Answer:
The correct answers: B, C and D.
Explanation:
- X-ray diffraction studies of the DNA reveal the following:
- The DNA is comprised of two strands which are coiled around each other in the shape of a helix.
- The backbone of the DNA is made up of phosphate and deoxyribose groups, alternately, which are exposed towards the outside of the helix.
- The nitrogenous bases which form the hydrogen bonds that link the two helices are directed towards the centre of the helix.
Answer:
Explanation:
heir behavior can be predicted and they are gentle with other animals generally. Mother bears have the innate nature to nurture the young ones and they are attentive in protecting them. Bears are also playful and have unique personality like humans. They take time to decide the animals/humans they meet
20C
The average is getting the total number of data points and diving by the number of how many data points were added together.
Average is similar to mean. Mean in statistics is the level where all the data points fall into or just simply the average point.
Answer:
b number is the answer is it ok
Answer:
One way in which complement activation destroys pathogens is by C3b binding to the surface of microbes, which then causes inflammation through histamine and heparin release.
Explanation:
C3b binds to the surface of microbes (opsonin), and functions as a component of C3 and C5 convertases while C3a stimulates inflammation.
The alternative pathway of complement activation is triggered by the deposition of C3b on the surface of a microbe. The microbe- bound C3b binds another protein called Factor B, which is then broken down by a plasma protease called Factor D to generate the Bb fragment.
This fragment remains attached to C3b, and the C3bBb complex functions as an enzyme, called C3 convertase, to break down more C3. The C3 convertase is stabilized by properdin, a positive regulator of the complement system.
As a result of this enzymatic activity, many more C3b and C3bBb molecules are produced and become attached to the microbe. Some of the C3bBb molecules bind an additional C3b molecule, and the resulting C3bBb3b complexes function as C5 convertases, to break down the complement protein C5 and initiate the late steps of complement activation.
The main effectors of the complement system are opsonization, cell lysis and inflammation. It also stimulates B cell responses and antibody production.