41 Questions
Based on the FRAP profiles shown, which SPT profile can be assigned to Protein X?
Cannot be determined
Based on the FRAP profiles shown, which SPT profile can be assigned to Protein Y?
B
Based on the FRAP profiles shown, which SPT profile can be assigned to Protein Z?
C
Which of the following is true about membrane proteins?
They can function as transporters, anchors, enzymes, and receptors
What is the function of the ER signal sequence?
It is recognized by the SRP and directs proteins to the ER
What happens to soluble proteins in the ER lumen?
They are translocated across the ER membrane
What is the role of signal peptidase?
It cleaves the N-terminus of a protein
Which of the following mechanisms is NOT involved in intracellular compartmentalization?
Transport through cytosol
What determines whether a protein will be made on a free ribosome in the cytosol or on a bound ribosome at the ER?
The presence of a signal sequence at the amino terminus
What is the role of signal peptidase in protein targeting?
To cleave off the signal peptide at the amino terminus
How do scientists determine whether a protein gets into an organelle in vitro?
By centrifuging the mixture and observing sedimentation
Which technique was used to collect data for the mobility of proteins X, Y, and Z?
Both FRAP and SPT
In the lipid bilayer of cell membranes, where are the polar head groups and hydrophobic tails located?
Polar head groups on the outside, hydrophobic tails on the inside
Which type of lipid makes the lipid more fluid in the bilayer?
Lipid with unsaturated tails
What is the difference between olive oil and butter in terms of their lipid composition?
Olive oil has more unsaturated fats
What effect does increasing temperature have on the fluidity of fats in the membrane?
Increases fluidity
What is the role of cholesterol in the membrane?
Increases fluidity
What can make a membrane more fluid?
Increasing the amount of cholesterol
What is the orientation of membranes generally maintained?
Horizontal orientation
What happens to phospholipids after synthesis in the ER?
They flip through the membrane
What is the role of the enzyme ippase in flipping phospholipids?
It requires ATP
Which of the following is true about signal sequences?
Signal sequences are necessary and sufficient to target a certain organelle.
What determines whether a protein will be made on a free ribosome in the cytosol or on a bound ribosome at the ER?
The presence of a signal sequence at the amino terminus.
What is the role of signal peptidase in protein targeting?
Signal peptidase cleaves off the signal peptide from a protein.
What happens to soluble proteins in the ER lumen?
Soluble proteins in the ER lumen stay in the lumen.
What is the function of the ER signal sequence?
The ER signal sequence directs proteins to the ER membrane.
Which of the following is NOT a mechanism involved in intracellular compartmentalization?
Transport through the ER membrane
What is the role of chaperones in protein folding?
Chaperones guide the proper folding of proteins.
How do scientists determine whether a protein gets into an organelle in vitro?
By centrifuging the mixture and observing sedimentation
What determines the number of times a membrane-bound protein crosses the membrane?
The presence of hydrophobic start transfer and stop transfer sequences
What is the consequence of changing the hydrophobic amino acids in the signal sequence to charged amino acids?
The protein will be targeted to the ER membrane instead of the cytosol.
Which of the following is true about membrane proteins?
Membrane proteins function as transporters, anchors, enzymes, and receptors.
What is the role of signal peptidase in protein targeting?
Signal peptidase cleaves off the signal sequence from proteins in the endoplasmic reticulum.
What determines whether a protein will be made on a free ribosome in the cytosol or on a bound ribosome at the ER?
The presence of a signal sequence on the protein.
What is the function of the ER signal sequence?
The ER signal sequence is involved in protein translocation across the ER membrane.
What happens to soluble proteins in the ER lumen?
Soluble proteins are retained in the ER lumen.
What is rough ER?
Rough ER is a type of organelle involved in protein synthesis.
What determines whether a protein goes into an organelle or stays in the cytoplasm?
The presence of a signal sequence on the protein.
What is the role of signal sequences in protein targeting?
Signal sequences direct proteins to their appropriate organelles.
What is the function of signal peptidase?
Signal peptidase cleaves off the signal sequence from proteins in the endoplasmic reticulum.
Which of the following mechanisms is NOT involved in intracellular compartmentalization?
Protein folding
Test your knowledge on protein mobility using FRAP and SPT data! Identify the fluorescence patterns and analyze the bleach time for proteins X, Y, and Z. This quiz will challenge your understanding of protein dynamics and experimental techniques.
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