Chapter 6.1: Cells Detect a Variety of Signals

Flashcards from Chapter 6.1 of Principles of Life, 3rd Edition.

Environmental variables

These signals were the first to be detected by individual cells, responding in order to maintain homeostasis

• Involves changes in the tertiary structure of a sensory receptor’s protein for a response

Cell-to-cell signalling

Signals that originate from a cell and convey specific information to another cell, enabling multicellularity

• Requires that a receptor be present

Receptor

One of these are required to ensure a cell can properly receive and respond to a signal

• Only expressed in cells that require it

Conformational change

A change in the shape of a protein

• Occurs in receptors when bound to a signal

Signal transduction

The amplified pathway that is followed after a signal binds to a receptor

• Typically occurs through an allosterically-regulated molecule activated via phosphorylation

Phosphorylation

The binding of phosphate groups, often to proteins for activation

Ligand

A molecule that binds to a specific receptor protein, such as proteins, lipids, or other molecules

• May be interpreted differently across different function cells

Short-term changes

Responses to signals in a cell including enzyme activation or ion channel openings

Long-term changes

Responses to signals in a cell including gene expression regulatory protein modification

Juxtacrine signaling

Cell-to-cell signaling involving direct contact, either through gap junctions, plasmodesmata, or signal and receptor molecules

Gap junctions

Junctions that link cells together to allow for the passage of material directly into the cytoplasm for juxtracrine signaling

Plasmodesmata

Pores in plant cells that serve a similar function to gap junctions in animal cells

Paracrine signaling

The diffusion of signals to nearby cells that possess the required receptors

Autocrine signaling

Self-cell signaling, as a type of paracrine signaling

• Seen widely in tumors, resulting in uncontrolled growth

Endocrine signaling

Signalling that uses tissue-specific molecules called hormones transported through a circulatory system across long distances

Hormones

Chemical signals transported to a distant receiving cell such as through a circulatory or vascular system