Answer:
A geneticist has devised a strategy to study protein translocation into the endoplasmic reticulum (ER) in yeast cells. She is interested in two different signal sequences that are thought to operate via slightly different translocation mechanisms. Using genetic engineering, she has fused the first signal sequence to a protein whose cytosolic expression is absolutely necessary for cell survival in the selective medium, but is inactive when in the ER. In the same cell, she has also fused the second signal sequence to a toxic protein whose cytosolic expression leads to cell lysis but is harmless when in the ER. Whereas wild-type cells undergo lysis upon the expression of these fusion proteins, she has been able to identify viable mutants, each of which has a loss-of-function mutation in a gene encoding a protein involved in membrane translocation. The products of these genes are probably ...
Explanation:
Involved in the transport of proteins with the first signal sequence but not the second one.
Answer:
b. Nucleotides
Explanation:
Nucleic acids are examples of structures formed from nucleotides. And in relation to the composition of DNA, we have the formation of the largest cellular macromolecule, all formed by nucleotides.
The nucleotide is a group formed by the association of 3 molecules - a nitrogen base, a phosphate group and a pentose glycide. Thus, we may have variations within these ligands, such as: in DNA we have the presence of pentose deoxyribose, while in RNA we have the presence of pentose ribose.
The nucleotides have differences in relation to its nitrogen base, which can be purine or pyrimidine. Purine bases vary in Adenine and Guanine, while pyrimidine bases are classified in Thymine, Uracil and Cytosine. Purine and pyrimidine bases are complementary and each have specific binders. Thus, we have that the purine base Adenina, binds with the pyrimidine bases Timina and Uracila, while the base Guanina binds exclusively to Cytosine and vice versa.
The protein structures can be classified into four levels, namely the primary structure, secondary structure, tertiary structure, and quaternary structure. The primary structure is the simplest of all the structures. When all the hydrogen bonds are disrupted, the secondary, tertiary and the quaternary structures gets disrupted, which leads the protein to the most simplest structural form, that is the primary structure. In this structure, the a carbon atom is bonded to hydrogen atom, carboxyl group, amino group, and an 'R' group.
Answer:B, D
Explanation:
When the roller coaster starts flying down the hill, it gains kinetic energy and loses potential energy.
Answer: In diagram B, the magma here is observed to be within the crust and could not come out to the surface. This signifies that the hot, rising magma, suddenly cooled down forming a huge block of mass which is considered to be an intrusive igneous body. It can be a batholith, lacolith or a pluton. This type of body is formed due to the cooling and the consolidation of hot magma.
