Chapter 1 Essay example

Submitted By PatelRushi512Gma
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Pages: 5

Chapter 1(Principles of Life):
Concept 1.1
Evidence suggests that all life originated from a single origin – a single common ancestor
All Organisms:
Are composed of a common set of chemical components such as nucleic acids and amino acids, and similar structures such as cells enclosed inside plasma membranes
Contain generic information that uses a nearly universal code to specify the assembling of proteins
Convert molecules obtained from their environment into new biological molecules
Extract energy from the environment and use it to do biological work
Regulate their internal environment
Replicate their genetic information in the same manner when reproducing themselves
Share sequence similarities among a fundamental set of genes
Evolve through gradual changes in their genetic information
Life arose from non-life via chemical evolution
Geologist estimate the earth was formed between 4.6 to 4.5 billion years ago
Critical step in the evolution of life was nucleic acids:
Molecules that could reproduce themselves and serve as a template for the synthesis of large molecules with complex, but stable shapes
Next step was the enclosure of complex proteins and other biological molecules by membranes that contained them in a compact internal environment separate from the surrounding environment
Molecules called fatty acids played a critical role because they do not dissolve in water, rather, they form membranous films
When agitated they formed spherical vesicles
The first unicellular organisms were prokaryotes:
Consist of genetic material and other biochemical enclosed in a membrane
Early prokaryotes were confined to oceans, where there was an abundance of complex molecules they could use as raw materials and source of energy
The ocean shielded them from the damaging effects of UV rays, which was intense at the time because there was no oxygen in the atmosphere, which meant no-protective ozone in the upper atmosphere
Prokaryotes took in molecules directly from the environment and broke these small molecules down to release and use the energy contained in there chemical bonds.
Cells with a nucleus are called eukaryotes
The chemical reactions of photosynthesis transforms the energy of sunlight into a form of biological energy that can power the synthesis of large molecules
These large molecules are the building blocks of cells, that can be broken down to provide metabolic energy
Early photosynthetic cells were probably similar to early prokaryotes called cyanobacteria
Aerobic metabolism(energy production of O2) is more efficient then anaerobic metabolism(non-O2-using), and it allows its organisms to grow larger
Aerobic metabolism is used by the majority of living organisms today
Photosynthesis might have originated when photosynthetic prokaryotes were ingested by a larger eukaryote. And when the larger Eukaryote failed to break down the intended food object, the prokaryote would provide the products of photosynthesis, while the Eukaryote provided a good environment for its small partner
Cellular Specialization:
Eukaryotes increased in size
Became more efficient at gathering resources
Adapting to specific environments
Mutations are the reason that organisms although came from the same decedent are different
Scientific name(Binomial)
First name identifies the “genus”
Second name is for “species”
Three Major Domains
Single-celled prokaryotes
Single-celled prokaryotes
Eukaryotic cells whose mitochondria and chloroplasts originated from endosymbiosis of bacteria
Biologist use model system for research

Concept 1.2
The information required for an organism to function, its “blueprint” is contained in the organisms genome
Genomes encode the proteins that govern an organisms structure
Nucleic acid molecules contain long sequences of four subunits called nucleotides
The sequence of these nucleotides in DNA, allows organisms to make proteins
A gene is a specific segment of DNA and each gene has specific