Unit 1.4c Flashcards
Is hydrophilic non-polar or polar?
Polar
Can hydrophilic signals pass through the hydrophobic part of the membrane?
No, they cannot
Do hydrophilic signals enter the cytosol?
They don’t
What do hydrophilic signalling molecules bind to?
They bind to transmembrane receptor
What are two examples of hydrophilic extracellular signalling molecules?
Peptide hormones and neurotransmitters
What are hydrophilic signalling molecule sometimes referred to as?
Ligands
What binds to the extracellular face of receptor proteins?
Hydrophilic signalling molecules
When does the receptor protein change conformation?
Once the hydrophilic signal on molecule binds to its extracellular face
What is caused due to the conformational change of the receptor protein?
A signal is transduced across the plasma membrane
So, in summary, what happens when a hydrophilic signalling molecule binds to the extracellular face of a protein receptor?
An intracellular signal occurs
What do intracellular signals cause?
They cause the cells behaviour to alter
What process causes a chemical or physical signal to transmit through a cell by series of molecular events?
Transduction
What does transduction result in?
A cellular response
So what do transmembrane receptor proteins do?
They convert an extra cellular hydrophilic binding event into a specific intercellular response
How do transmembrane receptor proteins create intracellular responses?
Signal transduction pathways
What do transduced hydrophilic signals involve in the signal transduction pathways?
G-proteins or phosphorylation cascades caused by kinase enzymes
What do G-proteins do?
Relay signals from activated receptors to target proteins like enzymes and ion channels
What do phosphorylation cascades allow?
They allow the activation of multiple intracellular signalling pathways
How does phosphorylation cause multiple proteins to be phosphorylated?
Because to allow the cascade to activate the signalling pathways a series of events where one kinase must activate the next sequence occurs.
What type of enzyme is the catalyst for phosphorylation?
Kinase
What is phosphorylation?
It’s the transfer of 1 phosphate group form ATP to a different protein
In blood, what level must glucose be kept be kept within?
3.9-6.1 mmol per litre
When would pancreas cells produce insulin?
Insulin will be produced when there was an increase in blood glucose concentration (that was detected by the pancreas)
What is insulins job in the body?
It helps fat tissue and skeletal muscles absorb glucose from the bloodstream
How does glucose travel into the cell?
It travels into the cell by facilitated diffusion in transporter proteins
What is insulin?
Insulin is a peptide hormone
What happens when insulin binds to the receptor?
The receptor undergoes a conformational change that triggers its phosphorylation
When insulin causes a phosphorylation cascade in a cell what is transported and where?
GLUT4 containing vesicles are transported to the fat and muscle cell membranes
What do GLUT4 proteins allow?
The passing of Glucose across the plasma membrane into the cell
What is the cause of type one diabetes?
Failure of insulin production in the pancreas
What is the treatment of type one diabetes?
Regular insulin injections throughout the day
What is the cause of type two diabetes?
Loss of insulin receptor function
What are the three treatments of type two diabetes?
- medication that lowers blood glucose levels
- Lifestyle changes
-Exercise, which triggers GLUT4 recruitment so improves glucose uptake in fat and muscle cells
What is type two diabetes associated with?
Obesity
