Secretion of human chorionic gonadotropin [HCG] only occur during pregnancy in the placenta. The concentration of this hormone increase rapidly during the first three months of pregnancy; the amount in the blood stream doubles every two to three days as the development of the placenta and embryo progress. The hormone reaches its maximum concentration peak around the sixth week of pregnancy and after this, its concentration decline.
Answer:
The binding of chemical messengers to receptors often results in a shape change, which affects receptor function.
Explanation:
Binding of specific chemical messengers to the corresponding receptors of target cells brings about change in the shape of the receptors. This structural change in the receptor results in the generation of the desired response. It reflects how the form and specific configuration of substances or biomolecules affect their functions.
For example, binding of neurotransmitters to the receptors present on neurons opens the associated ligand-gated ion channels to allow the movement of specific ions through it. In the absence of bound ligand, these channels are present in a closed conformation.
Answer:
Probably A.
Explanation:
The reticular formation can be said to be a network of nuclei in the brainstem that wakes or alert us to a sharp reaction or occurence at a particular time.
<span>If an island had 1000 cats on it, an ecologist would use the word 'population' to describe all the members of that species</span>
Patent fingerprints are made by a liquid or powder that sticks to the finger and then transfers to a surface, leaving an easily visible fingerprint behind. Substances that can leave patent fingerprints are ink, blood, dirt, flour, grease, etc.
