Membranes And Cell Devision Flashcards
What’s the function of glycoproteins?
Help with cell adhesion and act as receptors for chemical signals
What’s the function of glycolipids?
They are antigens or “cell markers” that are recognised by the immune system as self or non self.
What’s the function of channel proteins?
Allow passive movement of polar molecules and ions across the membranes.
What’s the function of carrier proteins?
Allows passive and active transport across membranes.
What is the function of cholesterol?
To maintain cell fluidity.
To add stability to the membrane.
To prevent the cell becoming too solid.
How does cholesterol add stability to cells?
The hydrophobic end interact with the phospholipid tails, and the hydrophilic end with the heads, pulling them closer together.
How does cholesterol prevent membranes becoming too solid?
Stops phospholipids grouping too closely and crystalising.
How does temperature effect cell membrane structure?
Higher temperatures = more movement of phospholipids = more kinetic energy. Cell becomes more fluid = loses shape = begins to break down.
How do solvents affect membrane structure?
Organic solvents dissolve cell membranes.
Less concentrated
What happens at prophase ?
- Chromatid fibres coil and condense to make chromosomes.
- Nuclear membrane begins to break down.
- Microtubules assemble to make spindle fibres
What happens during metaphase ?
Spindle fibres move chromatids to the equator.
What happens during Anaphase ?
Centromeres divide. Chromatids separate and are pulled on opposite poles by spindle fibres.
What happens during telophase?
2 new sets of chromosomes assemble at each pole. The nuclear envelope reforms around chromosomes. Chromosomes uncoil, nucleolus is formed.
What is cytolysis?
Plasma membrane can’t stand the pressure exerted onto it by water. The cell bursts.
What is crenation?
Volume of water decreases in cell, membrane shrinks/ is shrivelled
