Unit 1.2b(ii) Flashcards
What are the two components of the cell membrane?
Integral (permanently attached) proteins and peripheral (temporarily attached) proteins
What are peripheral proteins attached to?
Lipids or exposed integral proteins
What are the two protein components of the cell membrane involved in?
They’re involved in the the synthesis and processing of proteins and lipids
Which ER are lipids synthesised in?
Smooth ER
Where are proteins and lipids synthesised?
They’re synthesised in the ER
Once synthesised what do lipids do?
They insert themselves into the SER membrane
What are some examples of lipids?
Oil, phospholipids, steroid hormones
Where does all protein synthesis begin?
It all begins in cytosolic ribosomes found in the cytosol
Do cytosolic proteins complete translation the the ribosome?
Yes they do
After synthesis what happens to the cytosolic protein?
They are taken to the appropriate organelle where it moves through the membrane and into the organelles interior.
What are two examples of cytosolic proteins?
- enzymes of glycolysis
- enzymes that attach amino acids to tRNA molecules for protein synthesis
Are cytosolic ribosomes attached to anything?
No, they float freely in the cytosol
How do proteins locate cytosolic ribosome?
They have signal sequences that direct them to the ribosome
What is a signal sequence?
It’s a short stretch of amino acids at one end of the polypeptide
What is protein synthesis?
It’s the process of both transcription and translation.
