Module 1 Flashcards
What type of molecules are phospholipids?
Amphipathic - (both hydrophobic and hydrophilic parts)
What is cholesterol’s role in the cell membrane?
Controlling the fluidity in relationship to temperature (fluidity buffer)
6 major functions of membrane integral proteins
Transport (ions, ATP)
Enzymatic activity (catalysing reactions)
Signal transduction (receptors)
Cell-cell regulation (glycoproteins)
Intercellular joining
Attachment to cytoskeleton/extracellular matrix
Definition: passive transport
Diffusion of a substance across a membrane with no energy investment. Occurs along the concentration gradient
Definition: Osmosis
Diffusion of water through a selectively permeable membrane into another aqueous compartment containing solute at a higher concentration
Definition: Osmotica
Osmotically active, affecting osmosis
e.g. Ions, sugars, proteins, nutrients
Definition: Tonicity
The ability of a solution to cause a cell to gain or lose water
Isotonic
No difference
Hypertonic
Greater solute concentration, cell loses water
Hypotonic
Lower solute concentration, cell gains water
Definition: Facilitated diffusion
Transport proteins and channels used for passive movement
Definition: Electrogenic pump
Transport that changes the charge across the membrane
Definition: Cotransport
Active transport linked with facilitated diffusion
What are the 3 types of endocytosis?
Phagocytosis - engulfing particles
Pinocytosis - drinking
Receptor mediated
What are the two types of local cell-cell communication?
Paracrine: A secreting cell acts on nearby cells
Synaptic: Nerve cell releases neurotransmitter molecules
Long-distance cell-cell communication example
Hormone signalling: Hormones reach virtually all cells through blood flow
What are the four families of receptors?
Plasma membrane
- Ion channel receptors
- G protein-coupled receptors
- Tyrosine kinase linked receptors
Intracellular receptors
What is the process of G protein-coupled receptors?
- Signal molecule binds to G-protein-linked-receptor on cell membrane
- Sends signal to G-protein which forms GTP (like ATP but made of guanine)
- ATP coverts to cyclic AMP (cAMP)
- Causes a cellular response
Definition: Heterotrimeric
Formed of three different peptides
Details of tyrosine kinase
Kinases add phosphate groups to molecules (phosphorylation)
Causes the movement of many molecules and proteins
