Identify whether the statement is true or false, and why. "each type of receptor protein is specific to a certain signal or type of signal." a. true b. false, it should read "receptor proteins can receive signals from many types of signal molecules." c. false, it should read "receptor proteins are only used in synapses to receive neurotransmitters." d. false, it should read "receptor proteins are universal and can receive signals from any type of signal molecules."

A. True

Explanation: Cell receptors are proteins that receive  signals and trigger a signal cascade for the cell can respond. There's many types of  receptors, depend of their location and their enzymatic activity, and each type can recognize  certain  signals. For example, tyrosine-kinase receptors can recognize growth factors, JAK associated receptors can recognize cytokines, etc. That specificity is given by the structure of the receptor and the structure of the signal.

it creates acid rain

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle