Answer:
They are neither plants nor animals. They are organisms that are classified under the Kingdom Protista.
Explanation:
Answer:
<u>Active transport across membranes is like refilling an empty soda can after pouring the soda into a cup. It takes effort (energy in the form of ATP) to pour the soda back into the can, it wouldn't typically happen on its own.</u>
Explanation:
Cells use several transport mechanisms to move substances across their plasma membranes. Plasma membranes control all movement of substances through passive transport, which does not use energy; and active transport which requires chemical energy in the form of ATP.
Active transport moves substances out of cells against their gradients. In the cell, glucose can be transported inwards for respiration. However, because the internal environment is typically concentrated, (and glucose is needed in high amounts) this requires the use of transport enzymes and ATP.
Answer:
A.) circulatory, muscular, nervous
Receptor proteins are molecules inside a cell or on its surface on which ligands bind. A ligand is any substance (e.g. a hormone, drug, functional group) that binds specifically and reversibly to another chemical entity to form a large complex.
Receptor proteins found inside a cell are called internal receptors or intracellular receptors or cytoplasmic receptors.
They act as regulators of mRNA synthesis to mediate gene expression.
When a ligand binds to an internal receptor, the receptor changes in conformation and exposes on itself a site that can bind to DNA.
The receptor joined to the ligand moves into the nucleus where it binds to a specific site on the cell DNA. Once bound, it promotes the process of transcription where information is copied from DNA to mRNA