and reassembly of the nuclear lamina
Transcription from chromosomes, and reassembly of the nuclear lamina
Formation of the contractile ring, and formation of the phragmoplast
Formation of the contractile ring, and transcription from the chromosomes
The main organelle involved in modification and routing of newly synthesized proteins to their destination is :
Chloroplast
Mitochondria
Lysosome
Endoplasmic Reticulum
Carbohydrates, the most abundant biomolecules on earth, are produced by:
some bacteria, algae and green plant cells
fungi, algae and green plant cells
all bacteria, fungi and algae
viruses, fungi and bacteria
At what stage of the cell cycle are histone proteins synthesized in a eukaryotic cell?
During G-2 stage of prophase
During S-phase
During entire prophase
During telophase
According to widely accept “fluid mosaic model” cell membranes are semi- fluid, where lipids and integral proteins can diffuse randomly. In recent years, this model has been modified in several respects. In this regard, which of the following statements is incorrect?
Proteins in cell membranes can travel within the lipid bilayer .
Proteins can also undergo flip- flop movements in the lipid bilayer.
Proteins can remain confined within certain domains of the membrane.
Many proteins remain completely embedded within the lipid layer.
A student wishes to study the cell structure under a light microscope having 10 X eyepiece and 45 X eyepiece objective. He should illuminate the object by which one of the following colours of light so as to get the best possible resolution?
Blue
Green
Yellow
Red
Centromere is required for:
movement of chromosomes of towards poles
cytoplasmic cleavage
crossing over
transcription
Proteins synthesis in an animal cell occurs
only on the ribosomes present in cytosol
only on robosomes attached to the nuclear envelope and endoplasmic reticulum
on- ribosomes present in the nucleolus as well as in cytoplasm
on ribosomes present in cytoplasm as well present in cytoplasm as well as in mitochondria
Which of the following statement regarding mitochondrial membrane is not correct?
The enzymes of the electron transfer chain are embedded in the outer membrane
The inner membrane is highly convoluted forming a series of infoldings
The outer membrane resembles a sieve
The outer membrane is permeable to all kinds of molecules
A major break through in the studies of cells came with the development of electron microscope. This is because
the resolving power of the electron microscope is 200- 350 nm as compared to 0.1- 0.2 for the light microscope
electron beam can pass through thick materials, whereas light microscopy requires thin sections
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
the resolution power of the electron microscope in much higher than that of the light microscope