Stages of Cell Signaling
and Second Messengers
and Second Messengers
What is reception, transduction, and response.
What is the name of the class of signaling molecules used in endocrine signaling?
What is hormones
What are the phases of the cell cycle? How much time is spent in each phase
Interphase and Mitotic phase. 90% is spent in interphase, and 10% is spent in the mitotic phase.
What is a benign tumor?
What is a non-harmful tumor.
Where are the 3 checkpoints during the cell cycle? Where are they found?
What is G1, G2, and M checkpoints. The G1 checkpoint is found at the end of the G1 phase. The second one is found at the end of the S phase and before the G2 phase. The last one is found during metaphase in mitosis.
Describe the three main stages of cell singaling
What Reception: The target cell detects the signaling molecule, binding to a receptor protein located at the cells surface or outside the cell (causing the shape to change).
Transduction: A series of steps or cascades that converts the signal to bring out a specific cellular response.
Response: Final cellular activity such as catalysis, activation of genes.
What is the difference between the types of signaling (endocrine, paracrine, autocrine, contact-dependent)?
What is the distance at which the signal travels through the body.
What happens in Interphase and what are the three parts?
The cell grows in G1 and G2, replicates its DNA in S phase, and prepares for mitosis.
True or false benign tumors can become malignant?
What is true
What happens if the cell fails the G1 checkpoint?
It enters the G0 phase which is non-dividing state.
What happens during a phosphorylation cascade.
What is signaling pathway events where one enzyme phosphorylates another making it become active, causing a chain reaction leading to the phosphorylation of thousands of proteins. Until phosphorylizing the last one in a chain causing a cellular response
What are the 4 steps of RTK receptor.
1. Ligand Receptor binding
2. Dimerization
3. Phosphorylation
4. Activation
What happens during prophase and prometaphase?
what is the chromosomes begin to condense and kinetochores assemble on the centromeres. Specialized microtubules, called kinetochore microtubules later attach to these sites.The network of cytoskeletal components begins to break down and the mitotic spindle forms. The mitotic spindle is an arrangement of microtubules that is responsible for aligning duplicated chromosomes in later phases.
In prometaphase there is the breakdown of the nuclear envelope into small vesicles. Kinetochores also become fully matured on the centromeres of the chromosomes.
What is the importance of HeLa?
What is HeLa cells have been used to test the effects of radiation, cosmetics, toxins, and other chemicals on human cells. They have been instrumental in gene mapping and studying human diseases, especially cancer. They are also immortal and continue to grow and divide.
What is the most important checkpoint? And Why?
G1 because only if the cell gets the go in this phase it can move on to S phase and G2 and M phase, but if it doesnt it will move into G0 phase and the cell will not divide.
What are the 2 main types of secondary messengers? How do they work?
What is Cyclic AMP which is an enzyme is activated by reception and the activated enzyme converts ATP to cAMP. Release of cAMP triggers more molecules in transduction pathway. And Calcium ions; Cells usually have low concentration of calcium ions inside the cytosol but calcium ions pumps can alter levels of Ca2+ which triggers activation of other proteins
What are intracellular receptors? What is the signaling process for them?
Receptors located inside the cell.
Ligand enters cell --> binds to receptor --> hormone-receptor complex enters the nucleus
--> binds to certain genes and acts as transcription factor --> gene truns to mRNA
--> ribosomes translate mRNA to protein
What happens during metaphase and anaphase?
What is during metaphase chromosomes align at the center of the cell, half way between each of the mitoic spindle poles. Movement is mediated by the kinetochore microtubles, which push and pull on the chromosomes to align them into what is called the metaphase plate. Chromosomes on the metaphase plate are held there tightly by pushing and pulling forces from the microtubules.
In Anaphase is triggered by the inactivation of M phase-promoting factor that follows mitotic cyclin degradation. During anaphase, the kinetochore microtubules retract, increasing the seperation of the sister chromatids as they are moved further toward the opposite spindle poles
How does cell division of cancer cells differ from normal cell division?
What is cancer cells skip checkpoints that are supposed to regulate the cell before division, causing them to divide uncontrollably.
What is growth factor?
A protein released by certain cells that stimulate other cells to divide.
What are the 4 aspects of regulating a cellular response?
What is
1. Amplification
2. Specificity (differences in signaling pathways allow cells to "crosstalk")
3. Overall Efficiency (w/ scaffolding proteins)
4. Termination of signal
What type of receptors are located in the cytoplasm? What kind of ligands bind to them? Where do these receptors go after being activated?
Intracellular receptors; nonpolar/hydrophobic, small ligands; into the nucleus
What happens during telophase and cyctokinesis?
What is in telophase the sister chromatids reach opposite poles. The small nuclear vesicles in the cell begin to re-form around the group of chromosomes at each end. As the nuclear envelope re-forms by associating with the chromosomes, two nuclei are created in the one cell.
In cyctokimesis the cell actually divides into two. With the two nuclei already at opposite poles of the cell, the cell cytoplasm separates, and the cell pinches in the middle, ultimately leading to a cleavage furrow, and then the parent cell divides creating two daughter cells.
What is Metastasis?
What is the spread of cancer cells to a distant location from the orginial site.
In which phase of the cell cycle is the MPF levels highest?
What is the M phase