Transcription factors are necessary for an initiation of transcription at a regulated gene but not sufficient.
Transcription is the first step of gene expression in which DNA molecule is copied (transcribed) into RNA (mRNA) by RNA polymerase. The process of transcription is divided into three phases:
1. Initiation
• RNA polymerase with transcriptional factors bind to gene promoter Transcription factors can enhance the interaction between RNA polymerase and a DNA sequence- promoter, encouraging the expression of the gene. Such transcription factors are called activators. Otherwise, when the gene expression is inhibited, factors are called repressors and they bind to sequence –operator.
• RNA polymerase unwinds DNA double helix (transcription bubble is formed)
2. Elongation
• RNA polymerases adds nucleotides complementary to DNA
3. Termination
• RNA polymerase gets to stop codon (transcribes a sequence of DNA known as a terminator)
• Formed complementary RNA strand is released from DNA-RNA complex
Yes, If there were no concentration gradient of protons across the thylakoid membrane, the ATP synthase would not be able to convert ADP to ATP.
Answer:
Following information are needed to classify an organism.
1. Unicellular or multicellular : First we have to see that from how many cells the body of organisms formed.
2. Composition of cell wall: Secondly we have to see the cell wall composition.
3. Prokaryotic or eukaryotic cell: We have to see the nucleus of organisms, if it has nucleus we can say that it is a eukaryotic cell.
4. Mode of nutrition: Mode of nutrition means is the organisms is autotroph or heterotroph.
If they have similarities, so it is placed in one group. If not so it is placed in different group or kingdom.
Answer:
The correct answer is: (A) totipotent, pluripotent, multipotent.
Explanation:
Totipotent cells can differentiate into any type of cell, from the ones that make up the embryo to the ones that form extra-embryonic cells. Pluripotent cells can transform into any type of body cell (but not cells for the placenta). Multipotent cells can develop into a few types of cell from the same lineage.
