Which Molecule Is a First Messenger but Not a Second

question 10

Multiple Choice

Which molecule is a first messenger but not a second messenger?

• A) G protein
• B) Cyclic AMP
• C) Acetylcholine
• D) Protein kinase
• E) Adenylyl cyclase

Describe the significance of the thymus and bone marrow in immune cell development.

Recognize the role and mechanism of antibodies in the immune response.

Explain the processes involved in antigen presentation and immune cell activation.

Understand the concept of primary and secondary immune responses, including memory cell function.

---

Definitions:

Chi-square Distribution

A statistical distribution used particularly in hypothesis testing, derived from the sum of the squares of a set of variables that follow a normal distribution.

Critical Value

A point on the scale of the test statistic beyond which the null hypothesis is rejected.

Sampling Distribution

A probability distribution of a statistic obtained through a large number of samples drawn from a specific population.

Chi-square Distribution

A probability distribution that arises in statistics as the distribution of a sum of the squares of independent standard normal random variables.