Chapter 9- Flashcards
Cell to cell communication evolved from ____
Prokaryotes
Examples of Bacteria communication
Spore formation, biofilm formation, and bioluminescence
Signaling in bacteria is ___
Density dependent (Quorum Sensing)
Components of Quorum Sensing
Autoinducers (from bacteria)
Upregulate gene expression (a process that involves the signals of the cell)
What are the four categories of Signaling? (multicellular organism)
Autocrine
Contact-dependent
paracrine
endocrine
Paracrine signaling
signaling molecule diffuses across environment to target cell (quick and short lived, local signal) involving and relying on neurotransmitters
Autocrine signaling
A cell that produces ligand that targets itself
- example: cells infected with a virus already; sending signals that’ll bind to their own receptors, preventing the virus from spreading.
Endocrine Signaling
Signals from cells that are meant for distance target cells in the blood stream.
- its like a highway with the cars being the signals and the blood stream being the highway
Contact dependent signaling
-Surface receptors on two cells bind to each other locking them into place (ex: on the skin)
- gap junctions (channel between cells that signals can diffuse across)
Ligand : a molecule that binds to ____
a receptor
Examples of ligands (signaling molecules)
amino acids
lipids
proteins
Intercellular (cell surface) receptors
Transmembrane proteins
Intracellular receptors
inside the cytoplasm of the cell
signal transduction
when the ligand bonds to the receptor and causes a change in the cell (3 step process)
What are the three steps of signal transduction?
Reception: Ligand bonds to receptor
Transduction: shape change is made into a signal into the cytoplasm
Response: affect on the cell
Protein Kinase Signaling
Kinases phosphorylate other proteins
Cyclic AMP (cAMP)
Same function as proteins in the signaling cascade; it serves as a second messenger. Binds to activate PKA so it can phosphorylate with other proteins
andenylyl cyclase
Uses ATP to catalyze cAMP
Who discovered Nucleic Acids?
Friedrich Miecher
The Frederick Griffith experiments
Discovered that genetic material can be transferred between live and dead bacteria
Hershey and chase’s experiments
used radioactively labeled phosphorus and sulfur
Erwin Chargaff discovered…
base pairing rules for DNA
- Adenine pairs with thymine
- Guanine pairs with Cytosine
Who discovered the structure of DNA?
Rosalind Franklin (famous from watson and crick)
DNA replication is ____
semi-conservative (two strands separate, old strand is used as a template, and new strands are created)
what are the three stages of DNA replication in prokaryotes?
Initiation, elongation, and termination
Initiation is the…
origin of replication
creates a replication fork
