A signal reaches a cell mostly in the form of a signalling molecule binding to a receptor on the cell surface. This binding activates a chain of events that amplifies the signal and transfers it inside the cell. Protein kinases phosphorylate proteins and cause their activation or deactivation, or in general modify their activity. When a signalling molecule binds to a receptor, a cascade is activated and the second messengers, such as cAMP, are synthesized. cAMP molecules activate the protein kinases, which phosphorylate specific proteins and activate them.
Answer:
Following are the ways captive breeding helps conserve biodiversity:
- Captive breeding can increase population numbers
- Captive breeding can help remove species from the Endangered Species List
- Captive breeding can result in the eventual release of offspring into the wild.
Explanation:
Captive Breeding:
Captive breeding is an ex-situ conservation technique (taking the animal out of its natural habitat to increase population numbers in zoos or sanctuaries). Captive breeding involves selective breeding of endangered species to help produce a sizable population that can later be introduced back into the wild when their habitat improves.
Captive breeding programs include zoos, sanctuaries located away from the animal's original habitat. For example, the Toronto Zoo has operated a captive breeding program for the Blanding's turtle since 2012. The turtles are kept their for 2 years after birth and then released back into the wild.
<em />
The options for this question are:
- Requires genetic variation
- Results in descent with modification
- Involves differential reproductive success
- All of the above
Answer:
<u><em>The correct option is d) All of the above</em></u>
Explanation:
The theory of natural selection explains that genetic variations occur in organisms of a species. Those organisms which are better adapted to live in an environment are able to survive and pass on their characteristics to their offsprings, hence descent with modification. Through this phenomenon, evolution takes place with the passage of time. Natural selection favours survival of the fittest. Hence, all of the above statements are true.
Answer: EXERGONIC; ENDERGONIC
Explanation:
An Exergonic reaction is one that occurs spontaneously, with the release of high amount of energy usually in form of ATP. a good example of this is the oxidation of glucose (glycolysis) in the Human body.
Whereas an energetic reaction is one that will ONLY occur in the supply of energy. A good example is biosynthethic reaction such as
- formation of glycogen (glycogenesis)
- formation of lipids etc
The rock cycle<span> is a model that describes the formation, breakdown, and reformation of a </span>rock<span> as a result of sedimentary, igneous, and metamorphic processes. All </span>rocks<span> are made up of minerals.</span>
