D: needs to be present on both chromosomes to be expressed
Why: Because if there was a dominant trait present, then the dominant trait would overpower the recessive trait regardless of the matter.
Watson and Crick's model explained mutability because bases pairs can suffer changes (mutations) during DNA replication. Moreover, this model also explained stability because DNA strands are held together by hydrogen bonds.
Deoxyribonucleic acid (DNA) is a double helix molecule composed of two long chains of four types of nucleotides, each containing one different nitrogenous base, i.e., Adenine, Guanine, Cytosine and Thymine.
In Watson and Crick's model, both DNA strands are held together by hydrogen bonds between nitrogenous bases on opposite DNA strands, thereby providing stability to the DNA molecule.
In DNA, Guanine always pairs with Cytosine by three hydrogen bonds, while Adenine always pairs with Thymine by two hydrogen bonds.
Moreover, Watson and Crick suggested that mutations could occur as a consequence of a base occurring very infrequently in one of the less likely tautomeric forms during DNA replication, thereby also explaining the mutability of life.
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The 3rd Law because the action of the climber pulling on a rope causes a reaction that makes their body go up/lift up.:)
Answer:
The answer to the question: Class II MHC proteins are found on which of the following cell types, would be: on macrophages and lymphocytes, particularly T-Cells.
Explanation:
MHC, or Major histocompatibility complex, is a very important part of the immune response that the body gives against an invading pathogen, or other foreign substances. There are three types in the human body, Class I, Class II and Class III and each of them will play a role on the cellular membrance of different types of cells and mediate different types of responses. In the human body, this histocompatibility complex is best known as HLA, or human leukocyte antigen, and it will ensure the recognition, or non-recognition of substances, tissues, and other organisms, by the human immune system. Class II, as mentioned before, are most usually found on the immune cells macrophages and lymphocytes, and they are the ones responsible for presenting antigens to these proteinic antibodies so that the immune cells can initiate a proper immune response.
