BIOS222 Exam 4 Study Guide

A molecule that binds to a receptor, triggering a response in the cell.

Different signaling pathways have unique ligands and receptors; one ligand won't activate any receptor. Each pathway is specialized.

A cell not receiving signals will likely survive, not die.

Gβ and Gγ are parts of G protein complexes; they become active when detached from Gα.

Dimeric ligands activate enzyme-coupled receptors, not GPCRs or ion channels.

RTKs can phosphorylate themselves as part of activation, crucial for downstream signaling.

Epinephrine was the first messenger in Earl Sutherland's cAMP discovery.

Treating a cell with an antibody against an RTK can cause dimerization and activate the receptor.

Molecules that prevent uncontrolled cell growth by putting brakes on the cell cycle

A molecule that triggers the cell cycle by binding to its receptor and releasing the Rb block

Cyclin-dependent kinase crucial in mitosis, causing nuclear envelope disassembly by phosphorylating lamins.

Proteins that hold sister chromatids together after DNA replication.

A kinase that negatively affects M-CDK activity by phosphorylating it.

A protein that stops the cell cycle if DNA damage is detected, preventing cell division with damaged DNA.

A protein that blocks the cell cycle until mitogen binds to its receptor to allow entry to the cell cycle.

A molecule that ensures DNA replication happens only once per cell cycle.

Protein channels in cell membranes that open or close in response to a specific molecule (ligand), allowing ions to flow through.

Protein channels that open or close in response to changes in membrane potential, allowing potassium ions to flow.

Small sacs in nerve cells that store and release neurotransmitters, the chemical messengers of the nervous system.

The synaptic cleft, the gap between two nerve cells where neurotransmitters are released to communicate.

A cell-cell junction that prevents the passage of molecules between cells.

A type of cell-cell junction that connects cells together by linking actin filaments.

A type of cell-cell interaction where identical molecules on neighboring cells bind to one another.

Allow small molecules to pass freely between two connected cells directly.

A mutation in the Retinoblastoma gene, causing an increased risk of developing retinoblastoma but not necessarily guaranteeing cancer.

Viagra enhances signal transduction by inhibiting the breakdown of nitric oxide, leading to increased blood flow and relaxation of smooth muscle in the penis.

Phosphorylation of tyrosine residues occurs in the cytoplasmic domain of the receptor tyrosine kinase, which is activated by ligand binding.

Small GTP-binding proteins, like Ras and Ran, are active when bound to GTP (Guanosine Triphosphate).

In some signaling pathways, binding of a ligand outside the cell triggers a change in enzyme activity inside the cell.

Cyclic AMP (cAMP) can act as a second messenger in some signaling pathways, relaying the initial signal from the ligand.

Some signaling pathways involve dimeric ligands, which bind to receptors that also form dimers.

Some receptors, known as G protein-coupled receptors (GPCRs), have seven transmembrane domains, spanning the cell membrane.

Oncogenes are mutated forms of genes that promote cell growth and division in normal cells. These mutations can lead to uncontrolled cell growth, a hallmark of cancer.

Tumor suppressor genes normally prevent uncontrolled cell growth by regulating cell cycle progression and apoptosis (programmed cell death). Mutations in these genes can lead to cancer development.

Pluripotent stem cells can differentiate into any cell type in the body EXCEPT for the placenta and other extraembryonic tissues. Totipotent stem cells can differentiate into any cell type, including those of the placenta.

Induced pluripotent stem (iPS) cells are generated from adult cells by artificially driving the expression of a set of specific genes. This process essentially reprograms the adult cells to become pluripotent, much like embryonic stem cells.

One of the main risks of introducing embryonic stem cells into the human body is that they might develop into a tumor. This is due to their potential for uncontrolled growth and differentiation.

Transgenic flies are genetically modified flies that carry and express genes from other organisms, such as humans. These flies are often used as models to study the function of genes and the development of diseases.

Transgenic flies can be used to model cancer by expressing human genes, including those associated with cancer. This allows researchers to study the effects of these genes on fly development and identify potential cancer-causing mechanisms.

A gain of function mutation refers to a change in a gene that results in a new or enhanced function for the gene product. In the context of cancer, this can lead to uncontrolled cell growth.

GTPase activity terminates the activated state of a signaling pathway by hydrolyzing GTP to GDP, returning the signaling molecule to its inactive form.

When a receptor tyrosine kinase (RTK) is activated, its cytoplasmic domain gets phosphorylated on tyrosine residues, initiating downstream signaling.

Sound vibrations in the inner ear are sensed by mechanically gated ion channels in the outer hair cells, initiating auditory signal transduction.

Viagra delays the termination of signaling by inhibiting the breakdown of cGMP, a signaling molecule involved in erectile function.

Viagra's effect involves nitric oxide signaling (NO), which triggers the production of cGMP.

Ras is a small GTP-binding protein that acts as an intermediate in various signaling pathways including tyrosine kinase, Akt, and MAPK signaling.

Signaling pathways terminate by removing phosphate groups, hydrolyzing GTP, or degrading signaling molecules, returning the system to its resting state.

Protein kinase A (PKA) is an effector protein activated by the GPCR signaling pathway through adenylyl cyclase, mediating a variety of cellular responses.