Answer:
a. The maternal copy of UBE3A is expressed and the paternal copy is silenced.
Explanation:
When UBE3A chromosome is in neurons, paternal allele is silent and maternal allele is expressed in process of genomic imprinting. In some cases UBE3A is expressed from both paternal and maternal chromosomes. The paternal chromosome is blue whereas maternal chromosome is magenta.
Low concentration to high concentration
Answer:
Carbon dioxide
Explanation:
Xylem and phloem are the two conducting tissues of a vascular plants. They are referred to as vascular bundles. Xylem and phloem are responsible for conducting certain substances from one part of the plant to another.
The xylem is responsible for conducting WATER AND DISSOLVED MINERALS from the root of the plants to other parts e.g leaves, stem, flowers etc. while the phloem conducts sugar (product of photosynthesis) e.g glucose from the leaves of the plant to other parts including the stem, root etc.
According to this question, xylem or phloem does not conduct or carry gaseous substances like carbon dioxide (CO2).
Explanation:
1) The enzyme helicase catalyses the unwinding of the two DNA strands by disrupting the hydrogen bonds between complementary base pairs.
2) Single-stranded binding proteins attach to the DNA strands to stabilise them and prevent them from joining back together.
3) The enzyme primase catalyses the addition of a short primer consisting of RNA nulceotides to the DNA strand. This serves as an 'anchor' DNA polymerase to initiate replication.
4) The enzyme DNA polymerase synthesizes a new DNA strand by incorporating DNA nucleotides complementary to the existing strand. DNA polymerase activity only occurs in the 5' ---> 3' direction.
5) The enzyme ligase catalyses the formation of hydrogen bonds between the two new pairs of DNA strands, and seals any breakages in the sugar-phosphate backbone.
