AM - Biological Membranes (1 + 2) Flashcards
What is flip-flopping?
The movement of phospholipids between planes
How do double bonds in hydrocarbons affect fluidity?
Lipid Bilayer are more fluid
How do double bonds in hydrocarbons affect width?
Lipid Bilayer are thinner
What are lipid rafts?
Microdomains of the plasma membrane enriched in cholesterol and sphingolipids
What are the roles of lipid rafts?
- Cell Signalling
- Uptake of extracellular molecules via endocytosis
What does the Nuclear Pore Complex (NPC) do?
Mediates the movement of macromolecules between the nucleus and the cytoplasm
How many proteins are within the NPC?
How many NPCs per cell?
- Roughly 30
- 3000-4000
What can move into the nucleus?
DNA and RNA building blocks
Energy-rich molecules
Ribosomal proteins
What moves out of the nucleus?
Ribosomal subunits synthesised by the nuceolus
What stage of mitosis does the nuclear envelope break down in?
Prophase
What occurs in the Smooth Endoplasmic Reticulum (SER)?
Hormone and Lipid synthesis
Detoxification
Glycogenolysis
What is a polysome?
A cluster of ribosomes held together by a strand of mRNA
What is protein glycosylation?
- A form of post-translational modification
- The attachment of carbohydrates to protein backbones
What occurs in the Golgi?
- Carbohydrate synthesis
- Protein glycosylation
- Involved in the protein secretion pathway
Expand on the movement of vesicles from the ER to the Golgi
- Vesicles bud off the ER at specialised exit sites with a COPII coat
- COPII coat sheds and vesicles fuse to form the vesicular tubular cluster
- This fuses with the cis-Golgi
