Molecular Genetics. There’s Two Critical Functions a Cell must Perform during its Lifetime. 1. A Cell must divide (reproduce) and have some way to ensure that each of the new daughter cell is complete and somehow receives the information it will need to perform its life functions.
The answer of course is tree cell to make a root or a leaf?, or a jellyfish cell to make a tentacle?…. What is this set of instructions?
DNA instructs the cell’s ribosomes to build the proteins which are used to make all living organisms.
Actually, there’s two types of Nucleic Acids DNA and RNA…. More about RNA later.
This is how I draw a Nucleotide
The Phosphate Group is the same as the phosphates used to make ATP…. You do remember ATP don’t you?
This Nitrogenous Base is Adenine, it is one of 4 Nitrogenous Bases….. Nucleotides are Identified by their Nitrogenous Base.
The Sugar in DNA is Deoxyribose and is a 5 carbon ring sugar.
Adenine and Guanine are Purines. They have two Carbon Rings.
Cytosine and Thymine are Pyrimidines. They have only one Carbon Ring.
One Helix the other Helix
the symbol 5’ - means 5 prime
the symbol 3’ - means 3 prime
*the symbols 5’ and 3’ will become important to you later
The Nitrogenous Bases, Adenine and Thymine, are held together by 2 Weak Hydrogen Bonds
The Nitrogenous Bases, Guanine and Cytosine, are held together by 3 Weak Hydrogen Bonds
When a Mother Cell divides, producing 2 Daughter Cells, each of the new daughter cells must receive the information (DNA) it will need to perform its life functions. As a result of Replication, the Mother cell copies its DNA and gives an exact copy to each resulting Daughter cell. This ensures that the Daughter cells will have the genetic information (DNA) they need to survive.
Replication occurs during the “S” Phase of the Cell Cycle.
In Plants, compounds such as caffeine, nicotine, rubber, amino acids, which are needed for proteins, and nucleotides, which are needed to make DNA and RNA are produced during Respiration.
Respiration involves at least 50 different steps. Each step in the break-up of sugars results in different compounds.
Replication takes place in the 5’ to 3’ direction
Step 1. Helicase unzips the DNA
Step 2. DNA Polymerase attaches DNA nucleotides to the single DNA strand.
Step 3. DNA ligase glues the DNA back together by forming chemical bonds.