Cell Signaling Pathways Overview

Cyclic-AMP (cAMP) is activated through G protein-coupled receptors (GPCRs).

Phospholipase C (PLC) and Protein Kinase C (PKC) are involved in a signaling pathway.

Calcium ions (Ca2+) play a crucial role in various cellular processes, including muscle contraction, secretion, and fertilization.

Calcium signals can spread through cells via waves, often triggered by feedback mechanisms.

G protein-coupled receptors (GPCRs) are essential in smell and vision, regulating ion channels, and amplifying signals.

The lipid bilayer of the plasma membrane acts as a barrier, preventing most polar molecules from passing through. This creates concentration differences across the membrane.

The difference in concentration and electrical charge across the plasma membrane. This energy difference is used for processes like ATP production and transport.

Movement of a molecule from high concentration to low concentration without using energy. Simple diffusion and facilitated diffusion are examples.

Movement of a molecule from low concentration to high concentration, requiring energy input. This is needed to maintain concentration gradients.

The ability of a molecule to pass through the plasma membrane depends on its size and polarity. Non-polar molecules pass easily, while charged molecules cannot.

For uncharged molecules, concentration gradient is the driving force. For charged molecules, both concentration gradient and membrane potential determine transport.

Transport proteins with moving parts that carry molecules across the membrane. They can move molecules against their concentration gradient.

Transport proteins with hydrophilic pores that allow passive movement of small inorganic molecules down their concentration gradient.

Passive transport using membrane proteins to help molecules move across the membrane. These proteins act as 'helpers' for molecules that wouldn't normally pass through the membrane easily.

Membrane protein that binds to a molecule on one side, changes shape, and releases it on the other. Can be involved in both passive and active transport, acting like a delivery service.

Active transport protein found in most animal cells that pumps sodium ions out of the cell and potassium ions into the cell. Requires energy (ATP) and is crucial for nerve impulse transmission, maintaining cell volume, and regulating cell function.

Channel protein that facilitates the movement of water across the cell membrane. Allows water to pass quickly and passively, like a specialized water channel.

Membrane proteins that create pores for specific ions to pass through the membrane, allowing movement down their concentration gradient. They are crucial for nerve impulse transmission, muscle contraction, and many other cellular functions.

Proteins embedded in the cell membrane that open in response to neurotransmitters, allowing ions to flow in or out of the cell, leading to changes in membrane potential.

Neurotransmitters that cause depolarization of the postsynaptic membrane, increasing the likelihood of an action potential firing. They open cation channels, allowing positive ions to flow in.

Neurotransmitters that cause hyperpolarization of the postsynaptic membrane, decreasing the likelihood of an action potential firing. They open anion channels, allowing negative ions to flow in.

Neurotransmitters bind to transmitter-gated channels, triggering the opening of these channels and allowing ion flow. Excitatory neurotransmitters cause depolarization (more positive) while inhibitory neurotransmitters cause hyperpolarization (more negative).

Proteins found in some organisms that respond to light by opening and closing, allowing ions to flow into the cell. These are involved in light sensing and vision.

A technique that uses light to control the activity of specific cells in living tissue.

A light-sensitive protein found in algae that acts as an ion channel, opening in response to blue light.

Optogenetics allows researchers to precisely and dynamically control the activity of specific cells in living tissue.

Optogenetics works by introducing light-sensitive proteins, such as channelrhodopsins, into cells. When these proteins are exposed to light, they activate or deactivate the targeted cells.

A network of protein filaments that provide structure and support to cells.

The cytoskeleton provides structural support, allows for cell movement, and helps with the transport of materials within the cell.

Optogenetics has been used to study the brain, control behavior, and develop treatments for neurological disorders.

Optogenetics is a powerful tool for understanding and controlling cellular processes, potentially leading to new treatments for diseases.

A dynamic network of protein filaments that helps the cell change its shape, divide, and respond to its environment. It is involved in various cellular processes like cell migration, organelle transport, and chromosome segregation.

One of the three main types of protein filaments in the cytoskeleton, composed of the protein actin. Actin filaments are thin, flexible, and involved in cell movement, shape changes, and muscle contraction.

One of the three main types of protein filaments in the cytoskeleton. They are long, hollow tubes made of the protein tubulin. They provide structural support, facilitate cell division, and help transport materials within the cell.

One of the three main types of protein filaments in the cytoskeleton, providing structural support and helping cells resist stress. They are rope-like fibers made of various proteins, depending on the cell type.

A complex meshwork of proteins and carbohydrates that surrounds cells and provides structural support, helps with cell signaling, and aids in tissue development.

Specialized cell junctions that form a seal between adjacent cells, preventing the passage of water, solutes, and cells between them. They are crucial for maintaining cell polarity and regulating transport.

Cell junctions that mechanically link cells to each other or to the extracellular matrix, providing structural support and helping tissues withstand stress.

A type of anchoring junction that connects the intermediate filaments of adjacent cells indirectly, forming a continuous network throughout the tissue. They provide strong adhesion between cells.

The K+ channel is selective for potassium ions due to interactions between K+ ions and polar amino acid side chains lining the pore, which displace water molecules and allow dehydrated K+ to pass. It's less permeable to sodium ions (Na+).

These channels are sensitive to changes in membrane potential. They open when the membrane is depolarized, allowing ions like Na+, K+, and Ca2+ to flow across the membrane.

Resting potential is the stable, negative electrical charge of a neuron when it is not sending a signal. It's maintained by the balance of ion movement across the membrane, primarily K+ leak channels.

This equation calculates the equilibrium potential for a particular ion across a membrane, considering the concentration gradient and charge difference.

A nerve impulse travels along the axon as a wave of depolarization. It's directional, meaning it travels in one direction, and it's relatively fast, reaching up to 100 meters/second.

Voltage-gated channels along the neuron's axon are responsible for generating action potentials. Changes in membrane potential cause these channels to open and close, creating a rapid change in voltage.

Myelin sheath, produced by glial cells, wraps around the axon, insulating it and increasing the speed of action potential propagation.

These are gaps in the myelin sheath where a high density of Na+ channels is found. Action potentials jump from one node to another, increasing the speed of propagation.