Answer:a). mRNA is formed by copying a gene on one of the DNA strands
Explanation: Transcription is a process in which the nucleotide sequence in one strand of a double stranded DNA is converted to an mRNA. The genetic information in a DNA is copied into an mRNA. The mRNA produced is not the same with the DNA in base composition and sequence rather the mRNA is complementary to the DNA strand. In DNA, adenine, guanine, cytosine and thymine are found but in the mRNA adenine, guanine, cytosine and Uracil are found. In mRNA base pairing, adenine pairs with uracil while guanine pairs with cytosine.
Answer:
Distinction of crude density and ecological density necessary and which one of these densities are greater is explained below in details.
Explanation:
Density measure in courses of the amount of territory possible as existence reservation is ecological density. Crude density incorporates all the property within the animal's reach whereas ecological density incorporates only that division of property that can actually be established by the species.
Answer: First line of defense, the cells of the innate recognize and respond to pathogens in a generic and fast way and does not confer long-term or protective immunity. Recruitment of immune cells to the sites of infection and inflammation and activation of the complement system cascade.
Explanation:
Innate immunity is a defense system that you were born with and that protects you against all antigens. Innate immunity consists of barriers that prevent harmful materials from entering the body. These barriers form the first line of defense in the immune response. There are also <u>phagocytic cells</u> of the immune system which include: <u>macrophages, neutrophils, and dendritic cells</u>. The membrane receptors of those cells allow it to act on the recognition of danger signals and they are of the type TLR and PRR. These are Antigen Presenting cells which process the pathogens and display their antigens on their surface and takes it to B lymphocytes for the production of antibodies, which is part of the adaptive immune system.
<u>This means that the cells of the innate recognize and respond to pathogens in a generic and fast way</u> and, unlike the adaptive immune response, <u>does not confer long-term or protective immunity to the host.</u>
So, the main functions of the innate immune response include:
- Recruitment of immune cells to the sites of infection and inflammation, through the production of chemical factors, including specialized chemical mediators, called cytokines.
- Activation of the complement system cascade to identify bacteria, activate cells and promote clearance of dead cells or antibody complexes.
- The identification and removal of foreign substances present in organs, tissues, blood and lymph, by leukocytes.
- The activation of the adaptive immune response through a process known as antigen presentation.
- Inflammation is one of the first responses of the immune system to infection or irritation. It is stimulated by the release of chemical factors and serves to establish a physical barrier against the spread of infection, and to promote the recovery of some damaged tissue following clearance from pathogens. Chemical factors produced during inflammation (histamine, bradykinin, serotonin, leukotrienes) sensitize pain receptors, cause vasodilation of blood vessels at the scene, and attract phagocytes, especially neutrophils.
Heartwood. In contrast to sapwood, a term for the dead, clogged xylem cells near the center of a tree. Heartwood is the tree's main column of support.
