Receptors
What is the type of receptor that is embedded in the plasma membrane and interacts with hydrophilic ligands?
Transmembrane receptor
What term describes a molecule that binds to a receptor to initiate a signal?
Ligand
What is the term for the process where a ligand-receptor interaction triggers a sequence of intracellular events?
Signal Transduction
What event directly activates the G protein in a GPCR pathway?
GDP is replaced by GTP (on the alpha subunit)
- No credit given to ligand binding receptor/conformation change in the receptor
What type of feedback amplifies a change in a system?
positive feedback
Name the type of receptor that binds to hydrophobic signaling molecules like steroid hormones.
Intracellular receptor
Name a neurotransmitter that acts locally by diffusing across a synaptic gap.
Acetylcholine, Dopamine, Serotonin (just need one)
What secondary messenger is produced during the activation of the epinephrine signaling pathway?
cyclic AMP (cAMP)
What type of a receptor does insulin binds?
A tyrosine kinase receptor
What feedback mechanism helps maintain body temperature at a set point?
negative feedback
What happens to a transmembrane receptor when a ligand binds to its extracellular domain?
A conformational change that initiates a signaling cascade
Name two of the four functional categories of signaling chemicals in animals.
hormones, neurotransmitters, cytokines, or calcium ions (need two out of four)
How is the signal amplified in signaling pathway linked to a G-protein coupled receptor ?
- Activation of multiple G proteins
- Use of secondary messengers
(only 1 needed)
At what point do autoinducers activate quorum sensing behaviors?
when their concentration reaches a critical threshold
Which hormone regulates uterine contractions during childbirth via positive feedback?
oxytocin
Which receptor type initiates phosphorylation and activation of kinase enzymes when activated?
Tyrosine kinase receptor
What type of hormone is derived from amino acids and includes molecules like epinephrine?
amine hormones
What is the largest class of cell surface receptors in humans?
GPCRs (G protein coupled-receptors)
Which type of receptor triggers a phosphorylation cascade?
Tyrosine kinase receptor
How does negative feedback regulate blood glucose levels? (include the two chemicals responsible for controlling blood glucose)
by insulin lowering glucose levels when high and glucagon raising glucose levels when low
How does acetylcholine alter the voltage across a membrane?
By opening sodium ion channels, allowing Na+ to enter the cell
Why can steroid hormones diffuse through the plasma membrane while peptide hormones cannot?
Because steroid hormones are hydrophobic while peptide hormones are hydrophilic
Explain how insulin receptor activation leads to the movement of glucose transporters to the plasma membrane.
phosphorylation of the tyrosine kinase receptor initiates a cascade that moves vesicles containing glucose transporters to the membrane
What type of receptor is the nicotinic acetylcholine receptor?
Ligand-gated ion channel
When body temperature begins to rise above 37 degrees celsius, thermoreceptors in the hypothalamus activate effectors such as sweat glands and blood vessels in the skin. Sweating increases evaporative cooling, and vasodilation increases heat loss from the skin surface. Explain, in terms of feedback loops, why it's not a good idea to stick your head in the freezer when you feel overheated.
Temperature regulation is accomplished by negative feedback. Sticking your head in the freezer sends signals to the hypothalamus that the brain is cold rather than hot, so it would not trigger the mechanisms that cause body temperature to decrease (but rather the opposite)