When a person cries, tears are exported from cells through the process called Endocytosis.
Answer:
A) A corepressor must be present
Explanation:
The key to operon expression lies in the sequence of the operator and the presence or absence of a repressor. When the repressor binds the operator, it prevents RNA polymerase from initiating transcription. The capability of the repressor to bind the operator and inhibit transcription depends on the conformation of the repressor, which is regulated allosterically by a key compound in the metabolic pathway, such as lactose or tryptophan. In a repressible operon, such as the tryptophan (or trp) operon, the repressor is unable to bind to the operator DNA by itself. Instead, the repressor is active as a DNA-binding protein only when complexed with a specific factor, such as tryptophan , which functions as a corepressor.
When tryptophan is plentiful, tryptophan molecules act as corepressors by binding to the (1) inactive repressor and (2) change its shape, allowing it to bind to the operator, (3) preventing transcription of the structural genes
Answer:
B.photosynthesis
Only cells containing chloroplasts can photosynthesize as that is where it takes place.
This "cleanliness" refers to CO2 emission - so when you say that something is cleaner than coal, it means that it emits less carbon dioxide and thus pollutes air less.
Answer:
(A) States have been invaded by leafy spurge, a herbaceous plant from Eurasia with milky sap that gives mouth sores to cattle, displacing grasses and other cattle food and rendering
Explanation:
This is the way of writing it that makes it clearer and easier to read.