The bark of a tree is impervious to gases and water because bark cells are dead cells of the epidermis and compactly arranged without intercellular spaces. They contain a chemical called suberin in their walls that make them impervious to gases and water and it doesn't allow gases or water into the tree as bark cells are in the bark outer most layer of the tree.
All viruses have is a protein coat and a core of genetic material, either RNA or DNA. Unlike bacteria, viruses can't survive without a host. They can only reproduce by attaching themselves to cells. Unlike bacteria, most viruses do cause disease, and they're quite specific about the cells they attack.
Answer:
48 amino acids
Explanation:
The wild type gene codes for a protein with 100 amino acids. One amino acid is encoded by one triplet code of the gene. This means that the wild type gene has a total 100 triplets or 300 nucleotides to code for a protein of 100 amino acid. Mutation in this protein has introduced the code "UAA" at the 49th codon. The code "UAA" is a stop codon. Therefore, the mRNA transcribed from the mutant allele would code for a protein having 48 amino acids as the protein synthesis will be stopped once the stop codon at the 49th position is read.
Answer: white blood cells
Explanation: They fight off the bad bacteria.
