00:01
How does glucose enter cells from the blood? active transport, simple diffusion, facilitated diffusion, or osmosis.
00:10
Okay, so let's start by roaming up d.
00:12
Osmosis is for water, and we're looking at glucose.
00:16
So we have active and passive transport, first of all.
00:20
Active is against the gradient, the electrochemical gradient, and it requires the input of energy.
00:28
Passive, which is also known as diffusion, is along the gradient.
00:34
So, which way does the gradient go? the glucose entering cells from the blood.
00:42
So here's a capillary with the glucose in.
00:45
How much glucose is going to be in this neighboring cell? not much because this cell is breaking down glucose.
00:53
Your cells use up glucose for respiration.
00:56
So it has a lower concentration.
00:59
So the gradient goes this way.
01:01
So we don't need to use active transport here.
01:03
We can use passive.
01:05
The next question is, will it be simple or facilitated? well, simple means that there's diffusion directly across the membrane without any help.
01:16
So diffusion across the membrane without help.
01:21
And this is only possible for molecules that are either very small or are lipid soluble.
01:29
Even being very small, it's not always enough...