BIOL 124 Flashcards
(69 cards)
What is the difference between “discuss” and “describe” in essay titles?
Describe is to find and list the facts about that subject whereas describe is more talking around and about the subject and what it’s related to.
What types of signalling between cells are there?
Free diffusion between cells
Via cytoplasmic connections
Direct cell-to-cell contact
What are the 3 types of free diffusion signalling?
Autocrine (same cell, usually growth regulation)
Paracrine (nearby cells, coordination between cells)
Endocrine (distant cells via hormones)
How do cells signal via cytoplasmic connections?
The signals are transfered through pores in the membrane (fastest mode of signalling)
How do cells signal between cell-to-cell contact?
Interactions between surface proteins and receptor proteins.
What types of signalling molecules are there?
Local regulators and hormones
What are growth factors (local regulator)
Peptides or proteins that stimulate cell proliferation
What are nerve growth factors?
Small proteins that regulate growth of target neurones
How do gases act as local regulators?
Nitric acid can act by increasing vasodilation while only having a half life of 1-5 seconds
What are prostaglandins?
Modified fatty acids that have multiple functions such as exitability of the uterine wall in childbirth to induce labour
What type of signalling molecules are neurotransmitters?
local regulators
What are major glands of the endocrine system?
Pineal
Pituitary
Thyroid
Parathyroid
Thymus
Adrenal
Pancreas
Ovaries/testes
What are the two main classes of hormone?
Peptides and proteins (bind to cell surface receptors)
Steroids (cholesterol based so passes through membrane)
How does a signal binding to a receptor on the cell elicit a response?
Via the signal-transduction pathway
How does the complement of signalling proteins affect the response.
It can lead to a variety of different responses
What are the three stages of cell signaling?
Reception
Transduction
Response
What is reception in cell signalling?
When the signal molecule directly interacts with a receptor on cell surface or inside the cell
What are ligands in cell signaling?
They are signalling molecules that lead to a change in protein shape or aggregation of 2 or more receptors
What are G-protein-coupled receptors?
It is a plasma membrane receptor that spans the membrane as seven alpha hellices and they work with a G protein
What happens when GTP is bound to the G protein and what happens with GDP
When GTP is bound it is activated
When GDP is bound it is inactive
G protein also funcions ars GTPase
What are Receptor tyrosine kinases?
Membrane bound receptors with intrinsic enzyme activity
It adds phosphate residues onto other proteins that it gets from ATP molecules
They are involved in growth factors and division and can cause cancer if abnormal.
What are ligand-gated ion channels?
A receptor that acts as a gate in the plasma membrane which opens/closes in response to chemical messangers (e.g neurotransmitter synapse channel)
What are intracellular receptors?
Receptor proteins found in cytosol or nucleus of cell which are activated by small hydrophobic messengers that can travel through the cell membrane (e.g testosterone)
What are the main endocrine glands and organs?
Glands:
Hypothalamus
Pituitary
Pineal
Thyroid
Parathyroid
Adrenal
Organs:
Thymus
Pancreas
Ovary
Testis