Biology Chapter Summaries

3. Identify the 3 domains of living things. Which domains include one-celled organisms with no nucleus?

What is the function of ribosomes? What are their two components? Ribosomes are the cellular components that carry out protein synthesis. Their two components are a large subunit and a small subunit.

When life arose on Earth about 4 billion years ago, the first types of cells to evolve were prokaryotic cells. For approximately 2 billion years, prokaryotic-type cells were the only form of life on Earth. The oldest known sedimentary rocks found in Greenland are about 3.8 billion years old. The oldest known fossils are prokaryotic cells, 3.5 billion years in age, found in Western Australia and South Africa. The nature of these fossils, and the chemical composition of the rocks in which they are found, indicates that these first cells made use of simple chemical reactions to produce energy for their metabolism and growth. Eukaryotic cells evolved into being between 1.5 and 2 billion years ago. Eukaryotic cells appear to have arisen from prokaryotic cells, specifically out of the archaea. Indeed, there are many similarities in molecular biology of contemporary archaea and eukaryotes. However, the origin of the eukaryotic organelles, specifically chloroplasts and mitochondria, is explained by evolutionary associations between primitive nucleated cells and certain respiratory and photosynthetic bacteria, which led to the development of these organelles and the associated explosion of eukaryotic diversity. Today Prokaryotes

According to Margulis, the pre-eukaryotic cell engulfed an aerobic bacterium, but rather than digest and kill the bacterium, a symbiotic relationship was born. This relationship, the aerobic bacterium provided energy through ATP and the eukaryotic cell provided an environment to live while protecting the new symbiont from harm in environmental factors such as oxygen. Because almost all living eukaryotes have a mitochondria, it is safe to assume that this event happened before plants and animals split in the evolutionary lineage.After this first evolutionary leap came a

Carbohydrates: any of a class of organic compounds that are polyhydroxy aldehydes or polyhydroxy ketones, or change to such substances on simple chemical transformations, as hydrolysis, oxidation, or reduction, and that form the supporting tissues of plants and are important food for animals and people.

K. Paraphrase the three potential fates of the excited electron produced when a photon meets a chlorophyll molecule

Surface Tension: The measure of how difficult it is to stretch or break the surface of a liquid.

Currently, there are two major competing theories for the endosymbiotic origin of eukaryotic cells. The first theory claims that the eukaryotic cell is a combination of an archaeon with a

Prior to the development of DNA technology and the sequencing of organismal genomes, Charles Darwin suggested that the “tree” of life can be traced back to a single root (Koonin and Wolf, 2012). While Darwin’s theory was primitive, it laid the groundwork for the phylogenetic trees that are currently studied in science classrooms around the world. The three-domain tree, containing Eukarya, Archea, and Bacteria, soon became too simplistic due to the realization that some bacteria possessed the ability to exchange genetic information by horizontal gene transfer (Koonin and Wolf, 2012).

5. A. Fimbriae- hair like Gram-negative bacteria that allows attachment and through that the bacteria is able to colonize.

7. The theory of endosymbiosis says that mitochondria and plastids used to be small prokaryotes living within larger cells. The prokaryotic ancestors of mitochondria and plastids were bacteria engulfed by a larger cell. Because they both benefited from this situation, the bacteria living inside the cell was passed down from generation to generation. The evidence is that mitochondria reproduce and move independently within the cell.

Describe the important chemistry of early earth and how this may have given rise to life forms.

Bacteria and Archaea are prokaryotic, which are mostly single-celled incomplex microorganisms. Both Bacteria and Archaea have a variety of prokaryotes classified in multiple kingdoms (Reece, et al., Campbell Biology, 2014). There are a number of scientists who believe that Archaea cells may be the precursor to Eukaryotic cells and that they have more in common with Eukaryotes than Prokaryotes (Madigan, Martinko, & Dunlap, 2009).

Prokaryote cells - bacteria and archeans. They are single celled organisms, where the DNA is not separate from the cytoplasm. These prokaryote cells formed the earliest and most primitive life on earth.

Primarily, the Archaea were once believed to be just another rare group of bacteria, because like bacteria, they are single-celled microscopic prokaryotic organisms with no membrane bound nucleus (http://www.fossilmuseum.net/Evolution/archaeaevolution.htm). Despite the similarities in the cell structure of Eubacteria and Achaea, molecular research by Dr Carl Woese and his co-workers indicated that they differ significantly on the molecular level (Bacteria in Biology, Biotechnology and medicine, Paul singleton). In this essay, am going to discuss the differences and similarities in the fundamental cellular feature of both organisms.