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>In 80% of the cases of offspring with cri-du-chat syndrome, the father's gametes were the source of the deletion of the chromosome as opposed to the mother's egg being the cause. Therefore, cri-du-chat is largely caused by the father's genetics, not the mothers.</span>
Answer:
There are from 200-500 million alveoli (mean diameter = 200 micrometers) in adult human lungs
Explanation:
The epithelial cells of the alveolar septum are markedly thinned and the capillary network immediately beneath the epithelium is the richest in the body.hope this helps you :)
Answer:
Bad mutation: deletion/addition mutation
Good mutation: silent mutation
Explanation:
Addition or deletion mutation results in the reading frame of codons to be changed, leading to a extensive missense mutation that will lead to a non-functional protein product to form.
Good mutation are silent mutations that leads to no change to the final product but causes codons to change in sequence. This increases genetic diversity in the gene pool that enables the species to be more resilient to environmental changes.
I believe the answer is B. Hope I help! Sorry if not. ):)
