Answer:
Because older cultures of gram-positive bacteria tend to lose their ability to retain crystal-violet in the peptidoglycan of their cell walls and can be confused with gram-negative bacteria.
Explanation:
Gram staining is used to differentiate between two major groups of bacteria. Gram-positive and gram-negative, these bacteria differ in the amount of peptidoglycan in their cell walls. Gram-positive bacteria have a higher amount of peptidoglycan, which absorbs the violet crystal complex used in gram staining, staining them purple/violet. Old cultures of gram-positive bacteria tend to lose the ability to retain the violet crystal and are stained by safranine, staining them red/pink and appear to be gram-negative.
<h3>In general,the more massive a star is,the shorter it's life span on the main sequence.After the hydrogen fuel at the core has been consumed,the star evolves away from the main sequence on the HR diagram,into a supergiant,red giant,or directly to a white dwarf.</h3>
<h2>--SirGerick--</h2>
Answer and Explanation:
Example of a food-web:
(1) Algae --> (2) Protozoas --> (3) Krill --> (4) Cephallopods --> (5) Medium sized dolphin --> (6) Large Dolphin
The trophic web is the process of energy transference through a series of organisms, in which every organism feeds on the preceding one and becomes food for the next one.
1) The first link is an autotroph organism or producer, such as a vegetable, that can synthesize organic matter from inorganic matter. In this example, the autotroph organisms are algae, that make use of sunlight and inorganic matter.
The next links are the consumers:
2) Herbivores are primary consumers and feed on producers. In this example, herbivore organisms are protozoan.
3) Krills are the secondary consumers and feed on protozoans.
4) Some species of cephalopods feed on krill, among other species.
5) Specialized Cetaceans such as the Risso´s dolphin, feed especially on cephalopods, as they lack upper teeth and they only have a few teeth in their jaws.
6) The killer whale is a big sized-dolphin and a very important predator. It feeds on many animals, and one of them is the Risso´s dolphin.
Answer:
False.
Explanation:
An Haemoglobin molecule is made up of 4-polypeptides, with each of the polypeptide chain containing an haem group. These haem group can bind with one oxygen atom each.
T<u>he binding of the first oxygen atom by the first haem group weakens the tertiary protein structure of Quaternary structure Hb, thus it makes it easier for the second Oxygen atom to bind faster, and the 3rd oxygen very fast and the 4th oxygen atom the fastest.These accelerated binding of the oxygen atoms, facilitated by the first binding O2, is called cooperative binding.It aids oxygen binding capacity and tranport functions of Hb,</u>
<u />
<u>Myoglobin is an oxygen storage protein in muscles, and not oxygen carrying molecule, It releases stored O2 only in condition of low oxygen supply</u>.It has one haem group in its molecule.Therefore its structural features can not carry out cooperative binding.
