4.1 Cell Communication & 4.2 Cell Cycle

Which of the following types of signaling is represented in the figure?

• hormonal

• paracrine

• autocrine

• synaptic

In the figure, the dots in the space between the two structures represent which of the following types of molecules?

• neurotransmitters

• hormones

• receptor molecules

• signal transducers

Immediately after a membrane receptor protein binds to its ligand, which of the following processes occurs?

• The membrane receptor protein undergoes a conformational change.

• An intracellular G protein is activated.

• Cytoplasmic enzymes are activated by phosphorylation.

• The receptor/ligand complex enters the cytoplasm by endocytosis.

Which of the following statements best describes how the lack of receptors for local paracrine signal molecules would affect animal cells?

• The cells would not respond to growth factors from nearby cells.

• The cells would bind locally secreted growth factors, but signal transduction to alter gene expression would not occur.

• The cells would not respond to hormone signals delivered through the bloodstream.

• The cells would produce their own paracrine molecules internally.

Secreted signal molecules that travel only short distances and influence only cells in the immediate vicinity are associated with which of the following signaling pathways?

• endocrine signaling

• paracrine signaling

• hormonal signaling

• synaptic signaling

How is the plant hormone ethylene delivered to target cells?

• through plasmodesmata from adjacent cells

• through the plant vascular system

• through intracellular steroid hormone receptors

• through the air

Testosterone is most likely to alter cell function by which of the following mechanisms?

• binding to a receptor protein that enters the nucleus and activates specific genes

• binding to a transmembrane signal receptor that activates cell-signaling pathways

• serving as a second messenger that activates cell-signaling pathways

• acting as a steroid signal receptor that activates ion channel proteins

Transcription factors play a major role in regulating which of the following processes?

• the conversion of ATP into cAMP

• transmission of signals from steroid hormone receptors to intracellular G proteins

• gene expression

• DNA replication

Which of the following statements best describes the primary function of phosphatase enzymes in signal transduction pathways?

• amplify signal transduction by activating multiple relay molecules

• amplify production of the second messenger cAMP

• transfer a phosphate group from a kinase to the next relay molecule in a series

• inactivate protein kinases to turn off signal transduction pathways

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?

• Estrogen does not affect cells that lack estrogen receptors in the cell membrane.

• Estrogen binds to common receptors inside several cell types, and each cell responds in the same way to its binding.

• Estrogen is produced in high concentrations by a large number of different cell types.

• Estrogen binds to specific receptors inside many kinds of cells, each of which has different responses to its binding.

Tags

NGSS.HS-LS1-3