: Use the following words to fill in the blanks: transcription, dairy products, enzymes, proteins, repressor, rna polymerase, lactose intolerant, lactase, operator, ecoli, transcribe, bases, repressor, operator

An example of prokaryotic gene expression is the lac operon. When a person is 1), they do not produce the enzyme 2), which aids in the digestion of lactose, the sugar found in 3). If a person who is lactose intolerant eats or drinks a dairy product, lactose travels down the digestive tract into the large intestine, where the genes in the bacteria, 4) , are turned on to create the 5) / 6) needed to digest the lactose. In E. Coli, when lactose is present, it acts as an inducer and binds to the 7) protein, keeping it from attaching to the 8). 9) then is able to attach to and 10) the E. Coli gene by matching up the 11). When lactose is NOT present, the 12) protein binds to the 13 and transcription is blocked. This is an example of gene expression (production of proteins) being controlled at 14).

Hunting in the darksome fish rely on senses beyond sight. in the darkness of the marianas trench, a fish called the rattail has an extremely sensitive sense of smell. the fish uses scent, rather than sight, to steer toward food. once it's near food, the rattail uses a special organ on the bottom of its chin to guide itself by feel.marine snowone staple of the deep sea diet is "marine snow," flakes of organic, edible substances that sink down from the upper ocean. animals at the ocean's bottom find sustenance in everything from the bodies of dead creatures to fecal matter. marine snow is diverse enough to support numerous species. for instance, several species of snails and worms feed exclusively on deceased whales.microorganismsthe deep sea is an intricate ecosystem, and even the ocean floor itself plays a part. hydrothermal vents are cracks in the sea floor where erupting magma mixes with ocean water to produce plumes of hot, sulfur-rich chemicals. some microbes can use these chemicals for energy, sustaining their existence and that of the animals who depend on their roles in the deep sea food chain.