28 Questions
Which term best describes protein crystals?
Regular
What are protein crystals made of?
Identical molecules or molecular complexes
What is the structure of protein crystals?
Regular
Which of the following can act as a nucleus in the nucleation process?
A dust particle
What happens if the supersaturation is too high in a solution?
An overabundance of tiny crystals form
When does crystal growth often occur in supersaturated solutions?
Only in the presence of added nuclei or seeds
Which of the following can cause cessation of growth in crystal formation?
Development of growth defects
What is mother liquor in the context of crystal formation?
The solution in which the crystal exists
How is mother liquor different from the original crystallization screening solution?
It has a higher concentration of solute
What is the role of temperature in crystallization?
It determines the size of protein crystals
Which method is commonly used by crystallographers to obtain protein?
E. Coli expression systems
What can cause low expression yields in E. Coli expression systems?
Unstable plasmid or mRNA
What is a major issue with protein concentration?
Consistency and reproducibility
Which temperature is considered ideal for keeping an individual crystal screen constant?
4° C
At which temperatures should each set of conditions be screened during crystal formation?
4° C and room temperature
Which temperature should be tried during crystal screening, in addition to 4° C and room temperature?
12° C
Which type of interactions are more important than hydrophobic interactions in crystal packing?
Electrostatic interactions
What does crystal packing refer to?
The arrangement of molecules within a crystal
What is the main issue when it comes to reproducibility in crystal packing?
Buffer composition
Which temperature is commonly used for X-ray diffraction measurements of protein crystals?
Cryogenic temperatures
What is the purpose of adding cryoprotectants to protein crystals?
To stabilize the crystal structure
What effect does cryoprotectant addition have on the nucleation temperature of water?
Decreases the nucleation temperature
Why can't we see proteins with light microscopes?
Proteins are too small to be resolved by the wavelength of visible light
What is the wavelength range of visible light?
400 - 700 nm
What is the wavelength of X-rays?
1 angstrom (0.1 nm)
Which type of device is used to force electrons to follow a closed 'ring' trajectory?
Bending magnets
What is the main difference between a wiggler and an undulator?
Wigglers emit radiation as a series of sharp peaks at prescribed wavelengths
What is the purpose of insertion devices in synchrotron radiation facilities?
To produce higher intensity, shorter wavelength x-rays
Test your knowledge about protein crystals and their structure with this quiz. Learn about the regular 3D arrays and identical molecules that make up protein crystals, just like any other crystal of organic or inorganic compounds. Challenge yourself and expand your understanding of this fascinating topic.
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