Batrachospermum Occurrence:- (1) Batrachospermum is fresh water alga. (2) It is found in clear, cool, and running streams. (3) Deepwater plants are dark violet or reddish in color. But the shallow-water species are olive green. (4) The intensity of light changes the color of pigments. (5) The thallus is attached to the substratum. Vegetative structure (1) The thallus of an adult plant is soft, thick, filamentous. (2) It is freely branched and gelatinous. (3) The central axis is made up of a single row of large cells. Whorls of branches of limited growth are developed on this axis. (4) These branches are filamentous and dichotomously arranged. (5) The main axis is corticated. It consists of a row of elongated cylindrical cells....
Mitochondria :-
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| Mitochondria |
(sing.: mitochondrion), unless specifically
stained, are not easily visible under the microscope.
The number
of mitochondria per cell is variable
depending on the physiological activity of the cells.
In terms of shape and size also, considerable
degree of variability is observed.
Typically it
is sausage-shaped or cylindrical having a diameter of 0.2-1.0μm (average 0.5μm) and
length 1.0-4.1μm.
Each mitochondrion is a double membrane-bound
structure with the outer membrane and the innermembrane dividing its lumen
distinctly into two aqueous compartments, i.e., the outer compartment and the inner
compartment.
The inner compartment
is called the matrix.
The outer
membrane forms the continuous limiting boundary of the
organelle.
The inner membrane forms a number of
infoldings called the cristae (sing.: crista) towards the matrix .
The cristae
increase the surface area. The two membranes have their
own specific enzymes associated with the mitochondrial function.
Mitochondria are the sites of aerobic
respiration. They produce cellular energy in the form of ATP, hence they are called
‘power houses’ of the cell.
The matrix
also possesses single circular DNA molecule, a few RNA
molecules, ribosomes (70S) and the components required for the synthesis of
proteins.
The
mitochondria divide by fission.
Cell Membrane :-
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| Cell Membrane |
The detailed
structure of the membrane was studied only after the advent of the
electron microscope in the 1950s. Meanwhile, chemical studies on the
cell membrane, especially in human red blood cells (RBCs), enabled the
scientists to deduce the possible structure of plasma membrane.
These studies showed that the cell membrane is composed
of lipids that are arranged in a bilayer.
Also, the lipids are arranged within the membrane
with the polar head towards the outer sides and the hydrophobic
tails towards the inner part.
This
ensures that the nonpolar tail of saturated hydrocarbons is protected
from the aqueous environment .
The
lipid component of the membrane mainly consists of phosphoglycerides. Later,
biochemical investigation clearly revealed that the cell membranes also
possess protein and carbohydrate.
The
ratio of protein and lipid varies considerably in different cell types.
In human beings, the membrane of then erythrocyte has approximately 52 per cent protein and 40 per cent lipids.
Depending on the ease of extraction, membrane proteins
can be classified as integral or peripheral.
Peripheral proteins lie on the surface of membrane while the integral proteins are
partially or totally buried in the membrane.
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