<span>This is an example of facilitated diffusion using a channel. Diffusion is the process of an object moving across a concentration gradient, usually from areas of higher to lower concentration in membranes. In this case, the diffusion is "facilitated" by the aquaporin molecules and water is allowed to enter or exit the membrane based on concentration level.</span>
Answer:
polarized cells
Explanation:
The intestinal epithelium is lined with a single layer of polarized cells,
The Calvin Cycle
Once in the mesophyll cells, CO2 diffuses into the stroma of the chloroplast, the site of light-independent reactions of photosynthesis.
Answer:
The new research suggests that Earth's water came from both rocky material, such as asteroids, and from the vast cloud of dust and gas remaining after the sun's formation, called the solar nebula.
Explanation:
<u>Answer</u>:- Active transport
<u>Explanation</u>:-
There are two types of membrane transports
1. Passive transport - this type of transport occurs without the input of any energy and the molecules move along the concentration gradients that is from <em>high concetration to low concentration.</em>
2. Active transport- this type of transport takes place to move the molecules against the concentration gradient that is from <em>low concentration to high concentration.</em>
<em>The active transport is of two types:</em>
1. <em>Primary active transport-</em> in this type of transport <em>ATP</em> is used as an energy source to move the substances against the concentration gradient.
2.<em>Secondary active transport</em> - in this type of transport the gradient formed by the active transport is utilized and it involves the movement of 2 substances at a time aross the membrane. That is the movement of one molecule is coupled to another.
- The membrane proteins that are associated with active transport are called as <em>carrier proteins</em>. These proteins have a binding site for the molecules that they transport. Once they bind to the specific molecules, a conformation change is induced and this leads to the transport of the molecule across the membrane.
So, the <em>active transport is basically responsible for utilizing the energy from ATP and carrier proteins to move the substances across the membrane against their concentration gradient i.e. from low concentration to high concentration.</em>