Lecture 16 study guide Flashcards
Define tissue
Groups of cells that act together to perform a specific function
Definition of Gap junction
directly link cytoplasm of neighboring cells
Definition of desmosome
form strong physical connections between cells
Definition of tight junction
Seals neighboring cells together in an epithelial sheet to prevent leakage between the cells.
Definition of adherens junction
Joins an actin bundle in one cell to a neighboring bundle in another cell.
Definition of hemidesmosome
Anchors intermediate filaments in a cell to the basal lamina.
Researchers studying the molecular makeup of a structure packed near the surface of a sheet of cells in tissue determine it to be made up mostly of collagen, polysaccharides, and other proteins. What is the name of this structure?
Extracellular matrix
- What is the function of integrin?
links the cells to collagen of the ECM
Explain why a vitamin C deficiency leads to the weakening of cell tissue?
Vitamin C is necessary for the hydroxylation of proline- a post translational modification necessary for the construction of collagen.
True or False: Excluding predation or other external factors that could cause death, most microbial organisms like yeast are immortal
true
What percent of the proteins in a cell are dedicated to regulation?
90%
Name the 8 main types of protein regulation we have covered in class so far.
Product inhibition, feedback regulation, covalent modifications, localization, assembly, protein synthesis, protein degradation, cell communication and signaling
Product inhibition is able to regulate proteins as a direct consequence of what?
reversibility of the reaction
Methionine can inhibit a protein involved in the synthesis of methionine precursor molecules. This is what kind of regulation?
Feedback regulation
Name two types of covalent modifications used to regulate proteins.
Phosphorylation
ubiquitination
Acetylation
What are proteins called that phosphorylate other proteins?
Kinase
What are proteins called that dephosphorylate other proteins?
Phosphorylases
True or false: ubiquitination is only used as a way to target a protein for degradation?
false
What is the “ultimate turnoff mechanism?”
degradation
Fill in the blank: Some proteins require several modifications before they can execute a specific function. This process functions as a _______ and the combination of several modifications alters protein activity.
coincidence detector
Sar1 is only able to drive vesicle formation when it is localized to the ER membrane. What type of regulation is this?
Localization
What type of protein drives the process described in question 17?
GTPase
Sec23/24 coat proteins must bind to Sar1 and a cargo receptor protein before they are able to effectively drive vesicle formation. What kind of regulation is this?
assembly
What is the main form of regulation driving actin dynamism?
assembly
Which of the following is not a possible place to regulate protein synthesis?
a. Transcription
b. Translation
c. mRNA processing
d. mRNA export
e. mRNA stability
f. All of the above are possible place
All of the above
What are the two most important domains on transcription factors?
- protein binding domains
- transcription regulator domains
What are homeodomains?
Containing transcription factor
Homeodomains form _____ with nucleobases mostly via the major groove of the DNA
- hydrogen bonds
True or false: homeodomains are specific in the DNA sequences they can bind
TRUE
What is the basic structure and function of a leucine zipper?
each subunit provides an alpha helix for the formation of the DNA binding domain
Where do transcription factors usually bind in simple eukaryotes?
upstream close to the transcription site
True or False: In higher eukaryotes transcriptional factors can act from farther away and not specifically in the promoter region?
true
In higher eukaryotes, what is the name of the region that activator proteins bind to?
enhancers
What is the name of the complex in higher eukaryotes that contains several transcription factors, chromatin remodeling complexes, etc?
mediator
What is the term for a protein that inhibits transcription of DNA? What are the two mechanisms by which they usually act?
Repressor proteins, physically competing with the DNA binding region or suppressing translation via the mediator complex
What is the name of the region of DNA that can be bound by a repressor?
silensor region
