Fat or water decides the receptor

Science · The Human Body · ages 20-21

Name ______________________ Date ____________

Where do water soluble hormone receptors sit?
- Inside the nucleus
- On the surface
- Dissolved in blood
How do steroid hormones travel in blood?
- Bound to carrier proteins
- Floating free like peptides
- Inside red blood cells
Surface receptor signals act in seconds while steroid signals take hours but last longer.
Circle one: True False
Why does a peptide response fade faster than a steroid one?
- Cascades switch off quickly while new proteins linger
- Peptides rewrite genes permanently
- Steroids never bind receptors
A newly found hormone is strongly fatty. What follows?
- It docks at surface receptors
- It cannot signal at all
- It crosses to inner receptors
Tiny hormone amounts reshape whole cells. Why?
- Hormones multiply in blood
- Each relay step wakes many copies of the next
- Receptors copy the hormone
A peptide hormone can freely cross the membrane to reach nuclear receptors.
Circle one: True False
A student gives a steroid and expects full effect in seconds. What is the error?
- Steroids act only outside cells
- Steroids cannot enter any cell
- Gene level action needs hours to build proteins

Answer key

For grown-ups. Fold this page away before handing over the rest.

On the surface · Peptides cannot cross the membrane, so they dock outside.
Bound to carrier proteins · Fatty molecules cannot ride watery plasma alone.
True · Fast relays fade fast, and gene switching starts slow but lingers.
Cascades switch off quickly while new proteins linger · Relays shut down fast, but built proteins persist.
It crosses to inner receptors · Fat soluble molecules slip through to meet receptors inside.
Each relay step wakes many copies of the next · Relay chains amplify a whisper into a shout.
False · Water soluble molecules cannot cross, so they stop at the surface.
Gene level action needs hours to build proteins · Inner receptor work rewrites production, which cannot finish in seconds.