Answer:
The main function of viagra is to relax the muscles of the blood vessels in some areas of the body. It is used for the treatment of erectile dysfunction and for high blood pressure. The component of viagra is a competitor to the enzyme PDE5, breaking down cGMP. In the penis, blood is trapped, which results in the erection being maintained. When cGMP levels decrease, the concentration of calcium ions increases, causing smooth muscle contraction.
Explanation:
Firstly, the enzyme, DNA Helicase breaks the Hydrogen bonds between a specific region of the DNA molecule and unwinds the duplex DNA molecule at the targeted gene sequence site.
Then, RNA Polymerase binds at the 3` site of the gene sequence of the sense/coding strand(only one strand) that acts as the template for mRNA synthesis. RNA Polymerase then matches free nucleotides by complementary base-pairing(A-U & C=G), working in the 5`to3` direction. Hydrogen bonds then form between the complementary bases, holding the nucleotides in place. Each free adjacent nucleotide is joined at 3` ends by Condensation reactions with the other to form Phosphodiester bonds.
Once the mRNA molecule is formed, it is separated from the synthesis complex and leaves the nucleus through pores in the nuclear envelope to moves towards ribosomes for Translation.
Lastly, the DNA double helix rewinds by forming Hydrogen Bonds.
Answer:
D.
Explanation:
The immune system lowers the chances of bacteria, viruses, and diseases entering your body
Nucleotide bases are added to DNA strands in a 5' to 3' direction.
What is DNA replication?
When a cell divides, DNA copies itself through a process called replication.
- Generally speaking, DNA replication involves uncoiling the helix, strand separation by rupturing the hydrogen bonds between the complementary strands, and synthesis of two new strands through complimentary base pairing.
- The origin of replication, which is a precise location in the DNA, is where replication starts.
- From the point of origin, DNA replication is bidirectional.
- The two parent DNA strands unwind and split apart at the origin of replication to generate two "Y-shaped" replication forks in order to start DNA replication.
- These unwinding enzymes are known as DNA helicases.
- The real location of DNA copying is at these replication forks.
- Proteins that destabilize helices bind to the single-stranded areas to prevent the two strands from rejoining.
- To reduce stress on the helical molecule during replication, enzymes known as topoisomerases cause breaks in the DNA and then reunite them.
- The hydrogen bonding of free DNA nucleotides with those on each parent strand results in the formation of new complementary strands as the strands continue to unwind and split in both directions around the entire DNA molecule.
- The new nucleotides are joined by DNA polymerases using phosphodiester bonds as they align themselves opposite each parent strand using hydrogen bonds.
- Deoxynucleotide triphosphates, which are made up of a nitrogenous base called deoxyribose and three phosphates, are the actual nucleotides that are aligning through complementary base pairing.
- Two of the phosphates are withdrawn to provide energy for bonding as the phosphodiester bond forms between the 3' OH of the previous nucleotide in the DNA strand and the 5' phosphate group of the next nucleotide.
- In the end, two identical DNA molecules are created when each parent strand acts as a template for the synthesis of a complementary copy of itself.
Hence, nucleotide bases are added to DNA strands in a 5' to 3' direction.
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Answer: Shale changes into Slate.
Explanation:
Shale is a sedimentary rock, formed by the deposition and compression of clay and silt.
Shale layers is buried deep into the earth through the process of deposition (i.e the laying down of rock forming material by natural entities like glaciers, wind, and water).
Temperatures and pressures rise greatly because the shale’s layers are buried. When the temperatures and pressures become higher. The shale is changed into a metamorphic rock (with dark brown streak), called Slate.
