Test 1 Study Guide Week 1 Topic 1 Classification of Organisms Raven CH 1 2 483 483 28 28 1 28 1 CONCEPT QUESTIONS Q1 If the simple classification of an organism as a plant or animal is no longer sufficient why are newly discovered organisms still assigned genus and species names A Genus and species names designate how organisms are related to each other by determining what group that organism falls into Even though the means of classification is different that it once was the genus and species system has been adapted to the modern system of classification and is still a useful way to organize living things Q2 Explain the benefits of compartmentalization as a cell increases in size including a consideration of the chemistry within the cell A As cells increase in size there is more room for complex cellular reactions to occur but there is also more need of organization of these cellular functions Compartmentalization does just that it allows the cell to be more organized in this larger and more complex environment Q3 A research colleague has provided you with a single cell to identify Briefly describe the steps you would take to determine which domain this cell would most likely belong to A I would sequence the 16s rRNA gene from this cell then compare this sequence to the known 16s rRNA sequences to see which domain the sequence from the unknown cell most closely resembles Q4 Based on the revised tree of life as shown on the previous page which type of Eukaryote would you expect to have a small subunit rRNA sequence the most similar to an Archael species and why A Diplomonads Each fork in the tree represents an evolutionary divergence The fork for the Diplomonad group is closer to the fork where the Archaea split off than the other Eukaryotic forks Therefore the Diplomonads have a more recent common ancestor with the Archaea than do the other branches of the Eukaryotic portion of the tree and will have a more similar small subunit rRNA sequence Q5 Cells have the ability to take up fragments of DNA from their extracellular surroundings through a process called transformation With this information propose a very general hypothesis for how a bacterial cell might acquire DNA from a eukaryotic species through horizontal gene transfer Do not attempt to get technical with your answer a general proposal is sufficient A If a eukaryotic cell dies or bursts open it could release its DNA into the environment This could happen for a number of reasons perhaps a bacterial cell invades and kills a eukaryotic cell or a virus infects the eukaryotic cell and the cell dies This cell death could release the eukaryotic DNA into the environment and a bacterium could take up the DNA via transformation Once the eukaryotic DNA is inside the bacterial cell it could get incorporated into the genome of the bacterium QUIZ QUESTIONS Q1 Which one of the following statements about the domains of life is incorrect a The chromosomes of bacteria and archaea are typically circular b E coli is an example of an organism in the archael domain c d Structurally archaea more closely resemble bacteria than eukaryotes e The typical size of bacteria and archaea is approximately 1 10 microns In most molecular processes archaea are more related to humans than to bacteria Q2 Which of the following statements about archae is correct bacteria classification of prokaryotes a Archaea share similar structural features with bacteria but are not b Archaea are the only types of organisms currently believed to fall into the c Archaea typically have multiple circular chromosomes as their genetic material d Archaea are regularly found in all environments on Earth e Archaea typically have multiple linear chromosomes as their genetic material Q3 Which of the following statements about horizontal gene transfer is incorrect a Horizontal gene transfer allows genes to be exchanged across species lines b Horizontal gene transfer can only occur between organisms that belong to c Horizontal gene transfer involves genetic information being shared between cells d Horizontal gene transfer has occurred between eukaryotes and archaea e Horizontal gene transfer can lead to an organism with increased chance of survival the same domain Week 1 Topic 2 Basic Cell Structure and Macromolecules Raven CH 4 3 3 1 CONCEPT QUESTIONS Q1 Explain briefly and in your own words why cells are found in a fairly narrow size range on the scale of life A If cells get too large the surface area to volume ratio shrinks A cell that is too large would have a lot of volume and therefore ample room for cellular processes but the surface area part of the ratio is lower Meaning there is too little surface area sustain that volume This influences the ability of the cell to bring things into or out of the cell If a cell is too small the opposite is true cells have enough surface area to bring products in and remove waste but not enough volume to sustain the processes of life that occur inside of the cell Q2 There is a significant amount of overlap in the resolution of light and electron microscopes Propose at least one advantage to this amount of overlap with regard to experimental techniques A You can gain more information using all three techniques than you would with one alone You will get different perspectives of what you are looking at With a light microscope you will get the general layout of the sample and even some detail with the TEM you will see more detail and you also will get an idea of the density of a thin section of the sample With SEM allows you to gain a more 3D perspective of your sample Additionally for a sample that is on the edge of the resolving power of a particular microscope either your sample is almost too big or almost too small it might be more useful to use the alternative technique As an analogy to this last concept you probably would use binoculars if you are going bird watching However if a robin lands 2 feet away you can get a good look at it with the naked eye You wouldn t necessarily use binoculars to look at it even though you could Q3 Propose at least three problems difficulties issues a cell might encounter if its plasma membrane malfunctions A The cell would not maintain a constant internal environment and would therefore have issues regulating basic cellular functions The plasma membrane is selectively permeable If this malfunctions the cell might allow chemicals into the cell or release chemicals out of the cell in an abnormal manner This