Cell Communication And Cell Cycle Flashcards
What is essential for coordinating responses to stimuli in cells?
Cell communication
Involves signaling molecules (ligands) and specific receptors.
What type of signaling occurs when a cell signals itself?
Autocrine
Example: Immune cells releasing cytokines.
What is the term for local signaling where nearby cells communicate?
Paracrine
Example: Neurotransmitters.
What type of signaling involves long-distance communication through hormones?
Endocrine
Example: Insulin.
What is juxtacrine signaling?
Direct contact signaling
Example: Gap junctions in animal cells, plasmodesmata in plants.
What is a ligand in cell signaling?
A signaling molecule
Examples include hormones and neurotransmitters.
What is the function of a receptor protein in cell signaling?
Binds ligands
Found in the plasma membrane or inside the cell.
What is a signal transduction pathway?
A series of molecular interactions that lead to a cellular response
It results in actions such as gene expression or enzyme activation.
What are the stages of the cell cycle?
Interphase and mitotic phase
Interphase includes G1, S, and G2 phases.
What occurs during the G1 phase of interphase?
Cell grows and prepares for DNA replication
Produces proteins necessary for the next phase.
What happens during the S phase of the cell cycle?
DNA replication occurs
Doubling the genetic material.
What is the purpose of the G2 phase in the cell cycle?
Cell prepares for mitosis
Produces more proteins and organelles.
What is prophase in the mitotic phase?
Chromosomes condense and the nuclear envelope breaks down
Spindle fibers also form during this stage.
What occurs during metaphase?
Chromosomes align at the metaphase plate
What is the process of anaphase?
Sister chromatids separate and move to opposite poles
What happens during telophase?
Nuclear membranes reform around chromosomes
What is cytokinesis?
Division of cytoplasm
In animals: cleavage furrow; in plants: cell plate.
What causes cancer?
Uncontrolled cell division due to mutations affecting cell cycle regulation
What mutation turns proto-oncogenes into oncogenes?
Mutation in proto-oncogenes
Leads to excessive cell division.
What is the role of tumor suppressor genes?
Prevent cells from stopping division when needed
Example: p53.
What is failure of apoptosis?
Mutated cells survive and divide uncontrollably
What is loss of contact inhibition?
Normal cells stop dividing when touching others, but cancer cells do not
What external factors can contribute to cancer?
Environmental carcinogens
Examples include UV radiation, tobacco, chemicals, viruses (HPV).
What is genetic predisposition in relation to cancer?
Inherited mutations in genes like BRCA1
These mutations increase the risk for specific cancers such as breast cancer.
