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Flashcards by jennabarnes12387, updated more than 1 year ago
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Created by jennabarnes12387
almost 11 years ago
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| Question | Answer |
| describe briefly the structure of a prokaryotic cell. | they are simple single cell organisms made of a plasma membrane surrounded by a cell wall. They have a cytoplasm and ribosomes but have no membrane bound organelles. they often have flagella for movement and fimbriae for sexual reproduction. |
| What are the three different shapes of a prokaryotic cell? | cocci (spherical), bacilli (rod shaped), and spiral |
| What is the different between a gram positive and a gram negative cell? | gram positive cells have an exposed layer of peptidoglycan outside the cell. they are easier to kill with anitbiotics and less pathogenic. When involved in a gram stain they absorb and hold the dark purple dye (ultraviolet). gram negative cells have a thin layer of pepidoglycan wedged between there outer and plasma membrane. its harder to kill them with antibiotics and they tend to be more pathogenic. When involved in a gram stain they dont hold the purple stain and end up absorbing the second red stain as they have the space for it. |
| What are some structures many eukaryotic cells have that prokaryotic cells do not? | cytoskeletons, organelles, membrane sterol such as cholesterol, a nucleus, cillia and few but more complicated flagella, |
| what is symbiosis? | an interaction between species that are close in location. can be mutualism where both benefit, commensalism where one benefits and the other is not effected, or parasitism where one benefits and the other is harmed. |
| What is the endosymbiosis model? | the idea, which is written in a 1981 book by Lynn Magulis, is supported by many symbiotic relationships. if states that mitochondria and chloroplast in eukaryote evolved from a symbiotic relationship with prokaryotic bacteria cells. |
| How can this theory be supported by modern mitochondria and chloroplasts? How can it be criticized? | midocondria circular DNA has no histone proteins, similar to prokaryot cells. there processes of binary fission, protein synthesis, and electron transport chains are similar to the primitive functions performed in prokaryotes. to critise it is found that the DNA of mitocondria and chloroplasts dont have enough information for independent function and that transcription happen in the cells cytoplasm not in the organelles. |
| What is missing from the steps of Eukaryotic cell evolution? | we still don't know where cilia and flagella came from, mitosis and large genomes, the origin of meiosis and sex, and the origin of the nucleus. |
| What is the Mimi DNA virus? | a larged sized virus with genes that code for amino acids and nucleotides synthesis. The cant make proteins so they rely on a host to stay alive. They may have evolved before cellular organisms |
| What is a chimaera? Why do we use this term when describing prokaryotes? | A chimaera is a Greek mythical beast that is part goat, part lion, and part serpent. Eukaryotes are similar I that they are a mixture of prokaryotic parts. They took a mitochondria rom one bacteria, perhaps a plasmid from a virus, nucleus genome from different host cells, and the use of horizontal gene transfer to creat large and complex genomes and cell structure |
| Where do we think flagella and cilia evolved from? | May have evolved symbiotic relationships between bacteria and protozoans. This still does not explain the 9+2 structure |
| Order the levels from kingdom to species. | Kingdom, phylum, class, order, family, genus, and species |
| Up until the 1970s how were species divided? | Into one of two groups; animals or plants |
| What changed the grouping process in the 1980s | In 1987, Margulis and Schwartz wrote a book that proposed the idea of five kingdoms instead of just 2; monera, Protista, Plantae, Fungi, and Animalia. This idea was first proposed in 1969 by Whittaker. |
| What does the classification of Eukaryotes include? | All unicellular And multicellular Protists, and multicellular organisms |
| Eukaryotes are divided into what two groups. What do those groups include? | Multicellular and chemhetophyls. The multicellular include plants and the the chemhetophyls include fungi and animals |
| What are poly genetic systematics? | Groups that have more then one genetic history and come from more then one common ancestor |
| That are monophyletic groups? | Also called Claude's, they are groups with only one genetic history that all come from one common ancestor |
| What was added above kingdoms in the category scale in 1981? | Three domains were added; Achaea, Bacteria, and Eukaraya. This was proposed by Woese who stated that each domain came from one ancestor. |
| Which other domain is Achaea more related to? Why is this? | Eukaraya. This is because they both shared a common ancestor before Achaea broke off into its own domain. Achaea was never connected to bacteria in this way |
| What makes Achaea and eukaraya similar? | Both have several different kinds of rRNA polymerase, both have intron or non-coding DNA, and neither have cell wall peptidoglycan |
| What year did life originate? | 4500 billion years ago |
| What year did the first multicellular organisms originate? | 1.2 billion years ago |
| What are the advantages of being multicellular? | Allows for cellular specialization so no one cell has to do all the work, lower volume to surface area ratio, and it's easier to maintain homeostasis |
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