Lecture 1 Flashcards
(17 cards)
Explain Hypothalamic-pituitary-adrenal axis (HPA)
Stress , physical activity or cardian cycle trigger a signal to Hypothalamus which in respond release CRHto the pituitary and it will in response or produce ACTH to the adrenal cortex to produce cortisol which is also called the stress hormone
What is the definition of signal transduction ?
Is the process of signalling that link between activation of receptors and biological response
The signal transduction initiated by what ?
Activation of receptors
Mention the signalling molecules ?
Proteins
Lipid
Peptide
Nucleotides
Amino acids
Ions
Gasses
What are the types of signal transmission
Shorts range ( contact dependent- paracrine )
Long distance ( synaptic transmission- endocrine )
What are the types of receptors based on their locations
Nuclear
Cytosolic
Membrane bound receptors
What is the definition of enzymes
Proteins catalysts that speed up the reactions
How enzymes can be regulated by ?
Changing their numbers and location , and by post-translational modification ( phosphorylation)
Enzymes can be switch between active and inactive state by ?
Non-covelant interaction with molecules ( allosteric activator and inhibitor )
Where does the allosteric molecules bind ?
At the regulatory site of the enzyme whereas the competitive inhibitors bind at the active site of the enzymes
And enzyme can be switch between active and inactive state by which reaction ?
Post-translational modification ( phosphorylation )
Which substance that phosphorylase and dephosphorylate the enzyme
Protein kinase add phosphate group to activate the enzyme
Protein phosphates remove phosphate group to inhibit the enzyme
What are the three type of membrane bound receptors
- 7-transmembrane receptors
- ion channel receptors
- single hydrophobic domain receptors :
With enzymatic activity
Without enzymatic activity
One example of ion channel receptors
Nicotinic acetylcholine receptor
Explain the mechanism of nicotinic acetylcholine receptor ?
When Ac come and bind to the receptor the ion channel open and allow Na+ enter the cell
Mention one type of cytosolic receptors
InsP3
Explain the mechanism of InsP3 ?
Located in the ER allow Ca+ to exit ER and enter the cell
