Serous membrane is a thin membrane with two layers that lines and covers the wall and organs of the thoracic and abdominopelvic cavities, these organs includes the heart, lungs and the body cavity. Its role is to prevent friction between the organ and the body cavity wall. The membrane is formed by simple squamous epithelium which are filled with connective tissues.
Since Lithium has one valence electron that means it needs to lose it to form a stable structure. That means it's valence is equal to one. Oxygen has six atoms, in order to form a stable octet structure it needs to accept 2 electrons, therefore it's valence is 2.
Therefore two Lithium atoms bond with one oxygen atom to form Li2O
The correct answer is: b. It is free to bind to another promoter and begin transcription
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
• 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.
RNA polymerase is also released and can transcribe some other gene by binding to its promotor. RNA polymerase will transcribe just the genes whose products are needed at a particular moment.
