Answer:
Stem cell is taken either from bone marrow or from the blood directly
Explanation:
Stem cells are derived from two locations primarily a) Bone Marrow and b) Blood
The first step in this process is to remove the stem cell from its parent location and it is done in the following ways –
A) For deriving stem cell from blood – A drug with growth factor s is injected. Here no anesthesia is given to the patient. The growth factors leads to the movement of stem cells from bone marrow into the bloods. Blood with stem cells is taken out from the veins and filtered through the apheresis machine.
B) From Bone marrow – Bone marrow is removed from the pelvic bone through a needle and prepared for transplantation.
Answer:
1.The Sun, Earth and Moon are aligned with the Earth in the middle and the Moon furthest away from the Sun.
2.The Moon only partially covers the Sun during the eclipse.The Moon only partially covers the Sun during the eclipse.
3.Moon in perigee orbit; Moon moves a direct line between Sun and Earth; Moon in new moon phase.
4.The Earth's umbra fits inside the Moon creating an illuminated ring known as a annular eclipse.
Answer:
Both plant and fungal cells have a cell wall. The main difference between the fungal cell wall and the plant cell wall is that the plant cell wall is made up of cellulose whereas the cell wall of fungal cells are made up of chitin. Along with cellulose, the plant cell wall also comprises of hemicellulose and pectin.
Answer:
The molecule that is able to go back and correct an error in the DNA nucleotide sequence is DNA polymerase (option B).
Explanation:
DNA polymerase is not only the enzyme that contributes to the polymerization of a new DNA strand during the replication process, but it can also correct errors in synthesis, such as when a mismatched nucleotide is placed.
Once an error has been detected during synthesis, the DNA polymerase —acting as a 3'-5'- exonuclease— reverses the process, the direction of synthesis, to correct the error which in this case is the mismatched nucleotide.
The other options are not correct because:
<em> A. </em><u><em>DNA proofreadasa </em></u><em>does not exist.
</em>
<em> C. </em><u><em>Helicase</em></u><em> breaks the hydrogen bridges that bind the nucleotides allowing the separation of the DNA strands. In some cases, it also acts as a DNA repairer
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<em> D. </em><u><em>DNA Primase</em></u><em> is responsible for the synthesis of primers.</em>
