Answer: Promoter
Explanation:
Transcription is the first step in gene expression which consists of copying the DNA sequence of a gene to produce a RNA molecule. There are enzymes called <u>RNA polymerases which perform this process of transcription</u>. These enzymes bind nucleotides (the monomers which are part of the nucleic acids) to create a RNA strand using a DNA strand as a mold.
A promoter is a region of DNA that controls the initiation of transcription of a given portion of DNA to RNA. Therefore they promote the transcription of a gene. <u>The promoter region is composed of a specific sequence of DNA located just where the starting point of the DNA transcription is</u> and contains the information needed to activate or deactivate the gene it regulates. <u>The promoter has a binding site for the RNA polymerase enzyme </u>in charge of mRNA synthesis and when it recognizes this site, transcription begins.
<span>The use of human cells in research can lead to ethical problems
Because the new use of cells most often lead to this "grey area" in ethics as it is a new area of science and our society is not yet conditioned to this scientific breakthough. As there is no "moral code" on human cell use, ethical objections can arise and led to conflicts.
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When looking at the other options they do not cause negative effects on society
1) </span><span>Immortal animal cell lines can be used to model human cells.
----> This technology is not yet developed so it cannot be negative (yet)
2) Organ culture increases the time between donation and transplant.
-----> Organ culture are actualy </span><span>an alternative for organs from donors, and will not increase the time btween donation and transplant</span><span>
3) People are more aware of the results of cell technology research.
</span>-----> Awareness of research lead to greater understanding and unity
Answer:
The correct option is <em><u>B. Eukarya only</u></em>
Explanation:
Bacteria can be described as prokaryotic organisms that do not possess a nucleus. Their genetic material is generally present in the cytoplasm of the cell in a region called nucleoid. Some extra genetic material is found in them in the form of plasmids. Hence, option D is not correct.
The domain, Archae, contains prokaryotes and they lack a nucleus. Hence, option A and C are not correct.
Eukaryotes are multicellular organisms which contain a nucleus and other membrane-bound organelles. Hence, option B is correct.
Answer:
Cytotoxic T cells
Explanation:
Perforin is the cytosolic protein and upon degranulation forms pores in the target cell. Perforin protein helps in the transport of water and ions.
Perforin is present in the granules of cytotoxic T cells. These cells have the ability to kill virus infected cells and cancer cells. Cytotoxic T cells bind with the class 1 MHC molecules. These cells are also known as CD8+ T cells.
Thus, the correct answer is option (A).
