When cells need to divide, the cells have to replicate and copy its entire DNA so that each daughter cell gets one complete set of genetic information. The hydrogen pairs that are holding together the base pairs are broken by enzymes, like helicase, and the molecule is split in half creating two strands. This process is also called the “unzipping process”. These two strands have to follow the rules of base pairing. Each strand serves as a template for the attachment of complementary bases.
Describe each process (including differences between bacteria and eukaryotes) and explain the significance of the differences between replication and transcription When first going through DNA replication, the two strands of double helix unwind. Each strand is an outline for the formation of a new, complementary strand. DNA helicase enzymes hang along the DNA molecule, opening the double helix as they move. Once the strands are separated, helix-destabilizing proteins bind to single DNA strands, preventing re-formation of the double helix until the strands are copied. Enzymes called topoisomerases produce breaks in the DNA molecules and then reconnect the strands, relieving strain and effectively preventing tangling and knotting during replication.
This is the restriction enzyme and acts as “molecular scissors” cuts the two DNA chains at a specific area in the genome so that sections of DNA can be supplemented or detached. A piece of RNA known as guide RNA is the second key molecule. This consists of pre-designed RNA quite small in length sequence, consisting of about 20 bases, positioned within a longer RNA scaffold. The scaffold binds to DNA and the pre-designed sequence ‘guides’ Cas9 to the right part of the genome. ensuring that the Cas9 enzyme intersects at the right point in the genome.
The cell is now committed to progress from G1 to S phase, where the DNA is duplicated. After S phase comes G2. If the intracellular envronment is favourable, and the DNA has been deuplicated corerectly, the cell progress to the M phase. Here, the chromosomes condense and the nuclear envelope breaks down. The mitotic spindle forms, in preparation for chrmatid separation.
This complementary base pairing is what makes DNA a suitable molecule for carrying our genetic information—one strand of DNA can act as a template to direct the synthesis of a complementary strand. In this way, the information in a DNA sequence is readily copied and passed on to the next generation of cells. Because of the strict order of the chemical pairing, the double helix design facilitates the correct bonding of the appropriate chemical bases. However, some scientists suggest that the double helix design may also help to increase the physical strength of the gene. Gene construction is anti-parallel, meaning the strands run in opposite directions.
It exist as a double strand helix molecule. Each strand has a sugar phosphate backbone and a complementary base pair. The strands are held together by hydrogen bonding (non- covalent) between paired bases, adenine (A) with thymine (T) and guanine (G) with cytosine (C). DNA plays a great role in protein synthesis, because it holds the information for every sequence of the amino acids that make up a protein, in the gene. Mutation is a permanent change in the genetic sequence, which makes up protein.
The smaller plasmids make use of the host cell’s own DNA replicative enzymes in order to make copies of themselves, whereas some of the larger ones carry genes that code for special enzymes that are specific for plasmid replication. Size and copy number of plasmid is an important feature of plasmids for cloning purpose e.g. plasmid ranging from 6-10 Kb is very suitable for cloning and having copy number as many as 50. Plasmid may be of following type: • F-Plasmid: having ability to promote conjugal transfer of plasmid e.g. F-Plasmid of E.coli • R-Plasmid: responsible for providing resistance to host against foreign bodies such as anti bacterial resistance e.g.
The 5' cap consists of a terminal 7-methylguanosine residue that is linked through a 5'-5'-triphosphate bond to the first transcribed nucleotide. Its presence is critical for recognition by the ribosome and protection from RNases. Cap addition is coupled to transcription, and occurs co-transcriptionally, such that each influences the other.
We tested genetic transformation using Escherichia Coli (E. coli) as the bacteria or the host organism, because E. coli properties makes it ideal for transformation. The vector, a DNA molecule that carries DNA sequence into a host, in our experiment is Plasmids, which are the simplest bacterial vectors. We placed the plasmid only in the positive tube with E.coli and calcium chloride, that were cooled and heat shocked in order to make gap in the bilayer for the plasmid to slide through before phospholipid bilayer moves. We assume that E.coli cells with the plasmid will survive on a dish filled with ampicillin, also the E. coli cells that have no plasmid will survive in a petro dish without ampicillin and will die in a dish filled with ampicillin. Methods and materials: We first started by marking one micro tube “+” and other we labeled “-”.