00:01
Which of these is incorrect about peptide hormones? a, they are synthesized by the endoplasmic reticulum, gorgi complex system, b, they circulate by onto plasma proteins, they bind to surface receptors of the target cell, they exert their effects with secondary messenger systems, or they are released by exocytosis.
00:21
So i'll start with the answer.
00:22
The answer is b.
00:25
Let's go through why.
00:26
So peptide hormones are protein -based, so they are synthesized similarly to any other protein.
00:35
And their destination is outside the cell, so they do go through the endoplasmic reticulum, golgi system.
00:45
So they are synthesized at the rough endoplasmic reticulum and the ribosomes there, then ascents to the golgi, then exocytosed.
00:59
So they are packaged into vesicles at the golgi and released by exocytosis into the blood.
01:05
They can be released bit by bit in small vesicles or they can be stored and released in big bursts when required.
01:12
So a and e are true.
01:13
Just like any other protein, they are synthesised by the secretion pathway and released through vesicles.
01:22
There can be some changes.
01:24
For example, there can be some particular cleaving or removal of the end terminal.
01:28
But they are still amino acid -based.
01:32
What else does this mean about them? well, like any protein, they have polarity.
01:38
So they are not non -polar.
01:41
They might be charged, they might be polar, but they're not non -polar.
01:45
Which means they are water soluble, but not lipid soluble...