Structure and function of membranes Flashcards Preview

Chapter 5 Plasma Membranes > Structure and function of membranes > Flashcards

Flashcards in Structure and function of membranes Deck (10):
1

What are the functions of membranes at cell surface?

-Act as a barrier and control what enters and leaves the cell.
-Allow cell communication.
-Allow cell recognition.

2

What are the functions of membranes within cells?

-Compartmentalisation.
-Form vesicles.
-Control what leaves and enters organelles within a cell.
-Site of chemical reactions.

3

What is the fluid mosaic model?

-Suggests the arrangement of molecules in a membrane.
-Have a phospholipid bilayer made from phosphate hydrophilic heads and fatty acid hydrophobic tails.
-It is "fluid" due to the phospholipids constantly moving.
-Contain cholesterol molecules within the bilayer.
-Channel and carrier proteins within the bilayer.
-Have glycoproteins and glycolipids.

4

What are the functions of the phospholipid bilayer?

-Head is hydrophilic so attracts water, and tail is hydrophobic which repels water.
-Arranged in a way where heads face outwards and tails face inward and produce a hydrophobic core.
-The core doesn't allow water-soluble substances (like ions) through.

5

What are the functions of cholesterol?

-A type of lipid which fits between phospholipids causing them to pack closer together.
-Regulates the fluidity of the membrane.

6

What are the functions of channel proteins?

-Produce a hydrophilic channel where small and charged particles can pass through.

7

What are the functions of carrier proteins?

-Involved in transport of molecules and ions across the membrane by active transport or facilitated diffusion.

8

What are the functions of glycoproteins and glycolipids?

-Glycoproteins=proteins with a polysaccharide chain attached to it.
-Glycolipids=lipids with a polysaccharide chain attached to it.
-They stabilise the membrane by forming hydrogen bonds with surrounding water molecules.
-Sites where hormones, antibodies etc bind to.
-Act as receptors for cell signalling.
-act as antigens.

9

What is cell signalling?

-How cells communicate with each other.

10

How does cell signalling take place?

-One cell releases a messenger.
-This molecule travels to the target cell.
-Target cell detects the molecule as it binds to a receptor on the cell membrane.