ELM 6.2 Flashcards
A dye that selectively binds Ca2+ is:
FURA-2
Fura-2 binds calcium via its negatively charged carboxylic acid groups. Fura-2 AM is a esterified version of Fura-2. It can pass through membranes but cannot bind calcium.
Which of the following changes occur when FURA-2 binds calcium?
Absorption peak shifts to shorter wavelengths
FURA-2’s emission spectrum remains unchanged (510 nm) but its absorption spectrum shifts to shorter wavelengths when calcium binds (380->340 nm).
Which of the following is a GINA?:
a.
FURA-2 AM
b. cGMP c. GCaMP d. Halorhodopsin
GCaMP
GCaMP is a genetically encoded indicator of neuronal function (GINA). It is a fusion protein (GFP, M13 and calmodulin) whose fluorescence increases when it binds calcium.
Prof. Jenkinson is interested in how a certain class of cells in the mouse hippocampus affect the formation of memory. His hypothesis is that activating these cells will increase the rate at which mice learn a route through a maze and that inhibiting the cells will cause the mice to learn more slowly. He decides to use optogenetic methods to address this question.
In the paragraph below there are a series of numbered blanks. Each blank corresponds to a question. Use an option from each question to fill in the blanks. You should read the whole paragraph before answering the questions.
In his first experiment Prof. Jenkinson introduces a cation channel called _____________[1] into the hippocampal cells using ________________[2]. He then activates the channel using ______________[3] delivered via a(n) _________________[4] implanted in the mice’s brains. He is pleased to see that the mice solve the maze quicker than the control animals. Next, he uses the same methods to examine the effects of a protein from a(n) ___________[5] that allows anions to enter the cells. This protein, called ______________[6], is a(n) _________________[7] powered by ________________[8]. Again, Prof. Jenkinson’s experiment works exactly as he hypothesised: mice expressing [6] solve the maze more slowly than the controls. Prof. Jenkinson writes up his results and publishes them in Nature Neuroscience.
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