Biological Membra Flashcards
Describe the plasma membrane
It has a phospholipid bilayer which contains proteins(both intrinsic and extrinsic). Cholesterol is inside the bilayer between the phospolipid. Hydrophilic head faces out and hydrophobic tail turns inwards. Glycoproteins stick out of bilayer
What happens to plasma membrane at high temperature
The phospholipid vibrate more as they have more kinetic energy creating more gaps. The bilayer becomes more fluid and melts and the proteins denature
Two components of the plasma membrane and their functions
It has hydrophobic tails and hydrophilic head which doesn’t allow large polar molecules through. Cholesterol molecules are attached to the hydrophobic tail and they stabilize the membrane
What is cell signaling
Cell signaling is communication between cells where a molecule released by a cell causes a change in another cell
How do cell surface membranes contribute to cell signaling
Messenger molecule is released by exocystosis. Glycoproteins have receptors which are specific. The signal and receptor are complementary which allows it to enter
Which cells use active transport
Calcium ions move into muscle cells for contraction
Ions move into root hair cells against the concentration gradient
Why can glycoproteins act as receptors
As they have a specific shape which is complementary to the trigger molecule which it binds to
How do small non polar large substances and polar molecules travel
Small non polar travel through the phospholipid bilayer via diffusion
Large substances enter through carrier proteins or by endocytosis
Polar travel through channel proteins via facilitated diffusion
Function of glycoproteins
Act as antigens allow cell signaling acts as a receptor for hormones allows cell adhesion. Stabilizes cell by forming hydrogen bonds with water molecules
recognises cells as self and non self
What does atp contain
Adenine ribose sugar and phosphate group
How to water molecules move through the plasma membrane
Water molecules fit between phospholipids and move through via protein channels
What’s endocytosis
Plasma membrane invaginates when in contact with material ut then enfolds and forms a vesicle and then pinches off and moves into cytoplasm
how do vesicles move
vesicles move along microfilaments as the cytoskeleton provides tracks for it
what forms a more dense liquid in lipids
glycerol
