Explain the significance of mitosis in living organisms. (3) 3. Cell A in the diagram below has two pairs of chromosomes. Cell B, C and D have each arisen from A by cell division. [pic] For each of the cells labelled B and C, identify the type of cell division, which has occurred to produce the cell.
To form a strand of DNA, nucleotides are linked into chains, with the phosphate and sugar groups alternating (. DNA has a double helix structure and has two strands running in opposite directions (UIC, 2013). 2. How does an organism’s genotype determine its phenotype? Genotype determines the genetic makeup of an individual organism.
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.
This way, DNA can write codes out of the nitrogen containing base molecule. These codes contain the message that tells the cell what to do. My model base pairs because the yellow pipe cleaners represent cytosine and the green, guanine; the red pipe cleaners and the blue show a base pair between adenine and thymine. The purple in my model is phosphate groups and the silver is deoxyribose sugars. 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.
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.
Transgenesis and Cloning Transgenesis is the process of inserting a gene from one source into a living organism that would not normally contain the inserted gene. The gene can come from the same species (called Cisgenesis) or from a different species entirely. To facilitate the transfer of genes from one organism to another, often a Transgenic Organism with Recombinant DNA is created: -The first step in creating an organism capable of carrying out the transformation process is to isolate the required gene. This is done so using Restriction Enzymes, which target a specific gene sequence. The gene is often cut with staggered ends, called “Sticky Ends” which only allow specific and complementary gene sequences bond by base pairing.
Mutation is a permanent change in the genetic sequence, which makes up protein. DNA mutation does not affect the 3 D structure rather it affect the order in which each base pair sequencing. The effect of DNA mutation is dependent up on the location where the mutation occur. If it occurs in the junk DNA, it may not have any effect at all. Other types of mutations in DNA can occur when small part of DNA break off the chromosome.
During transcription, RNA polymerase makes a copy of a gene from the DNA to mRNA as needed. This process is similar in eukaryotes and prokaryotes. One notable difference, however, is that prokaryotic RNA polymerase associates with mRNA-processing enzymes during transcription so that processing can proceed quickly after the start of transcription. The short-lived, unprocessed or partially processed, product is termed pre-mRNA; once completely processed, it is termed mature mRNA.  Eukaryotic pre-mRNA processingMain article: Post-transcriptional modification Processing of mRNA differs greatly among eukaryotes, bacteria, and archea.