AP Bio Signal Transduction Review

Which of the following can activate a protein by transferring a phosphate group to it?

• cAMP

• G-protein

• protein kinases

• phosphatases

Which two terms describe this image?

• long distance signal

• local signal

• synaptic

• paracrine

Communication between neighboring/touching cells is common in plants.

• True

• False

We have discovered a vast majority of cell surface receptor proteins.

• True

• False

The epinephrine signaling pathway plays a role in regulating glucose homeostasis in muscle cells. The signaling pathway is activated by the binding of epinephrine to the beta-2 adrenergic receptor. A simplified model of the epinephrine signaling pathway is represented in Figure 1. Based on Figure 1, which of the following statements best describes the epinephrine signaling pathway?

• It involves the opening and closing of ion channels.

• It involves enzymes activating other enzymes.

• It involves changes in the expression of target genes.

• It involves protons moving down a concentration gradient.

Tags

NGSS.HS-LS1-3

The epinephrine signaling pathway plays a role in regulating glucose homeostasis in muscle cells. The signaling pathway is activated by the binding of epinephrine to the beta-2 adrenergic receptor. A simplified model of the epinephrine signaling pathway is represented in Figure 1. A researcher claims that the epinephrine signaling pathway controls a catabolic process in muscle cells. Which of the following statements best helps justify the researcher’s claim?

• Epinephrine is a signaling molecule that binds to a transmembrane protein.

• The G protein in the epinephrine signaling pathway consists of three different subunits.

• Phosphorylase kinase catalyzes the hydrolysis of ATP.

• Glycogen phosphorylase catalyzes the conversion of glycogen to glucose-1-phosphate.

Figure 1 shows a model of a signal transduction cascade, initiated by the binding of a ligand to the transmembrane receptor protein A. A DNA mutation changes the shape of the extracellular domain of transmembrane receptor protein A produced by the cell. Which of the following predictions is the most likely consequence of the mutation?

• Production of activated molecule 1 will stop, but production of activated molecules 2 and 3 will continue.

• The molecule that normally binds to protein A will no longer attach, deactivating the cellular response.

• The molecule that normally binds to protein A will not enter the cell, thus no cellular response will occur.

• Since protein A is embedded in the membrane, the mutation will be silent and not affect the cellular response.

Tags

NGSS.HS-LS3-2

Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells because

• only target cells retain the appropriate DNA segments.

• intracellular receptors are present only in target cells.

• only target cells have enzymes that break down aldosterone.

• only in target cells is aldosterone able to initiate the phosphorylation cascade that turns genes on.

When a signal transduction pathway involves a phosphorylation casade, what turns off the cell's response?

• a relay molecule that activates protein kinase 1

• protein kinase 2

• protein phosphatases

• active transcription factors

Vertebrate immune responses involve communication over short and long distances. Which of the following statements best helps explain how cell surface proteins, such as MHC proteins and T cell receptors, mediate cell communication over short distances?

• The proteins receive electrical signals from nerve cells.

• The proteins leave the cell and travel in the bloodstream to other cells.

• The proteins interact directly with proteins on the surfaces of other cells.

• The proteins bind to molecules secreted by cells located in other parts of the body.