Genetic Macromolecules

The importance of the cell membrane to the evolution of living organisms is that the cell membrane provided a barrier between the inside environment and outside environment of a cell. The amphipathic nature of fatty acids formed a lipid bilayer protocell which had water trapped in it along with other molecules. These large molecules of DNA and RNA did not cross the protocell bilayer. Only sugars and nucleic acids could cross the bilayer. If RNA was in the protocell, it created polynucleotide chains by using nucleic acids from the outside. The protocell evolved and contains the characteristics of living

Living cells are the functional biological building blocks of animals. They come together to form complex organic tissues, organs, and whole bodies, as well as some of these organisms themselves existing in a unicellular form. Cells vary in size and dimension, with Eukaryotes ranging from 1x10-3m to 1x10-4m in length, whilst the smaller and less structurally complex Prokaryotes exist between measurements of 1x10-4m to 1x10-7m in length. This size is contained by the cell membrane; providing surface area, whilst the three-dimensional formations offer volume to the cell, which comes from the structural sum of all constituents present in the cytoplasm.

Unit 2 - The Chemical Basis of Life Part 1 - Molecules of Life Part 2 - DNA Replication and Protein Synthesis Enzymes DNA Structure DNA Replication Protein Synthesis Overview Transcription Translation Mutations Part 3 - Cellular Respiration and Photosynthesis Unit 3 - Genetics

Although groundbreaking, these discoveries have shown us that scientific progress is more of a long-term investment into human knowledge, and, a priori, such investments require much work and dedication regardless of the results. The whole journey to the discoveries like the one concerning DNA structure is filled with endless hypotheses that scientists have tested multiple times,

Over the past years the last universal common ancestor (LUCA) has been debated on what exactly it is. It is known to be the start of all living things. Many scientists suggest that LUCA is simply a formation of molecular fragments that evolution has played a role on. Others argue about if LUCA was a cell or not. Overall, with the most recent research and proof, the LUCA is a complex cell in which has similar cell structure to the common cell we study today. According to intensive research, they have found storage of polyphosphate within the organelle that once was assumed to be lost in bacteria and archaea. This validation of research has proven to be in three main domains such as archaea, eukaryotes (animals, algae, plant, and etc.) and bacteria (Science Daily. 2008). Due to the commonality of this structure, there have been scientists who refer and compare to the organelle in singled-cell eukaryotes called acidocalcisome.

Deoxyribonucleic acid (DNA) is an extensive molecule that contains genetic material that makes up almost all living organisms including plants, animals, and even some viruses. This genetic material or genetic code in DNA is composed of biological instructions that are responsible for the development, survival, and reproduction of organisms. Information stored in DNA is made of four chemical bases or building blocks, adenine (A), guanine (G), cytosine (C), and thymine (T) which come together to form pairs in molecules: Adenine to Thymine, and Cytosine to Guanine. Humans have billions of these base pairs within their bodies. These pairs separate to form into paired packages that resemble X’s called chromosomes that are made of structure of nucleic acids and protein stored in the nucleus of cells (National Human Genome Research Institute, 2015). The DNA in cells contains structural proteins (responsible for the structure, function, and regulation of the body 's tissues and organs) and endoenzyme or intracellular enzymes (that control cytoplmic and nuclear activities) called genes. Genes operate as a list of instructions for molecules and are in control of the promotion of reproduction within the cell. All organisms are different from one another and have a unique combination of traits. However, many organisms share similarities, like when a child (offspring) has similar features or characteristics, like height or having brown hair like their parents. This is because hereditary

Because on the work of all of the scientists cited below, DNA can be identified as the molecular carrier of genetic information. By knowing DNA carries genetic information, and not proteins, by knowing DNA’s structure, and knowing DNA is the transforming principle, DNA has become the basis of genetic research and its study has advanced biological and medical science.

The experiments of the past week allowed examination of cell division and DNA replication, the processes by which cells carry out important functions. It is important to have an understanding of these processes in order to have an understanding of biology. These most small occurrences are the basis for life in all cells. Without division and DNA replication, organism could not grow and carry out complex tasks, such as metabolism. In addition, natural selection can only occur where genetic variation does. This makes division of cells and the recombination of their DNA essential to the continuance of human life.

By looking at the basic biochemistry most organisms share, we can start putting together how the biochemical systems evolved. However, up until the eighties, scientists were still baffled by a “chicken and egg” debate. All modern organisms require nucleic acids (DNA and RNA) to build proteins (Leslie 99), and the proteins are needed in the formation of nucleic acids. The mystery of which came first: RNA or DNA was solved when a new property of RNA was discovered. There are some RNAs that are capable of catalyzing chemical reactions. This means that RNA is capable of storing genetic information, as well as cause chemical reactions vital for self-replication. This breakthrough tentatively solved the mystery of which came first: RNA or DNA.

Over time one prokaryotic cell engulfed another and formed a symbiotic relationship. Scientists believe that mitochondria and chloroplasts originated from these ancestors and have since become a part of most cells. The fact that these two organelles contain a separate set of DNA supports the scientists theory. Scientist also believe that as these prokaryotes were engulfed they were surrounded by membrane that never dissolved. Furthermore, this idea is supported by the fact that mitochondria and chloroplasts have a double membrane. The structures of these two organelles are similar to that of a prokaryotic cell. Both structures contain an exterior membrane, DNA, and no membrane bound organelles. In addition, the idea that prokaryotic cells do not contain mitochondria or chloroplast helps prove that this idea could be

The development of complex proteomes without a comparable increase in gene number is due to the different patterns of splicing by the spliceosome machinery. Not only are there mechanics to consider with the spliceosome complex, but there is a kinetic component to splicing as well (Larochelle, 2017). When a DNA sequence is transcribed into a pre-mRNA sequence, it includes exons and introns, which are coding sequences and noncoding sequences respectively. The introns are removed through a two-step cleavage-ligation reaction using a spliceosome. 5′ and 3′ splice site (SS) consensus sequences outline the intron-exon boundaries. In the first step, the 2’ hydroxyl group on the nucleotide on the branch site strikes the 5’ splice site, and the

The Serial Endosymbiotic Theory (SET) was a hypothesized process by which prokaryotes give rise to the first eukaryotic (an organism which contains a nucleus and organelles enclosed within a membrane ). Was pioneered in the 1960’s by the seminal work of Lynn Margulis. This theory attempts to explain the origins of eukaryotic cell organelles, specifically the mitochondria (providing the cells ATP (used for the cells metabolism) supply used by the cell as chemical energy ). With the theory suggesting that the mitochondria and plastids within a eukaryotic cell were once independent prokaryotic cells (a single celled organism, which contains a nucleus and other organelles that are absent of a membrane ), having been obtained by another organism through endosymbiosis, to become endosymbiot around 1.5 billion years ago. Where the eukaryotes several key organelles originated through a process called symbiosis, with this occurring between separate single celled organisms (prokaryotic cells). Through research and locating molecular and biochemical evidence, it suggests that the mitochondrion developed from proteobacteria, and chloroplast from cyanobacteria.

“According to Dr. Lipton, the true secret to life does not lie within your DNA, but rather within the mechanisms of your cell membrane.”

There is no one universally accepted paradigm for the origin of life. Rather, there are two competing schools of thought that debate the question: Was the origin of life terrestrial or extraterrestrial? Both of these theories recognize that life must have been synthesized under natural conditions, that molecules organized themselves into the first molecular system, that atmospheric oxygen and ozone were rare, and that electrical activity may have produced monomers. The scientific and technological advancements that have emerged as a result of investigations into the origin of life have profoundly impacted our society and our knowledge of life, space, and cosmochemistry.

Aristotle, a famous philosopher, believed in the notion of spontaneous generation, the idea that life could arise from inanimate objects. Louis Pasteur famously dispelled this theory, when he showed that organisms will only arise if the parental species is initially present in a closed system. However, this conclusion relates to the generation of new organisms from parental ones, not the origin of life itself. The first “organism” had no “parental” species, therefore the organism had to have originated from non-living matter. Stanley L. Miller kick-started the study of the origin of life with his famous 1953 “prebiotic soup” experiment in which he took a mixture of reduced gases – believed to represent the atmospheric conditions on primordial Earth – and reacted them together in a spark discharge apparatus. The results were surprising, with a mixture of biochemically relevant organic molecules spontaneously being formed, including amino acids – an essential building block of life. Miller’s results showed that organic molecules could be generated from inorganic ones, a finding that inspired the modern era of understanding the origin of life and challenged common perceptions. Now, in the dawn of the 20th century, there are two main theories that dominate the field, the “metabolism first” theory and the “RNA world” theory.