Other molecules such as proteins, starch and sugar are simply too large to diffuse across the membrane. Sometimes, some of these large molecules are transported across the cell membranes by carrier proteins; this does not require energy and as a result is a form of passive transpor
The renal corpuscle is made up of Bowman's capsule and glomerulus.
Partial pressure of oxygen inside the alveolus is higher than in pulmonary capillary vessels, that allows oxygen molecules to diffuse into the blood.
<span>Some 120 prescription drugs sold worldwide today are derived directly from rainforest plants. And according to the U.S. National Cancer Institute, more than two-thirds of all medicines found to have cancer-fighting properties come from rainforest plants. Examples abound. Ingredients obtained and synthesized from a now-extinct periwinkle plant found only in Madagascar (until deforestation wiped it out) have increased the chances of survival for children with leukemia from 20 percent to 80 percent.</span>
Explanation:
In molecular and genetic biology, a transcription factor (sometimes called a specific DNA sequence binding factor) is a protein that binds to specific DNA sequences, thus controlling the transcription of genetic information from DNA to messenger RNA. Transcription factors do this alone or in conjunction with other protein complexes by promoting (as an activator) or silencing (as a repressor) the recruitment of RNA polymerase (the enzyme that transcribes genetic information from DNA to RNA) to specific genes
A determining feature of transcription factors is that they contain one or more DNA-binding domains (DBDs), which bind to specific DNA sequences adjacent to the genes they regulate. Additional proteins such as coactivators, chromatin remodelers, histone acetyltransferases, deacetylases, kinases and methyltransferases, also play crucial roles in genetic regulation, but lack DBDs and, therefore, are not classified as transcription factors.