Answer:
Homeostatic control mechanisms have at least three interdependent components: a receptor, integrating center, and effector. ... The integrating center, generally a region of the brain called the hypothalamus, signals an effector (e.g. muscles or an organ ) to respond to the stimuli.
Explanation:
Answer:
The voltage-gated potassium channels associated with an action potential provide an example of what type of membrane transport?
A. Simple diffusion.
B.<u> Facilitated diffusion.
</u>
C. Coupled transport.
D. Active transport.
You are studying the entry of a small molecule into red blood cells. You determine the rate of movement across the membrane under a variety of conditions and make the following observations:
i. The molecules can move across the membrane in either direction.
ii. The molecules always move down their concentration gradient.
iii. No energy source is required for the molecules to move across the membrane.
iv. As the difference in concentration across the membrane increases, the rate of transport reaches a maximum.
The mechanism used to get this molecule across the membrane is most likely:
A. simple diffusion.
<u>B. facilitated diffusion.
</u>
C. active transport.
D. There is not enough information to determine a mechanism.
Carrier proteins - exist in two conformations, altered by high affinity binding of the transported molecule. Moves material in either direction, down concentration gradient (facilitated diffusion). EXAMPLE: GluT1 erythrocyte glucose transporter.
Channel proteins - primarily for ion transport. Form an aqueous pore through the lipid bilayer. May be gated. Moves material in either direction, down concentration gradient (facilitated diffusion). EXAMPLES: Voltage-gated sodium channel, erytrhocyte bicarbonate exchange protein.
This might be helpful... because I don't know anything about facilitated diffusion.
The answer is; D
The plasticity of rock in the mantle and the convection currents in the region are responsible for tectonic plate movements. The hot molten rock from deep in the mantle rise and is replaced by the cooler rock at the upper mantle. These convections are similar to those of water in a boiling pot. As the tectonic plates move (as they are dragged by these convections) and collide, earthquakes are caused. In addition, at subductions zones (where two plates collide) there occurs high volcanic activity.
