Answer:
A gene mutation can be described as errors in the nucleotide sequence of a gene due to errors in the DNA replication process or due to any mutagen. On the other hand, a chromosomal mutation can be described as a change in the structure of a DNA or changes in the number of chromosomes.
A gene mutation occurs in a single gene whereas a chromosomal mutation will affect many genes. Hence, gene mutations will be comparatively less lethal than chromosomal mutations.
Example of gene mutation: Sickle cell anemia
Example of chromosomal mutation: Down's Syndrome
- An object's kinetic energy depends on its mass and its speed.
- The faster something is moving and the heavier it is, the more work it can do.
- Kinetic energy increases as an object moves faster.
- If an objects speed is doubled > kinetic energy is quadrupled.
<em>If an object is not moving, it does not have kinetic energy. </em>
Answer:
Explanation: The cell wall surrounds the plasma membrane of plant cells and provides tensile strength and protection against mechanical and osmotic stress. It also allows cells to develop turgor pressure, which is the pressure of the cell contents against the cell wall.
Easy. Answer is oxygen because it says which one was missing before any life was on earth. And in order to have life on earth you need oxygen!
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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.
