Answer:
The correct answer is: d. REs activity is best preserved by freezing the RE and thawing it out for brief periods of time as needed.
Explanation:
- Restriction enzymes can be defined as endonucleases that can recognize specific nucleotide sequence in a DNA (Deoxyribonucleic acid) sequence and cause breakage of phosphodiester bond in the DNA at the target site. Hence, it has the capacity of cleaving a DNA sequence.
- These are made up of proteins which are required to be present in the accurately folded conformation in order to function.
- Any form of alteration in the three-dimensional structure of the protein induced due to physical, chemical, mechanical or physiological factors can cause denaturation of the protein which in turn can render the protein non-functional.
- Freezing of restriction enzymes (REs) directly without the use of glycerol will cause the movement of water molecules within the proteins as well layering of water molecules on the protein surface.
- At low temperature these water molecules change to ice crystals which can alter the conformation of the protein or can cause breakage of peptide bonds in the proteins by physical force.
- This can cause the protein to get denatured and hence non-functional.
- Hence, it is never advisable to preserve REs by freezing directly without glycerol.
- Glycerol forms a layer around the protein molecules and prevents the protein molecules from coming into direct contact with the water molecules and hence prevents protein denaturation.
<span>The mineral crystals in obsidian are too small to see without a microscope. This is because the rock cools so rapidly from magma that crystals barely have time to form. Obsidian is a normally happening volcanic glass framed as an extrusive molten shake. It is delivered when felsic magma expelled from a well of lava cools quickly with negligible precious stone development.</span>
<span>B. tiny structures in the cell that carry out the cell's activities</span>
Answer:
Experiment to show that sunlight is necessary for photosynthesis - definition. Take a plant with destarched leaf. Leaf is partially covered with black paper on which a design is cut. Expose this plant to sunlight for few hours and perform a starch test with iodine solution.
Explanation:
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