Genes are DNA & DNA structure and replication The Tumornators

Genes are dna In the 1940’s much of what was understood about DNA was mislead and incorrect. DNA is not all the same in organisms. Different organisms have different base pairing. That’s what differentiate one organism from the next. A gene is a small segment of the DNA, these segments are called bases. There are for bases: Adenine, Thymine, Guanine and Cytosine. DNA bases pair with one another. Base paring must always link A with T and C with G. DNA has 3 components: 2’-dioxyribose with triphosphate hanging off of the 5’ prime carbon and a base coming out of the 1’ prime. Chargaff studied DNA and discovered many traits. Chargaff’s rule states that DNA must have a 1:1 ratio of the purines: Guanine to Adenine, and the Pyrimidines: Cytosine to Thymine. In other words, A=T and G=C.

DNA structure and replication DNA and RNA polymers have direction 5’3’ and polymerization must always go 5’3’. Base- pairing must always be A-T (2 H-bonds) or A-U (2 H-bonds) and G-C (3 H-bonds). Bases can only be added to the 3’ end of the DNA strand, not the 5’ end. Base paired strands must always be anti-parallel. DNA is replicated by an enzyme that is called DNA polymerase. On the 5’ strand, DNA synthesis must re-start because it is discontinuous. It’s considered the lagging strand. On the 3’ strand, DNA synthesis is continuous and therefore is considered the leading strand. Every human being has DNA. Any part of the human body contains cells, and those cells contain all the DNA that are in the human body. DNA sequences are the same in all cells of the same person and are different in different individuals. DNA can carry information. The order of the bases along a strand is a code. The code is for making proteins. The backbone of a DNA molecule is held together through covalent bonds and the strands are held together by two hydrogen bonds. A DNA molecule can “peel” apart the strands for replication and transcription without breaking the backbone.

Questions How does radiation cause mutation in DNA? What happens when mistakes are made in DNA replication and mutagens occur? What effect does it have in the body that causes the DNA Polymerase to alter while doing its job to replicate correctly? Do certain frequencies of bases indicate anything for organisms? If we were to connect two different strands of DNA from 2 different organisms (1 from each) and connect the bases, will the DNA be able to transcribe? Is it possible to break apart a DNA, find the composition of the bases and take that knowledge to replicate a DNA strand? What happens if a mutation occurs, when a base goes in the wrong place in a DNA structure? How does the composition of A, T, C, G determine traits?