<h3><u>Answer;</u></h3>
b). Activation of an upstream guanine nucleotide exchange factor
<h3><u>Explanation</u>;</h3>
- <em><u>When a ligand activates the G protein-coupled receptor, it induces a conformational change in the receptor that allows the receptor to function as a guanine nucleotide exchange factor (GEF) that exchanges GDP for GTPthus turning the G protein-coupled receptor on.</u></em>
- The activated G-protein then dissociates into an alpha (G-alpha) and a beta-gamma complex.
Answer:haemoglobin
Explanation:
Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.
1.a
2.c
3.a
4.a
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